Effects of valproic acid and levetiracetam monotherapy on balance functions in patients with generalized epilepsy.

BACKGROUND: It is reported that antiepileptic drugs have an effect on balance functions. The aim of the study was to evaluate and compare the effects of valproic acid and levetiracetam monotherapy on balance functions in patients with generalized epilepsy using objective test methods. METHODS: The study included 43 generalized epilepsy patients aged 18-60 years, including 20 patients receiving valproic acid monotherapy, 23 patients receiving levetiracetam monotherapy, and 25 healthy individuals as controls, in the Neurology Clinic of a university hospital in eastern Turkey. The demographic data form was filled out and the Video Head Impulse Test and Vestibular Evoked Myogenic Potentials test were performed. RESULTS: Statistically significant differences were obtained between the groups in lateral, posterior, and anterior semicircular canal gains and RALP and LARP asymmetry values in the V-HIT test (p < 0.05). Statistically significant differences were obtained between the groups in P1, N1 latency and asymmetry values in the C-VEMP test and in N1, P1 latency, amplitude, and asymmetry values in the o-VEMP test (p < 0.05). CONCLUSION: Valproic acid and levetiracetam may affect the vestibulocular and vestibulocolic reflex pathways negatively. In this cohort, valproic acid had more pronounced adverse effects on balance functions as compared to levetiracetam.

Predictive nomograms and an algorithm for managing patients with probable Meniere's disease.

PURPOSE: To explore the efficacy of diagnostic tests in accurately reclassifying patients initially diagnosed with probable Meniere's disease (MD) into either definite or non-MD categories. MATERIALS AND METHODS: A retrospective cohort study was conducted at a neurotology clinic between 1/2016 and 5/2022. Patients underwent a battery of tests, from which sensitivity, specificity, positive and negative predictive values, as well as positive and negative likelihood ratios, were calculated. Additionally, prediction nomograms were developed. RESULTS: Of the 69 patients, 25 (36.2 %) were initially classified as definite MD, 21 (30.4 %), probable MD, and 23 (33.4 %) non-MD. The mean follow-up was 3.5 years. The sensitivity of electrocochleography (ECochG) was the highest (92 %), with a negative likelihood ratio of 15 %. Magnetic resonance imaging (MRI) with MD-protocol had the highest specificity (100 %), with a positive likelihood ratio of 100 %. Videonystagmography, video head impulse test, and cervical vestibular-evoked myogenic potentials, had lower sensitivity and specificity. We were able to reclassify 18 (86 %) patients with probable MD: 12 (57 %) were diagnosed with definite MD, and 6 (29 %) were diagnosed with non-MD, consistent with their clinical course. CONCLUSIONS: The combination of ECochG and MRI with MD-protocol provides the most reliable approach to reclassify patients with Probable MD, ensuring a precise and accurate diagnosis. Vestibular tests express the functional status of the labyrinth and may not be reliable. Our findings provide valuable insights into clinical decision-making for patients with Probable MD and raise the consideration of additional diagnostic tests as supplementary to the existing clinical-only diagnosis criteria.

The clinical meaning and significance of OVEMP morphology.

PURPOSE: While some OVEMP recordings are morphologically straightforward, some are poor in appearance, which can create a challenge, as they often require a "second look" by another experienced assessor. Even OVEMPs in normal subjects are sometimes poorly formed, but we wondered if the morphological assessment of the OVEMP response might provide some additional diagnostic information. METHODS: A single experienced assessor evaluated the OVEMP recordings of 60 patients referred sequentially to a tertiary care centre, and categorized them as "easy to assess" (i.e. obvious to a minimally trained assessor) or "difficult to assess", often requiring a second look by another experienced assessor. RESULTS: In 48 patients, the results were easy to assess (regardless of the actual clinical results) while 12 were classified as "difficult". This figure reflected the rate of morphologically poor responses we found in our population of normative data. CONCLUSION: Our clinical concern is that many centres have given up relying on OVEMP assessment because the morphology of the wave may be challenging to interpret. OVEMP assessment often calls for a "second look", requiring a collaboration between two experienced assessors. It seems that this feature may not be diagnostically useful and poor OVEMP morphology may present a challenge in interpretation, but this should not be used as a reason to defer OVEMP testing.

