10.14639/0392-100X-N0502
To evaluate the effective incidence of vascular factor in the recurrence of benign paroxysmal positional vertigo (BPPV), we studied 50 subjects, 32 affected by idiopathic recurrent BPPV (study group) and 18 healthy subjects (control group). All subjects underwent complete otoneurological balance and haemodynamic evaluation by extracranial colour-coded duplex sonography (ECCS) of vertebral arteries (VA) with indication of arterial flow in ml/min, and retinal fluorangiography (FAG). The ECCS of 19 patients (59.3%) within the study group presented a reduction in vertebral arterial flow, exceeding the limits established by normative values (&lt; 100 ml/min). In all cases, the same side was affected by BPPV, emphasised by vertebral hypoperfusion. The remaining 13 patients (40.6%) showed an arterial vertebral flow entirely within the normative values. The FAG excluded qualitative alterations of the cerebral microcirculation. The ECCS demonstrated that 59.3% of the study group showed a significant reduction in vertebral arterial flow ipsilateral to the semicircular canal affected by BPPV. This increased to 68.75% when the flow difference (D) between both the vertebral arteries were considered and reached 71.8% when vascular risk factors were evaluated. We conclude that reduced perfusion of the vestibular structures makes an already critical situation even more difficult, which can eventually develop into labyrinth suffering. The absence of fluorangiographic signs suggests that the labyrinthine neuroepithelium is much more sensitive to hypoperfusion than the retina. We hypothesise that this ischaemic situation could degenerate utricular macula, otolith detachment, leading to the development of recurrent BPPV. This risk situation for the labyrinth can also be revealed by the evaluation of three parameters: presence of vascular risk factors, reduction of vertebral flow &lt; 100 ml/min and the difference in flow between the 2 vertebral arteries &gt; 29 ml/min.
application/xml
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502
en
Laith Khasawneh
https://creativecommons.org/licenses/by-nc-nd/4.0
ACTA Otorhinolaryngologica Italica
retinal fluorangiography
Recurring paroxysmal positional vertigo: evaluation of the vascular factor
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Vestibology
2021-03-19
2019-10-14
2021-03-19
2021-03-24
77-83
1
Laith Khasawneh
2021/03/19
10.14639/0392-100X-N0502
77
Department of General and Special Surgery, Hashemite University of Jordan, Zarqa, Jordan
1827-675X
retinal fluorangiography
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Recurring paroxysmal positional vertigo: evaluation of the vascular factor
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ACTA OTORHINOLARYNGOLOGICA ITALICA 2021;41:77-83; doi: 10.14639/0392-100X-N0502




Vestibology


Recurring paroxysmal positional vertigo: evaluation
of the vascular factor
La valutazione del fattore vascolare nella vertigine parossistica ricorrente
Giampiero Neri1, Giulio Romano Filograna Pignatelli1, Alessandro Pacella1, Rocco Ortore2, Laith Khasawneh3
1
  Department of Neurosciences Imaging and Clinical Sciences, University Gabriele D’Annunzio of Chieti-Pescara, Italy
2
  Department of Otolaryngology (ENT), IRCCS Hospital Home for the Relief of Suffering, San Giovanni Rotondo, Italy
3
  Department of General and Special Surgery, Hashemite University of Jordan, Zarqa, Jordan


