Neurology_Adams

Neurology_Adams. Sudden changes in position, particularly of the head, may induce vertigo and nystagmus or cause a worsening of these symptoms in patients with all types of vestibular–labyrinthine disease, including Ménière disease and the types associated with vertebrobasilar stroke, trauma, and posterior fossa tumors. However, only if the paroxysm has the special characteristics noted previously—namely, elicitation by change in head position, latency of onset, brevity, reversal of direction of nystagmus on sitting up, fatigability with repetition of the test, and the presence of distressing subjective symptoms of vertigo or its recurrence for months or years without other symptoms—can it be regarded as “benign paroxysmal” in type.


Neurology_Adams

Neurology_Adams. Schuknecht is credited with demonstrating that benign positional vertigo was caused by cupulolithiasis, in which otolithic crystals become detached and attach themselves to the cupula of the posterior semicircular canal. It is now generally believed that the debris, probably detached from the otolith, forms a free-floating clot in the endolymph of the canal (canalolithiasis) and gravitates to the most dependent part of the canal during changes in the position of the head (see Brandt et al). In 90 percent of cases, the posterior semicircular canal is implicated; the remaining 10 percent are caused by cupulolithiasis in the lateral canal. As mentioned, the conventional maneuver to elicit BPPV may not only fail to induce symptoms in cases of lateral canal cupulolithiasis but the corrective maneuver may even inadvertently produce it. The disorder of the lateral canal is nicely summarized by De la Meilleure and coworkers.


Neurology_Adams

Neurology_Adams. The debris is thought to act by inducing currents on the cupula and triggering an attack of vertigo. Based on this presumed mechanism, several canalith repositioning maneuvers have been devised (Semont et al; Epley), allowing the debris to gravitate out of the semicircular canal and into the vestibule, where it will not induce a current during angular acceleration.


Neurology_Adams

Neurology_Adams. The first part of the Epley canalith repositioning maneuver (Fig. 14-6) is similar to the diagnostic Hallpike maneuver, the only difference being that the patient is positioned without extending the head into the hanging position of the Dix-Hall-pike diagnostic maneuver, first with one ear down and the head turned, then the other ear, in order to establish the side responsible for symptoms. Next, with the patient in the position that causes symptoms, the head is turned in a series of three steps, each separated by about 20 s: first the head is turned 45 to 60 degrees toward the opposite ear; the patient is then turned onto his side and the head turned an additional 45 degrees, until the head is parallel to the ground; then the head is turned once more until it more nearly faces the floor. We have become aware that this last step, which is a necessary part of the maneuver, is sometimes omitted by neurologists. After about 20 s, the patient is returned to the upright position. It was


Neurology_Adams

Neurology_Adams. We have become aware that this last step, which is a necessary part of the maneuver, is sometimes omitted by neurologists. After about 20 s, the patient is returned to the upright position. It was formerly believed that the patient should be instructed to avoid the head-down position for 24 hours, but recent studies have demonstrated that this is probably not necessary. Often a single treatment sequence suffices to terminate a period of positional vertigo (approximately 80 percent respond), but a second sequence carried out immediately after the first probably gains another small group who derive benefit. Additional treatments carried out in the same session are said to add no further benefit. In recalcitrant cases, our otolaryngology colleagues have applied a large vibrator to the temporal bone while the Epley maneuver was being performed, after which the episodes ceased; presumably this mobilizes the crystals and aids in moving them out of the canal. An incompletely implemented


Neurology_Adams

Neurology_Adams. bone while the Epley maneuver was being performed, after which the episodes ceased; presumably this mobilizes the crystals and aids in moving them out of the canal. An incompletely implemented Epley maneuver risks converting the usual posterior semicircular canal cupulolithiasis to one involving the lateral canal, which may be more difficult to treat.


Neurology_Adams

Neurology_Adams. Patients who fail to respond to the Epley maneuver may respond to variations of repositioning such as the Semont maneuver (the patient begins in a sitting position with the head turned 45 degrees to one side, then drops laterally to a side lying position on the opposite ear, followed by a brisk swing of the body to drop the opposite side lying position) or the similar Brandt-Daroff exercises (sitting, to side lying, to sitting, performed repeatedly). Positional vertigo caused by lateral canalolithiasis causes a purely horizontal nystagmus rather than the torsional and vertical type described previously. In this case, another repositioning maneuver that involves rolling from one side to the other is used to liberate and reposition the otolithic debris.


Neurology_Adams

Neurology_Adams. It is important to reiterate that in some patients with positional vertigo, the disorder is neither benign nor paroxysmal. Jannetta and colleagues have described a group of patients in whom symptoms of vertigo and disequilibrium were almost constant (even in the upright position) and disabling and unresponsive to habituation and other medical therapy (disabling positional vertigo). They attributed this disorder to cross-compression of the root entry zone of the eighth cranial nerve by an adjacent blood vessel and have reported that decompression of the nerve provides lasting relief of symptoms.


Neurology_Adams

Neurology_Adams. The common and serious ototoxic effects of the aminoglycoside antibiotics have already been mentioned—both on the cochlear hair cells, with loss of hearing and independently, on the vestibular labyrinths. Prolonged exposure to these agents produces a bilateral vestibulopathy without vertigo. Instead, there tends to be a disequilibrium associated with oscillopsia. The symptoms are especially troublesome when the patient moves. Often the disequilibrium is not discovered until a bedbound patient tries to walk.


Neurology_Adams

Neurology_Adams. Less-well appreciated is the occurrence of a slowly progressive vestibulopathy for which no cause can be discerned. The disorder affects men and women alike, with onset in middle or late adult life with the main abnormalities being unsteadiness of gait, which is worse in the dark or with eyes closed, and oscillopsia, which occurs with head movements and is particularly noticeable when walking. Vertigo and hearing loss are absent, as are other neurologic abnormalities. Bilateral vestibular loss can be documented with caloric and rotational testing. Baloh and colleagues, in a report of 22 patients with idiopathic vestibulopathy of this type, found that a significant proportion (9 of 22 cases) had a prior history of prolonged episodes of vertigo consistent with the diagnosis of bilateral sequential vestibular neuritis (see the following text).


Neurology_Adams

Neurology_Adams. This was the term applied originally by Dix and Hallpike to a distinctive disturbance of vestibular function, characterized clinically by a paroxysmal and usually a prolonged single attack of vertigo and by a conspicuous absence of tinnitus and deafness. The entity is, however, more nebulous than most discussions indicate.


Neurology_Adams

Neurology_Adams. This disorder occurs mainly in young to middle-aged adults (children and older individuals also may be affected), without preference for either sex. The patient frequently gives a history of an antecedent upper respiratory infection of nonspecific type, but it is not clear whether this is requisite for the diagnosis. Usually, the onset of vertigo is fairly abrupt, although some patients describe a prodromal period of several hours or days in which they felt “top-heavy” or “off balance.” Persistence of the symptoms for a day or more differentiates the process from Ménière disease. The vertigo is severe as a rule and is associated with nausea, vomiting, and the need to remain immobile.


Neurology_Adams

Neurology_Adams. Nystagmus (quick component) and a sense of body motion are to the opposite side, whereas falling and past pointing are to the side of the affected labyrinth. In some patients, the caloric responses are abnormal bilaterally, and in some, the vertigo may recur, affecting the same or the other ear. Auditory function is normal. Examination discloses vestibular paresis on one side, that is, an absent or diminished response to caloric stimulation of the horizontal semicircular canal. If the patient will tolerate small head movements, the previously described rapid-head-impulse test of Halmagyi and Cremer is one of the best means of demonstrating absent function of one lateral semicircular canal.


Neurology_Adams

Neurology_Adams. Although the symptoms can be quite disabling for a short period, vestibular neuritis is an ostensibly benign disorder. The severe vertigo and associated symptoms subside in a matter of several days, but lesser degrees of these symptoms, made worse by rapid movements of the head, may persist for months. The caloric responses are gradually restored to normal as well. In some patients, there has been a recurrence months or years later, as already mentioned.


Neurology_Adams

Neurology_Adams. The portion of the vestibular pathway that is primarily affected in this disease is thought to be the superior part of the vestibular nerve trunk, which was observed to show degenerative changes by Schuknecht and Kitamura. Earlier, Dix and Hallpike had reasoned that the lesion was located central to the labyrinth, as hearing is spared and vestibular function usually returns to normal. They used the term vestibular neuritis because of the uncertainty of more precise localization within the peripheral vestibular pathway. The cause of vestibular neuritis is still uncertain, but many authorities have attributed it to a viral infection of the vestibular nerve, analogous to Bell palsy, and from time to time, enhancement of the eighth nerve or the membranous labyrinth is seen after gadolinium administration on MRI. For want of more specific etiologic or pathologic data, many neurologists prefer the term vestibular neuropathy or neuritis or acute unilateral peripheral vestibulopathy. It is


Neurology_Adams

Neurology_Adams. administration on MRI. For want of more specific etiologic or pathologic data, many neurologists prefer the term vestibular neuropathy or neuritis or acute unilateral peripheral vestibulopathy. It is likely that the conditions described under the terms epidemic vertigo, epidemic labyrinthitis, and acute labyrinthitis or neurolabyrinthitis refer to the same process. Certainly, herpes zoster oticus causes this syndrome (as well as affecting the seventh nerve); this characterizes the Ramsay Hunt syndrome described in Chaps. 9 and 44.


Neurology_Adams

Neurology_Adams. During the acute stage, antihistamine drugs, promethazine, clonazepam, and scopolamine may be helpful in reducing the symptoms. Vestibular exercises are recommended by Baloh (2003) in his review of the subject. One clinical trial has demonstrated a more rapid recovery with the use of methylprednisolone, 100 mg orally, tapered over 3 weeks; valacyclovir did not have this effect (Strupp et al). Other Causes of Vertigo of Vestibular Vertigo may occur with diseases that involve the eighth nerve in the petrous bone or at the cerebellopontine angle. Aside from vestibular neuritis, discussed previously, the two most common causes of vertigo of eighth nerve origin are probably an acoustic or vestibular schwannoma and vascular irritation or compression by a small branch of the basilar artery. The frequency of the vascular compression syndrome as a cause of otherwise undifferentiated vertigo is not known (see earlier).


Neurology_Adams

Neurology_Adams. Regarding vestibular schwannoma, vertigo is rarely the initial symptom; the usual sequence is deafness affecting the high-frequency tones initially, followed some months or years later by mild chronic imbalance rather than vertigo and by impaired caloric responses, and then, if untreated, by additional cranial nerve palsies (the seventh, fifth, and tenth nerves), ipsilateral ataxia of limbs, and headache. Variations in the sequence of development of symptoms are frequent, and probably many vestibular schwannomas discovered in the process of an evaluation for vertigo are incidental; that is, almost 1 percent of the general population harbors small tumors. In the diagnosis of vestibular and acoustic schwannoma, MRI and BAEP are the most important ancillary examinations. Bilateral vestibular/acoustic Schwannomas are almost always a manifestation of neurofibromatosis type 2.