Bone conducted cervical vestibular evoked myogenic potentials: comparison of tone burst stimulus vs chirp stimulus.

PURPOSE: Vestibular evoked myogenic potential (VEMP) is a test used to evaluate the function of otolith organs. In healthy individuals, air-conducted (AC) responses are obtained, whereas, in conductive hearing loss, the inability to transmit the signal well enough with AC stimuli has led to the need for bone-conducted (BC) stimuli. This study aimed to compare 500 Hz Chirp and Tone Burst stimuli in terms of latency and amplitude in BC cVEMP. METHODS: This prospective observational case control study included 35 healthy participants (70 ears) between the age of 20-50. Participants underwent VEMP testing with BC 500 Hz Tone Burst stimulus and 500 Hz narrow band Chirp stimulus without changing the position of the bone conducted vibrator. The intensity of the stimuli was 50 dB nHL. RESULTS: Response rate of 500 Hz TB Stimulus was 51.4% and 95.7% in Chirp stimulus. It was observed that significantly more responses were obtained with Chirp stimulus than TB stimulus (p < 0.001). In terms of p1 latency, n1 latency, both latencies were significantly shorter in Chirp stimulus (p < 0.001). p1n1 amplitude was found significantly larger in Chirp stimulus (p < 0.001). CONCLUSION: Compared to 500 Hz TB stimulus, 500 Hz Chirp stimulus results in a higher response rate, larger p1n1 amplitude, and shorter p1 and n1 latency. A higher response rate may provide a more accurate assessment of otolith organs, reducing false negatives due to signal transmission in patients.

The role of cochlear and vestibular afferents in long-latency cervical vestibular evoked myogenic potentials.

OBJECTIVE: To examine the origin of cervical vestibular evoked myogenic potential (cVEMP) late waves (n34-p44) elicited with air-conducted click stimuli. DESIGN: Using a retrospective design, cVEMPs from normal volunteers were compared to those obtained from patients with vestibular and auditory pathologies. STUDY SAMPLE: (1) Normal volunteers (n = 56); (2) severe-to-profound sensorineural hearing loss (SNHL) with normal vestibular function (n = 21); (3) peripheral vestibular impairment with preserved hearing (n = 16); (4) total vestibulocochlear deficit (n = 23). RESULTS: All normal volunteers had ipsilateral-dominant early p13-n23 peaks. Late peaks were present bilaterally in 78%. The p13-n23 response was present in all patients with SNHL but normal vestibular function, and 43% had late waves. Statistical comparison of these patients to a subset of age-matched controls showed no significant difference in the frequencies, amplitudes or latencies of their ipsilateral early and late peaks. cVEMPs were absent in all patients with vestibular impairment. CONCLUSION: The presence of long-latency cVEMP waves was not dependent on the integrity of sensorineural hearing pathways, but instead correlated with intact vestibular function. This finding conflicts with the view that these late waves are cochlear in origin, and suggests that vestibular afferents may assume a more prominent role in their generation.

[Update on diagnostic procedures in third window syndromes. German version]. / Update zur Diagnostik der Drittfenstersyndrome.

BACKGROUND: The diagnosis of third window syndromes often poses a challenge in clinical practice. OBJECTIVE: This paper provides an up-to-date overview of diagnostic procedures in third window syndromes, with special emphasis on superior canal dehiscence syndrome (SCDS), large vestibular aqueduct syndrome (LVAS), and X-chromosomal malformation of the cochlea. MATERIALS AND METHODS: A literature search was performed in PubMed up to December 2023. Furthermore, a selection of the authors' own cases is presented. RESULTS: Audiovestibular tests for the diagnosis of third window syndromes are most often reported for patients with SCDS in the literature. In this context, cut-off values with different sensitivities and specificities have been defined for different outcome parameters of vestibular evoked myogenic potentials. Current developments include the application of electrocochleography, broadband tympanometry, video head impulse testing, and vibration-induced nystagmus. Genetic analyses are increasingly applied in LVAS. CONCLUSION: The diagnosis of third window syndromes is always based on the synthesis of patients' symptoms, clinical signs, audiovestibular test results, and imaging.