SUMMARY
To evaluate the effective incidence of vascular factor in the recurrence of benign paroxys-
mal positional vertigo (BPPV), we studied 50 subjects, 32 affected by idiopathic recurrent
BPPV (study group) and 18 healthy subjects (control group). All subjects underwent com-
plete otoneurological balance and haemodynamic evaluation by extracranial colour-coded
duplex sonography (ECCS) of vertebral arteries (VA) with indication of arterial flow in
ml/min, and retinal fluorangiography (FAG). The ECCS of 19 patients (59.3%) within the
study group presented a reduction in vertebral arterial flow, exceeding the limits established
by normative values (< 100 ml/min). In all cases, the same side was affected by BPPV, em-
phasised by vertebral hypoperfusion. The remaining 13 patients (40.6%) showed an arterial
vertebral flow entirely within the normative values. The FAG excluded qualitative altera-
tions of the cerebral microcirculation. The ECCS demonstrated that 59.3% of the study
group showed a significant reduction in vertebral arterial flow ipsilateral to the semicircular    Received: October 11, 2019
canal affected by BPPV. This increased to 68.75% when the flow difference (D) between              Accepted: April 13, 2020
both the vertebral arteries were considered and reached 71.8% when vascular risk factors
were evaluated. We conclude that reduced perfusion of the vestibular structures makes an           Correspondence
already critical situation even more difficult, which can eventually develop into labyrinth        Giampiero Neri
suffering. The absence of fluorangiographic signs suggests that the labyrinthine neuroepi-         Department of Neurosciences Imaging and Clinical
thelium is much more sensitive to hypoperfusion than the retina. We hypothesise that this          Sciences, University Gabriele D’Annunzio of
ischaemic situation could degenerate utricular macula, otolith detachment, leading to the          Chieti-Pescara, Italy, 136-65125
development of recurrent BPPV. This risk situation for the labyrinth can also be revealed by       Fax +39 0871 358550
                                                                                                   E-mail: giampiero.neri@unich.it
the evaluation of three parameters: presence of vascular risk factors, reduction of vertebral
flow < 100 ml/min and the difference in flow between the 2 vertebral arteries > 29 ml/min.
                                                                                                   Funding
KEY WORDS: BPPV, cerebral blood flow, EcoColorCodedSonography, ECCS, vertebral                     None.
flow, vascular vertigo, retinal fluorangiography
                                                                                                   Conflict of interest
                                                                                                   The Authors declare no conflict of interest.
RIASSUNTO
La vascolarizzazione dell’orecchio interno è termino-terminale, questo espone il labirinto
a danni da ipossia o ipossia-rivascolarizzazione. Riduzioni ulteriori di flusso ematico po-          How to cite this article: Neri G, Filograna Pign-
                                                                                                     atelli GR, Pacella A, et al. Recurring paroxysmal
trebbero essere alla base non solo della insorgenza, ma anche della maggiore frequenza
                                                                                                     positional vertigo: evaluation of the vascular fac-
di recidive della vertigine parossistica. Allo scopo di valutare l’incidenza di questi fattori       tor. Acta Otorhinolaryngol Ital 2021;41:77-83.
abbiamo studiato 50 pazienti, 32 con VPPB ricorrenti e 18 soggetti sani. Tutti i soggetti            https://doi.org/10.14639/0392-100X-N0502
sono stati sottoposti a esame otoneurologico completo, a valutazione emodinamica con
ecocolordoppler (ECD) delle arterie vertebrali con indicazione del flusso in ml/min e a            © Società Italiana di Otorinolaringoiatria
fluorangiografia retinica (FAG). Nel gruppo di studio 19 pazienti (59,3%) all’ECD hanno            e Chirurgia Cervico-Facciale
presentato una riduzione del flusso vertebrale rispetto ai valori di normalità (< 100 ml/
min). In tutti i casi il lato con maggiore ipoafflusso era lo stesso affetto da VPPB. I restanti                  OPEN ACCESS
13 pazienti (40,6%) avevano valori ECD nella norma. La FAG non ha evidenziato alte-                This is an open access article distributed in accordance with
razioni vascolari del microcircolo. L’esame ultrasonografico ha dimostrato quindi che il           the CC-BY-NC-ND (Creative Commons Attribution-Non-
59% dei soggetti con VPPB ricorrenti ha una riduzione significativa nel flusso vertebrale          Commercial-NoDerivatives 4.0 International) license. The
                                                                                                   article can be used by giving appropriate credit and mentio-
omolaterale al lato affetto e che questo valore aumenta al 68,75% se la differenza del flusso
                                                                                                   ning the license, but only for non-commercial purposes and
tra le due arterie vertebrali è maggiore del valore soglia riscontrato nei soggetti normali        only in the original version. For further information: https://
e al 71,8%, se viene considerata anche la presenza di fattori di rischio. In conclusione, lo       creativecommons.org/licenses/by-nc-nd/4.0/deed.en




                                                                                                                                                             77
G. Neri et al.




studio evidenzia che il labirinto è molto più sensibile della retina all’insulto ischemico. Infatti, anche in assenza di segni retinici di alterazione
del microcircolo, una ridotta perfusione labirintica, precipitando la già precaria irrorazione del labirinto, può determinare la degenerazione
della macula utricolare portando al distacco otoconiale e al conseguente sviluppo della VPPB ricorrente. Questa situazione di rischio per il
labirinto inoltre può essere svelata dalla valutazione di tre parametri: la presenza di fattori di rischio vascolare, la riduzione del flusso verte-
brale < 100 ml/min. e la differenza di flusso tra le 2 arterie vertebrali > 29 ml/min.
KEY WORDS: VPPB, flusso ematico cerebrale, ecocolordoppler, flusso vertebrale, vertigine vascolare



