An acoustically evoked short latency negative response in profound hearing loss infants

OBJECTIVE: A large negative deflection with a 3-4 ms latency within the auditory brainstem response has been reported in some profound hearing loss ears under intense stimuli in adult subjects. The wave has been termed the N3 potential or acoustically evoked short latency negative response and it is assumed to be a vestibular-evoked potential. The purpose of the current study was to investigate the relationship between the vestibular-evoked myogenic potentials and the acoustically evoked short latency negative response in infants with a functionless cochlea and normal or impaired semicircular canal. METHODS: Seventeen 3 months old infants with profound bilateral sensorineural hearing loss had acoustically evoked short latency negative responses and vestibular-evoked myogenic potentials recorded and caloric tests performed. RESULTS: No spontaneous symptoms of vestibular dysfunction were found in the examined infants. ASNR with medium latency 3.3 ms and threshold value 80-90 dB normal hearing level was elicited from 10 ears. VEMPs were present in 12 ears. ASNRs and VEMPs were absent in two ears with normal response to caloric stimulation. No response to caloric stimulation was elicited from other two ears with normal saccular function. For the ears with absence of ASNR, four had normal VEMP and the rest were considered to have saccular afunction. Significant correlation was found between the presence of ASNRs and VEMPs. CONCLUSION: Acoustically evoked short latency negative responses could be a valuable tool for assessing vestibular function in infants with profound sensorineural hearing loss.     

Vestibular status in partial deafness

IntroductionThe hair cells of the cochlea and the vestibulum are closely connected and may be susceptible to the same noxious factors. The relationship between their function has been a continuing field of investigation. The indications for cochlear implantation have been broadened and now include the patients with partial deafness. This raises the question of their vestibular status.ObjectiveThe aim of the study was to investigate whether there is any difference between the vestibular function of patients with low frequency residual hearing and those with totally deaf ears.MethodsA total of 360 ears with profound sensorineural hearing loss were analysed before cochlear implantation. The patients were divided into four groups, according to their low frequency residual hearing (Group 1 ? normal or slightly elevated low frequency residual hearing; Group 2 ? elevated threshold but still usable hearing at low frequencies; Group 3 – non-functional residual hearing; Group 4 ? no detectable hearing threshold within the limits of the audiometer). The patients underwent vestibular tests: cervical vestibular evoked myogenic potential, ocular vestibular evoked myogenic potential, caloric test and video-head impulse test.ResultsThe rates of elicited responses in cervical vestibular evoked myogenic potential were as follows: in Group 1 (59.3 %); Group 2 (57.5 %); Group 3 (35.2 %); Group 4 (7.7 %). For ocular vestibular evoked myogenic potential the percentage of correct outcomes was: Group 1 (70.8 %); Group 2 (56.0 %); Group 3 (40.0 %); Group 4 (14.3 %). For the caloric test we counted normal responses in 88.9 % of Group 1; 81.6 % of Group 2; 57.9 % of Group 3; 53.3 % of Group 4. For video-head impulse test we also found markedly better results in Group1, followed by Group 2, and much worse in Group 3 and 4.ConclusionPatients with partial deafness not only have a better cochlea but also better vestibular function, which needs to be protected. In summary, the better the low frequency residual hearing, the better the vestibular status.     

Vestibular evoked myogenic potentials in brainstem stroke

OBJECTIVES/HYPOTHESIS: Despite its widespread application in the posterior fossa tumor, the study of vestibular evoked myogenic potential (VEMP) in cases of posterior fossa stroke remains scarce. The purpose of the study was to establish the role of VEMP in patients with brainstem stroke. STUDY DESIGN: Retrospective study. METHODS: Patients with acute vertigo were admitted and underwent a battery of auditory vestibular tests including caloric and VEMP tests; then they were surveyed by magnetic resonance imaging scan. Seven patients (two men and five women) were demonstrated as having brainstem stroke, including infarction in five patients and hemorrhage in two. RESULTS: Clinical manifestations consisted of dizziness/vertigo in all patients, spontaneous nystagmus in five (71%), and ataxia in three. No patients had experienced conscious change or conventional neurological deficits (eg, long tract signs). Electronystagmography revealed abnormal findings on eye tracking test in 100% of patients, on optokinetic nystagmus test in 71% of the patients, and on caloric testing in 10 ears (71%), including absent ice-water caloric test response in 7 ears and canal paresis in 3 ears. Vestibular evoked myogenic potential testing displayed normal response in 3 ears and abnormal response in 11 ears (79%), including absent vestibular evoked myogenic potentials in 8 ears and delayed vestibular evoked myogenic potentials in 3 ears. When results of both caloric testing and VEMP test were combined, the abnormal rate increased to 93% (13 of 14 patients). CONCLUSIONS: Caloric testing assesses the vestibulo-ocular reflex, which passes upward through the upper brainstem, whereas VEMP testing evaluates the sacculocollic reflex, which travels downward through the lower brainstem. Hence, in evaluating the extension of brainstem stroke, both caloric and VEMP testing should be performed.     