[The "difficult" patient-pearls and pitfalls of vestibular diagnostic tests: Part 2 : Difficult aspects of vestibular laboratory testing]. / "Schwierige" Patient:innen ­ Vestibularisdiagnostik unter erschwerten Bedingungen: Teil 2 : Schwierige Aspekte der apparativen Vestibularisprüfung.

Patients with the cardinal symptoms "vertigo" or "dizziness" may be a real challenge for the treating otorhinolaryngologist. While the first part of this educational series was focused on history taking and bedside neurotological examination, the present paper is devoted to difficult aspects of vestibular laboratory testing, including getting the indication right, what to do if my patient is not able to fully cooperate during the tests, how to choose the adequate diagnostic procedure depending on the patient's comorbidities, how to interpret discordant results of various tests. Finally the paper addresses which conclusions can be drawn (and cannot be drawn) from normal findings in vestibular testing and how to communicate this result to the dizzy patient.

Interventional Study of Flunarizine Therapy on Symptom Relief and Vestibular Evoked Myogenic Potential Changes in Individuals with Vestibular Migraine.

INTRODUCTION: Migraine is the third most common disease in the world with an estimated prevalence of 14.7%. The purpose of this study was to identify the characteristic changes in cervical and ocular vestibular evoked myogenic potential (VEMP) and analyse changes in symptoms and VEMP after flunarizine therapy in patients diagnosed with vestibular migraine (VM). METHODS: Prospective interventional study was conducted on 31 VM patients. Cervical VEMP (cVEMP) and ocular VEMP (oVEMP) were recorded. Flunarizine (10 mg) was given once daily for two consecutive months. Prophylactic therapy was monitored with a monthly follow-up assessment of their symptoms and VEMP was repeated after 2 months. RESULTS: Headache was the chief complaint (67.7%). Vertigo was spontaneous and mostly moderate in intensity (93%). cVEMP was absent in 1 patient and oVEMP was absent in 3 patients. Post prophylactic treatment with flunarizine, there was significant reduction in the frequency (p = 0.001) and duration (p = 0.001) of headache and frequency (p = 0.001), duration (p = 0.001), and intensity (p = 0.009) of vertigo. cVEMP and oVEMP showed no significant differences (p > 0.05) between pre- and post-treatment recordings. CONCLUSION: Treatment with flunarizine helps in considerably reducing the episodes and duration of headache, as well as episodes, duration, and intensity of vertigo.

Recurrent Vestibulopathy: Comparison of Vestibular Test Results with Ménière's Disease and Vestibular Migraine.

INTRODUCTION: Recurrent and episodic vestibular symptoms not fulfilling criteria for known episodic vestibular syndromes are named as recurrent vestibulopathy (RV). We aimed to compare the vestibular test results of RV patients with vestibular migraine (VM) and Ménière's disease (MD). METHODS: Twenty patients with MD, 20 patients with VM, 18 patients with RV, and 20 healthy volunteers (HC) were evaluated. Pure-tone hearing thresholds (PTHTs), video head impulse test (vHIT), functional head impulse test (fHIT), and cervical vestibular evoked myogenic potentials (cVEMPs) were studied. RESULTS: PTHT of the MD-affected ears were significantly high, and cVEMP-corrected amplitudes were low when compared with the VM, RV, and HC (p < 0.001 for all). Amplitude asymmetry ratio was significantly high in MD-affected ears when compared with the HC (p = 0.014), VM (p = 0.038), and RV (p = 0.045). VEMP latencies and lateral canal vHIT gain were not different between groups (p > 0.05). The percentage of correctly identified optotypes on fHIT of the MD (p > 0.001), VM (p = 0.004), and RV (p = 0.001) patients were low in comparison with the HC. CONCLUSION: Apart from hearing loss, low cVEMP amplitudes on the affected side were the main feature in MD differentiating it from VM and RV. Vestibular test results of patients with RV and VM were similar. Low fHIT results in all groups indicate a functional deficit in gaze stabilization. Disabling vertigo attacks disturbing attention may be the cause of this functional impairment. MD, VM, and RV may be parts of a broad-spectrum disorder, RV patients representing milder forms not associated with cochlear or migrainous features.

