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Objective: Several studies have investigated the efficacy of VEMP (vestibular evoked myogenic potential) in patients with vestibular disorders and BPPV (benign paroxysmal positional vertigo). However, previous data were inconclusive. The aim of this study was to investigate the difference in latency, amplitude P1-N1, asymmetry ratio (AR), and cervical/ocular-VEMP values between BPPV patients and healthy controls. Methods: 125 healthy subjects and 42 BPPV patients were prospectively enrolled in the study. In both groups, c/oVEMP tests with 500 Hz tone-burst stimuli were performed. Latencies P1, N1 peaks, and corrected amplitudes (CA) were measured, and AR was calculated. Results: in the BPPV group, 14.29% of patients lacked oVEMPs that recovered after therapy. N1 latencies were significantly elongated, and 50% of patients had pathological AR; this value normalized at follow-up sessions. In addition, there was a reduction in CA in the pathologic ear compared to healthy ears (p = 0.04) and compared to healthy controls (p = 0.01). For cVEMP, a significant reduction in latency-P1 was observed in BPPV patients compared to controls; no significant differences were observed for P1, N1, and CA values between the two ears. The cVEMPs were absent in 14.29% of BPPV patients (AR > 35) that recovered after therapy. Conclusion: We identified several abnormal c/oVemp values in BPPV patients compared with healthy controls, with most changes in values occurring in oVEMPs, suggesting that utricular dysfunction may be more common than saccular. In addition, patients with oVEMP alteration showed later clinical recovery, suggesting a possible prognostic role of the test.

Objective: Several studies have investigated the efficacy of VEMP (vestibular evoked myogenic potential) in patients with vestibular disorders and BPPV (benign paroxysmal positional vertigo). However, previous data were inconclusive. The aim of this study was to investigate the difference in latency, amplitude P1-N1, asymmetry ratio (AR), and cervical/ocular-VEMP values between BPPV patients and healthy controls. Methods: 125 healthy subjects and 42 BPPV patients were prospectively enrolled in the study. In both groups, c/oVEMP tests with 500 Hz tone-burst stimuli were performed. Latencies P1, N1 peaks, and corrected amplitudes (CA) were measured, and AR was calculated. Results: in the BPPV group, 14.29% of patients lacked oVEMPs that recovered after therapy. N1 latencies were significantly elongated, and 50% of patients had pathological AR; this value normalized at follow-up sessions. In addition, there was a reduction in CA in the pathologic ear compared to healthy ears (p = 0.04) and compared to healthy controls (p = 0.01). For cVEMP, a significant reduction in latency-P1 was observed in BPPV patients compared to controls; no significant differences were observed for P1, N1, and CA values between the two ears. The cVEMPs were absent in 14.29% of BPPV patients (AR > 35) that recovered after therapy. Conclusion: We identified several abnormal c/oVemp values in BPPV patients compared with healthy controls, with most changes in values occurring in oVEMPs, suggesting that utricular dysfunction may be more common than saccular. In addition, patients with oVEMP alteration showed later clinical recovery, suggesting a possible prognostic role of the test. [ABSTRACT FROM AUTHOR]

Inner ear hemorrhage (IEH) is an increasingly recognized cochlear lesion that can cause sensorineural hearing loss (SNHL). Magnetic resonance imaging (MRI) is known to be the best imaging modality for clarifying the causes of SNHL and providing images that point to those causes. Evaluate the lesional patterns in patients with presumed Inner ear hemorrhage (IEH) from radiological and functional aspects. We retrospectively reviewed 10 patients performed in our institution from 2014 to 2020, with suspected labyrinthine hemorrhage based on radiological and functional examination. We included 8 patients with IEH and sensorineural hearing loss (SNHL). The median age was 55 years (range: 3 months − 78 years). The results from the MRI and functional tests were compared for each end-organ. Only three cases (37.5%) showed a correlation between signal abnormalities and dysfunction in the labyrinthine apparatus. In patients with SNHL inner ear hemorrhage needs to be ruled out in the differential diagnosis, so specific MRI sequences should be requested. It represents a way to a better understanding of the disorder and the variety of findings claim for a complete auditory and vestibular testing. [ABSTRACT FROM AUTHOR]