Introduction                                                                 is not only proportional to the vertebral blood flow, but can
                                                                             also depend on the side in which the flow is reduced.
Benign paroxysmal positional vertigo (BPPV) is the most                      It is well known that common variations of size and flow
frequent cause of vertigo 1. The number of relapses is vari-                 capacity between the two vertebral arteries exist, which
able, but it has been observed that 27% of patients suffer                   may range from a slight asymmetry to marked hypoplasia
from at least one new episode and of these 14% have one                      of one side, with prevalence of unilateral vertebral artery
episode, 10% two relapses and about 3% of patients have 3                    hypoplasia between 2 to 25% 14. This has also been ob-
episodes per year 2. In 50% of cases, relapses occur within                  served in patients with vertebrobasilar insufficiency 15 and
the first 6 months from the onset of the disease. The strong                 Seidel 16 and Jeng 17 reported that the vertebral artery flow is
social impact of BPPV has encouraged continuous clinical                     considered pathological when it is lower than 100 ml/min.
research that has revealed many aspects of this pathological                 The aim of our study is to evaluate the incidence of the vas-
condition. However, the reasons for the frequent recurrence                  cular factor in recurring BPPV with quantitative analysis of
of idiopathic BPPV, without apparent cause, are yet to be                    vertebral flow using ECCSVA and the analysis of cerebral
clarified 3.                                                                 microcirculation using retinal fluorangiography (FAG) 18.
A new vertigo episode after a pause almost two months
must be interpreted as a new event, where an unknown “fa-
cilitating factor” has a relevant role 4.                                    Materials and methods
At present, there are no diagnostic exams that allow us to                   Fifty consecutive samples were recruited from January
observe this “facilitating factor”, but when the recurrence                  2016 to December 2017 in our Audiovestibology Unit of
is verified, we are normally oriented towards a hypothetical                 the ENT Department in the University Hospital SS An-
vascular cause 5.                                                            nunziata in Chieti. Of these, 32 patients were affected by
According to Baloh 6, vertigo is often caused by verte-                      recurring idiopathic BPPV with a frequency of recurrence
brobasilar insufficiency, and is present in many diseases                    not less than 3 episodes/year, and the remaining 18 subjects
caused by vascular damage, such as cerebellar infarct, lat-                  were enlisted as the control group.
eral medullary infarct, and labyrinth and pons-medullar                      The exclusion criteria were a recurrence frequency of < 3
tract infarct. In two cases, hearing loss was associated with                episodes/year; labyrinthine disease different from BPPV,
vertigo and caused by either vessel occlusion or simple re-                  age 70 years and over; a history of trauma or cervico-facial
duction of vascular flux 7,8.                                                district contusion; and degenerative neurological patholo-
The vascularisation of the inner ear depends on the internal                 gies.
auditory artery, a branch of the basilar artery or anterior in-              All patients were informed about the study in detail, which
ferior cerebellar artery, which is a terminal vessel and make                adhered to the Declaration of Helsinki and ICH-GCP, GU
the labyrinth sensitive to ischaemic phenomena 9.                            184/2003. Written informed consent was obtained from all
The experimental study on blood flow distribution in the                     patients.
Circle of Willis 10,11 showed that reductions in cerebral cap-               All subjects underwent physical ENT examination, pure
illary arterial flow in the posterior circulation are directly               tone audiometry, vestibular spontaneous and positional
proportional to reductions in the vertebral arteries flow.                   testing using videonystagmoscopy and bithermal caloric
Extracranial colour-coded duplex sonography of vertebral                     evaluation according to Fitzgerald-Hallpike.
arteries (ECCSVA) can be a useful and low-cost screening                     The haemodynamic quantitative analysis of vertebral artery
tool for the evaluation of posterior cerebral circulation 12.                flow, expressed in ml/min, was obtained by the same opera-
It has been demonstrated, furthermore, that the blood that                   tor using ECCS Mindray DC-70 through the acoustic win-
comes from the two vertebral arteries, after having en-                      dows from the transverse processes of the vertebrae in one
gaged in the basilar artery, flows separately and is divided                 segment (or more) of the V2 section. The Doppler wave-
from a central zone where the flux is absent, defined “dead                  forms and flux were obtained with an angle of insonation of
point” 13. This indicates that the perfusion of the labyrinth                60° or less. On the basis of the literature 17, we considered