Neurology_Adams

Neurology_Adams. Labyrinthine infarction can be a component of the stroke syndrome from occlusion of the anterior inferior cerebellar artery (AICA). In the complete syndrome there is hearing loss, cerebellar ataxia, and sometimes “screaming tinnitus” or lesser degrees of tonal tinnitus. Also reported is a clinical syndrome of unknown nature consisting of a single abrupt attack of severe vertigo, nausea, and vomiting without tinnitus or hearing loss but with permanent ablation of labyrinthine function on one side. It has been suggested that this syndrome is a result of occlusion of the labyrinthine division of the internal auditory artery, but so far, anatomic confirmation has not been obtained. Labyrinthine hemorrhage has been demonstrated by MRI in some of these patients; others are attributed, speculatively, to viral infection.


Neurology_Adams

Neurology_Adams. Basser described a particular form of paroxysmal vertigo that occurs in childhood. The attacks occur in a setting of good health and are of sudden onset and brief duration. Pallor, sweating, and immobility are prominent manifestations; occasionally, vomiting and nystagmus occur. No relation to posture or movement has been observed. The attacks are recurrent but tend to cease spontaneously after a period of several months or years. The outstanding abnormality is demonstrated by caloric testing, which shows impairment or loss of vestibular function, bilaterally or unilaterally, frequently persisting after the attacks have ceased. Cochlear function is unimpaired. The pathologic basis of this disorder has not been determined, and a suggested connection with migraine is tenuous. The special case of basilar artery migraine is discussed below.


Neurology_Adams

Neurology_Adams. Cogan has described an infrequent syndrome in young adults in which a nonsyphilitic interstitial keratitis is associated with vertigo, tinnitus, nystagmus, and rapidly progressive deafness. The prognosis for vision is good, but the deafness and loss of vestibular function are usually permanent. The cause and pathogenesis of this syndrome are unknown, although approximately half of the patients later develop aortic insufficiency or a systemic vasculitis that resembles polyarteritis nodosa. These vascular complications proved fatal in 7 of 78 cases reviewed by Vollertsen and colleagues.


Neurology_Adams

Neurology_Adams. There are many other causes of aural vertigo, such as purulent labyrinthitis complicating mastoiditis or meningitis; serous labyrinthitis caused by infection of the middle ear; “toxic labyrinthitis” caused by intoxication with alcohol, quinine, or salicylates; motion sickness; and hemorrhage into the inner ear. Bárány (1911) was the first to draw attention to the nystagmus and positional vertigo, worse on closing the eyes that occurs at a certain level of intoxication with alcohol and lasts a few hours. Such an episode of alcohol-induced vertigo tends to last longer than a vertiginous attack of Ménière disease, but in other respects, the symptoms (excepting tinnitus) are similar.


Neurology_Adams

Neurology_Adams. Vertigo with varying degrees of spontaneous or positional nystagmus and reduced vestibular responses is a frequent complication of cranial trauma. Vertigo, often of the nonrotatory, to-and-fro type, may follow cerebral concussion or whiplash injury, in which the head has not been impacted. Brandt has attributed this syndrome to a loosening or dislodgement of the otoconia in the otoliths. The vertigo in these circumstances usually improves in a few days or weeks and is rarely accompanied by impairment of hearing—in distinction to the vertigo that follows fractures of the temporal bones (as described earlier in this chapter in the discussion of deafness). Dizziness is also a prominent complaint as part of the syndrome of a postconcussion syndrome as described in Chap. 35, but usually this proves to be ill-defined giddiness rather than true vertigo.


Neurology_Adams

Neurology_Adams. There is, nonetheless, a type of vestibular concussion accompanying closed head trauma that may leave the patient with imbalance or positional vertigo. Otolaryngologists are familiar with a syndrome resulting from a perilymph fistula after traumatic injury. The trauma may be minor, even forceful coughing, sneezing, or lifting; some cases are a result of chronic ear infection or cholesteatoma. Disruption of the oval or round windows causes a leak of perilymph into the middle ear. Vertigo and nystagmus can be induced by pressure in the external ear canal (the fistula test). If enough perilymph migrates to the middle ear, a conductive hearing loss may also be detected. Superior canal dehiscence, in which loud sounds induce brief vertigo and nystagmus (Tullio phenomenon) is another result of perilymphatic fistula, as discussed earlier. A perilymph fistula may be pronounced enough to also cause low pressure of the spinal fluid with the characteristic enhancement of the dura on MRI.


Neurology_Adams

Vertigo of Brainstem Origin

Neurology_Adams. Vertigo of Brainstem Origin


Neurology_Adams

Neurology_Adams. Reference was made above to the occurrence of vertigo and nystagmus with lower and upper brainstem lesions. In these cases, vestibular nuclei and their connections are implicated. Auditory function is nearly always spared, because the vestibular and cochlear fibers diverge upon entering the brainstem at the junction of the medulla and pons. The vertigo of brainstem origin, as well as the accompanying nausea, vomiting, nystagmus, and disequilibrium, is generally more protracted but less severe than with labyrinthine lesions, but one can think of exceptions to this statement. Nevertheless, with brainstem lesions, one often observes marked nystagmus without the slightest degree of vertigo—which does not happen with labyrinthine disease. The nystagmus of brainstem origin may be unior bidirectional, purely horizontal, vertical or rotary, and is characteristically worsened by attempted visual fixation. In contrast, nystagmus of labyrinthine origin is unidirectional when the head is in a


Neurology_Adams

Neurology_Adams. purely horizontal, vertical or rotary, and is characteristically worsened by attempted visual fixation. In contrast, nystagmus of labyrinthine origin is unidirectional when the head is in a single position, usually with a rotary component, and past pointing and falling are in the direction of the slow phase; purely vertical nystagmus does not occur, and a purely horizontal nystagmus without a rotary component is unusual. Furthermore, labyrinthine nystagmus is inhibited by visual fixation and reverses direction with changes in the position of the head; nystagmus of brainstem origin generally displays none of these features. Either may have a positionalor movement-induced worsening, but this finding is more prominent in labyrinthine disease. Table 14-2 summarizes these findings.


Neurology_Adams

Neurology_Adams. The central localization of vertigo is confirmed mainly by finding signs of involvement of other structures within the brainstem (cranial nerves, sensory and motor tracts, etc.). Furthermore, Newman-Toker and colleagues have devised a combination of the head impulse test, nystagmus, and skew deviation (termed by them “HINTS”) that dependably differentiates central from peripheral; causes of and are particularly useful in emergency room diagnosis of vertigo. Vertigo is a prominent symptom of ischemic attacks and of brainstem infarction occurring in the territory of the vertebrobasilar arteries, particularly the Wallenberg syndrome of lateral medullary infarction.


Neurology_Adams

Neurology_Adams. On the other hand, our colleague C.M. Fisher had pointed out that vertigo as the sole manifestation of brainstem ischemia from basilar arterial disease is rare. Unless other symptoms and signs of a brainstem disorder appear contemporaneously or soon after the vertigo, one can usually postulate an aural origin and nearly always exclude vascular disease of the brainstem. However, we have encountered rare patients with repeated brief attacks of vertigo that later proved to be caused by basilar artery stenosis, but in whom only a few episodes were associated with signs of brainstem disease such as dysarthria, facial numbness, or diplopia. In other words, frequent and sudden episodes of vertigo lasting a minute or so may infrequently be related to transient brainstem ischemia.


Neurology_Adams

Neurology_Adams. Vertigo of cerebellar origin is exceptional in this respect in that it may rarely be the sole manifestation of cerebellar infarction or hemorrhage, as described earlier in the introductory sections of the chapter and in Chap. 33. It follows that isolated vertigo may be the result of occlusion of the posterior inferior cerebellar artery or its parent vertebral artery although most often, there are additional features related to damage to the lateral medulla. In instances of isolated vertigo, one seeks confirmation that there are no features pointing to a central origin or conversely, if there are signs such as nystagmus in more than one direction of gaze with a single position of the head, or vertical nystagmus, there is concern for ischemia of the brainstem. The nystagmus and ataxia of gait (more of a propelling, or pulsion, to one side) that accompany acute cerebellar lesions are toward the same side (the side of the lesion), while in acute vestibulopathies, nystagmus beats away from


Neurology_Adams

Neurology_Adams. (more of a propelling, or pulsion, to one side) that accompany acute cerebellar lesions are toward the same side (the side of the lesion), while in acute vestibulopathies, nystagmus beats away from the side of the lesion and pulsion is still toward the affected side.


Neurology_Adams

Neurology_Adams. Multiple sclerosis may be the explanation of persistent vertigo in an adolescent or young adult, sometimes with little or no nystagmus. In most cases, there are other characteristic features of multiple sclerosis (e.g., internuclear ophthalmoplegia) but rarely, a demyelinating plaque in the vicinity of the vestibular nuclei simulates a peripheral vestibular disorder.


Neurology_Adams

Neurology_Adams. The relationship of migraine to vertigo was mentioned earlier. This refers to otherwise mundane migraine in which the vertigo is perhaps an aura, or to episodes of paroxysmal vertigo in adults that are considered to be migraine equivalents. In addition, attacks of vertigo followed by an intense unilateral and often suboccipital headache and vomiting are the characteristic features of basilar artery migraine. The prodromal visual symptoms take the form of blindness or of photopsia that occupies all of the visual fields. Between headaches, tests of cochlear and vestibular function in these patients are normal. Some authorities have stated that most cases of recurrent vertigo without hearing loss over many years can be attributed to migraine and not to Ménière disease. An instructive series of such cases has been published by Dieterich and Brandt.


Neurology_Adams

Neurology_Adams. Finally, mention should be made of a familial vestibulocerebellar syndrome, beginning in childhood or early adult life and characterized by recurrent episodes of vertigo and imbalance. Diplopia and dysarthria complicate some attacks, which seem to be precipitated by extreme exertion and emotion. Repeated attacks are followed by a mild, persistent ataxia, mainly of the trunk. This disorder was first described by Farmer and Mustian and more recently by Baloh and Winder, who have pointed out that both the episodic vertigo and ataxia are markedly reduced or abolished by the administration of acetazolamide. This process is most likely related to the inherited acetazolamide-responsive ataxic channelopathy syndrome described in Chap. 5. A form that is kinesigenic, that is, brought on by activity, has a similar appearance.


