A Survey of SSR Mechanism and Application
---
paper_title: Sympathetic skin response: review of the method and its clinical use.

paper_content:

Sympathetic skin response (SSR) represents a potential generated in skin sweat glands; it originates by activation of the reflex arch with different kinds of stimuli. The potential of rapid habituation after repeated stimuli is formed by biphasic or triphasic slow wave activity with relatively stable latency and variable amplitude. In healthy subjects younger than 60 years of age the response is always present in all extremities. SSR is most frequently used in diagnosing the functional impairment of non-myelinated postganglionic sudomotor sympathetic fibers in peripheral neuropathies. In this study a more complex and informative view on the anatomical and physiological substrates of SSR, its character, normal values and technique are presented, focusing on problems in evaluation of the response and factors that have influence on it. Based on personal experience normative latency and amplitude values of SSR in a group of 20 healthy individuals (x +/- SD), upper extremities: 1.48 +/- 0.80 sec., 444 +/- 167 microV, respectively; lower extremities: 2.06 +/- 0.93 sec., 203 +/- 87.4 microV, respectively) and recommendations for qualitative evaluation preference--the presence or absence of the response--over quantitative evaluation of latency and amplitude of the response in practical clinical use of the method are presented. (Tab. 1, Fig. 2, Ref. 148.).
---
paper_title: Sympathetic skin response--a method of assessing unmyelinated axon dysfunction in peripheral neuropathies.

paper_content:

The sympathetic skin response (SSR) was measured in 33 patients with peripheral neuropathies and in 30 normal control subjects. Abnormalities of the response were correlated with clinical, pathologic, and EMG observations. The response was usually absent in axonal neuropathies, but present in demyelinating disorders. Abnormalities of the sympathetic skin response did not correlate well with clinical evidence of dysautonomia, but were a reliable indicator of disorders affecting unmyelinated axons.
---
paper_title: Peripheral autonomic surface potential: A quantitative technique for recording sympathetic conduction in man

paper_content:

Using EMG equipment with time locked recording and standard averaging facilities we were able to record a previously poorly defined skin potential. The potential, termed by us the peripheral autonomic surface potential (PASP), was recorded from the palmar surface of the hand and the plantar surface of the foot in 30 normal subjects. The PASP usually consisted of a biphasic potential with an initial negative and a later positive peak. It was elicited by randomly timed electrical stimuli over the median nerve at the wrist. The mean palmar PASP latency was 1.52 +/- 0.13 s and the mean plantar PASP latency was 2.07 +/- 0.16 s. The mean palmar and plantar PASP amplitudes were 479 +/- 105 microV and 101 +/- 40 microV, respectively. A mean sympathetic conduction velocity was calculated to be 1.28 +/- 0.18 m/s. In 5 normal subjects a similar technique was used to record a PASP from the volar surface of the left middle finger. Iontophoresis of atropine into the skin under the recording site abolished the PASP in all subjects. Palmar and plantar PASPs were recorded in 10 diabetic patients. The amplitudes (palmar 179 +/- 158 microV, plantar 17 +/- 16 microV) were significantly reduced compared to normals (P less than 0.001). Five patients with unilateral lumbar or cervical sympathectomy were studied. The PASP was absent or markedly reduced on the side of the sympathectomy in all patients.
---
paper_title: Sudomotor skin responses to brain stimulation do not depend on nerve sensory fiber functionality

paper_content:

Abstract Evaluation of sudomotor innervation to the limbs was performed via electrical stimulation of the median nerve at the wrist and transcranial magnetic stimulation of the brain. Sympathetic skin responses (SSRs) from the palms and the soles were recorded in a patient suffering from a form of predominantly sensory neuropathy. Motor responses to nerve stimulation were present, even if with slower than normal conduction velocity. However, median, ulnar and sural nerve sensory potentials were absent. SSRs to median nerve stimulation at the wrist were missing on palms and soles. By contrast, during brain stimulation of the hand motor area with magnetic impulses, SSRs were reliably identifiable at all recording sites. It is hypothesized that SSRs to mixed nerve stimulation need normal functionality of afferent fibers, while those to brain stimulation can be elicited without any sensory information from the limbs.
---
paper_title: Sympathetic skin response--a method of assessing unmyelinated axon dysfunction in peripheral neuropathies.

paper_content:

The sympathetic skin response (SSR) was measured in 33 patients with peripheral neuropathies and in 30 normal control subjects. Abnormalities of the response were correlated with clinical, pathologic, and EMG observations. The response was usually absent in axonal neuropathies, but present in demyelinating disorders. Abnormalities of the sympathetic skin response did not correlate well with clinical evidence of dysautonomia, but were a reliable indicator of disorders affecting unmyelinated axons.
---
paper_title: Sympathetic skin response: normal results in different experimental conditions

paper_content:

Abstract 1. (1) The sympathetic skin response (SSR) is a slow wave, generated in deep layers of the skin, resulting from reflex activation of the sudomotor sympathetic efferent fibres. The aim of this study was to define experimental conditions, best stimulation and recording procedures, and the criteria for validation of the responses. 2. (2) Thirty normal subjects (aged 25–56) were tested. The stimulation was an electrical pulse train applied to the median nerve at the wrist, a binaural tone burst, or both simultaneously. Records were made with surface electrodes on hand and foot contralateral to the stimulated median nerve. 3. (3) Response shape was most often biphasic in feet, biphasic or triphasic in hands. SSR amplitude was 3.1 ± 1.8 mV in hands, 1.4 ± 0.8 mV in feet. Normal mean onset latency was 1.5 ± 0.08 sec for hand response, 2.05 ± 0.10 sec for foot response. The mean conduction velovity along peripheral sympathetic nerve fibres was 1.40 ± 0.14 m/sec in lower limbs. 4. (4) Bimodal stimulation (burst + median) provided responses of larger amplitude. The influence of stimulation intensity was also investigated. A decrease in amplitude and lengthening of latencies were observed after 15–20 min of testing. 5. (5) The criteria for validation of responses are discussed. The importance of central processing time in the response delay is pointed out. In good methodological conditions, SSR would appear to be a simple, effective means of assessing sympathetic sudomotor outflow in central and peripheral nervous system disorders.
---
paper_title: Peripheral autonomic surface potential: A quantitative technique for recording sympathetic conduction in man

paper_content:

Using EMG equipment with time locked recording and standard averaging facilities we were able to record a previously poorly defined skin potential. The potential, termed by us the peripheral autonomic surface potential (PASP), was recorded from the palmar surface of the hand and the plantar surface of the foot in 30 normal subjects. The PASP usually consisted of a biphasic potential with an initial negative and a later positive peak. It was elicited by randomly timed electrical stimuli over the median nerve at the wrist. The mean palmar PASP latency was 1.52 +/- 0.13 s and the mean plantar PASP latency was 2.07 +/- 0.16 s. The mean palmar and plantar PASP amplitudes were 479 +/- 105 microV and 101 +/- 40 microV, respectively. A mean sympathetic conduction velocity was calculated to be 1.28 +/- 0.18 m/s. In 5 normal subjects a similar technique was used to record a PASP from the volar surface of the left middle finger. Iontophoresis of atropine into the skin under the recording site abolished the PASP in all subjects. Palmar and plantar PASPs were recorded in 10 diabetic patients. The amplitudes (palmar 179 +/- 158 microV, plantar 17 +/- 16 microV) were significantly reduced compared to normals (P less than 0.001). Five patients with unilateral lumbar or cervical sympathectomy were studied. The PASP was absent or markedly reduced on the side of the sympathectomy in all patients.
---
paper_title: Sympathetic skin response in Parkinsonian patients

paper_content:

Sympathetic skin response (SSR) was recorded in 23 patients with idiopathic Parkinson's disease (IPD) using mechanical as well as electrical stimuli. Significant delay of SSR latencies and decrease in amplitude of SSR compared to healthy volunteers were found (p < 0.05). Furthermore the clinical parameters of the autonomic impairment correlated well with the Webster score. Central mechanisms might be responsible for these findings and the role of central sympathetic pathway damage in parkinsonian patients is discussed.
---
paper_title: Early detection of diabetic neuropathy: a neurophysiological study on 100 patients.

paper_content:

As a long-term complication of diabetes mellitus, autonomic neuropathy has received considerable attention in the last few years since a tripled 5-year-mortality of patients with diabetic neuropathy including autonomic disturbances has been observed. In a total of 100 diabetics with clinical manifest neuropathy of different stages (N0 = 8, N1 = 15, N2a = 24, N2b = 28, N3 = 25), 26 of whom were insulin-dependent and 74 non-insulin-dependent, the validity of different neurophysiologic and autonomic function test procedures proposed in literature was assessed. Apart from clinical examination, nerve conduction velocity measurement of five nerves as well as amplitude measurement of evoked sensory and motor actin potentials, electromyography of at least four muscles of the lower limbs, and measurement of sympathetic skin response on hands and feet were performed. Furthermore, heart rate variation at deep periodical breathing (E/I-ratio), during Valsalva's manoeuver and after standing up (30/15-ratio) was determined. In addition, the drop in systolic blood pressure to standing up was measured. The further developed the clinical picture of neuropathy, the more pathological were the results obtained in different tests. The results suggest that most changes leading to pathological values of nerve conduction velocity and heart rate variation measurement take place in a clinical stage, in which no or only very slight clinical signs give evidence of diabetic neuropathy (N0-N1). Therefore, especially these examinations should be performed on diabetics with no or only slight clinical signs of neuropathy in order to reveal those with beginning neuropathic disturbances. EMG examination is preferable in later stages of the disease.
---
paper_title: Sympathetic skin response: a decade later

paper_content:

Sympathetic skin response (SSR) is a simple, reproducible test of function of a polysynaptic reflex having diverse afferents, a common efferent pathway through the spinal cord, pre and post-ganglionic sympathetic fibers and with sweat glands as effectors. The reflex is co-ordinated in the posterior hypothalamus or upper brainstem reticular formation. It has been used in a variety of disorders of peripheral and central nervous system. Methodology, possible anatomic substrates, changes in SSR in various diseases and their correlation with clinical features of dysautonomia, bed side tests for dysautonomia and other electrophysiological parameters are critically evaluated. Almost a decade after the start of its widespread clinical utilization, several aspects of SSR remain inconclusive. A consensus as to what change in SSR to consider abnormal is yet to be reached. Though its ease of application supersedes a variety of other autonomic function tests, relying only on SSR changes for prognostication or therapeutic decisions appears impracticable. A battery of tests is thus a necessity.
---
paper_title: Sympathetic skin response: review of the method and its clinical use.

paper_content:

Sympathetic skin response (SSR) represents a potential generated in skin sweat glands; it originates by activation of the reflex arch with different kinds of stimuli. The potential of rapid habituation after repeated stimuli is formed by biphasic or triphasic slow wave activity with relatively stable latency and variable amplitude. In healthy subjects younger than 60 years of age the response is always present in all extremities. SSR is most frequently used in diagnosing the functional impairment of non-myelinated postganglionic sudomotor sympathetic fibers in peripheral neuropathies. In this study a more complex and informative view on the anatomical and physiological substrates of SSR, its character, normal values and technique are presented, focusing on problems in evaluation of the response and factors that have influence on it. Based on personal experience normative latency and amplitude values of SSR in a group of 20 healthy individuals (x +/- SD), upper extremities: 1.48 +/- 0.80 sec., 444 +/- 167 microV, respectively; lower extremities: 2.06 +/- 0.93 sec., 203 +/- 87.4 microV, respectively) and recommendations for qualitative evaluation preference--the presence or absence of the response--over quantitative evaluation of latency and amplitude of the response in practical clinical use of the method are presented. (Tab. 1, Fig. 2, Ref. 148.).
---
paper_title: Sympathetic skin response Basic mechanisms and clinical applications

paper_content:

Abstract Sympathetic skin response (SSR), defined as the momentary change of the electrical potential of the skin, may be spontaneous or reflexively evoked by a variety of internal or by externally applied arousal stimuli. Although the suprasegmental structures influencing the SSR in humans are not well known, SSR has been proposed as a non-invasive approach to investigate the function of the sympathetic system. SSR is easy to apply but current procedures are not sufficiently reliable for diagnostic purposes, and show imperfect correlations both with clinical features and other measurements of autonomic, in particular, sudomotor dysfunction.
---
paper_title: Sympathetic skin response Basic mechanisms and clinical applications

paper_content:

Abstract Sympathetic skin response (SSR), defined as the momentary change of the electrical potential of the skin, may be spontaneous or reflexively evoked by a variety of internal or by externally applied arousal stimuli. Although the suprasegmental structures influencing the SSR in humans are not well known, SSR has been proposed as a non-invasive approach to investigate the function of the sympathetic system. SSR is easy to apply but current procedures are not sufficiently reliable for diagnostic purposes, and show imperfect correlations both with clinical features and other measurements of autonomic, in particular, sudomotor dysfunction.
---
paper_title: Sympathetic skin response: normal results in different experimental conditions

paper_content:

Abstract 1. (1) The sympathetic skin response (SSR) is a slow wave, generated in deep layers of the skin, resulting from reflex activation of the sudomotor sympathetic efferent fibres. The aim of this study was to define experimental conditions, best stimulation and recording procedures, and the criteria for validation of the responses. 2. (2) Thirty normal subjects (aged 25–56) were tested. The stimulation was an electrical pulse train applied to the median nerve at the wrist, a binaural tone burst, or both simultaneously. Records were made with surface electrodes on hand and foot contralateral to the stimulated median nerve. 3. (3) Response shape was most often biphasic in feet, biphasic or triphasic in hands. SSR amplitude was 3.1 ± 1.8 mV in hands, 1.4 ± 0.8 mV in feet. Normal mean onset latency was 1.5 ± 0.08 sec for hand response, 2.05 ± 0.10 sec for foot response. The mean conduction velovity along peripheral sympathetic nerve fibres was 1.40 ± 0.14 m/sec in lower limbs. 4. (4) Bimodal stimulation (burst + median) provided responses of larger amplitude. The influence of stimulation intensity was also investigated. A decrease in amplitude and lengthening of latencies were observed after 15–20 min of testing. 5. (5) The criteria for validation of responses are discussed. The importance of central processing time in the response delay is pointed out. In good methodological conditions, SSR would appear to be a simple, effective means of assessing sympathetic sudomotor outflow in central and peripheral nervous system disorders.
---
paper_title: Sympathetic skin response: a new test to diagnose erectile dysfunction.