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                                                                                                                        Recurring vascular vertigo




that a vertebral artery flow of < 100 ml/min was valid indi-                   (37.5%) presented a documented pathological vascular risk
cator of vertebral artery hypoperfusion.                                       (Tab. I) while in 20 cases (62.5%), BPPV was idiopathic.
Evaluation of cerebral microcirculation was investigated                       The most common vascular risk factors were hypertension
using retinal fluorescein angiography (FAG).                                   (28%), diabetes (18.7%) and hyperlipidaemia (15.6%).
Finally, we evaluated in each person of both groups the flow                   Types of BPPV were found to be distributed as right poste-
difference between the vertebral arteries (D) considering as                   rior in 11 (34%), right lateral in 6 (18.7%), left posterior in
normal the highest difference found in the control group                       10 (31%) and left lateral canal in 5 (15%).
(29 ml/min) (Tab. I). Statistical analysis was performed us-                   In the study group, on bithermal caloric testing 14 patients
ing independent-samples t-test for P ≤ 0.05 to determine if                    (43%) were found to have labyrinthine hypofunction of the
a difference exists between two means of two independent                       affected side.
groups on continuous dependent variables.                                      Ultrasonography in the control group showed normal
                                                                               vertebral flow in all subjects with values between 104
Results                                                                        and 218 ml/min (average 149.6) in the right side, 109
                                                                               and 195 ml/min (150.3) in the left side end with a D be-
Fifty subjects, 36 females (72%) and 14 males (28%), were                      tween 2 and 29 ml/min. The ECCSVA in the study group
included in this study; 32 patients (study group) had recur-                   presented in 19 patients (59.3%) a reduction in arterial
ring BPPV and 18 subjects (control group) had no vertigo
                                                                               vertebral flow, exceeding the normal range (< 100 ml/
or vascular pathologies. Audiometry results showed age-
                                                                               min) between 26 and 96 ml/min, 13 patients (40.6%)
related disorders in all 50 subjects.
                                                                               demonstrated hypoperfusion on only one side, and 6 pa-
The study population was composed of 22 females (69%)
                                                                               tients (18.75%) presented a reduction on both sides. In all
and 10 males (31%) with age ranged between 24 and 70
                                                                               pathological cases (64%), BPPV was present on the side
years (average age 52 years). In this sample, 12 patients
                                                                               where the blood flow was most decreased. The remain-
                                                                               ing 13 patients (40.6%) had a normal VA flow (> 100 ml/
Table I. Vertebral flow in ml/min in the control group. We hypothesised that   min) (Tabs. II, III).
the highest difference in flow between the two arteries (D = 29 ml/min) was    In the 12 patients (37.5%) with vascular risk, we detected
the normal limit.
                                                                               hypoperfusion in 9 subjects (75%): unilateral in 4 subjects
 Patient        Age          Right Vert. A.      Left Vert. A.       D         and bilateral in 5.
                               (ml/min)           (ml/min)
                                                                               The hypoperfusion in the 20 patients (62.5%) with idio-
 C.G.          56              143                 132             11
                                                                               pathic BPPV was unilateral in 8 (25%) and bilateral in 2
 C.V.          24              108                 125             -17
                                                                               subjects.
 D.A.          47              165                 176             -11
                                                                               In the study group, the D between the two VAs observed
 D.R.M.        34              104                 115             -11         in each patient was superior to the normality range in 21
 D.F.T         43              115                 110              5          cases (65.6%): 9 patients (28.1%) with vascular risk and 12
 P.T.          62              160                 188             -28         patients (37.5%) with idiopathic BPPV.
 D.R.          49              172                 170              2          FAG exam in all patients excluded qualitative and dynamic
 G.A.          63              151                 129             22          alterations of the retinal situation that could explain the
 G.L.          26              104                 109              -5         eventual damage at the microcirculatory level.
 L.E.          65              168                 157             11          The results of the control group are shown in Table I.
 G.S.          68              166                 160              6
 P.R.          45              149                 165             -16         Discussion
 R.M.          50              115                 131             -16
 S.F.          61              157                 186             -29
                                                                               BPPV is a recurring pathological condition. While a clear
 S.L.          46              170                 154             16
                                                                               clinical diagnosis is available in 86% of cases 19, the fre-
                                                                               quency of relapses depends on unknown causes. Since
 M.O.          67              165                 158              7
                                                                               instrumental exams and imaging are often not capable of
 T.A.          60              163                 145             18
                                                                               demonstrating evident alterations, it is possible that the fre-
 V.M.          52              218                 195             23
                                                                               quency of relapses may have a facilitating factor that re-
              Mean            Mean                Mean              D
                                                                               mains unknown.
               51             149.6               150.3            23
                                                                               When it is not possible to identify a definite cause of BPPV,
                        Standard Deviation                                     a vascular cause is suspected. The main cause of vascular
                              28.2                                             aetiology is vertebrobasilar ischaemia, generated by pa-