Neurology_Adams

Neurology_Adams. In summary, the nature of the nystagmus, instability of the eyes during the head impulse test, and the other features of the neurologic examination allow a distinction to be made between central and peripheral cases of vertigo. Associated hearing loss favors a vestibular cause of vertigo. Tables 14-2 and 14-3 summarize the features of the various vertiginous syndromes. Adler JR, Ropper AH: Self-audible venous bruits and high jugular bulb. Arch Neurol 43:257, 1986. Amarenco P, Roullet E, Hommel M, et al: Infarction in the territory of the medial branch of the posterior inferior cerebellar artery. J Neurol Neurosurg Psychiatry 53:731, 1990. Badia L, Parikh A, Bookes GB: Management of middle ear myoclonus. J Laryngol Otol 108:380, 1994. Baloh RW: Clinical Neurotology. London, Bailliére Tindall, 1994. Baloh RW: Vertigo. Lancet 352:1841, 1998. Baloh RW: Vestibular neuronitis. N Engl J Med 348:1027, 2003.


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Neurology_Adams. Baloh RW: Clinical Neurotology. London, Bailliére Tindall, 1994. Baloh RW: Vertigo. Lancet 352:1841, 1998. Baloh RW: Vestibular neuronitis. N Engl J Med 348:1027, 2003. Baloh RW, Honrubia V: Clinical Neurophysiology of the Vestibular System, 2nd ed. Philadelphia, Davis, 1990. Baloh RW, Honrubia V, Jacobson K: Benign positional vertigo: Clinical and oculographic features in 240 cases. Neurology 37:371, 1987. Baloh RW, Jacobson K, Honrubia V: Idiopathic bilateral vestibulopathy. Neurology 39:272, 1989. Baloh RW, Jacobson K, Wilson T: Drop attacks with Ménière’s syndrome. Ann Neurol 28:384, 1990. Baloh RW, Winder A: Acetazolamide responsive vestibulocerebellar syndrome. Clinical and oculographic features. Neurology 41:429, 1991. Bárány R: Diagnose von Krankheitserscheinungen im Bereiche des Otolithenapparatus. Acta Otolaryngol 2:234, 1921. Bárány R: Experimentelle alkohol-intoxication. Monatsschr Ohrenheilk 45:959, 1911.


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Neurology_Adams. Bárány R: Diagnose von Krankheitserscheinungen im Bereiche des Otolithenapparatus. Acta Otolaryngol 2:234, 1921. Bárány R: Experimentelle alkohol-intoxication. Monatsschr Ohrenheilk 45:959, 1911. Basser LS: Benign paroxysmal vertigo of childhood. A variety of vestibular neuronitis. Brain 87:141, 1964. Biemond A, DeJong JMBV: On cervical nystagmus and related disorders. Brain 92:437, 1969. Brandt T: Man in motion: Historical and clinical aspects of vestibular function—a review. Brain 114:2159, 1991. Brandt T: Phobic postural vertigo. Neurology 46:1515, 1996. Brandt T, Steddin S, Daroff RB: Therapy for benign paroxysmal positioning vertigo, revisited. Neurology 44:796, 1994. Brodal A: The cranial nerves. In: Neurological Anatomy, 3rd ed. New York, Oxford University Press, 1981, pp 448–577. Cascino G, Adams RD: Brainstem auditory hallucinosis. Neurology 36:1042, 1986. Celesia GG: Organization of auditory cortical areas in man. Brain 99:403, 1976.


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Neurology_Adams. Cascino G, Adams RD: Brainstem auditory hallucinosis. Neurology 36:1042, 1986. Celesia GG: Organization of auditory cortical areas in man. Brain 99:403, 1976. Chinnery PF, Elliott C, Green GR, et al: The spectrum of hearing loss due to mitochondrial DNA defects. Brain 123:82, 2000. Cogan DG: Syndrome of nonsyphilitic interstitial keratitis and vestibuloauditory symptoms. Arch Ophthalmol 34:144, 1945. DeFelice C, DeCapua B, Tassi R, et al: Non-functioning posterior communicating arteries of circle of Willis in idiopathic sudden hearing loss. Lancet 356:1237, 2000. De la Meilleure G, Dehaene I, Depondt M, et al. Benign paroxysmal positional vertigo of the horizontal canal. J neurol Neurosurg Psychiatr 60:68, 1991. DeRidder D, DeMulder G, Verstraeten E, et al: Primary and secondary auditory cortex stimulation for intractable tinnitus. ORL J Otorhinolarygol Res 68:48, 2006.


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Neurology_Adams. DeRidder D, DeMulder G, Verstraeten E, et al: Primary and secondary auditory cortex stimulation for intractable tinnitus. ORL J Otorhinolarygol Res 68:48, 2006. Dieterich M, Brandt T: Episodic vertigo related to migraine (90 cases): Vestibular migraine? J Neurol 246:883, 1999. Dix M, Hallpike C: Pathology, symptomatology and diagnosis of certain disorders of the vestibular system. Proc R Soc Med 45:341, 1952. Duncan GW, Parker SW, Fisher CM: Acute cerebellar infarction in the PICA territory. Arch Neurol 32:364, 1975. Epley JM: The canalith repositioning procedure for treatment of benign paroxysmal positional vertigo. Otolaryngol Head Neck Surg 107:399, 1992. Estivill X, Fortina P, Surrey S, et al: Connexin-26 mutations in sporadic and inherited sensorineural deafness. Lancet 351:394, 1998. Evan KE, Tavill MA, Goldberg AN, Siverstein H: Sudden sensorineural hearing loss after general anesthesia for nonotologic surgery. Laryngoscope 107:747, 1997.


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Neurology_Adams. Evan KE, Tavill MA, Goldberg AN, Siverstein H: Sudden sensorineural hearing loss after general anesthesia for nonotologic surgery. Laryngoscope 107:747, 1997. Farmer TW, Mustian VM: Vestibulocerebellar ataxia. Arch Neurol 8:471, 1963. Fetterman BL, Luxford WM, Saunders JE: Sudden bilateral sensorineural hearing loss. Laryngoscope 106:1347, 1996. Fowler EP: Head noises in normal and in disordered ears. Arch Otolaryngol 39:498, 1944. Friedmann I: Ultrastructure of ear in normal and diseased states. In: Hinchcliffe R, Harrison D (eds): Scientific Foundations of Otolaryngology. London, Heinemann, 1976, pp 202–211. Froehling DA, Silverstein MD, Mohr DN, et al: Benign positional vertigo: Incidence and prognosis in a population-based study in Olmsted County, Minnesota. Mayo Clin Proc 16:596, 1991. Furman JM, Cass SP: Benign paroxysmal positional vertigo. N Engl J Med 341:1591, 1999. Furman JM, Jacob RG: Psychiatric dizziness. Neurology 48:1161, 1997.


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Neurology_Adams. Furman JM, Cass SP: Benign paroxysmal positional vertigo. N Engl J Med 341:1591, 1999. Furman JM, Jacob RG: Psychiatric dizziness. Neurology 48:1161, 1997. Gorlin RS, Pindborg JJ, Cohen MM Jr: Syndromes of the Head and Neck. New York, McGraw-Hill, 1976. Halmagyi GM, Cremer PD: Assessment and treatment of dizziness. J Neurol Neurosurg Psychiatry 68:129, 2000. Hammeke TA, McQuillen MP, Cohen BA: Musical hallucinations associated with acquired deafness. J Neurol Neurosurg Psychiatry 46:570, 1983. Jamieson DRS, Mann C, O’Reilly B, Thomas AM: Ear click in palatal tremor caused by activity of the levator veli palatini. Neurology 46:1168, 1996. Jannetta PJ: Neurovascular decompression in cranial nerve and systemic disease. Am J Surg 192:518, 1980. Jannetta PJ, Møller MB, Møller AR: Disabling positional vertigo. N Engl J Med 310:1700, 1984. Jeong SH, Choi SH, Kim JY, et al. Osteopenia and osteoporosis in idiopathic benign positional vertigo. Neurology 24:1069–1076. 2009.


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Neurology_Adams. N Engl J Med 310:1700, 1984. Jeong SH, Choi SH, Kim JY, et al. Osteopenia and osteoporosis in idiopathic benign positional vertigo. Neurology 24:1069–1076. 2009. Kasai K, Asada T, Yumoto M, et al: Evidence for functional abnormality in the right auditory cortex during musical hallucinosis. Lancet 354:1703, 1999. Konigsmark BW: Hereditary deafness in man. N Engl J Med 281:713, 774, 827, 1969. Konigsmark BW: Hereditary diseases of the nervous system with hearing loss. In: Vinken PJ, Bruyn GW (eds): Handbook of Clinical Neurology. Vol 22. Amsterdam, North-Holland, 1975, pp 499–526. Kroenke K, Mangelsdorff AD: Common symptoms in ambulatory care: Incidence, evaluation, therapy, and outcome. Am J Med 86:262, 1989. Lockwood AH, Salvi RJ, Burkard RF: Tinnitus. N Engl J Med 347:904, 2002. Marion MS, Cevette MJ: Tinnitus. Mayo Clin Proc 66:614, 1991. Mattox DE, Simmons FB: Natural history of sudden sensorineural hearing loss. Ann Otol Rhinol Laryngol 86:463, 1977.


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Neurology_Adams. Marion MS, Cevette MJ: Tinnitus. Mayo Clin Proc 66:614, 1991. Mattox DE, Simmons FB: Natural history of sudden sensorineural hearing loss. Ann Otol Rhinol Laryngol 86:463, 1977. Møller AR: Pathophysiology of tinnitus. Ann Otol Rhinol Laryngol 93:39, 1984. Morell RJ, Kim HJ, Hood LJ, et al: Mutations in the connexin 26 gene (GJB2) among Ashkenazi Jews with nonsyndromic recessive deafness. N Engl J Med 339:1500, 1998. Nadol JB Jr: Hearing loss. N Engl J Med 329:1092, 1993. National Institute on Deafness and Other Communication Disorders: A Report of the Task Force on the National Strategic Research Plan. Bethesda, MD, National Institutes of Health, 1989. Neuhauser H, Leopold M, van Brevern M, et al: The interpretation of migraine, vertigo and migrainous vertigo. Neurology 56:436, 2001. Newman-Toker DM, Curthoys I, Halmagyi GM: Diagnosing stroke in acute vertigo: The HINTS family of eye movement tests and the future of the “Eye ECG”. Semin Neurol 35:506, 2015.


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Neurology_Adams. Newman-Toker DM, Curthoys I, Halmagyi GM: Diagnosing stroke in acute vertigo: The HINTS family of eye movement tests and the future of the “Eye ECG”. Semin Neurol 35:506, 2015. Nodar RH, Graham JT: An investigation of frequency characteristics of tinnitus associated with Ménière’s disease. Arch Otolaryngol 82:28, 1965. Rasmussen GI: An efferent cochlear bundle. Anat Rec 82:441, 1942. Schuknecht HF: Cupulolithiasis. Arch Otolaryngol Head Neck Surg 90:765, 1969. Schuknecht HF, Kitamura K: Vestibular neuronitis. Ann Otol Rhinol Laryngol 90:1, 1981. Semont A, Freyss G, Vitte E: Curing the BPPV with a liberatory maneuver. Adv Otorhinolaryngol 42:290, 1988. Sismanis A, Smoker WR: Pulsatile tinnitus: Recent advances in diagnosis. Laryngoscope 104:681, 1994. Stouffer JL, Tyler RS: Characterization of tinnitus by tinnitus patients. J Speech Hear Disord 55:439, 1990.