Background Age-related changes to auditory function have been attributed to, through histopathological study, specific degradation of the sensory, supporting, and afferent structures of the cochlea. Similar to age-related hearing loss (ARHL), agerelated changes to the vestibular sensory and supporting structures with specific degeneration of the saccule, utricle, otoconia, primary vestibular afferents have also been noted. Significant decreases in postural control with age are also well-documented in the literature attributed to multifactorial changes in function. Purpose The purpose of this study is to further evaluate the association of ARHL and saccule/utricle function as measured by VEMPs and postural control measures. Study Sample Audiologic, vestibular and postural control results from 34 participants were analyzed. The age range was from 50 to 70 years old with 16 males and 18 females. Group 1 consisted of 33 ears fromparticipants age 50-70 with normal hearing with average age of 60.8 years (sd 6.287 years) and an average speech-frequency PTA of 14.8 dB HL. Group 2 consisted of 27 ears from participants age 50-70 years with ARHL and an average age of 62.9 years (sd 4.984 years) with an average speech-frequency PTA of 39.9 dB HL. Data Collection and Analysis Independent samples t-tests were used to assess group mean differences for dependent variables. The independent variable was group with 2 levels (normal hearing, ARHL). The dependent variables were cVEMP P1/N1 Amplitude, cVEMP P1 Latency, cVEMP N1 Latency, cVEMP P2 Latency, oVEMP N1/P1 Amplitude, oVEMP N1 Latency, and oVEMP P1 Latency. Additional analyses were completed using Pearson correlation to evaluate the relationship of audiometric findings to the dependent variables. Results Results indicated significantly decreased cVEMP P1/N1 amplitude and oVEMP N1/P1 amplitude adults 50-70-years of age with ARHL compared with their normal counterparts. Significant correlations were also found for audiometric results and both cVEMP and oVEMP measures. Conclusions Overall, the results of this study describe concomitant auditory and vestibular degeneration as measured by audiometric testing and vestibular function testing involving the saccule and to a lesser degree the utricle. [ABSTRACT FROM AUTHOR]

Objective: Several studies have demonstrated the possibility to obtain vestibular potentials elicited with electrical stimulation from cochlear and vestibular implants. The objective of this study is to analyze the vestibular-evoked myogenic potentials (VEMPs) obtained from patients implanted with cochlear and vestibulo-cochlear implant.Material and Methods: We compared two groups: in the first group, four cochlear implant (CI) recipients with present acoustic cVEMPs before CI surgery were included. In the second group, three patients with bilaterally absent cVEMPs and bilateral vestibular dysfunction were selected. The latter group received a unilateral cochleo-vestibular implant. We analyze the electrically elicited cVEMPs in all patients after stimulation with cochlear and vestibular electrode array stimulation.Results: We present the results obtained post-operatively in both groups. All patients (100%) with direct electrical vestibular stimulation via the vestibular electrode array had present cVEMPs. The P1 and N1 latencies were 11.33–13.6 ms and 18.3–21 ms, respectively. In CI patients, electrical cVEMPs were present only in one of the four subjects (25%) with cochlear implant (“cross”) stimulation, and P1 and N1 latencies were 9.67 and 16.33, respectively. In these patients, the responses present shorter latencies than those observed acoustically.Conclusions: Electrically evoked cVEMPs can be present after cochlear and vestibular stimulation and suggest stimulation of vestibular elements, although clinical effect must be further studied.

Objective: Several studies have demonstrated the possibility to obtain vestibular potentials elicited with electrical stimulation from cochlear and vestibular implants. The objective of this study is to analyze the vestibular-evoked myogenic potentials (VEMPs) obtained from patients implanted with cochlear and vestibulo-cochlear implant. Material and Methods: We compared two groups: in the first group, four cochlear implant (CI) recipients with present acoustic cVEMPs before CI surgery were included. In the second group, three patients with bilaterally absent cVEMPs and bilateral vestibular dysfunction were selected. The latter group received a unilateral cochleo-vestibular implant. We analyze the electrically elicited cVEMPs in all patients after stimulation with cochlear and vestibular electrode array stimulation. Results: We present the results obtained post-operatively in both groups. All patients (100%) with direct electrical vestibular stimulation via the vestibular electrode array had present cVEMPs. The P1 and N1 latencies were 11.33–13.6 ms and 18.3–21 ms, respectively. In CI patients, electrical cVEMPs were present only in one of the four subjects (25%) with cochlear implant ("cross") stimulation, and P1 and N1 latencies were 9.67 and 16.33, respectively. In these patients, the responses present shorter latencies than those observed acoustically. Conclusions: Electrically evoked cVEMPs can be present after cochlear and vestibular stimulation and suggest stimulation of vestibular elements, although clinical effect must be further studied. [ABSTRACT FROM AUTHOR]