A study of otolith function in patients with orthostatic dizziness.

BACKGROUND: Orthostatic dizziness (OD) is the dizziness that occurs when moving from a sitting or a supine to a standing position. It is typically thought to be connected to orthostatic hypotension (OH). The otolithic control of respiratory and cardiovascular system through vestibulosympathetic reflex has been the focus of considerable recent interest. This study aimed to evaluate the relationship between the orthostatic dizziness and otolith organ function. METHODS: This study was carried on 50 adults aged from 18 to 50 years with normal peripheral hearing. Subjects were divided into two groups: controls (GI): 20 healthy adults and study group (GII): 30 patients who were complaining of OD. Patients were submitted to; blood pressure measurement in sitting and standing positions, combined vestibular-evoked myogenic potentials (VEMPs) and subjective visual vertical and horizontal tests (SVV) and (SVH). RESULTS: The study group showed abnormal absent cVEMP, oVEMP. There were also statistically significant differences of P13 and N23 latencies and (P13N23) amplitudes between the two groups in the left ears. Both groups differed significantly in SVH values deviated to the left side. Study group were further subdivided into ten patients with OH and 20 patients with OD without OH. The both study subgroups showed abnormal absent cVEMP, oVEMP and abnormal SVH. OH patients showed statistically significant differences of cVEMP waves P13, N23 latencies in the left ears when compared with the control. CONCLUSIONS: Otolith malfunction may be the cause of orthostatic dizziness (OD) in patients with and without orthostatic hypotension.

Usefulness of masseter vestibular evoked myogenic potentials in identifying brainstem dysfunction among individuals with multiple sclerosis.

OBJECTIVE: The present study aimed to investigate the findings of cervical, ocular and masseter vestibular evoked myogenic potentials (cVEMP, oVEMP and mVEMP) among Multiple sclerosis (MS) and correlate with clinical and MRI findings. DESIGN: Standard group comparison research design. STUDY SAMPLE: Individuals with relapsing-remitting MS (n = 45) and age-sex-matched controls (n = 45) were the participants. All of them underwent case history, neurological examination, cVEMP, oVEMP and mVEMP testing. MRI was obtained only for MS participants. RESULTS: Abnormal result on at least one vestibular evoked myogenic potential (VEMP) sub-type was evidenced in 95.56% of participants whereas, unilateral or bilateral abnormal result on all three VEMP sub-types was observed in 60% of participants. The mVEMP abnormality was higher (82.22%) than cVEMP (75.56%) and oVEMP (75.56%) abnormalities but the differences were not significant (p > 0.05). There was no significant association of VEMP abnormalities with the presence of the brainstem symptoms, the brainstem signs, or the MRI lesions (p > 0.05). In the MS group, 38% had normal brainstem MRI; however, mVEMP, cVEMP and oVEMP abnormalities were evidenced in 82.4%, 64.7% and 52.94%, respectively. CONCLUSIONS: Among the three VEMP sub-types, mVEMP appears to be of greater value in identifying silent brainstem dysfunction undetected by clinical and MRI findings in the MS population.

Peripheral Vestibular System Involvement in Multiple Sclerosis and Associations with the Disease Severity.

INTRODUCTION: Multiple sclerosis (MS) is an autoimmune disease that can affect balance, gait, and improve fall risk. The aim of this study was to investigate peripheral vestibular system involvement in MS and associations with the disease severity. METHODS: Thirty-five adult patients with MS and 14 age- and gender-matched healthy controls were evaluated using video head impulse test (v-HIT), cervical vestibular evoked myogenic potential (c-VEMP), ocular vestibular evoked myogenic potentials (o-VEMPs), and sensory organization test (SOT) of computerized dynamic posturography (CDP). The results of both groups were compared, and association with EDSS scores was evaluated. RESULTS: There was no significant difference between the groups regarding v-HIT and c-VEMP results (p > 0.05). There was no association of the v-HIT, c-VEMP, and o-VEMP results with EDSS scores (p > 0.05). There was no significant difference between the o-VEMP results of the groups (p > 0.05) except for N1-P1 amplitudes (p = 0.01). The amplitudes of N1-P1 were significantly lower in the patients compared to controls (p = 0.01). There was no significant difference between the SOT results of the groups (p > 0.05). However, significant differences were found within and between groups when the patients were categorized according to their EDSS scores with a cutoff point of 3 (p < 0.05). There were negative correlations between the EDSS scores and composite (r = -396, p = 0.02) and somatosensory (SOM) scores (r = -487, p = 0.04) of CDP in the MS group. CONCLUSION: Although central and peripheral balance-related systems are affected in MS, the impact of disease on the peripheral vestibular end organ is subtle. In particular, the v-HIT, which was mentioned previously as a detector of brainstem dysfunction could not be a reliable tool in the detection of brainstem pathologies in MS patients. The o-VEMP amplitudes may be affected in the early stages of the disease, possibly due to the crossed ventral tegmental tract, oculomotor nuclei, or interstitial nucleus of Cajal involvements. An EDSS score >3 seems a cutoff level indicating abnormalities in balance integration.