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Neurology_Adams. Stouffer JL, Tyler RS: Characterization of tinnitus by tinnitus patients. J Speech Hear Disord 55:439, 1990. Strupp M, Zingler VC, Anbusow V, et al: Methylprednisolone, valacyclovir, or the combination for vestibular neuritis. N Engl J Med 351:354, 2004. Suga S, Lindsay JR: Histopathological observations of presbyacusis. Ann Otol Rhinol Laryngol 85:169, 1976. Tanaka Y, Kamo T, Yoshida M, Yamadori A: So-called cortical deafness. Brain 114:2385, 1991. Tekin M, Arnos KS, Pandy A: Advances in hereditary deafness. Lancet 358:1082, 2001. Toole JF, Tucker H: Influence of head position upon cerebral circulation. Arch Neurol 2:616, 1960. Tumarkin A: The otolithic catastrophe: A new syndrome. Br Med J 1:175, 1936. Vollertsen RS, McDonald TJ, Younge BR, et al: Cogan’s syndrome: 18 cases and a review of the literature. Mayo Clin Proc 61:344, 1986.


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Neurology_Adams. Vollertsen RS, McDonald TJ, Younge BR, et al: Cogan’s syndrome: 18 cases and a review of the literature. Mayo Clin Proc 61:344, 1986. von Brevern M, Seelig T, Neuhauser H, et al: Benign positional vertigo predominantly affects the right labyrinth. J Neurol Neurosurg Psychiatry 75:1487, 2004.


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Neurology_Adams. Figure 14-1. The auditory and vestibular systems. A. The right ear, viewed from the front, showing the external ear and auditory canal, the middle ear and its ossicles, and the inner ear. B. The main parts of the right inner ear, viewed from the front. The perilymph is located between the wall of the bony labyrinth and the membranous labyrinth. In the cochlea, the perilymphatic space takes the form of two coiled tubes—the scala vestibuli and scala tympani. The endolymph is located within the membranous labyrinth, which includes the three semicircular ducts, the utricle, and the saccule. C. The organ of Corti. This is the end organ of hearing; it consists of a single row of inner hair cells and three rows of outer hair cells. The stereocilia of the hair cells are embedded in the tectorial membrane. D. Diagram of a crista ampulla, the specialized sensory epithelium of a semicircular canal. The crista senses the displacement of endolymph during head rotation. The direction of head


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Neurology_Adams. membrane. D. Diagram of a crista ampulla, the specialized sensory epithelium of a semicircular canal. The crista senses the displacement of endolymph during head rotation. The direction of head rotation is indicated by the red arrow, and endolymph flow by the black arrow. The macula is the locus of the sensory epithelium in the utricle and saccule. Note that the tips of the hair cells are in contact with the otoliths (calcareous material), which are embedded in a gelatinous mass called the cupula.


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Neurology_Adams. CochlearnucleiTrapezoid bodyN. VIIINucleus of lateral lemniscusSuperior olivarynucleiDorsalacousticstriaIntermediateacoustic striaInferior colliculusMedial geniculatenucleus (thalamus)To superiorcolliculusPrimaryauditory cortexMidbrainMidbrainPonsPonsMedulla Figure 14-2. The ascending auditory pathways. The lower part of the diagram is a horizontal section through the upper medulla. (Reproduced with permission from Noback CR: The Human Nervous System, 3rd ed. New York, McGraw-Hill, 1981.) Figure 14-3. A simplified diagram of the vestibulocerebellar and vestibulospinal pathways and connections between vestibular and ocular motor nuclei. The medial longitudinal fasciculi (blue lines) are the main pathways for ascending vestibular impulses. (See text and also Fig. 14-1.) Figure 14-4. The vestibular reflex pathways. (Reproduced by permission from House EL: A Systematic Approach to Neuroscience. New York, McGraw-Hill, 1979.)


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Neurology_Adams. Figure 14-4. The vestibular reflex pathways. (Reproduced by permission from House EL: A Systematic Approach to Neuroscience. New York, McGraw-Hill, 1979.) Figure 14-5. Dix-Hallpike maneuver to elicit benign positional vertigo (originating in the right ear). A. The maneuver begins with the patient seated and the head turned to one side at 45 degrees, which aligns the right posterior semicircular canal with the sagittal plane of the head.


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Neurology_Adams. B. The patient is then helped to recline rapidly so that the head hangs over the edge of the table, still turned 45 degrees from the midline. Within several seconds, this elicits vertigo and nystagmus that is right beating with a rotary (counterclockwise) component. An important feature of this type of “peripheral” vertigo is a change in the direction of nystagmus when the patient sits up again with his head still rotated. If no nystagmus is elicited, the maneuver is repeated after a pause of 30 s, with the head turned to the left. Treatment with the canalith repositioning maneuver is shown in Fig. 14-6.


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Neurology_Adams. Figure 14-6. Bedside maneuver for the treatment of a patient with benign paroxysmal positional vertigo affecting the right ear. The presumed position of the debris within the labyrinth during the maneuver is shown on each panel. The maneuver is a four-step procedure. First, a Dix-Hallpike test is performed with the patient’s head rotated 45 degrees toward the (affected) right ear and the neck slightly extended with the chin pointed slightly upward. A. This position results in the patient’s head hanging to the right. B. Once the vertigo and nystagmus provoked by this maneuver cease, the patient’s head is rotated about the rostral–caudal body axis until the left ear is down. C. Then the head and body are further rotated until the head is almost facing down. The vertex of the head is kept tilted upward throughout the rotation. The patient should be kept in the final, face down position for about 10 to 15 s. D. With the head kept turned toward the left shoulder, the patient is brought


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Neurology_Adams. tilted upward throughout the rotation. The patient should be kept in the final, face down position for about 10 to 15 s. D. With the head kept turned toward the left shoulder, the patient is brought into the seated position.


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Neurology_Adams. Chapter 14 Deafness, Dizziness, and Disorders of Equilibrium Chapter 16 Coma and Related Disorders of Consciousness


Neurology_Adams

Neurology_Adams. The prevalence and importance of epilepsy, recurrent unprovoked seizures, can hardly be overstated. From the epidemiologic studies of Hauser and colleagues, one may extrapolate an incidence of approximately 2 million individuals in the United States who have epilepsy and predict about 44 new cases per 100,000 persons each year. These figures are exclusive of patients in whom seizures transiently complicate febrile and other illnesses or injuries. It has also been estimated that slightly less than 1 percent of persons in the United States will have epilepsy by the age of 20 years (Hauser and Annegers). Over two-thirds of all epileptic seizures begin in childhood (most in the first year of life), and this is the period when seizures assume the widest array of forms. In the practice of pediatric neurology, epilepsy is one of the most common disorders, and the chronicity of childhood forms adds to their importance. The incidence increases again after age 60 years. For all these reasons,


Neurology_Adams

Neurology_Adams. neurology, epilepsy is one of the most common disorders, and the chronicity of childhood forms adds to their importance. The incidence increases again after age 60 years. For all these reasons, physicians should know something of the nature of seizure disorders and their treatment. It is notable that, in striking contrast to the many treatments available for epilepsy, as pointed out by J. Engel, 80 to 90 percent of persons with epilepsy in the developing world never receive medical attention.


Neurology_Adams

Neurology_Adams. The word epilepsy is derived from Greek words meaning “to seize upon” or a “taking hold of.” Our predecessors referred to it as the “falling sickness” or the “falling evil.” Although a useful medical term to denote recurrent seizures, the words epilepsy and epileptic may still have unpleasant connotations and should be used advisedly in dealing with patients. In 1870, Hughlings Jackson, the eminent British neurologist, postulated that seizures were due to “an excessive and disorderly discharge of cerebral nervous tissue on muscles.” The discharge may result in an almost instantaneous loss of consciousness, alteration of perception or impairment of psychic function, convulsive movements, disturbance of sensation, or some combination thereof.


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Neurology_Adams. Terminologic difficulty arises from the diversity of the clinical manifestations of seizures. The term convulsion, referring as it does to an intense paroxysm of involuntary repetitive muscular contractions, does not fully capture the range of disorders resulting from abnormal electrical discharges, or seizures, that may consist only of an alteration of sensation or consciousness. Seizure is preferable as a generic term because it embraces all paroxysmal electrical discharges of the brain, and also because it lends itself to qualification. The term motor or convulsive seizure, therefore, is not tautologic, and one may likewise speak of a sensory seizure or psychic seizure. There is also an entity of “nonconvulsive seizure” that may impair consciousness, but not manifest any abnormal convulsive movement. This represents an important and potentially treatable form of an encephalopathy or confusional state.


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Neurology_Adams. A first solitary seizure or brief outburst of seizures may occur during the course of many medical illnesses. It indicates that the cerebral cortex has been affected by disease, either primarily or secondarily. If prolonged or repeated every few minutes, the condition termed status epilepticus, it may threaten life. Equally important, a seizure or a series of seizures may be the manifestation of an ongoing neurologic disease that requires special diagnostic and therapeutic measures. Status epilepticus may be of the nonconvulsive type, and continuously impair consciousness and is difficult to detect clinically because of the absence of characteristic movements.


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Neurology_Adams. A more common and less-grave circumstance is for a seizure to be but one in an extensive series recurring over a long period of time, with most of the attacks being more or less similar in type. In this instance, they may be the result of an inactive lesion that remains as a scar in the cerebral cortex. The original disease may have passed unnoticed, or perhaps had occurred in utero, at birth, in infancy, or in parts of the brain inaccessible for examination or too immature to manifest signs. The increasingly refined techniques of MRI now also reveal small zones of developmental cortical dysplasia and hippocampal sclerosis, both of which tend to be epileptogenic. Patients with such long-standing but subtle lesions probably make up a large portion of those with recurrent seizures. If there is no underlying lesion, the condition is classified as idiopathic or primary, but in the modern era, this is come to be almost synonymous with a genetic cause. In this category, there are a large


Neurology_Adams

Neurology_Adams. is no underlying lesion, the condition is classified as idiopathic or primary, but in the modern era, this is come to be almost synonymous with a genetic cause. In this category, there are a large number of important types of epilepsy for which no pathologic basis has been established, and for which there is no apparent underlying cause except a genetic disorder of ion channel function. Included here are special hereditary forms such as generalized tonic-clonic (grand mal), and “absence” seizure states as suggested in classifications many years ago by Lennox and Forster. Persistent seizures, regardless of cause, can secondarily damage cortical tissue by several mechanisms that include excitotoxicity and, in the setting of prolonged tonic seizures, systemic hypoxia.