Purpose: Idiopathic sudden sensorineural hearing loss (ISSHL) is a hearing impairment greater than 30 dB at three consecutive frequencies developing in less than 3 days. The aim of this study was to evaluate VEMPs and caloric testing in patients affected by ISSHL without vertigo. Methods: We retrospectively evaluated 35 subjects affected by ISSHL. The audio-vestibular investigation consisted of pure-tone and speech audiometry, impedance, bithermal caloric testing, oVEMPs and cVEMPs. Results: VEMPS were abnormal in 21 patients (60%): cVEMPs in 12 (34.2%) and oVEMPs in 19 (54.2%). 10 patients (28.5%) presented with both c-and oVEMPs altered. Subjects without vestibular involvement showed a significant lower PTA in the affected ear both at admission and at discharge. Recovery rate was significantly higher in group without vestibular involvement. Conclusion: The evaluation of the vestibular system can be useful for predicting the auditory recovery in patients without vertigo also. [ABSTRACT FROM AUTHOR]

Objective: Vestibular-Evoked Myogenic potential (VEMP) is a non invasive test for vestibular function. It is a series of electrical waves that are generated by vestibular pathway in response to loud acoustic stimulation. It can be recorded from surface electrodes placed over muscles and according to the site of recording there are two types cervical VEMP and ocular VEMP. The primary goal of the present study is to compare cervical evoked myogenic potential (cVEMP) findings in normal hearing children and adults. Materials and Methods: This study included 60 subjects of normal hearing. They were selected from relatives; friends and relatives of patients attending Audiology Unit of Alzahraa University Hospital. 30 were children in the age range of 5-15 years and 30 were adults in the age range of 20-40 years. All subjects were submitted to cVEMP (air-conducted sound). Amplitude, latencies, asymmetry amplitude ratio and threshold were measured. Results: There was statistically significant difference in latencies and amplitudes and no statistically significant difference in asymmetry ratio of cVEMP responses between children and adults. There was no statistically significant difference in threshold between right and left ears in adult and children but there was statistically significant difference between the two groups as regard cVEMP threshold. Conclusion: cVEMPs responses in children have shorter latencies and lower thershold than adult responses, which should be considered in interpretation of cVEMP responses in children. Normative data for different age groups should be collected as cVEMPs responses, as age has a significant effect on them. [ABSTRACT FROM AUTHOR]

Gaze stabilization and postural control are two key functions of the vestibular system. In consequence, oscillopsia and chronic imbalance are the two main complaints of patients presenting with a severe bilateral vestibular function loss. The vestibular implant is emerging as a promising treatment for this group of patients whose quality of life is significantly impaired. Although the final aim of the vestibular implant should be to restore vestibular function as a whole, until now the research has focused mainly on the restoration of the vestibulo-ocular reflex to improve gaze stabilization. In this study, we aimed to explore whether the vestibulo-collic and vestibulo-spinal pathways could be activated and controlled with the electrical stimuli provided by our vestibular implant prototype. This was first explored and demonstrated with recordings of electrically elicited cervical vestibular evoked myogenic potentials (ecVEMPs). ecVEMPs with characteristics similar to the classical acoustically elicited cervical vestibular evoked myogenic potentials (cVEMPs) were successfully evoked in five out of the eight tested patients. Amplitudes of the electrically elicited N–P complex varied, ranging from 44 to 120 µV. Mean latencies of the N and P waves were of 9.71(± 1.17) ms and 17.24 ms (± 1.74), respectively. We also evaluated the possibility of generating controlled postural responses using a stepping test. Here, we showed that controlled and consistent whole-body postural responses can be effectively obtained with rapid changes in the "baseline" (constant rate and amplitude) electrical activity delivered by the vestibular implant in two out of the three tested subjects. Furthermore, obtained amplitude of body rotations was significantly correlated with the intensity of stimulation and direction of body rotations correlated with the side of the delivered stimulus (implanted side). Altogether, these data suggest that the vestibular implant could also be used to improve postural control in patients with bilateral vestibulopathy. [ABSTRACT FROM AUTHOR]