paper_content:

Aim: Electrophysiological monitoring of the activity of the penile sympathetic skin responses (PSSR) in healthy men and patients with erectile dysfunction (ED). Methods: PSSR were recorded from the skin of penis with disk electrodes at the time of electric stimulation of left median nerves. Results: PSSR were recorded from all the healthy men and almost all the patients. In healthy men the latency of P(-0) the latency of N(-1) the duration of N(-1) and the amplitude of N(-1) were 1249±111 ms 2239±286 ms 1832±505 ms and 470 µV (median) respectively. In ED patients the latency of P(-0) the latency of N(-1) the duration of N(-1) and the amplitude of N(-1) were 1467±183 ms (P<0.01) 2561±453 ms (P<0.05) 2560±861 ms (P<0.01) and 91 µV (P<0.01) respectively. The normal latency of P(-0) was less than 1471 ms. The normal amplitude of N(-1) was more than 235 µV. According to this normal value of 20 patients 11 showed longer latency of P(-0) and 14 showed lower amplitude of N(-1) as compared with those of normal subjects. Conclusion: PSSR can be used as an electrophysiological method in assisting the diagnosis of ED. (authors)
---
paper_title: Recovery of sympathetic skin responses after digit-to-digit replantation and toe-to-digit transplantation in humans.

paper_content:

Sympathetic skin response was utilized to study recovery of sudomotor function in 8 patients who had digit-to-digit replantation and 9 patients who had toe-to-digit transplantation. Sympathetic skin responses evoked by median nerve stimulation or magnetic stimulation of the neck were recorded from the tip of the replanted digits or transplanted toes. The contralateral normal fingers served as controls. The mean intervals between surgery and study were 33 and 37 months, respectively, for digit replantation and toe transplantation. In normal subjects, the sympathetic skin responses recorded from the fingertip were abolished by local anesthesia or cooling of the finger, while those recorded from the palm were not affected. Ischemia of the finger only transiently affected the digit sympathetic skin responses. These data indicate that the digit responses were locally generated and mediated by unmyelinated fibers. After digit replantation, the palm and digit sympathetic skin responses were not different between replanted and normal sides. After toe transplantation, palm sympathetic skin responses were normal, but digit ones had prolonged latency and reduced amplitude. The present findings suggest that recovery of sympathetic sudomotor activity can be nearly complete in digit replantation but less satisfactory in toe transplantation.
---
paper_title: Skin potentials (SP) recorded from the extremities and genital regions in normal and impotent subjects.

paper_content:

Skin potentials (SP) were evoked by peripheral nerve stimulation from the hands and feet of 41 and from the genital skin of 28 male, controls. The same methods were also applied in 10 functionally impotent cases, 32 diabetic impotent and 8 diabetic normopotent cases. The SP was easily obtained from all 3 sites in all normal subjects and in 10 functionally impotent cases. The SP recorded from the genital skin was either absent or abnormal in 53% of diabetic impotent cases with or without polyneuropathy, while the incidence of abnormalities encountered in the hand and/or foot recordings was 28%. In 8 diabetic normopotent cases the SP recorded from the genital and extremity skin were completely normal. SP recorded from the genital skin is a useful method of evaluating the autonomic-sympathetic dysfunction causing impotence, especially in patients who may have autonomic disorders either located in lumbosacral spinal cord and its efferents, or generalized autonomic-peripheral dysfunction.
---
paper_title: Sympathetic skin response: a decade later

paper_content:

Sympathetic skin response (SSR) is a simple, reproducible test of function of a polysynaptic reflex having diverse afferents, a common efferent pathway through the spinal cord, pre and post-ganglionic sympathetic fibers and with sweat glands as effectors. The reflex is co-ordinated in the posterior hypothalamus or upper brainstem reticular formation. It has been used in a variety of disorders of peripheral and central nervous system. Methodology, possible anatomic substrates, changes in SSR in various diseases and their correlation with clinical features of dysautonomia, bed side tests for dysautonomia and other electrophysiological parameters are critically evaluated. Almost a decade after the start of its widespread clinical utilization, several aspects of SSR remain inconclusive. A consensus as to what change in SSR to consider abnormal is yet to be reached. Though its ease of application supersedes a variety of other autonomic function tests, relying only on SSR changes for prognostication or therapeutic decisions appears impracticable. A battery of tests is thus a necessity.
---
paper_title: Sympathetic skin response: review of the method and its clinical use.

paper_content:

Sympathetic skin response (SSR) represents a potential generated in skin sweat glands; it originates by activation of the reflex arch with different kinds of stimuli. The potential of rapid habituation after repeated stimuli is formed by biphasic or triphasic slow wave activity with relatively stable latency and variable amplitude. In healthy subjects younger than 60 years of age the response is always present in all extremities. SSR is most frequently used in diagnosing the functional impairment of non-myelinated postganglionic sudomotor sympathetic fibers in peripheral neuropathies. In this study a more complex and informative view on the anatomical and physiological substrates of SSR, its character, normal values and technique are presented, focusing on problems in evaluation of the response and factors that have influence on it. Based on personal experience normative latency and amplitude values of SSR in a group of 20 healthy individuals (x +/- SD), upper extremities: 1.48 +/- 0.80 sec., 444 +/- 167 microV, respectively; lower extremities: 2.06 +/- 0.93 sec., 203 +/- 87.4 microV, respectively) and recommendations for qualitative evaluation preference--the presence or absence of the response--over quantitative evaluation of latency and amplitude of the response in practical clinical use of the method are presented. (Tab. 1, Fig. 2, Ref. 148.).
---
paper_title: Sympathetic skin response Age effect

paper_content:

We examined the sympathetic skin response in 100 normal subjects aged 20 to 91 years. The response was present in all younger subjects, but, in the elderly, was present in the lower limbs of only 50% and in the upper limbs of 73%. The amplitude of the response showed a marked decline with age in both the upper and lower limbs.
---
paper_title: Sympathetic skin response Basic mechanisms and clinical applications

paper_content:

Abstract Sympathetic skin response (SSR), defined as the momentary change of the electrical potential of the skin, may be spontaneous or reflexively evoked by a variety of internal or by externally applied arousal stimuli. Although the suprasegmental structures influencing the SSR in humans are not well known, SSR has been proposed as a non-invasive approach to investigate the function of the sympathetic system. SSR is easy to apply but current procedures are not sufficiently reliable for diagnostic purposes, and show imperfect correlations both with clinical features and other measurements of autonomic, in particular, sudomotor dysfunction.
---
paper_title: Sympathetic skin response (SSR) is abnormal in multiple sclerosis

paper_content:

As the function of the autonomic nervous system is often compromised in multiple sclerosis (MS), different standardized tests are used to detect disseminated abnormalities in cardiovascular autonomic functions. Sympathetic skin response (SSR), a slow wave generated in deep layers of the skin, is induced by reflex activation of sudomotor sympathetic efferent fibers. SSR was studied in 70 patients classified into different categories according to the diagnostic criteria for MS. We also obtained pattern reversal visually evoked potentials and brainstem auditory evoked potentials as well as somatosensory evoked potentials (by median and posterior tibial nerve stimulation). SSR was abnormal in 66 patients (94.2%), including abnormal foot latency with normal hand latency in 30 (42.8%), delayed foot and hand latencies in 30 (42.8%), and no response in 6 (8.6%). The percentages of SSR abnormalities were similar in the different patient categories. Pathological SSR were more common than abnormal evoked potentials in suspected and probable MS. SSR appears to be a simple and effective means of assessing sympathetic sudomotor outflow disturbances in MS, providing a valuable addition to current electrophysiological procedures for the detection of MS lesions.© 1995 John Wiley &Sons, Inc.
---
paper_title: Sympathetic skin response Basic mechanisms and clinical applications

paper_content:

Abstract Sympathetic skin response (SSR), defined as the momentary change of the electrical potential of the skin, may be spontaneous or reflexively evoked by a variety of internal or by externally applied arousal stimuli. Although the suprasegmental structures influencing the SSR in humans are not well known, SSR has been proposed as a non-invasive approach to investigate the function of the sympathetic system. SSR is easy to apply but current procedures are not sufficiently reliable for diagnostic purposes, and show imperfect correlations both with clinical features and other measurements of autonomic, in particular, sudomotor dysfunction.
---
paper_title: Sympathetic skin response--a method of assessing unmyelinated axon dysfunction in peripheral neuropathies.

paper_content:

The sympathetic skin response (SSR) was measured in 33 patients with peripheral neuropathies and in 30 normal control subjects. Abnormalities of the response were correlated with clinical, pathologic, and EMG observations. The response was usually absent in axonal neuropathies, but present in demyelinating disorders. Abnormalities of the sympathetic skin response did not correlate well with clinical evidence of dysautonomia, but were a reliable indicator of disorders affecting unmyelinated axons.
---
paper_title: Sympathetic skin response: normal results in different experimental conditions

paper_content:

Abstract 1. (1) The sympathetic skin response (SSR) is a slow wave, generated in deep layers of the skin, resulting from reflex activation of the sudomotor sympathetic efferent fibres. The aim of this study was to define experimental conditions, best stimulation and recording procedures, and the criteria for validation of the responses. 2. (2) Thirty normal subjects (aged 25–56) were tested. The stimulation was an electrical pulse train applied to the median nerve at the wrist, a binaural tone burst, or both simultaneously. Records were made with surface electrodes on hand and foot contralateral to the stimulated median nerve. 3. (3) Response shape was most often biphasic in feet, biphasic or triphasic in hands. SSR amplitude was 3.1 ± 1.8 mV in hands, 1.4 ± 0.8 mV in feet. Normal mean onset latency was 1.5 ± 0.08 sec for hand response, 2.05 ± 0.10 sec for foot response. The mean conduction velovity along peripheral sympathetic nerve fibres was 1.40 ± 0.14 m/sec in lower limbs. 4. (4) Bimodal stimulation (burst + median) provided responses of larger amplitude. The influence of stimulation intensity was also investigated. A decrease in amplitude and lengthening of latencies were observed after 15–20 min of testing. 5. (5) The criteria for validation of responses are discussed. The importance of central processing time in the response delay is pointed out. In good methodological conditions, SSR would appear to be a simple, effective means of assessing sympathetic sudomotor outflow in central and peripheral nervous system disorders.
---
paper_title: Sympathetic skin response in Parkinsonian patients

paper_content:

Sympathetic skin response (SSR) was recorded in 23 patients with idiopathic Parkinson's disease (IPD) using mechanical as well as electrical stimuli. Significant delay of SSR latencies and decrease in amplitude of SSR compared to healthy volunteers were found (p < 0.05). Furthermore the clinical parameters of the autonomic impairment correlated well with the Webster score. Central mechanisms might be responsible for these findings and the role of central sympathetic pathway damage in parkinsonian patients is discussed.
---
paper_title: Magnetic stimulation over different brain regions : no differential effects on the elicited sympathetic skin responses

paper_content:

Abstract Peak latencies and amplitudes of sympathetic skin responses (SSRs) of the hand following magnetic stimulation at different sites with two or five consecutive 10-Hz stimuli were investigated with regard to safety aspects of repetitive transcranial magnetic cortex stimulation (rTMS). The amount of sympathetic activation as assessed by the amplitudes of the SSRs depended on the stimulation site and decreased in the following order: brachial plexus stimulation>nerve root stimulation>stimulation over the brain>activation by acoustic coil artefact. When stimulating over six different regions of the cortex (frontal, central, parieto-occipital, and both hemispheres), the elicited SSRs had similar amplitudes and peak latencies. The SSRs elicited by rTMS over the motor cortex were not related to the sum of the amplitudes of excitatory muscle compound responses. Currents with opposite directions over the motor cortex markedly influenced the size of the motor responses but not of the SSRs. The number of consecutive 10-Hz stimuli did not influence the latencies or amplitudes of the SSRs. It can be concluded that SSRs after magnetic stimulation over peripheral nerves or the brain are a correlate of an unspecific arousal reaction. A therapeutic application of short series of rTMS should not be limited by the amount of sympathetic activation.
---
paper_title: Sympathetic skin response: a decade later

paper_content:

Sympathetic skin response (SSR) is a simple, reproducible test of function of a polysynaptic reflex having diverse afferents, a common efferent pathway through the spinal cord, pre and post-ganglionic sympathetic fibers and with sweat glands as effectors. The reflex is co-ordinated in the posterior hypothalamus or upper brainstem reticular formation. It has been used in a variety of disorders of peripheral and central nervous system. Methodology, possible anatomic substrates, changes in SSR in various diseases and their correlation with clinical features of dysautonomia, bed side tests for dysautonomia and other electrophysiological parameters are critically evaluated. Almost a decade after the start of its widespread clinical utilization, several aspects of SSR remain inconclusive. A consensus as to what change in SSR to consider abnormal is yet to be reached. Though its ease of application supersedes a variety of other autonomic function tests, relying only on SSR changes for prognostication or therapeutic decisions appears impracticable. A battery of tests is thus a necessity.
---
paper_title: Influence of stimulus intensity on waveform of sympathetic skin response evoked by magnetic stimulation

paper_content:

Abstract Objective : The aim of this study was to investigate the influence of stimulus intensity on the waveform of sympathetic skin response (SSR). The origin of the SSR waveform was discussed. Methods : A total of 12 SSRs from palm skin were analyzed in 40 normal subjects. SSR was evoked by magnetic stimulation to the neck at 3 different intensities (10, 35, and 70% of the maximum output). The 3 stimuli were repeatedly applied in 4 separate sets. Waveforms were classified as either the P type, in which the positive component was larger than the negative one, or the N type, in which the negative component was larger than the positive one. Amplitude values of peak-to-peak, the first negative (N1), and subsequent positive (P1) components were compared among the 12 responses. Results : When the stimulation was increased, the SSR size became larger. The P type SSR was most frequently found in the maximum stimulation. Strong stimulation generally produced a large P1. Only the N type SSR exhibited a large N1 response to the maximum stimulation. There was a significant, negative correlation between N1 peak duration (difference between the SSR onset and N1 peak latencies) and P1 amplitude. Conclusions : These results suggested that strong responses probably produced a P type SSR with a large P1 component. In this condition, a rapid change of potential from negative to positive prevented any correlation between N1 amplitude and the magnitude of the response. In the N type SSR, however, a large N1 was associated with a strong response. These findings can be explained by a newly presented theory on the neurophysiological origin of the negative and positive components, based on a model of equivalent current dipole dependent on the Na + concentration gradient. Significance : The present study provided some suggestions on the neurophysiological mechanism of SSR waveform.
---
paper_title: Sudomotor skin responses to brain stimulation do not depend on nerve sensory fiber functionality

paper_content:

Abstract Evaluation of sudomotor innervation to the limbs was performed via electrical stimulation of the median nerve at the wrist and transcranial magnetic stimulation of the brain. Sympathetic skin responses (SSRs) from the palms and the soles were recorded in a patient suffering from a form of predominantly sensory neuropathy. Motor responses to nerve stimulation were present, even if with slower than normal conduction velocity. However, median, ulnar and sural nerve sensory potentials were absent. SSRs to median nerve stimulation at the wrist were missing on palms and soles. By contrast, during brain stimulation of the hand motor area with magnetic impulses, SSRs were reliably identifiable at all recording sites. It is hypothesized that SSRs to mixed nerve stimulation need normal functionality of afferent fibers, while those to brain stimulation can be elicited without any sensory information from the limbs.
---
paper_title: Sympathetic skin response in patients with Duchenne muscular dystrophy.

paper_content:

To verify an eventual disfunction of the palmar sympathetic skin activity in Duchenne Muscular Dystrophy, we studied the sympathetic skin response (SSR) with endogenous, Deep Breathing (DB-SSR), exogenous Startle (SE-SSR) and Electric type stimuli (EE-SSR) in a group of patients and a control group. At the same time as the SSR, the heart rate (HR) and the basic R-R interval variation (RRIV) as well as the EMG diaphragmatic activity were checked. In this way, significant differences in the latency (p = 0.02) and amplitude (p = 0.009) values of the EE-SSR and in the amplitude values of the SE-SSR (p = 0.001) and of the DB-SSR (p = 0.02) were noted in the DMD group compared to the control group. In the group of patients the rise in latency of the EE-SSR correlates with the age (p = 0.0001) and with the reduction of its amplitude (p = 0.03). This last parameter correlates with the stage of the illness (p = 0.02). In the control group the mean amplitude of the EE-SSR is approximately 30 % greater than that of startle and 50 % of deep breathing. Although with amplitudes homogeneously reduced, these ratios are also conserved in the DMD group. Moreover the HR is greater (p = 0.0001) whilst the RRIV is reduced (p = 0.02) in the group of the patients. However these parameters do not correlated either to the cardiac involvement or to the stage of the illness. The presence of the SSR for all the modalities of stimulation indicates the substantial integrity of the afferent and the efferent paths of the ANS. The alterations in latency and amplitude of the SSR in the patients could be the consequence of a lack of dystrophin at the level of the sudoriparous myopithelium in analogy to what has been demonstrated in the mdx mouse.
---
paper_title: Sympathetic skin response evoked by laser skin stimulation

paper_content:

The objective of this study was to evoke sympathetic skin responses (SSRs) in healthy subjects using laser stimulation and to compare these responses with those induced by conventional electrical stimuli. Twenty healthy subjects were investigated. SSRs were obtained using electrical and laser stimuli delivered to the wrist controlateral to the recording site. The sympathetic sudomotor conduction velocity (SSFCV) was measured in 8 subjects by simultaneously recording the SSR from the hand and the axilla. The latency (L) of the laser-induced SSR (ISSR) was significantly longer than that of the electrically-evoked SSR (eSSR) (mean ISSRL= 1.7+/-0.145 ms, mean eSSRL= 1.56+/-0.14 ms, p<0.05). The amplitude (A) of the ISSR was lower than the eSSR amplitude (mean ISSRA = 1.31+/-0.26 mV, mean eSSRA = 2.59+/-0.49 mV, p<0.05). No significant difference between the ISSR and eSSR was observed in either the SSFCV or the variability and reproducibility parameters. Our findings show that SSRs can easily be induced by laser stimuli and that this method shares the technical limitations of conventional eSSRs.
---
paper_title: Sympathetic skin response Basic mechanisms and clinical applications

paper_content:

Abstract Sympathetic skin response (SSR), defined as the momentary change of the electrical potential of the skin, may be spontaneous or reflexively evoked by a variety of internal or by externally applied arousal stimuli. Although the suprasegmental structures influencing the SSR in humans are not well known, SSR has been proposed as a non-invasive approach to investigate the function of the sympathetic system. SSR is easy to apply but current procedures are not sufficiently reliable for diagnostic purposes, and show imperfect correlations both with clinical features and other measurements of autonomic, in particular, sudomotor dysfunction.
---
paper_title: Local heat effect on sympathetic skin responses after pain of electrical stimulus

paper_content:

Abstract Objective: To investigate the analgesic effect of local superficial heating by studying sympathetic skin responses. Design: Randomized trial. Setting: Electromyography laboratory in the department of physical therapy and rehabilitation of a university hospital. Subjects: Twenty healthy volunteers participated with informed consent. Interventions: Sympathetic skin response (SSR) amplitudes following electrical stimulation of the right peroneal nerve and skin temperatures in both hands were recorded simultaneously. All of the recordings were repeated at 5-minute intervals during local heat application over the right palm and within 15 minutes after heat application was stopped. Results: SSR amplitudes in both hands decreased significantly during local heating ( p p p Conclusion: Therapeutic local heat application reduces the sudomotor response to a painful stimulus. This analgesic effect may be due to suppression of cortical pain sensation resulting from increased levels of endorphins, and may also be a result of local inhibition of both afferent and efferent C fibres.
---
paper_title: Sympathetic skin response: normal results in different experimental conditions

paper_content:

Abstract 1. (1) The sympathetic skin response (SSR) is a slow wave, generated in deep layers of the skin, resulting from reflex activation of the sudomotor sympathetic efferent fibres. The aim of this study was to define experimental conditions, best stimulation and recording procedures, and the criteria for validation of the responses. 2. (2) Thirty normal subjects (aged 25–56) were tested. The stimulation was an electrical pulse train applied to the median nerve at the wrist, a binaural tone burst, or both simultaneously. Records were made with surface electrodes on hand and foot contralateral to the stimulated median nerve. 3. (3) Response shape was most often biphasic in feet, biphasic or triphasic in hands. SSR amplitude was 3.1 ± 1.8 mV in hands, 1.4 ± 0.8 mV in feet. Normal mean onset latency was 1.5 ± 0.08 sec for hand response, 2.05 ± 0.10 sec for foot response. The mean conduction velovity along peripheral sympathetic nerve fibres was 1.40 ± 0.14 m/sec in lower limbs. 4. (4) Bimodal stimulation (burst + median) provided responses of larger amplitude. The influence of stimulation intensity was also investigated. A decrease in amplitude and lengthening of latencies were observed after 15–20 min of testing. 5. (5) The criteria for validation of responses are discussed. The importance of central processing time in the response delay is pointed out. In good methodological conditions, SSR would appear to be a simple, effective means of assessing sympathetic sudomotor outflow in central and peripheral nervous system disorders.
---
paper_title: Sympathetic skin response: a decade later

paper_content:

Sympathetic skin response (SSR) is a simple, reproducible test of function of a polysynaptic reflex having diverse afferents, a common efferent pathway through the spinal cord, pre and post-ganglionic sympathetic fibers and with sweat glands as effectors. The reflex is co-ordinated in the posterior hypothalamus or upper brainstem reticular formation. It has been used in a variety of disorders of peripheral and central nervous system. Methodology, possible anatomic substrates, changes in SSR in various diseases and their correlation with clinical features of dysautonomia, bed side tests for dysautonomia and other electrophysiological parameters are critically evaluated. Almost a decade after the start of its widespread clinical utilization, several aspects of SSR remain inconclusive. A consensus as to what change in SSR to consider abnormal is yet to be reached. Though its ease of application supersedes a variety of other autonomic function tests, relying only on SSR changes for prognostication or therapeutic decisions appears impracticable. A battery of tests is thus a necessity.
---
paper_title: Studies on the diphasic wave form of the galvanic skin reflex

paper_content:

Abstract The galvanic skin reflex at the palm and the dorsum of hand were investigated on 27 human subjects, changing room temperature and local skin temperature mainly in order to study the mechanismunderlying the appearance of the diphasic potential GSR curve. Experimental factors which might cause the wave form distortion of the potential GSR curve were carefully excluded in the performance of the experiments. Simultaneous recording from the palm and the dorsum of hand was applied so as to enable a comparison of the results with each other. 1. (1) With the rise of skin temperatures as a result of increasing room temperature or of local warming, the potential GSR curve at the dorsum of hand as well as the palm showed shorter latency. 2. (2) At the low room temperature of 15°C, the GSR failed to appear in high percentage (67.0 per cent) at the dorsum of hand, while monophasic GSR curve was observed most frequently (53.8 per cent) at the palm. 3. (3) With the rise of room temperature, it became easier to cause the GSR to appear at the dorsum of hand and the percentage of diphasic GSR curves with deeper positive deflection (type d ) continued to increase until the room temperature reached 40°C (from 0.8 to 95.2 per cent). The situation at the palm was different from this: the diphasic GSR curve with deeper positive deflection (type d ) increased in percentage until the room temperature of 30°C (from 24.5 to 52.8 per cent), above which it decreased markedly (8.2 per cent at 40°C); then monophasic wave form increased again. These phenomena at the palm might be attributable to the suppressed mental sweating on the palm at higher room temperature which was found by Kuno (1956). 4. (4) By means of local warming, it was possible to make shorter the latency of the GSR both at the palm and at the dorsum of hand and to elicit more frequently the diphasic potential GSR curve with deeper positive deflection. However, the change of the wave form from diphasic to monophasic of the palm as was observed at higher room temperature, was not caused by local warming even when the skin temperature of the warmed area was raised up to 40°C. This might suggest that the suppression of the GSR at the palm at higher room temperature is due to some central mechanism. 5. (5) The rationality was discussed of classifying the wave form of the potential GSR curve into four types according to the depth of its positive deflection in order to express the intensity of reflex activity.
---
paper_title: The influence of skin temperature on latency and amplitude of the sympathetic skin response in normal subjects

paper_content:

The influence of skin temperature on latency and amplitude of the sympathetic skin response (SSR) was studied in 10 normal subjects. SSRs were elicited in all four limbs of each subject by electrical stimulation after cooling of the right arm and after cooling of the right hand only. At low skin temperature, the latency was prolonged and the amplitude decreased. Latency and amplitude were linearly correlated with skin temperature of the right arm. There were no changes in the left arm and the legs, which basically excludes involvement of central pathways in these response parameters. With regard to the skin temperature of the arm, a temperature correction factor of 0.088 s/degrees C was calculated for latency. With regard to the skin temperature of the hand, latency prolongation was significantly greater after cooling of the whole arm. This suggests that not only the neuroglandular junction, but also the postganglionic sympathetic C fibers were responsible for latency modifications. In contrast, amplitude was reduced similarly after cooling of the whole arm and the hand only, suggesting that mainly the neuroglandular junction is responsible for amplitude modifications. We conclude that skin temperature is a mandatory measurement in the study of the SSR.
---
paper_title: Sympathetic skin response.

paper_content:

SummaryThe sympathetic skin response (SSR) is the potential generated by sweat in response to different stimuli. This potential has a waveform that habituates with closely repeated stimuli and a latency of 1.3–1.5 s at the hand and 1.9–2.1 s at the foot. It has been used to study the peripheral symp
---
paper_title: Sympathetic skin response in scleroderma.

paper_content:

Examination of the sympathetic skin response (SSR) was performed in 32 patients with systemic sclerosis, morphea and mixed connective tissue disease displaying scleroderma-like features. The control group consisted of 26 healthy subjects and 12 patients with other skin diseases and asymmetrical cutaneous changes. Right and left median and tibial nerves were stimulated successively and the responses were recorded from the palms and soles simultaneously. SSR abnormalities (delayed latency, decrease and/or asymmetry of amplitude, absent response) were observed in 68.8% of the patients, most frequently in linear scleroderma. An amplitude asymmetry of the responses from upper extremities was the most characteristic pattern of abnormalities. There was no correlation between the SSR and the localization, degree and character (inclurated oedema, atrophy, sclerosis) of skin changes, the duration of the disease, symptoms of the disorder of the autonomic nervous system symptoms (vasomotor and/or sudomotor) and the changes in capillaroscopy. All patients with slow motor conduction and sensor conduction velocities (MCV and SCV) had lower SSR amplitude and the patients with prolonged skin sensory chronaxy had more often delayed latency. The results revealed presence of disturbances of the autonomic nervous system in all varieties of scleroderma, both systemic and localized forms, even without any other signs of autonomic dysfunction.
---
paper_title: Sympathetic skin response--a method of assessing unmyelinated axon dysfunction in peripheral neuropathies.