Neurology_Adams

Neurology_Adams. Seizures have been grouped in several ways: according to their presumed etiology, that is, idiopathic (primary) or symptomatic (secondary); their site of origin; their clinical form (generalized or focal); their frequency (isolated, cyclic, or repetitive, or the closely spaced sequence of status epilepticus); or by special electroencephalographic (EEG) patterns. A distinction must be made between the classification of seizures: generalized tonic clonic (grand mal), absence (petit mal), myoclonic, partial, and others, and the classification of the epilepsies, or epileptic syndromes, which are specific diseases, many of which may manifest several seizure types. These are discussed later in the chapter. A further distinction is made by clinical and EEG features. This approach allows for the reasonable predictability of response to specific medications and to some extent, in prognosis.


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Neurology_Adams. Basically, this classification divides seizures into two types—focal (formerly termed partial), in which a focal or localized onset can be discerned clinically or by EEG, or generalized, in which the seizures appear to begin bilaterally. Generalized seizures are of two types—convulsive and nonconvulsive. The common convulsive type is the tonic-clonic (grand mal) seizure. Less common is a purely tonic, purely clonic, atonic, and myoclonic. The typical nonconvulsive generalized seizure is the brief lapse of consciousness or absence (petit mal); included also under this heading are minor motor phenomena. Focal seizures can also be convulsive or uncommonly, nonconvulsive. Furthermore, focal seizures can secondarily generalize into any of the types listed above.


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Neurology_Adams. The classification followed here was first proposed by Gastaut et al in 1970 and has been refined repeatedly by the Commission on Classification and Terminology of the International League against Epilepsy. This nomenclature, based mainly on the clinical form of the seizure, and its EEG features, has been adopted worldwide and is generally referred to as the “International Classification.” A modified version of it is reproduced in Table 15-1. Focal seizures are further classified according to their additional features such as a specific subjective experience (aura), motor, autonomic, and most importantly, whether awareness or consciousness is disturbed; the latter was formerly called partial complex seizure, now termed focal seizures with dyscognitive features. In reality, an aura represents the initial phase of a focal seizure; in some instances, it may constitute the entire epileptic attack.


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Neurology_Adams. A complementary classification is provided by considering the epilepsy syndromes, a group of somewhat diverse, age-dependent and usually genetically determined entities that arise without underlying structural abnormalities. The syndromes are characterized the age of onset, type of seizure, and often, by a particular EEG pattern. By contrast, epilepsies manifesting as seizures that begin locally and may evolve into generalized tonic-clonic seizures, termed secondarily generalized tonic clonic seizures (termed bilateral convulsive in Fig. 15-1), generally have no such genetic component and are usually the result of underlying brain disease, either acquired or a result of congenital malformations or metabolic defects. Quite often, the initial focal phase is not appreciated, leading to misdiagnosis. An increasing frequency and severity of this group of disorders with age reflects the accumulation of focal cerebral damage from trauma, strokes, and other damage.


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Neurology_Adams. We begin our discussion with a practical approximation of the classification shown in Fig. 15-1, followed by consideration of a number of well-defined epilepsies and epileptic syndromes. A proposed current classification of epileptic syndromes based on the age of onset of the seizure disorder is shown in Fig. 15-2, and the distribution of the seizure types for each age epoch, obtained and aggregated from several sources is shown in Fig. 15-3. There has been substantial progress in defining the molecular basis of familial and hereditary epilepsies over the last decade; it is likely that these insights will lead to modification of both the clinical classifications and management of the epilepsies. (Tonic-Clonic, Grand Mal)


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Neurology_Adams. (Tonic-Clonic, Grand Mal) In the common primary type of seizure, most often a convulsion starts with little or no warning. Sometimes the patient senses the approach of a seizure by several subjective phenomena (prodrome) even prior to an epileptic aura, which represents a focal seizure. For some hours, the patient may feel apathetic, depressed, irritable, or, rarely, the opposite—ecstatic. In a patient with generalized epilepsy (juvenile myoclonic epilepsy being one typical type), one or more myoclonic jerks of the trunk or limbs on awakening may herald a seizure later in the day. Abdominal pains or cramps, a sinking, rising, or gripping feeling in the epigastrium, pallor or redness of the face, throbbing headache, constipation, or diarrhea have been given prodromal status, but they do not occur consistently enough to be predictive of an oncoming seizure.


Neurology_Adams

Neurology_Adams. Most often, generalized seizure strikes without warning, beginning with a sudden loss of consciousness and a fall to the ground that may lead to facial and other injuries. In some cases of generalized seizure there may be momentary movement of one part of the body before consciousness is lost (turning of the head and eyes or whole body or intermittent jerking of a limb), although the patient often fails to form a memory of this and such information is obtained only from an observer. At times, this movement represents a focal onset of a seizure and, as has already been pointed out, it is useful to distinguish between a primary (generalized) type of seizure with widespread EEG abnormalities at the onset, and a secondarily generalized type. The secondary generalized type implicates a focal brain lesion.


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Neurology_Adams. The initial motor signs are typically a brief flexion of the trunk, an opening of the mouth and eyelids, and upward deviation of the eyes. The arms are elevated and abducted, the elbows semiflexed, and the hands pronated. These are followed by a more protracted extension (tonic) phase, involving first the back and neck, then the arms and legs. There may be a piercing cry as the whole musculature is seized in a spasm with biting of the lateral margin of the tongue, and air is forcibly emitted through the closed vocal cords. Because the respiratory muscles are caught up in the tonic spasm, breathing is suspended and after some seconds the skin and lips may become cyanotic. The pupils are dilated and unreactive to light. The bladder may empty at this stage or later, during the postictal coma. This is the tonic phase of the seizure and lasts for 10 to 20 s.


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Neurology_Adams. There then occurs a transition from the tonic to the clonic phase of the convulsion. At first, there is a mild generalized tremor, which is, in effect, a repetitive relaxation of the tonic contraction. It begins at a rate of approximately 8 per second and coarsens to 4 per second; then it rapidly gives way to brief, violent flexor spasms that come in rhythmic salvos and agitate the entire body. If prolonged, the face becomes violaceous and contorted by a series of grimaces. Autonomic signs are prominent: the pulse is rapid, blood pressure is elevated, pupils are dilated, and salivation and sweating are prominent; bladder pressure may increase sixfold during this phase. The clonic jerks decrease in amplitude and frequency over a period of about 30 s. The patient remains apneic until the end of the clonic phase, which is often marked by a deep inspiration. Instead of the whole dramatic sequence described above, the seizures may be abbreviated or limited in scope by medications.


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Neurology_Adams. In the terminal phase of the seizure, all movements end and the patient is motionless and limp in a deep coma. The pupils begin to contract to light. Breathing may be quiet or stertorous. This state persists for several minutes, after which the patient opens his eyes, begins to look about, and appears bewildered and is confused and may be quite agitated. The patient may speak and later not remember anything that has been said and undisturbed becomes drowsy and falls asleep, sometimes for several hours, then often awakens with a pulsatile headache. When fully recovered, such a patient has no memory of any part of the spell but knows that something has happened because of the strange surroundings (in ambulance or hospital), the obvious concern of those around him, and often, a sore, bitten tongue and aching muscles from the violent movements. The convulsive contractions, if violent enough, may crush a vertebral body or result in a serious injury; a fracture, periorbital hemorrhages,


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Neurology_Adams. tongue and aching muscles from the violent movements. The convulsive contractions, if violent enough, may crush a vertebral body or result in a serious injury; a fracture, periorbital hemorrhages, subdural hematoma, posterior shoulder dislocation, or burn may have been sustained in the fall.


Neurology_Adams

Neurology_Adams. Each of these phases of the generalized tonic-clonic seizure has characteristic EEG accompaniments. Initially, movement artifacts obscure the EEG tracing; sometimes there are repetitive spikes or spike-wave discharges lasting a few seconds, followed by an approximately 10-s period of 10-Hz spikes. As the clonic phase asserts itself, the spikes become mixed with slow waves and then the EEG slowly assumes a polyspike-and-wave pattern. When all movements have ceased, the EEG tracing is nearly isoelectric for a variable time, and then the brain waves gradually resume their preseizure pattern.


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Neurology_Adams. Severe seizures may be accompanied by a systemic lactic acidosis with a fall in arterial pH, reduction in arterial oxygen saturation, and rise in PCO2. These effects are secondary to the respiratory arrest and excessive muscular activity. If prolonged, they may cause hypoxic-ischemic damage to remote areas in the cerebrum, basal ganglia, and cerebellum. In paralyzed and artificially ventilated subjects receiving electroconvulsive therapy, these changes are less marked and the oxygen tension in cerebral venous blood may actually rise. Heart rate, blood pressure, and particularly CSF pressure rise briskly during an ECT-induced seizure. According to Plum and colleagues, the rise in blood pressure evoked by a seizure usually causes a sufficient increase in cerebral blood flow to meet the increased metabolic needs of the brain.


Neurology_Adams

Neurology_Adams. Convulsions of this type ordinarily come singly or in groups of two or three and may occur when the patient is awake and active or during sleep, or when falling asleep or awakening. It is useful to know that seizures on awakening usually signify a generalized type, whereas those occurring during the period of sleep are more often focal in nature. Some 5 to 8 percent of such patients will at some time have a prolonged series of such seizures without resumption of consciousness between them; this is status epilepticus and demands urgent treatment. The first outburst of seizures in an individual may take the form of status epilepticus.


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Neurology_Adams. Aside from psychogenic episodes that imitate seizures, few clinical states simulate a generalized tonic-clonic seizure, but several are worthy of mention. One is a clonic jerking of the extended limbs (usually less severe than those of a grand mal seizure) that occurs with vasodepressor syncope or a Stokes-Adams hypotensive attack. In contrast to an epileptic type of EEG, the brain waves are slow in frequency and low in amplitude during the jerking movements. A rarer phenomenon that may be indistinguishable from a generalized convulsion occurs as part of the syndrome of basilar artery occlusion. This presumably has its basis in ischemia of the corticospinal tracts in the pons (Ropper); a similar ischemic mechanism in the cortex has been invoked for “limb-shaking TIAs” (transient ischemic attacks), in which there are clonic movements of one limb or one side of the body during an episode of cerebral ischemia. Clonic limb movements occur immediately after a traumatic concussion and an


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Neurology_Adams. attacks), in which there are clonic movements of one limb or one side of the body during an episode of cerebral ischemia. Clonic limb movements occur immediately after a traumatic concussion and an observer who arrives at this moment will be unable to determine if the inciting event was a seizure causing a fall with head injury, or a collision causing a concussion and convulsive movements. In infants, a breath-holding spell may closely simulate the tonic phase of a generalized seizure. Another disorder that simulates a seizure, albeit self-induced, is the fainting lark (or in the British, the “mess trick”). By hyperventilating in a squatting position and standing rapidly combined with a Valsalva maneuver, a syncopal episode is induced that ends with generalized convulsive movements (see Lempert et al).