Background: Cervical VEMPs and ocular VEMPs are tests for evaluating otolith function in clinical practice. We developed a simple, portable and affordable device to record VEMP responses on patients, named μVEMP. Our aim was to validate and field test the new μVEMP device.Methods: We recorded cervical VEMPs and ocular VEMPs in response to bone conducted vibration using taps tendon hammer to the forehead (Fz) and to air conducted sounds using clicks. We simultaneously recorded VEMP responses (same subject, same electrode, same stimuli) in three healthy volunteers (2 females, age range: 29–57 years) with the μVEMP device and with a standard research grade commercial (CED) system used in clinics. We also used the μVEMP device to record VEMP responses from six patients (6 females, age mean±SD: 50.3 ± 20.8 years) with classical peripheral audio-vestibular diseases (unilateral vestibular neuritis, unilateral neurectomy, bilateral vestibular loss, unilateral superior canal dehiscence, unilateral otosclerosis).Results: The first part of this paper compared the devices using simultaneous recordings. The average of the concordance correlation coefficient was rc = 0.997 ± 0.003 showing a strong similarity between the measures. VEMP responses recorded with the μVEMP device on patients with audio-vestibular diseases were similar to those typically found in the literature.Conclusions: We developed, validated and field tested a new device to record ocular and cervical VEMPs in response to sound and vibration.This new device is portable (powered by a phone or tablet) with pocket-size dimensions (105 × 66 × 27 mm) and light weight (150 g). Although further studies and normative data are required, our μVEMP device is simpler (easier to use) and potentially more accessible than standard, commercially available equipment.

Background: Cervical VEMPs and ocular VEMPs are tests for evaluating otolith function in clinical practice. We developed a simple, portable and affordable device to record VEMP responses on patients, named μVEMP. Our aim was to validate and field test the new μVEMP device. Methods: We recorded cervical VEMPs and ocular VEMPs in response to bone conducted vibration using taps tendon hammer to the forehead (Fz) and to air conducted sounds using clicks. We simultaneously recorded VEMP responses (same subject, same electrode, same stimuli) in three healthy volunteers (2 females, age range: 29–57 years) with the μVEMP device and with a standard research grade commercial (CED) system used in clinics. We also used the μVEMP device to record VEMP responses from six patients (6 females, age mean±SD: 50.3 ± 20.8 years) with classical peripheral audio-vestibular diseases (unilateral vestibular neuritis, unilateral neurectomy, bilateral vestibular loss, unilateral superior canal dehiscence, unilateral otosclerosis). Results: The first part of this paper compared the devices using simultaneous recordings. The average of the concordance correlation coefficient was rc = 0.997 ± 0.003 showing a strong similarity between the measures. VEMP responses recorded with the μVEMP device on patients with audio-vestibular diseases were similar to those typically found in the literature. Conclusions: We developed, validated and field tested a new device to record ocular and cervical VEMPs in response to sound and vibration.This new device is portable (powered by a phone or tablet) with pocket-size dimensions (105 × 66 × 27 mm) and light weight (150 g). Although further studies and normative data are required, our μVEMP device is simpler (easier to use) and potentially more accessible than standard, commercially available equipment. [ABSTRACT FROM AUTHOR]

To determine whether vestibular evoked myogenic potential (VEMP) measurements that combine the VEMP 500/1000 Hz frequency tuning ratio and the inter-aural asymmetry ratio can reliably detect unilateral Meniere's disease ears as compared to healthy controls. Forty-two consecutive patients with certain unilateral Meniere's disease (as confirmed using a locally enhanced inner ear MRI (LEIM)) were assessed. Cervical vestibular evoked myogenic potentials (cVEMP) and ocular vestibular evoked myogenic potentials (oVEMP) were recorded at 500 and 1000 Hz. The VEMP amplitudes, asymmetry ratios, and the 500/1000 Hz amplitude ratios were compared with those of 21 age-matched healthy controls. A multi-frequency VEMPs score that combined: (1) the cVEMP 500/1000 Hz amplitude ratio, (2) the oVEMP 500/1000 Hz amplitude ratio, (3) the 500 Hz cVEMP asymmetry ratio, (4) the 1000 Hz cVEMP asymmetry ratio, produced a ROC curve with an area under the curve (AUC) of 0.814. The inclusion of audiology data further improved the result to 0.906. This score can be used to discriminate with a good degree of clinical accuracy between Meniere's ears (unilateral) and those of healthy controls. Multi-frequency VEMP analysis offers a simple, cost-effective solution to the diagnostic difficulties presented by Meniere's disease. [ABSTRACT FROM AUTHOR]