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G. Neri et al.




Table II. Vertebral flow in ml/min in BPPV group with vascular risk.
 Patient                  Age              Risk factors                               Right VA                       Left VA                     BPPV                  D
                                                                                      (ml/min)                      (ml/min)
 F.P.                        50                 Hypertension                             140                           164                      R PSC                  24
 D.P.M.                      68                   Diabetes                                81                            45                      L LSC                  36
 D.L.G.                      64          Hypertension dyslipidaemia                       63                           198                      R PSC                  135
 C.F.                        65          Hypertension dyslipideamia                       86                            24                      L PSC                   62
 C.S.                        57            Hypertension diabetes                          49                           137                      R LSC                   88
 S.Z.                        50            Hypertension diabetes                          96                            25                      L PSC                   70
 L.D.C.                      63          Hypertension dyslipidaemia                       59                           182                      R PSC                  123
 M.V.                        58          Hypertension dyslipidaemia                       76                            44                      L LSC                   32
 F.C.                        68                   Diabetes                                52                           140                      R LSC                   88
 G.S.                        66            Hypertension diabetes                         145                           155                      R PSC                   10
 PP                          62                   Diabetes                                77                            56                      L PSC                   21
 M.C.                        51          Hypertension dyslipidaemia                      130                           160                      L PSC                   30
R PSC: Right Posterior Semicircular Canal; R LSC: Right Lateral Semicircular Canal; L LSC: Left Lateral Semicircular Canal; L PSC: Left Posterior Semicircular Canal



Table III. Vertebral flow in ml/min in BPPV group without vascular risk.                     most important vascular pathologies (myocardial infarc-
 Patient       Age       Right VA        Left VA      BPPV            D                      tion, heart failure, ictus). The reduction in vertebral arterial
                         (ml/min)       (ml/min)                                             flow, moreover, might not be significant for organs like the
 C.F.             56           64              119           R PSC            -55            brain or cerebellum, which are endowed with a remark-
 D.L.             45          160              189           R PSC            -29            able compensatory capacity 22, but can have a significant
 D.A.             45           89              154           R LSC            -65            role in compromising the perfusion of organs supplied by a
 D.AR.            51          195              129           L PSC             66            terminal-type circulation 23. For example, it might affect the
 M.F.             70          128               66           L PSC             62            utricular macula or semicircular canals, and this ischaemia
 T.M.             64          164              179           L PSC            -15            of their neuroepithelium can facilitate its degeneration with
 T.R.             52          128              129           R LSC             -1            consequent detachment of otoliths 24.
 T.A.             70           66               33           L LSC             33            In this study, we tried to understand whether the use of tests
 L.M.             58          140              149           L LSC             -9
                                                                                             that specifically explore the vascular district, namely retinal
                                                                                             FAG for microcirculation and ECCS for the vertebral ar-
 V.L.             53          188              160           R PSC             28
                                                                                             tery, may be useful for diagnosis in patients with recurring
 C.R.             57           72              128           R PSC            -56
                                                                                             BPPV. A normal vertebral flow upper to 100 ml/min was
 F.G.             58           34              135           R PSC           -101
                                                                                             considered. This is in agreement with Jang 17 who reported
 DA.P.            49          170              113           L PSC             57
                                                                                             a normal limit of vertebral hypoperfusion < 100 ml/min.
 M.M              51          198              228           R PSC            -30            The results showed that the retinal FAG is inadequate for
 D.P.E.           35          133              143           R PSC            -10            indirect evaluation of vestibular microcirculation because
 C.S.             57           49              136           R LSC            -87            patients, even those with verified reduction in vertebral ar-
 D’A.P.           36           93               82           L PSC             11            terial flow, did not present alterations in retinal microcir-
 C.P              56          141              148           L LSC             -7            culation. This result is possibly due to differences between
 M.M.             47          75               110           L PSC            -35            the diameters of the central retinal artery (0.16 mm) 25 and
 C.C.             55          87               140           R LSC            -53            internal auditory artery (0.05 mm) 26 which makes the laby-
R PSC: Right Posterior Semicircular Canal; R LSC: Right Lateral Semicircular Canal;          rinth more susceptible to ischaemia than the eye.
L LSC: Left Lateral Semicircular Canal; L PSC: Left Posterior Semicircular Canal
                                                                                             Using ECCS, we found that 59.3% of subjects in the
                                                                                             study group presented a significant reduction in VA flow
thologies such as atherosclerosis, congenital or acquired                                    (< 100 ml/min) compared to the control group. Our data
arterial malformation, cervical arthrosis and peripheral mi-                                 is in agreement with the study by Seidel et al. 16,17. In these
croangiopathy 4,20.                                                                          subjects, the pathology of the semicircular canal was found
It has been hypothesised that otolith detachment in idi-                                     to be ipsilateral to the vertebral artery with haemodynamic
opathic BPPV could be secondary to microvascular prob-                                       insufficiency. In 6 cases, where both vertebral arteries had a
lems 20,21, without necessarily being accompanied by the                                     reduced flow with compared to the mean, the pathology of