Neurology_Adams

Neurology_Adams. In contrast to major generalized seizures, absence seizures (formerly referred to as petit mal or pyknoepilepsy) are notable for their brevity, rapid onset and cessation, and frequency and the paucity of motor activity. Indeed, they may be so brief that the patients themselves are sometimes not aware of them; to an onlooker, they resemble a moment of absentmindedness or daydreaming. The attack, coming without warning, consists of a sudden interruption of consciousness, for which the French word absence (“not present,” “not in attendance”) has been retained. The patient stares and briefly stops talking or ceases to respond. Only about 10 percent of such patients are completely motionless during the attack; in the remainder, one observes a brief burst of fine clonic (myoclonic) movements of the eyelids, facial muscles, or fingers or small synchronous movements of both arms, all at a rate of 3 per second as shown many years ago by Penry and colleagues. This rate corresponds to that of


Neurology_Adams

Neurology_Adams. of the eyelids, facial muscles, or fingers or small synchronous movements of both arms, all at a rate of 3 per second as shown many years ago by Penry and colleagues. This rate corresponds to that of the EEG abnormality, which takes the form of a generalized 3-per-second spike-and-wave pattern (see Fig. 2-7I). Absence seizures are said to be “typical” if they have a rapid onset and offset, typical three per second spike and wave, and complete loss of awareness.


Neurology_Adams

Neurology_Adams. Minor automatisms—in the form of lip-smacking, chewing, and fumbling movements of the fingers—are common during an attack but may be subtle. Postural tone may be slightly decreased or increased, and occasionally there is a mild vasomotor disorder. As a rule, such patients do not fall; they may even continue complex acts such as walking or riding a bicycle. After 2 to 10 s, occasionally longer, the patient reestablishes full contact with the environment and resumes his preseizure activity. Only a loss of the thread of conversation or the place in reading betrays the occurrence of the momentary “blank” period (the absence). In many such patients, voluntary hyperventilation for 2 to 3 min is an effective way of inducing absence attacks.


Neurology_Adams

Neurology_Adams. Typical absence seizures constitute the most characteristic epilepsy of childhood (“childhood absence”); rarely do the seizures begin before 4 years of age or after puberty. Another attribute is their great frequency (hence, the old term pykno, meaning “compact” or “dense”). As many as several hundred may occur in a single day, sometimes in bursts at certain consistent times of the day. They produce periods of inattention and may appear in the classroom when the child is sitting quietly rather than participating actively in his lessons. If frequent, they disturb attention and thinking to the point that the child’s performance in school is impaired. Less frequently, such attacks may last for hours with no interval of normal mental activity between them—so-called absence or petit mal status. Absence epilepsy of adolescent onset (“juvenile absence”) does not have the very high seizure frequency of the childhood type. Cases of absence status have also been described in adults with frontal


Neurology_Adams

Neurology_Adams. Absence epilepsy of adolescent onset (“juvenile absence”) does not have the very high seizure frequency of the childhood type. Cases of absence status have also been described in adults with frontal lobe epilepsy (see in the following text). In contrast to childhood absence seizures, the disorder may last well into adulthood and be punctuated by generalized tonic-clonic seizures or a burst of seizures. Akinesia (motionlessness) is not unique to any seizure type.


Neurology_Adams

Neurology_Adams. The typical absence, with or without myoclonic jerks, rarely causes the patient to fall. Absence should be considered a separate entity because of its relative benignity. It may be the only type of seizure during childhood. The attacks tend to diminish in frequency in adolescence and then often disappear, only to be replaced in many instances by major generalized seizures. About one-third of children with absence attacks will, in addition, display symmetrical or asymmetrical myoclonic jerks without loss of consciousness, and about half will at some time have major generalized (tonic-clonic) convulsions.


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Neurology_Adams. Distinguished from typical absence seizures are variants in which the loss of consciousness is less complete or in which myoclonus is prominent, and others in which the EEG abnormalities are less regularly of a 3-per-second spike-and-wave type (they may occur at the rate of 2 to 2.5 per second or take the form of irregular 4to 6-Hz polyspike-and-wave complexes). Atypical absence is a term that was introduced to describe long runs of slow spike-and-wave activity, usually with no apparent loss of consciousness. External stimuli, such as asking the patient to answer a question or to count, interrupt the run of abnormal EEG activity. The current classification (Fig. 15-1) separates the disorder into groups that are identified as typical, atypical, and having special features, namely, myoclonic jerks or eyelid myoclonus.


Neurology_Adams

Neurology_Adams. In sharp contrast to the typical absence epilepsies, is a form that has its onset between 2 and 6 years of age and is characterized by atonic, or astatic, seizures (i.e., falling attacks), often succeeded by various combinations of minor motor, tonic-clonic, and partial seizures and by progressive intellectual impairment in association with a distinctive, slow (1to 2-Hz) spike-and-wave EEG pattern. This is the Lennox-Gastaut syndrome. Often it is preceded in earlier life by infantile spasms, a characteristic high-amplitude chaotic EEG picture (hypsarrhythmia), and an arrest in mental development, a triad sometimes referred to as the West syndrome (see further on). The early onset of atonic seizures with abrupt falls, injuries, and associated abnormalities nearly always has a grave implication—namely, the presence of serious neurologic disease. Prematurity, perinatal injury and metabolic diseases of infancy are the most common underlying conditions. This is essentially a form of


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Neurology_Adams. the presence of serious neurologic disease. Prematurity, perinatal injury and metabolic diseases of infancy are the most common underlying conditions. This is essentially a form of symptomatic generalized epilepsy, in contrast to the foregoing idiopathic types such as typical absence epilepsy (petit mal). The Lennox-Gastaut syndrome may persist into adult life and is one of the most difficult forms of epilepsy to treat.


Neurology_Adams

Neurology_Adams. The phenomenon of myoclonus was discussed in Chap. 4, where the relationship to seizures was emphasized. Characterized by a brusque, brief, muscular contraction, some myoclonic jerks may be so small as to involve only one muscle or part of a muscle; others are so large as to displace a limb on one or both sides of the body or the entire trunk musculature. Many are brief, lasting 50 to 100 ms; they may occur intermittently and unpredictably or present as a single jerk or a brief salvo.


Neurology_Adams

Neurology_Adams. As mentioned earlier, a series of several small, rhythmic myoclonic jerks may appear with varying frequency as part of atypical absence seizures, and as isolated events in patients with generalized clonic-tonic-clonic or tonic-clonic seizures. As a rule, seizure-associated myoclonus, when occurring in isolation, is relatively common, signifies nothing more than the seizure disorder, and usually responds well to antiepileptic medication. In contrast, there are diseases in which myoclonus is progressive in severity or very frequent. These disorders have their onset in childhood and raise the suspicion of entities such as the myoclonus-opsoclonus-ataxia syndrome, lithium or other drug toxicity or, if lasting a few weeks, subacute sclerosing panencephalitis. Chronic progressive polymyoclonus with dementia characterizes the group of juvenile lipidosis (see Chap. 36), Lafora-type familial myoclonic epilepsy, certain mitochondrial disorders, and other chronic familial degenerative diseases


Neurology_Adams

Neurology_Adams. with dementia characterizes the group of juvenile lipidosis (see Chap. 36), Lafora-type familial myoclonic epilepsy, certain mitochondrial disorders, and other chronic familial degenerative diseases of undefined type (paramyoclonus multiplex of Friedreich) as noted further on in Table 15-3. The large number of adult diseases causative of myoclonus and seizure disorders are discussed in later chapters. Myoclonus as a phenomenon is further described in Chap. 4.


Neurology_Adams

Neurology_Adams. This is the most common form of idiopathic generalized epilepsy in older children and young adults. It begins in adolescence, typically around age 15 years, with a range that essentially spans all of the teenage years. The patient comes to attention because of a generalized tonic-clonic seizure, often upon awakening or because of myoclonic jerks in the morning that involve the entire body; sometimes absence seizures are prominent. The family reports that the patient has occasional myoclonic jerks of the arm and upper trunk that is brought out with fatigue, early stages of sleep, or alcohol ingestion. A few patients in our experience have had only the myoclonic phenomena and rare absence or tonic-clonic seizures that persisted unnoticed for years. The EEG shows characteristic bursts of 4to 6-Hz irregular polyspike activity. A linkage has been established to several loci, mainly of ion channels and of GABA-related receptors.


Neurology_Adams

Neurology_Adams. The disorder does not impair intelligence and tends not to be progressive, for which reason it has been called “benign,” but a proclivity to infrequent seizures usually continues throughout life. A report by Baykan and colleagues has indicated that, over an average of two decades, the majority of patients have long seizure-free periods and a large reduction in myoclonic seizures by the fourth decade but only one-fifth become virtually seizure free. Valproic acid in particular and some other antiepileptic drugs are highly effective in eliminating the seizures and myoclonus but they should be continued indefinitely as discontinuation of medication is associated with a high rate of relapse. Owing to the potential teratogenicity of valproate, women of childbearing age are often given levitiracetam or lamotrigine, acknowledging that they may not be as effective as the first choice of drug. It has been observed that carbamazepine and phenytoin may exaggerate the seizures.


Neurology_Adams

Neurology_Adams. As indicated earlier, the International Classification divides all seizures into two types—generalized, in which the clinical and EEG manifestations indicate bilateral and diffuse cerebral cortical involvement from the onset, and focal, in which the seizure is often the product of a demonstrable focal lesion or EEG abnormality in some part of the cerebral cortex. The manifestations of focal seizures reflect the locale of the lesion. In the past focal seizures were classified by whether consciousness was retained (partial) or impaired (complex), but are now subsumed under the term “dyscognitive” if awareness is altered. Focal seizures with sensory or motor features at the onset most often arise from foci in the sensorimotor cortex. Those with impairment of consciousness, which occurs in many forms, most often have their focus in the limbic and autonomic areas or in the temporal lobe, but a frontal localization is also known. Table 15-2 lists the common sites of the lesions and the


Neurology_Adams

Neurology_Adams. many forms, most often have their focus in the limbic and autonomic areas or in the temporal lobe, but a frontal localization is also known. Table 15-2 lists the common sites of the lesions and the corresponding types of seizures.


Neurology_Adams

Neurology_Adams. Relatively few focal seizures can be localized precisely from clinical data alone. However, when combined with scalp and intracranial EEG recording and MRI, the localization is reasonably accurate.