Objectives Vestibular migraine (VM) is one of the most common causes of episodic vertigo. Several studies have reported abnormal cervical vestibular evoked myogenic potentials (cVEMPs) in VM patients. Recent studies have investigated the diagnostic values of ocular vestibular myogenic evoked potentials (oVEMPs) in VM patients. However, they were few and rarely attempted to correlate the finding with the results of other vestibular tests. So this study aimed to investigate both cVEMPs and oVEMPs in VM patients and to correlate their results with other clinical findings. Subjects and methods The study group consisted of twenty adult patients with criteria of definite VM. The control group included age and gender matched twenty healthy subjects. For all subjects detailed history and basic audiologic evaluation were done. Vestibular evaluation included clinical office tests and VEMPs (cVEMPs and oVEMPs). Patients were examined during interictal period and in the absence of vertigo. Results True vertigo was experienced in 60% of patients, while 40% patients had sense of unsteadiness. Office tests for vestibulo-spinal reflex were abnormal in 5 patients (25%). Abnormal oVEMPs responses were more frequent (No. = 19 “95%”) than cVEMPs (No = 15 “75%”). The main abnormality was prolonged latency and/or decreased amplitude. Affection was more bilateral while absent response was less frequently encountered. Significant correlation was found between abnormal office tests and VEMPs abnormalities. Conclusions Both cVEMPs and oVEMPs abnormalities were detected in VM patients. Abnormal office tests were among patients with severe VEMPs affection during interictal period. [ABSTRACT FROM AUTHOR]

“Auditory neuropathy spectrum disorder” is a clinical disorder where the outer hair cell functioning is intact but the functioning of the auditory nerve is affected. Since, the 8th nerve is constituted by both the auditory and vestibular branch of nerve fibers, there are chances that the vestibular nerve might also be affected. Hence, the current study was carried out in order to determine the functioning of vestibular nerve in individuals with Auditory Neuropathy. A total of 11 participants were considered for the current study. cVEMPs and oVEMPs were administered using the conventional protocol. In all the participants (100%) the oVEMPs were absent whereas in 2 ears out of 22 ears tested (90.90%) the cVEMPs were absent. The results of the present study indicate a high incidence of vestibular involvement in individuals with auditory neuropathy spectrum disorders. Also, it necessitates the inclusion of vestibular tests in the test battery used to assess individuals with auditory neuropathy spectrum disorder.

Background: Vestibular evoked myogenic potential (VEMP) is a test to assess the functioning of otolith organs of the inner ear. Cervical VEMPs (cVEMPs) assess the saccule and the inferior vestibular nerve, whereas ocular VEMPs (oVEMPs) assess the utricle and superior vestibular nerve. In individuals with sensorineural hearing loss, disturbances of cochlear function could accompany vestibular impairment since both these parts of the inner ear are anatomically related. The aim of the present study was to find out the prevalence of cVEMPs and oVEMPs in individuals with congenital severe to profound sensorineural hearing loss. Material and methods: There were 46 participants in the present study: 23 with normal hearing and 23 with bilateral severe to profound hearing loss, and cVEMPs and oVEMPs were recorded from all of them. Results: cVEMPs were present in 100% of subjects, both in the control and experimental groups; oVEMPs were present in 100% of the control and 66% of the experimental group. In hearing impaired individuals no correlation was found between cVEMPs and oVEMPs, although a Mann-Whitney test revealed that the amplitude of cVEMPs and oVEMPs were significantly smaller in the hearing impaired group compared to normals. Conclusions: The results indicate impairment of both utricular and saccular function in individuals with severe to profound hearing loss. Also oVEMPs were absent in more individuals compared to cVEMPs, which suggests that utricular function is more linked with the cochlea compared to that of the saccule. [ABSTRACT FROM AUTHOR]