[Vestibular evoked myogenic potentials in patients with recurrent benign paroxysmal positional vertigo]. / Vestibulyarnye vyzvannye miogennye potentsialy u patsientov s retsidiviruyushchim dobrokachestvennym paroksizmal'nym pozitsionnym golovokruzheniem.

Registration of ocular and cervical vestibular evoked myogenic potentials (oVEMPs and cVEMPs) reflects the function of otolith receptors: sacculus and utriculus. Benign paroxysmal positional vertigo (BPPV) is a disease of the inner ear as a result of the utriculus disfunction and migration of otoliths into semicircular channels. OBJECTIVE: To study the function of otolith receptors (sacculus and utriculus) with using VEMPs registration in patients with first-time and recurrent posterior semicircular canal BPPV before and after repositional maneuvers. MATERIAL AND METHODS: Registration and comparison of the results of oVEMPs and cVEMPs were performed in 50 patients with first-time posterior semicircular canal idiopathic BPPV and 26 patients with recurrent posterior semicircular canal BPPV before and after repositional treatment. RESULTS AND DISCUSSION: Clinically significant asymmetry of the amplitude of oVEMPs before treatment was recorded in 14 (38%) of patients with first-time BPPV and in 15 (57.7%) of patients with recurrent BPPV; cVEMPs - in 6 (12%) of patients with first-time BPPV and in 6 (23.1%) of patients with recurrent BPPV. Successful repositional treatment did not affect the amplitude of cVEMPs in any of the groups of patients, but led to a significant increase in the amplitude of oVEMPs on the affected side in patients with first-time BPPV. In patients with recurrent BPPV, despite the absence of symptoms of otolithiasis, the asymmetry of the amplitude of oVEMPs persisted during remission (p<0.05), which can be considered as a prognostically unfavorable factor of disease recurrence.

[Method of registration of vestibular myogenic evoked potentials in the diagnosis of diseases of the inner ear]. / Metod registratsii vestibulyarnykh miogennykh vyzvannykh potentsialov v diagnostike zabolevanii vnutrennego ukha.

The literature review is devoted to the practical application of the method of recording vestibular evoked myogenic potentials (VEMPs) in the diagnosis of the inner ear diseases: superior semicircular canal dehiscence syndrome, Meniere's disease, benign paroxysmal positional vertigo (BPPV), vestibular neuritis. Registration of VMEP is an electrophysiological research method that allows to assess objectively the functional state of the otolith receptors (sacculus and utriculus) and their pathways, which expands the diagnostic capabilities in diagnosis of the inner ear diseases.

Post headshake nystagmus: further correlation with other vestibular test results.