80
                                                                                                                               Recurring vascular vertigo




the semicircular canal was ipsilateral to the side most hypo                          Notably, the results of the two parameters (D and flow in ml/
perfused (Tabs. II, III).                                                             min) are comparable and documented independently from
The predominance of the VA compared to the one on the                                 each other, along with the validity of the methodology and
contralateral side is physiologically normal. Hence, our                              their extreme correlation with the onset of recurring BPPV.
study, using statistical analysis on the control group, high-                         The study of blood flow distribution on experimental mod-
lighted that such a prevalence does not exceed the limits of                          els of the Circle of Willis, constructed by David in 2002 10
normality (Tab. III).                                                                 showed that blood confluence from the vertebral arteries
Our study demonstrated that the reduction of the VA flow,                             into the basilar artery is almost diverted into the larger ar-
unilateral to the injured side, was present in 59.3% of pa-                           tery like the posterior cerebral artery. It was also demon-
tients with recurring BPPV. In particular, it was observed                            strated that only a moderate quantity of blood is distributed
in 10 patients with idiopathic recurring BPPV (31.2%) and                             in smaller vessels, like the posterior cerebellar artery, and
9 patients (28.1%) with recurring BPPV and documented                                 above all, the internal auditory artery. In other words, the
vascular risk.                                                                        labyrinth is physiologically less supplied.
These results confirm the absolute dependence of the                                  In this situation, further reduction in perfusion can pre-
vestibular system of one side to the ipsilateral VA flow,                             cipitate an already critical condition that can translate into
as demonstrated by studies of circulatory physiology of                               labyrinthine suffering.
the Circle of Willis by Mc Donald and Potter (1951) and                               However, ischaemia cannot be compensated by the flow of
Carney (1981) 13. These studies demonstrated that, inside                             the opposite vertebral artery because, as previously men-
the basilar artery (BA), the blood flow merger by the two                             tioned, the flow of the two vertebral arteries remains sepa-
vertebral arteries remains distinct and separated by a zone                           rated inside the basilar artery. This can be translated into
defined as the “dead point,” where the value of vertebral                             degeneration of the utricular macula with repeated detach-
flow is zero. Consequently, the pressure of the flow in the                           ment of otolith material and consequent BPPV 27. There-
vertebral vessels, measured by ECCS in ml/min (Fig. 1),                               fore, we can legitimately hypothesise that the influence of
was found to be directly proportional to the flow of the ip-                          general factors, like the vascular factors during persistent
silateral internal auditory artery.                                                   ischaemic states in the vertebrobasilar area lead to second-
Another parameter considered is D which represents the                                ary distress of neuroepithelial structures of the macula,
highest difference in flow values registered between the                              which can be followed by detachments of the otoconial
two vertebral arteries (Tabs. II, III). In the healthy sub-                           membrane 28. This could also be the cause of the subclinical
jects of our case series (Tab. I), this value is 29 ml/min.                           labyrinthine hypofunction revealed by the bithermal caloric
In the study group, this parameter was greater than 29 ml/                            tests in 40% of our sample.
min in 21 patients (65.6%), and most precisely 12 of them                             Deterioration of the circulation in the vertebral artery, which
(37.5%) among those without vascular risk and 9 (28.1%)                               is already hypofunctional, can result in the alteration of the
with reported vascular risk.                                                          endothelial wall, which might even be insignificant and not