paper_content:

The sympathetic skin response (SSR) was measured in 33 patients with peripheral neuropathies and in 30 normal control subjects. Abnormalities of the response were correlated with clinical, pathologic, and EMG observations. The response was usually absent in axonal neuropathies, but present in demyelinating disorders. Abnormalities of the sympathetic skin response did not correlate well with clinical evidence of dysautonomia, but were a reliable indicator of disorders affecting unmyelinated axons.
---
paper_title: The sympathetic skin response: Normal values, elucidation of afferent components and application limits

paper_content:

The sympathetic skin response (SSR), recorded at the hand and foot, was elicited using different classes of stimuli in 20 normal controls and 10 patients with peripheral neuropathy. We found that SSR latencies changed significantly with different recording sites, but not with different stimulation sites. Additionally, after ischemic conduction block of the arm in 3 normal controls, the previously obtainable SSR recorded at the hand became unobtainable with median nerve stimulation. Also, in one patient with subacute ganglionitis and 3 patients with demyelinating neuropathies, the SSR could not be elicited by electrical stimulation, but it could with deep inspiration. These results suggest that large diameter myelinated fibers may serve as afferents for the SSR. Furthermore, these findings imply that an unobtainable SSR by electrical stimulation may be due not only to dysfunction of the autonomic efferent nerve fibers, but also to abnormalities of the sensory afferents of the reflex. Therefore, investigations of autonomic dysfunction utilizing the SSR must be interpreted with caution in patients with peripheral neuropathies.
---
paper_title: Peripheral autonomic surface potential: A quantitative technique for recording sympathetic conduction in man

paper_content:

Using EMG equipment with time locked recording and standard averaging facilities we were able to record a previously poorly defined skin potential. The potential, termed by us the peripheral autonomic surface potential (PASP), was recorded from the palmar surface of the hand and the plantar surface of the foot in 30 normal subjects. The PASP usually consisted of a biphasic potential with an initial negative and a later positive peak. It was elicited by randomly timed electrical stimuli over the median nerve at the wrist. The mean palmar PASP latency was 1.52 +/- 0.13 s and the mean plantar PASP latency was 2.07 +/- 0.16 s. The mean palmar and plantar PASP amplitudes were 479 +/- 105 microV and 101 +/- 40 microV, respectively. A mean sympathetic conduction velocity was calculated to be 1.28 +/- 0.18 m/s. In 5 normal subjects a similar technique was used to record a PASP from the volar surface of the left middle finger. Iontophoresis of atropine into the skin under the recording site abolished the PASP in all subjects. Palmar and plantar PASPs were recorded in 10 diabetic patients. The amplitudes (palmar 179 +/- 158 microV, plantar 17 +/- 16 microV) were significantly reduced compared to normals (P less than 0.001). Five patients with unilateral lumbar or cervical sympathectomy were studied. The PASP was absent or markedly reduced on the side of the sympathectomy in all patients.
---
paper_title: Sympathetic skin response in Parkinsonian patients

paper_content:

Sympathetic skin response (SSR) was recorded in 23 patients with idiopathic Parkinson's disease (IPD) using mechanical as well as electrical stimuli. Significant delay of SSR latencies and decrease in amplitude of SSR compared to healthy volunteers were found (p < 0.05). Furthermore the clinical parameters of the autonomic impairment correlated well with the Webster score. Central mechanisms might be responsible for these findings and the role of central sympathetic pathway damage in parkinsonian patients is discussed.
---
paper_title: Sympathetic skin response in amyotrophic lateral sclerosis

paper_content:

OBJECTIVES ::: The aim of our study was to verify the usefulness of the sympathetic skin response (SSR) as an instrument for assessing autonomic involvement in amyotrophic lateral sclerosis (ALS). ::: ::: ::: MATERIAL AND METHODS ::: - We studied palmar and plantar SSR in 31 patients with ALS (mean age: 58.4+/-9.3 years); 48 age-matched healthy subjects constituted the control group. ::: ::: ::: RESULTS ::: Palmar SSR was elicitable in all patients, and its latency and amplitude did not significantly differ from that of the controls. Plantar response was evoked in all but 7 patients. The lack of response was significantly related to the functional disability and duration of the disease. ::: ::: ::: CONCLUSIONS ::: We conclude that SSR, even the plantar response, cannot be considered a useful tool for detecting early autonomic involvement in ALS.
---
paper_title: Electrodermal Activity (Eda) -- State-of-the-Art Measurement and Techniques for Parapsychological Purposes

paper_content:

HARALD WALACH [1] ABSTRACT: In most of the direct mental interactions with living systems (DMILS)/Remote Staring studies, electrodermal activity (EDA) is the only dependent variable. Therefore the quality of EDA recording is crucial. This is the reason why we studied EDA-related literature and contacted some of the leading psychophysiological labs in Germany to debate critical topics of the EDA measurement. We also checked the Methods section of all studies using FDA data published from 1995 to 1999 in the leading psychophysiological journals. In addition, we surveyed all DMILS/Remote Staring publications using EDA to find out whether parapsychologists adhere to these standards. In the first part of our paper we outline a current state-of-the-art FDA methodology. We also address various technical problems and describe sources for potential artifacts. In the second part we compare 24 DMILS/Remote Staring with a sample of 39 recent psychophysiological studies published in Psychophysiology and International Journal of Psychophysi ology. The analysis reveals that parapsychologists do not meet the current standards. There is not even one study conducted by parapsychologists which refers to psychophysiology's measurement standards published in 1981. Therefore, DMILS/Remote Staring data may either contain artifacts, or, on the other hand, may not detect the supposed effects. Although there is an ongoing trend of finding irregularities in FDA data of DMILS/Remote Staring experiments that can be related to different intentional conditions, there have not been any efforts to understand the results of EDA experiments or to address the origin of the irregularities in detail. INTRODUCTION Since the early 1970s psychophysiological variables have been given growing importance in parapsychological research. Electrodermal activity (EDA), with its high lability, freely varying activity (Braud & Schlitz, 1991) and ability to map the orienting response (OR) has shown to be a promising outcome measure in experimental studies such as direct mental interaction with living systems (DMILS) and Remote Staring or presentiment experiments. Therefore, some psychophysiologists are getting more and more interested in parapsychological research, and there is an advantageous exchange between those disciplines. But this exchange presupposes that the parapsychological community is willing to use EDA measurement, equipment and techniques that are state of the art from a psychophysiological point of view. The psychophysiological community developed its standards for EDA measurement in the 1970s and published them in the beginning of the 1980s (Fowles et al., 1981; Lykken & Venables, 1971; Venables & Christie, 1980). In the 1990s, the fast progress in computer processing brought about a change in signal scoring and recording changing from polygraph and ruler to digital data recording and electronic analysis. This development enabled new possibilities of parametrization but left the measurement principles untouched. In addition to using a technique that is also acceptable for researchers working in other disciplines than parapsychology, it is a required standard in every parapsychological publication to provide a detailed and clear description of the techniques and procedures which have been used. The reason for that is first to meet the scientific standard which in turn ensures a replication of that study with the information provided in the publication. Second, such description is necessary for future meta-analyses. Meta-analyses are becoming increasingly important because, in addition to the mean main effect size over a large body of studies, they provide detailed correlations between study characteristics and effect sizes (see e.g., Bem & Honorton, 1994; Honorton & Ferrari, 1989). For identifying study characteristics and applying quality ratings, detailed descriptions are necessary, even if they look very obvious. …
---
paper_title: Investigating Methodological Issues in Eda-Dmils: Results from a Pilot Study

paper_content:

HARALD WALACH [1] ABSTRACT: This article addresses methodological issues in current EDA-DMILS research. The authors conducted an exploratory DMILS pilot study with 26 sessions and found a medium size effect. No significant psi finding is claimed, as the experiment was not designed to find or investigate any; instead, the authors studied the variation of this effect as a function of different methodological approaches. They compared different EDA parameters (tonic or phasic) and found effects similar in size. Furthermore, they contrasted the traditional parapsychological way to parameterize data with methods adapted from psychophysiological research. These new parameters clearly outperformed the parameter used so far in DMILS/Remote Staring research. Respiration is correlated with the electrodermal system. The authors investigated whether EDA responses that are caused by sudden irregular patterns in breathing are also part of the remote intention effect. Therefore, they discarded all these responses from the data. The effect si ze dropped down to 30%-77% (depending on the parameter) of its original value. This indicates that the remote intention effect is very likely to also affect the pulmonary system. Finally, they compared different statistical methods for the evaluation of EDA-DMILS data and show the traditional percentage influence score method is neither appropriate nor suitable. The authors present alternative methods, and compare their power using the pilot study data. Direct mental interaction between living systems (DMILS) is a standard experimental procedure for the investigation of the possibility that one system or person intentionally influences another system's or person's physiology from a distance. The majority of the DMILS studies include electrodermal activity (EDA) as the dependent variable; they are referred to as EDA-DMILS experiments. At least 30 EDA-DMILS experiments were conducted through 1997 (see Schlitz & Braud, 1997, for an overview). This figure also includes experiments on Remote Staring, a similar experimental paradigm that investigates whether a person's physiology can "detect" a distant gaze. Schlitz and Braud's (1997) overview of the results of all EDA--DMILS studies and all Remote Staring studies shows that 14 out of 30 experiments have yielded significant results. The studies show nonhomogeneous effect sizes, with a mean of .25 (Rosenthal's r) for both research paradigms. Because EDA is the only dependent variable in most of the studies described by Schlitz & Braud (1997), the recording, processing, parameterization, and evaluation of the EDA data is the crucial point in interpreting them. Therefore, Schmidt and Walach (2000) evaluated the EDA methodology of all published EDA-DMILS and Remote Staring studies and compared them with a sample of studies published in leading psychophysiological journals. The results of this evaluation indicated that the EDA methodology applied by parapsychologists did not compare to state-of-the-art EDA measurement recommended by psychophysiologists (Boucsein, 1992; Venables & Christie, 1980). None of the studies complied with the "Publication Recommendations for Electrodermal Measurements" issued by leading psychophysiologists in 1981 (Fowles et al., 1981), and most of them even violated common psychophysiological knowledge. Therefore, we rearranged our EDA methodology in the DMILS facility in Freiburg, Germany, in collaboration with the Department of Psychological Physiology of the University of Wuppertal, Germany. When we modified procedures according to psychophysiological standards, new questions about the DMILS paradigm arose, namely, the following. 1. Which component should be investigated within the DMILS paradigm considering EDA itself is not a unitary phenomenon and consists of two components? For one of the components (the fast-changing phasic component) there are also different parameterization possibilities. …
---
paper_title: Are electrophysiological autonomic tests useful in the assessment of dysautonomia in Parkinson's disease?

paper_content:

To assess the autonomic system in Parkinson's disease (PD), the sympathetic skin response (SSR) and the R–R interval variation (RRIV) tests were studied in 26 PD patients and in 24 healthy controls. The aim of the study was to evaluate the sympathetic and parasympathetic system function in PD, to define the pattern of autonomic abnormalities found in SSR and RRIV in parkinsonian patients as well as to analyze the usefulness of both tests in paraclinical assessment of the dysautonomia, compared with clinical symptoms and signs of the autonomic nervous system involvement. The corrrelations between both autonomic tests results were also studied. In PD patients SSR test was abnormal in about 35% and RRIV was abnormal in about 54% of patients. SSR and RRIV were both abnormal in about 27% of PD patients whereas at least one of electrophysiological autonomic tests was abnormal in about 62% of PD patients. Clinical and paraclinical signs of dysautonomia occured in a similar proportion of patients (i.e. in about 62%). A weak correlation was found between the latency of SSR from upper limbs and the value of RRIV during deep breathing (p=0.063). Our results show that SSR and RRIV are non-invasive paraclinical electrophysiological tests that confirm clinical dysautonomia in PD and can supplement the clinical differentiation of Parkinsonian syndromes.
---

Title: A Survey of SSR Mechanism and Application

Section 1: INTRODUCTION
Description 1: This section introduces the role of technology in medical advancements and the significance of measuring the human body's response for disease diagnosis.

Section 2: SYMPATHETIC SKIN RESPONSE
Description 2: This section provides an overview of the Sympathetic Skin Response (SSR), including its historical discovery, various names, and its medical relevance.

Section 3: THE STRUCTURE OF SYMPATHETIC SKIN RESPONSE
Description 3: This section elaborates on the structure of SSR, particularly focusing on latency, amplitude, and the different waveform types observed.

Section 4: MEASUREMENT TECHNIQUES OF SYMPATHETIC SKIN RESPONSE
Description 4: This section describes the methods and techniques involved in recording SSR, including electrode placement, types of stimulation, and recording conditions.

Section 5: FACTORS AFFECTING SYMPATHETIC SKIN RESPONSE
Description 5: This section discusses various factors that may influence SSR measurements, such as adaptation, gender, age, weight, stimulation methods, and body temperature.

Section 6: EVALUATION PARAMETERS OF THE SYMPATHETIC SKIN RESPONSE
Description 6: This section details the parameters used to evaluate SSR, noting different approaches to qualitative and quantitative assessments.

Section 7: CLINICAL APPLICATIONS OF SYMPATHETIC SKIN RESPONSE
Description 7: This section explores the clinical applications of SSR in diagnosing autonomic nervous system diseases and other medical conditions.

Section 8: RESULTS
Description 8: This section summarizes the recent advancements and future potential of using SSR for diagnosing autonomic nervous system diseases.

Section 9: CONCLUSION
Description 9: This section concludes by emphasizing the importance and benefits of SSR in medical diagnostics, and its potential for future studies and advancements.