Our aim is to compare short tone burst (STB)-and clicks-stimuli to evoke vestibular-evoked myogenic potentials (VEMPs) in healthy controls. A cross-sectional study in which VEMPs were measured in two sets of 185 and 55 normal volunteers by an air-conducted 500 Hz STBs and clicks, respectively. The test-retest reliability between different sessions was assessed in two subsets of 35 individuals. Moreover, 53 individuals were examined with both stimuli within the same session. Intraclass correlation coefficients (ICC) were used to assess reliability for P1 and N1 latencies, corrected amplitude and asymmetry ratio (AR). The results included that STBs produced a reliable response between different sessions ( N = 35; [ICC] = 0.61-0.94, all p < 0.0001). Although clicks produced a reliable response for P1 and N1 latencies and corrected amplitudes (ICC = 0.62-0.74, all p < 0.0001), the amplitude ratio showed a lower reliability [ICC = 0.32 (−0.10 to 0.59)]. The amplitude of VEMP was consistently larger with 500 Hz STBs than clicks for a given sound pressure level. Within the same session, STBs evoked a response in 52/53 subjects (98%) whereas clicks evoked VEMPs only in 44/53 individuals (83%). Conclusions revealed that a 500 Hz STBs elicited consistently larger amplitudes, better reliability across recording sessions and fewer missing responses compared with click-induced VEMPs. [ABSTRACT FROM AUTHOR]

Vestibular assessments in children are essential for the early identification of vestibular and balance dysfunctions. Vestibular evoked myogenic potentials, cervical (cVEMPs) and ocular (oVEMPs) have been reported to be feasible and effective when assessing otolith function in children. The main aim of the study was to obtain normative data for cVEMPs and oVEMPs from preschool and primary school-aged Malaysian children. A group of 33 healthy children, aged from 5 years 9 months–12 years 4 months (mean ± SD = 8.83 ± 1.92 years), was recruited. Their otolith saccular function was assessed using 750 Hz tone burst for cVEMPs (with ER3A insert phone), while their utricular function was assessed using Brüel & Kjaer Mini-shaker Type 4810 (Naerum, Denmark) for oVEMPs. For cVEMPs, the mean value of P13 latency, N23 latency, P13–N23 interamplitude and asymmetry ratio were 12.62 ± 1.38 ms, 19.85 ± 1.95 ms, 92.47 ± 50.35 μV and 14.03 ± 9.75%, respectively. For oVEMPs, the mean value of N10 latency, P15 latency, N10–P15 interamplitude and asymmetry ratio were 9.23 ± 1.07 ms, 14.41 ± 1.04 ms, 10.32 ± 5.65 μV and 15.84 ± 11.49%, respectively. Two-way ANOVA analysis found that ear laterality and gender had no significant effect on all cVEMPs and oVEMPs parameters. No significant correlation was found between age and all VEMPs parameters. The normative data for cVEMPs and oVEMPs obtained in this study can be used as a guide by health professionals to assess saccular and utricular functions among children age from 5 to 12 years of age. [ABSTRACT FROM AUTHOR]

BACKGROUND: Pseudotumor cerebri is a disorder of unknown etiology that results in raised intracranial pressure (ICP) and characterized by attendant signs and symptoms of increased ICP in an alert and oriented patient but without localizing neurologic findings. Vestibular evoked myogenic potentials (VEMPs) are short latency reflex responses produced by stimulation of the vestibular apparatus. OBJECTIVE: The purpose of this study was to determine whether group of pseudotumor cerebri patients have abnormal changes in VEMPs (cervical and ocular) and to analyze the results and compare them with matched group of normal subjects. MATERIALS and METHODS: Ocular and cervical VEMPs were performed to the entire study groups. The responses were obtained from thirteen pseudotumor cerebri patients and compared to fifteen age matched normal subjects. All participants were subjected to audiological assessments that include pure tone audiometry, tympanometry and acoustic reflexes. RESULTS: Ocular and cervical VEMPs amplitudes were reduced in response in pseudotumor cerebri patients than normal but still of non-statistical significant difference p>0.05. DISCUSSION AND CONCLUSION: The results of this study suggest that patients with pseudotumor cerebri do not have statistically significant changes in comparison with the normal control as regard ocular and cervical VEMPs testing. Hence, asserting a query whether there is affection of VEMPs in pseudotumor cerebri patients. [ABSTRACT FROM AUTHOR]