BACKGROUND: It is generally accepted that headshake nystagmus (HSN) is generated from an asymmetrical peripheral vestibular input and a correlation exists between HSN and canal paresis. There have been limited reports, however, how HSN correlates with the more recently introduced tests of vestibular function. AIMS/OBJECTIVES: To evaluate the correlation between HSN and unilateral weakness on caloric testing, high-frequency vestibulo-ocular reflex (VOR) function on video head impulse testing (VHIT) and otolith function determined by vestibular evoked myogenic potentials (VEMPs). METHODS: A retrospective study of all patients who underwent complete vestibular function testing at our tertiary referral center from 2016 to 2019 was performed. Demographic data, clinical diagnosis (where available), the results of video-nystagmography, vHIT, and VEMPs were evaluated. RESULTS: Of the 1499 patients in the study period, 101 (6.7%) had HSN. Vestibular test abnormalities were more common in patients with HSN. The sensitivity of HSN for underlying pathology was low in comparison with vestibular testing. However, HSN demonstrated a high specificity. CONCLUSIONS AND SIGNIFICANCE: HSN generation is likely more complex than caloric-induced nystagmus, probably due to additional variables within the vestibular system. HSN may provide clinicians with additional information concerning high-frequency VOR function involving lateral semicircular and otolith dysfunction.

Endolymphatic hydrops in the unaffected ear of patients with unilateral Ménière's disease.

PURPOSE: Current studies show that frequency tuning modification is a good marker for the detection of endolymphatic hydrops (EH) employing magnetic resonance imaging (MRI) in patients with Ménière's disease (MD). The purpose of the present study is to analyze the auditory and vestibular function with audiometric and vestibular-evoked myogenic potentials (VEMP) responses, respectively, in both the affected and unaffected ears of patients with unilateral MD using MRI as diagnostic support for the degree of EH. METHODS: We retrospectively reviewed the medical records of 76 consecutive patients with unilateral definite MD (age 55 (28-75); 39 women, 37 men). MRI was used through intravenous gadolinium administration, audiometry, and VEMPs. Functional tests were performed up to a week after the MRI. All were followed up one year after imaging utilizing clinical, auditory, and vestibular testing to rule out bilateral involvement. RESULTS: In the unaffected ear, the mean pure-tone average is normal even in cases with hydrops and, for a similar severity of hydrops is significantly lower than in the affected ear. Significant differences for the amplitude of the response at 0.5 kHz, at 1 kHz between the affected and unaffected ears were found to be lower in the affected ears. The relative amplitude ratio (1 Kz-0.5 kHz) was significantly lower in the affected ear and in the case of the oVEMP response depends on the degree of EH. The response in the unaffected ear was not modified by the presence or the degree of hydrops. CONCLUSION: In the unaffected ear, hydrops is not associated with hearing deterioration. For a similar degree of hydrops, hearing loss is significantly greater in the affected ear. The endolymphatic hydrops in the vestibule induces a frequency bias in the VEMP response only in the affected ear and not in the unaffected ear. Because of these findings we consider that hydrops does not represent an active disorder in the unaffected ear.

Evaluation of vestibular function following endolymphatic sac surgery.

PURPOSE: To evaluate objective vestibular function after endolymphatic sac surgery (ELSS) for Menière's disease (MD), using comparative vestibular function tests: videonystagmography (VNG), vestibular evoked myogenic potentials (VEMP) and video head-impulse test (VHIT) METHODS: Patients with definite MD using the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) of 1995 criteria modified in 2015 and treated with ELSS (sac decompression or sac opening) were included. The primary outcome was the preservation of vestibular function, comparing pre- and postoperative vestibular function tests: VNG, VEMP, VHIT. Secondary outcomes were control of episodes of vertigo, hearing outcome using AAO-HNS criteria, and QoL using the Menière's disease outcome questionnaire. RESULTS: 73 patients were included in the study. We found a significant preservation of vestibular function as measured by VNG and VHIT. There was no statistical difference in the presence or absence of cervical and ocular (P13/N23 and N1/P1) waves on VEMP pre- and postoperatively. 67% of patients had good control of episodes of vertigo post-operatively, with significantly better results in the sac opening group (75%). There was no significant change in hearing postoperatively, and QoL scores were significantly improved after surgery (p < 0.0001). CONCLUSION: Endolymphatic sac surgery (ELSS) is a conservative surgical treatment, which does not negatively impact vestibular function. It was associated with improved control of episodes of vertigo, preservation of hearing, and a clear improvement in QoL scores. Despite its pathophysiology not being fully understood, it remains a first-line procedure preserving vestibular function, for MD refractory to medical management.

Prevalence of abnormal vestibular responses in children with sensorineural hearing loss.