Neurology_Adams

Neurology_Adams. Focal motor seizures are attributable to a discharging lesion of the frontal lobe. A common type, originating in the supplementary motor area, takes the form of a turning movement of the head and eyes to the side opposite the irritative focus, often associated with a tonic extension of limbs, also on the side contralateral to the affected hemisphere. This may constitute the entire seizure, or it may be followed by generalized clonic movements. The extension of the limbs may occur just before or simultaneously with loss of consciousness but a lesion in one frontal lobe may give rise to a major generalized convulsion without an initial turning of the head and eyes. It has been postulated that, if there is loss of consciousness, it is the result of a rapid spread of the discharge from the frontal lobe to integrating centers in the thalamic or high midbrain reticular formation.


Neurology_Adams

Neurology_Adams. One form of focal frontal convulsion is the Jacksonian motor seizure, which begins with tonic and then clonic contraction of the fingers of one hand, the face on one side, or the muscles of one foot. Sometimes a series of clonic movements of increasing frequency build up to a tonic contraction. The characteristic feature is that the movements spread (march) from the part first affected to other contiguous muscles on the same side of the body. In its typical form, the seizure spreads from the hand, up the arm, to the face, and down the leg; or if the first movement is in the foot, the seizure marches up the leg, down the arm, and to the face, usually in a matter of 20 to 30 s. Rarely, the first muscular contraction is in the abdomen, thorax, or neck. In some cases, the one-sided seizure activity is followed by turning of the head and eyes to the convulsing side, occasionally to the opposite side, and then by a generalized seizure with loss of consciousness. Consciousness is not lost if


Neurology_Adams

Neurology_Adams. is followed by turning of the head and eyes to the convulsing side, occasionally to the opposite side, and then by a generalized seizure with loss of consciousness. Consciousness is not lost if the sensorimotor symptoms remain confined to one side.


Neurology_Adams

Neurology_Adams. The frontal lobe, being so large, can give rise to numerous forms of seizure including the typical Jacksonian type described above, but also adversive (contralateral turning of the body or of a body part), speech arrest, frontal, absence types, and a number of unusual disorders related to discharges from the supplementary motor area including hyperkinetic and postural tonic varieties. In practice, it is often difficult to distinguish such seizures from parasomnic (sleep related) events (see Chap. 18).


Neurology_Adams

Neurology_Adams. Focal motor seizures may begin with forceful, sustained deviation of the head and eyes, and sometimes of the entire body, are referred to as versive or adversive. The turning movements are usually to the side opposite the electrical focus but sometimes, to the same side. The same is true for the head and eye turning that occurs at the end of the generalized tonic-clonic phase of seizures (Wylie et al). In seizures of temporal lobe origin, early in the seizure, there may be head turning ipsilaterally followed by forceful, contraversive head (and body) turning. These head and body movements, if they occur, may be preceded by quiet staring or automatisms. Nonforceful, unsustained, or seemingly random lateral head movements during the ictus do not have localizing value and suggest that the phenomena are epileptic.


Neurology_Adams

Neurology_Adams. Following convulsions that have a prominent focal motor signature, there is often a transient paralysis of the affected limbs. This “Todd paralysis” persists for minutes or at times for hours after the seizure, usually in proportion to the duration of the convulsion. Continued focal paralysis beyond this time usually indicates the presence of a focal brain lesion as the underlying cause of the seizure or persisting seizures in a nonconvulsive form. A similar Todd phenomenon is found in cases of focal epilepsy that involve the language, somesthetic, or visual areas; here the persistent deficit corresponds to the region of brain affected.


Neurology_Adams

Neurology_Adams. The high incidence of focal motor epilepsy that originates with movements in the face, hands, and toes is probably related to the disproportionately large cortical representation of these parts. Contraversive deviation of only the head and eyes can be induced most consistently by electrical stimulation of the superolateral frontal region (area 8), just anterior to area 6 (see Figs. 21-1 and 21-2). The disease process or focus of excitation is usually in or near the rolandic (motor) cortex, that is, area 4 of Brodmann (see Figs. 3-3 and 22-2); in some cases, and especially if there is a sensory accompaniment, it has been found in the postrolandic convolution.


Neurology_Adams

Neurology_Adams. Lesions confined to the motor cortex are reported to assume the form of clonic contractions, and those confined to the premotor cortex (area 6), tonic contractions of the contralateral arm, face, neck, or all of one side of the body. Tonic elevation and extension of the contralateral arm and flexion of the ipsilateral arm (fencing posture) and choreoathetotic and dystonic postures have been associated with high medial frontal lesions (area 8 and supplementary motor cortex), as have complex, bizarre, and flailing movements of a contralateral limb, but this always raises the suspicion of a nonepileptic phenomenon. Perspiration and piloerection occur occasionally in parts of the body involved in a focal motor seizure, suggesting that these autonomic functions have a cortical representation in or adjacent to the rolandic area. Focal motor and Jacksonian seizures have essentially the same localizing significance.


Neurology_Adams

Neurology_Adams. Seizure discharges arising from the cortical language areas may give rise to a brief aphasic disturbance (ictal aphasia) and ejaculation of a word or loud sound or, more frequently, a vocal arrest. Ictal aphasia is usually succeeded by other focal or generalized seizure activity but may occur in isolation, without loss of consciousness, in which case it can later be described by the patient. Postictal aphasia is more common than ictal aphasia. Verbalization at the onset of a seizure has no consistent lateralizing significance and, paradoxically, is usually associated with an origin in the nondominant hemisphere. These disturbances should be distinguished from the stereotyped repetition of words or phrases or the garbled speech that characterizes some complex partial seizures or the postictal confusional state and, of course, Wernicke aphasia. Somatosensory, Visual, and Other Types of Sensory Seizures


Neurology_Adams

Neurology_Adams. Somatosensory seizures, either focal or “marching” to other parts of the body on one side, are nearly always indicative of a focus in or near the postrolandic convolution of the opposite cerebral hemisphere. Penfield and Kristiansen found the seizure focus in the postcentral or precentral convolution in 49 of 55 such cases. The sensory disorder is usually described as numbness, tingling, or a “pins-and-needles” feeling and occasionally as a sensation of crawling (formication), electricity, or movement of the part. Pain and thermal sensations may occur but are exceedingly rare. In the majority of cases, the onset of the sensory seizure is in the lips, fingers, or toes, and the spread to adjacent parts of the body follows a pattern determined by sensory arrangements in the postcentral (postrolandic) convolution of the parietal lobe see Salanova et al). If the sensory symptoms are localized to the head, the focus is in or adjacent to the lowest part of the convolution, near the sylvian


Neurology_Adams

Neurology_Adams. convolution of the parietal lobe see Salanova et al). If the sensory symptoms are localized to the head, the focus is in or adjacent to the lowest part of the convolution, near the sylvian fissure; if the symptoms are in the leg or foot, the upper part of the convolution, near the superior sagittal sinus or on the medial surface of the hemisphere, is involved.


Neurology_Adams

Neurology_Adams. Olfactory hallucinations, perhaps the most important of the sensory seizures because they signify a particular localization, are associated with disease of the inferior and medial parts of the temporal lobe, usually in the region of the parahippocampal convolution or the uncus [hence Jackson’s term uncinate seizures (see also Chap. 11)]. Usually the perceived odor is exteriorized, that is, projected to someplace in the environment, and is described as disagreeable or foul, though otherwise unidentifiable. Gustatory hallucinations also have been recorded in proven cases of temporal lobe disease and less often with lesions of the insula and parietal operculum; salivation and a sensation of thirst may be associated. Electrical stimulation in the depths of the sylvian fissure, extending into the insular region, has produced peculiar sensations of taste.


Neurology_Adams

Neurology_Adams. Visual seizures are relatively rare but also have localizing significance. Lesions in or near the striate cortex of the occipital lobe usually produce elemental visual sensations of darkness or sparks and flashes of light, which may be stationary or moving and colorless or colored. According to Gowers, red is the most frequently reported color, followed by blue, green, and yellow. These images may be referred to the visual field on the side opposite of the lesion or may appear straight ahead. If they occur on one side of the visual field, patients perceive that only one eye is affected (the one opposite the lesion), probably because most persons are aware of only the temporal half of a homonymous field defect. Curiously, a seizure arising in one occipital lobe may cause momentary blindness in both fields. It has been noted that lesions on the lateral surface of the occipital lobe (Brodmann areas 18 and 19) are likely to cause a sensation of twinkling or pulsating lights. More complex


Neurology_Adams

Neurology_Adams. in both fields. It has been noted that lesions on the lateral surface of the occipital lobe (Brodmann areas 18 and 19) are likely to cause a sensation of twinkling or pulsating lights. More complex or formed visual hallucinations are usually caused by a focus in the posterior part of the temporal lobe, near its junction with the occipital lobe, and may be associated with auditory hallucinations. The localizing value of visual auras has been confirmed by Bien and colleagues (2000) in a group of 20 surgically treated patients with intractable seizures. They found that elementary visual hallucinations and visual loss were typical of occipital lobe epilepsy but could also occur with seizure foci in the anteromedial temporal and occipitotemporal regions. Reference is made here to the childhood occipital seizure disorder described by Panayiotopoulos, discussed further on. These patients experience rudimentary visual hallucinations. One interesting feature that we have observed is of extreme


Neurology_Adams

Neurology_Adams. occipital seizure disorder described by Panayiotopoulos, discussed further on. These patients experience rudimentary visual hallucinations. One interesting feature that we have observed is of extreme turning of the head and eyes toward the visual images.


Neurology_Adams

Neurology_Adams. Auditory hallucinations are infrequent as an initial manifestation of a seizure and usually represent a psychotic disorder or one of several more benign conditions. Occasionally, a patient with a focus in one superior temporal convolution will report a buzzing or roaring in the ears. A human voice, sometimes repeating unrecognizable words, or the sound of music has been noted a few times with lesions in the more posterior part of one temporal lobe. Some people with epilepsy and a strong family history of seizures with auditory auras, may have normal imaging but turn out to have mutations in the LGI1 gene.


Neurology_Adams

Neurology_Adams. Vertiginous sensations of a type suggesting a vestibular origin may on rare occasions be the first symptom of a seizure. The lesion is usually located in the superoposterior temporal region or the junction between parietal and temporal lobes. In one of the cases reported by Penfield and Jasper, a sensation of vertigo was evoked by stimulating the cortex at the junction of the parietal and occipital lobes. Occasionally with a temporal focus, the vertigo is followed by an auditory sensation. Giddiness, or light-headedness, is a frequent prelude to a seizure, but this symptom, as discussed in Chap. 14, has so many different connotations that it is of little diagnostic value.