Figure 1. ECCS of the vascular vertebral left (A) and right (B) arteries fFlow value in ml/min is circled in red).



                                                                                                                                                     81
G. Neri et al.




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patients during autopsy, while in 60-70% of subjects who                7
                                                                             Doyle KJ, Fowler C, Starr A. Audiologic findings in unilateral
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during the three days immediately preceding the stroke, or              8
                                                                             Yamasoba T, Kikuchi S, O’Uchi T, et al. Magnetic reso-
during the last six weeks. These observations suggest that                   nance angiographic patients with slow vertebrobasilar blood
when diagnosing BPPV it is very useful to utilise other di-                  flow. Acta Otolaryngol 1995(Suppl);115:153-6. https://doi.
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agnostic, and not vestibological, tools, such as ECCS of the            9
                                                                             Seo T, Tominaga S, Sagakami M. Relationship between neurologi-
VA, which gives information directly on labyrinthic vascular                 cal asymptomatic vertigo and vertebrobasilar system as revealed by
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new risk factor for recurrent BPPV and vascular risk.                        https://doi.org/10.1159/000027719
In conclusion, from our results, we confirm that ultrasound             10
                                                                             David T, Ferrandez A, Brown M. Computational model of blood flow
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examination of the vertebral arteries represents a method of                 2000;4:1-26. https://doi.org/10.1080/10255840008907996
choice in the diagnosis of recurring vascular vertigo, pro-             11
                                                                             Šutalo ID, Bui AV, Ahmed S, et al. Modeling of flow through the Cir-
vided that the vertebral artery flow is specifically measured                cle of Willis and cerebral vasculature to assess the effects of changes
in ml/min and not in cm/sec as normally occurs in ultra-                     in the peripheral small cerebral vasculature on the inflows. Engineer-
                                                                             ing Applications of Computational Fluid Mechanics 2014;8:4, 60922.
sound laboratories. This value, in fact, does not indicate the
                                                                             https://doi.org/10.1080/19942060.2014.11083311
flow rate of blood, but rather the speed relative to the calib-         12
                                                                             Nazerian P, Bigiarini S, Pecci R, et al. Duplex sonography of verte-
er of the artery, an observation therefore only indirect and                 bral arteries for evaluation of patients with acute vertigo. Ultrasound
in our opinion not very significant. The absence of fluoran-                 Med Biol 2017;44:584-92. https://doi.org/10.1016/j.ultrasmed-
giographic signs suggests that the labyrinthine neuroepi-                    bio.2017.11.002
thelium is much more sensitive to hypoperfusion than the
                                                                        13
                                                                             Carney AL. Vertebral artery surgery: historical development, basic
                                                                             concepts of brain hemodynamic, and clinical experience of 102 cases.
retina. For this reason, the labyrinth could be considered to                Adv Neurol 1981;30:249-82.
be a more reliable sentinel than the retina to intercept mi-            14
                                                                             Park JH, Kim JM, Roh JK. Hypoplastic vertebral artery: frequency
crocirculatory vascular disorders even earlier. BPPV, espe-                  and associations with ischemic stroke territory. J Neurol Neurosurg
cially if recurrent, should always be evaluated with ECCS                    Psychiatry 2007;78:954-8. https://doi.org/10.1136/jnnp.2006.105767
to reveal possible signs of hypoperfusion. The vascular risk            15
                                                                             Miura M, Naito Y, Naito E, et al. Usefulness of magnetic resonance
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evaluation of all three parameters: presence of vascular risk           16
                                                                             Seidel E, Eicke BM, Tettenborn B, et al. Reference values for vertebral
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min. Moreover, this data is confirmed empirically by the re-            17
                                                                             Jeng JS, Yip PK. Evaluation of vertebral artery hypoplasia and asym-
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