PURPOSE: Dysfunction of the vestibular organs has a great deal of influence on children's balance. Children with sensorineural hearing loss (SNHL) may often have accompanying abnormal vestibular responses. Video head impulse test (vHIT) combined with a test battery of cervical and ocular vestibular evoked myogenic potentials (cVEMPs, oVEMPs) make it possible to determine the prevalence of abnormal vestibular response in any of the five paired vestibular organs amongst children with SNHL. METHOD: Prospective cross-sectional study including children aged 3-17 years with uni- or bilateral SNHL (bone-conduction (BC) pure tone average (PTA4) above 20 dB). Assessments included vHIT, cVEMP, and oVEMP. Descriptive data were analyzed. T-tests were performed to detect any correlation between the degree of SNHL and abnormal vestibular responses. RESULTS: 42 children (27 males), a total of 63 ears with SNHL, mean BC PTA4 SNHL of 42.3 dB (32.0; 58.4 IR) were included. 28.6% had at least one ear with abnormal vestibular response. 97.6% (41/42) completed one and 75.0% (27/36) completed all vestibular examinations. Ears with two pathological examinations had significantly more severe SNHL than ears with one pathological or normal vestibular examinations (p = 0.008, p = 0.005). CONCLUSION: All test methods used with this study were easy, fast, and comfortable for children (as young as 3 years of age) to undergo. Even a moderate SNHL might be associated with abnormal vestibular response. Structural damage to the organs is the most likely cause of vestibular deficit. Consensus on criteria defining pathological examinations with both vHIT and VEMPs are required for more accurate comparison with previous studies.

Vestibular contributions to the Romberg test: Testing semicircular canal and otolith function.

Normal stance relies on three sensory inputs: vision, proprioception and vestibular function. The Romberg test, trying to stand with feet together and eyes closed, is familiar to every medical student as a test of distal proprioceptive impairment. It remains the best known of Romberg's many remarkable contributions to clinical neurology. In Romberg's time almost nothing was known about the function of the vestibular system. We now know that standing with the eyes closed on a compliant rather than a firm surface is more a test of vestibular than proprioceptive function. Peripheral vestibular function tests in clinical use today all rely on measurements of oligosynaptic brainstem reflexes. Short-latency eye rotations in response to rapid, brief head rotations (head impulses) give an accurate, robust and reproducible measure of the function of any and each of the six semicircular canals. Short-latency evoked potentials from sternomastoid and inferior oblique muscles in response to loud clicks or skull taps (vestibular evoked myogenic potentials) give an accurate and reproducible measure of the function of each and any of the four otolith organs. In the present paper, we briefly review what is now known about the anatomy and physiology of the peripheral receptors and brainstem pathways mediating these reflexes and examine how this knowledge can help interpret the Romberg test.

Vestibulo-perceptual influences upon the vestibulo-spinal reflex.

The vestibular system facilitates gaze and postural stability via the vestibulo-ocular (VOR) and vestibulo-spinal reflexes, respectively. Cortical and perceptual mechanisms can modulate long-duration VOR responses, but little is known about whether high-order neural phenomena can modulate short-latency vestibulo-spinal responses. Here, we investigate this by assessing click-evoked cervical vestibular myogenic-evoked potentials (VEMPS) during visual roll motion that elicited an illusionary sensation of self-motion (i.e. vection). We observed that during vection, the amplitude of the VEMPs was enhanced when compared to baseline measures. This modulation in VEMP amplitude was positively correlated with the subjective reports of vection strength. That is, those subjects reporting greater subjective vection scores exhibited a greater increase in VEMP amplitude. Control experiments showed that simple arousal (cold-induced discomfort) also increased VEMP amplitude but that, unlike vection, it did not modulate VEMP amplitude linearly. In agreement, small-field visual roll motion that did not induce vection failed to increase VEMP amplitude. Taken together, our results demonstrate that vection can modify the response of vestibulo-collic reflexes. Even short-latency brainstem vestibulo-spinal reflexes are influenced by high-order mechanisms, illustrating the functional importance of perceptual mechanisms in human postural control. As VEMPs are inhibitory responses, we argue that the findings may represent a mechanism whereby high-order CNS mechanisms reduce activity levels in vestibulo-collic reflexes, necessary for instance when voluntary head movements need to be performed.