Neurology_Adams

Neurology_Adams. Vague and often indefinable visceral sensations arising in the thorax, epigastrium, and abdomen are among the most frequent of auras, as already indicated. Most often they have a temporal lobe origin, although in several such cases the seizure discharge has been localized to the upper bank of the sylvian fissure, in the upper or middle frontal gyrus, or in the medial frontal area near the cingulate gyrus. Palpitation and acceleration of the heart rate at the beginning of the attack have also been related mainly to a temporal lobe focus. Temporal Lobe Seizures (Characterized by Altered Responsiveness, Complex Partial Seizures, Psychomotor Seizures)


Neurology_Adams

Neurology_Adams. Temporal Lobe Seizures (Characterized by Altered Responsiveness, Complex Partial Seizures, Psychomotor Seizures) These differ from the major generalized and absence seizures discussed above in that (1) they signify a focal onset in the temporal lobe as reflected by an aura that may be a hallucination or perceptual illusion, or (2) a period of altered behavior and incomplete impairment of consciousness, a dyscognitive state, in contrast to the loss of connection to the environment typical of absence epilepsy.


Neurology_Adams

Neurology_Adams. Although it is difficult to enumerate all the psychic experiences that may occur during these types of seizures, they may be categorized as illusions, hallucinations, depersonalization states, and affective experiences. Among the altered psychic states are a feeling of intense perception of familiarity in an unfamiliar circumstance or place (déjà vu) or, conversely, of strangeness or unfamiliarity (jamais vu) in a previously known place or circumstance. There may be the experience of autoscopy, a type of depersonalization, or dream-like state in which the patient views himself as an external observer. Fragments of certain old memories or scenes may insert themselves into the patient’s mind and recur with striking clarity, or there may be an abrupt interruption of memory. (See Gloor for a more detailed description of the experiential phenomena of temporal lobe epilepsy.) Sensory illusions, or distortions of ongoing perceptions, are the most common. Objects or persons in the environment


Neurology_Adams

Neurology_Adams. detailed description of the experiential phenomena of temporal lobe epilepsy.) Sensory illusions, or distortions of ongoing perceptions, are the most common. Objects or persons in the environment may shrink or recede into the distance, or they may enlarge (micropsia and macropsia), or perseverate as the head is moved (palinopsia). Tilting of the visual environment has been reported. Hallucinations are most often visual or auditory, consisting of formed or unformed visual images, sounds, and voices; less frequently, they may be olfactory (usually unpleasant, unidentifiable sensations of smell), gustatory, or vertiginous. Associated epigastric and abdominal sensations have been alluded to above and likely have their origin in autonomic and limbic structures.


Neurology_Adams

Neurology_Adams. Emotional experiences as a result of seizure, while less common, may be dramatic—fear, anxiety, sadness, anger, happiness, ecstasy, and sexual excitement have all been recorded. Fear and anxiety are the most common affective experiences, while occasionally the patient describes a feeling of rage or intense anger as part of a temporal lobe seizure. Each of these subjective psychic states may constitute the entire seizure or some combination may occur and immediately precedes a period of altered awareness. These “auras” represent electrical seizures as already mentioned and have the same localizing significance as motor convulsions do for the frontal cortex. All the temporal lobe ictal experiences have no apparent connection to objective circumstances and are generally not related to the situation in which the patient finds himself during the seizure.


Neurology_Adams

Neurology_Adams. The motor components of a focal temporal lobe or limbic seizure, if they occur, arise during the later phase of the seizure and take the form of automatisms such as lip-smacking, chewing or swallowing movements, salivation, fumbling of the hands, or shuffling of the feet. Patients may walk around in a daze or act inappropriately. Complex acts that were initiated before the loss of consciousness—such as walking, chewing food, turning the pages of a book, or even driving—may continue. However, when asked a specific question or given a command, the patients are obviously out of contact with their surroundings. There may be no response at all, or the patient may look toward the examiner in a perplexed way or utter a few stereotyped phrases. The patient may walk repetitively in small circles (volvular epilepsy), run (epilepsia procursiva), or simply wander aimlessly, either as an ictal or postictal phenomenon (poriomania). These forms of seizure, according to some epileptologists, are


Neurology_Adams

Neurology_Adams. (volvular epilepsy), run (epilepsia procursiva), or simply wander aimlessly, either as an ictal or postictal phenomenon (poriomania). These forms of seizure, according to some epileptologists, are actually more common with frontal lobe than with temporal lobe foci of origin. Dystonic stiffness of the arm and leg contralateral to the seizure focus is found to be an accompaniment of temporal lobe seizures (more often this is from the supplementary motor of the frontal than the temporal lobes).


Neurology_Adams

Neurology_Adams. In a small number of patients with temporal lobe seizures (7 of 123 patients studied by Ebner et al), some degree of responsiveness (to simple questions and motor commands) is preserved in the presence of prominent automatisms such as lip-smacking and swallowing. Interestingly, the seizures originate in the right temporal lobe. That consciousness should be altered with temporal lobe epilepsy is not at all self-evident. Several mechanisms have been studied, particularly by Blumenfeld’s group, and converge on the effects of temporal lobe discharge on deep structures such as the medial thalamus and the septal nuclei. Amnesia is an important component of the alteration in the state of consciousness in temporal lobe epilepsy but does not explain the entire syndrome.


Neurology_Adams

Neurology_Adams. The patient, in a confused and irritable state, may resist or strike out at the examiner. These types of behaviors, which occur in a limited number of patients with temporal lobe or frontal seizures, usually take the form of nondirected oppositional resistance to restraint. These behaviors manifest during a period of automatic behavior (so called because the patient presumably acts like an automaton) or, more often, in the postictal period. Unprovoked assault or outbursts of intense rage or blind fury are very unusual; Currie and associates found such outbursts in only 16 of 666 patients (2.4 percent) with temporal lobe epilepsy. Penfield once commented that he had never observed a rage state as a result of temporal lobe stimulation. It is exceedingly unlikely that an organized violent act requiring several sequential steps in its performance, such as obtaining a weapon and using it in a directed manner, could represent a temporal lobe seizure.


Neurology_Adams

Neurology_Adams. Rarely, laughter may be the most striking feature of a seizure (gelastic epilepsy). A particular combination of gelastic seizures and precocious puberty has been traced to a hamartoma of the hypothalamus. Crying, or dacrystic epilepsy, on the other hand, while demonstrated in children, is very infrequent and more often indicates a psychogenically induced episode. The patient with temporal lobe seizures may exhibit only one of the foregoing manifestations of seizure activity or various combinations. In a series of 414 patients studied by Lennox, 43 percent displayed some of the motor changes; 32 percent, automatic behavior; and 25 percent, alterations in psychic function. Because of the frequent concurrence of these symptom complexes, he referred to them as the psycho-motor triad. Probably the clinical pattern varies with the precise locality of the lesion and the direction and extent of spread of the electrical discharge.


Neurology_Adams

Neurology_Adams. After the attack, the patient usually has no memory or only fragments of recall for what was said or done. Any type of complex partial seizures may proceed to other forms of secondary generalized seizures. The tendency to generalization holds true for all types of partial or focal epilepsy.


Neurology_Adams

Neurology_Adams. Temporal lobe seizures are not peculiar to any period of life, but they do show an increased incidence in adolescence and the adult years and have an uncertain relationship to childhood febrile seizures. The topic of febrile seizures is broader than this association suggests; it is taken up in a later section of the chapter. Neonatal convulsions, head trauma, and various other nonprogressive perinatal neurologic disorders are other antecedents that place a child at risk of developing complex partial seizures (Rocca et al). Two-thirds of patients with temporal lobe seizures also have generalized tonic-clonic seizures or have had them in early childhood, and it has been theorized that the generalized seizures may have led to secondary excitotoxic damage to the hippocampal portions of the temporal lobes. In the latter cases, carefully performed and quantitated MRI in the coronal plane may disclose a loss of volume and gliosis in the hippocampi and adjacent gyri on one or both sides—that


Neurology_Adams

Neurology_Adams. lobes. In the latter cases, carefully performed and quantitated MRI in the coronal plane may disclose a loss of volume and gliosis in the hippocampi and adjacent gyri on one or both sides—that is, medial (or mesial) temporal sclerosis, discussed later in the chapter (Fig. 15-4).


Neurology_Adams

Neurology_Adams. Temporal lobe seizures are highly variable in duration. Behavioral automatisms rarely last longer than a minute or two, although postictal confusion and amnesia may persist for a considerably longer time. Some consist only of a momentary change in facial expression and a blank spell, resembling an absence. Almost always, however, temporal lobe events are characterized by distinct ictal and postictal phases, whereas patients with absence attacks usually have an instantaneous return of full consciousness following the ictus.


Neurology_Adams

Neurology_Adams. Postictal behavior after temporal lobe seizures is often accompanied by widespread or focal slowing in the EEG. Prolonged disorientation for time and place suggests a right-sided source. Automatisms in the postictal period have no lateralizing connotation (Devinsky et al). However, postictal posturing and paresis of an arm (Todd’s paralysis) or an aphasic difficulty are helpful in determining the side of the lesion (Cascino). Postictal nose wiping, which is reported on video recording to occur in half of patients with temporal lobe seizures, is carried out by the hand ipsilateral to the seizure focus according to Leutzmezer and colleagues.


Neurology_Adams

Neurology_Adams. Rarely, recurrent attacks of transient amnesia are the only manifestations of temporal lobe epilepsy, although it is unclear whether the amnesia in such patients represents an ictal or postictal phenomenon. These attacks of pure amnesia have been referred to as transient epileptic amnesia (TEA; Palmini et al; Zeman et al). If the patient functions at a fairly high level during the attack, as may happen, there is a resemblance to transient global amnesia (described in Chap. 20). However, in contrast to transient global amnesia, the relative brevity and frequency of the amnesic spells, their tendency to occur on awakening, the impaired performance on complex cognitive tasks, and the absence of repetitive stereotyped questions help to make the distinction.


Neurology_Adams

Neurology_Adams. Some comments are in order concerning the issues of behavioral and psychiatric disorders in patients who have seizures. Data as to prevalence of these disorders have been derived mainly from studies of selected groups of patients attending specialty clinics that tend to treat the most difficult and complicated cases. In one such study (Victoroff), approximately one-third of epileptic patients had a history of major depressive illness, and an equal number had symptoms of anxiety disorder; psychotic symptoms were found in 10 percent. Similar figures, also from a university-based epilepsy center, have been reported by Blumer et al. It must be emphasized that these remarkably high rates of psychiatric morbidity do not reflect the prevalence in the entire population of patients with epilepsy. Epidemiologic studies provide only limited evidence of an association with psychosis in the overall population of epileptics (see Trimble and the review by Trimble for a critical discussion of this


Neurology_Adams

Neurology_Adams. Epidemiologic studies provide only limited evidence of an association with psychosis in the overall population of epileptics (see Trimble and the review by Trimble for a critical discussion of this subject). Furthermore, it should be borne in mind that many chronic medical conditions are associated with psychiatric reactions. On the other hand, the unpredictability and stigma of the epileptic disorders may contribute to depression and anxiety.