Vestibular evoked myogenic potentials in basilar artery migraine

OBJECTIVES/HYPOTHESIS: Because the sacculocollic reflex is a descending pathway passing through the territory of basilar artery, the aim of the study was to investigate whether hypoperfusion affects this pathway by applying vestibular evoked myogenic potential (VEMP) testing in patients with basilar artery migraine. STUDY DESIGN: A prospective study from May 2000 to April 2002. METHODS: Twenty patients were diagnosed as having basilar artery migraine according to the criteria of the International Headache Society and literature. Eight were male and 12 were female patients, and their ages ranged from 9 to 48 years (mean age, 40 y). Each patient underwent a battery of audio-vestibular tests. RESULTS: Electronystagmography disclosed abnormal eye tracking test in six patients (30%), and there were abnormal optokinetic nystagmus test results in nine patients (45%). Caloric test revealed canal paresis in seven patients, directional preponderance in four patients, and normal responses in nine patients (45%). Vestibular evoked myogenic potential testing disclosed absent vestibular evoked myogenic potentials in seven patients and delayed vestibular evoked myogenic potentials in two patients, with one patient showing absent vestibular evoked myogenic potentials on one side and delayed vestibular evoked myogenic potentials on the other side. The remaining 10 patients (50%) had bilateral normal vestibular evoked myogenic potentials. Five patients had preserved both caloric and VEMP test responses, six patients displayed absent caloric and VEMP test responses, and the remaining nine patients had either abnormal caloric test responses or abnormal vestibular evoked myogenic potentials, exhibiting a nonsignificant relationship between caloric test responses and vestibular evoked myogenic potentials. Relief of headache and vertigo was achieved after 3 months of medication. Ten asymptomatic patients with either absent or delayed vestibular evoked myogenic potentials before treatment underwent follow-up VEMP test, and nine patients (90%) displayed normal vestibular evoked myogenic potentials bilaterally. CONCLUSION: Vestibular evoked myogenic potential testing evaluates the sacculocollic reflex, which descends through the lower brainstem. Some patients with basilar artery migraine have absent or delayed vestibular evoked myogenic potentials, presumably because the descending pathway from the saccule through the brainstem to cranial nerve XI is interrupted, which is attributed to hypoperfusion in the territory of the basilar artery. After 3 months of medication, recovery of normal vestibular evoked myogenic potentials in an asymptomatic patient indicates reversible ischemia in the territory of the basilar artery.     

大前庭水管综合征患者的听力学及前庭诱发肌源性电位检测的特点

目的:探讨大前庭水管综合征(LVAS)患者的听力学、前庭诱发肌源性电位(VEMP)检测的特点及诊断意义。方法:对30例(60耳)LVAS患者行纯音测听、声导抗、ABR、畸变产物耳声发射(DPOAE)、VEMP及冷热实验检测,分析其诊断意义。结果:30例(60耳)LVAS患者均呈进行性、波动性听力下降,16例在听力波动性下降时伴眩晕。纯音测听主要呈感音神经性聋,但47耳(94.0%)在中耳功能正常的情况下于低频250、500Hz分别出现(43±17)dBHL及(33±18)dBHL骨气导差,呈混合性聋。ABR检测18耳(64.3%)于(3.06±0.52)ms引出声诱发短潜伏期负反应。42耳VEMP振幅均值为(147.10±107.55)μV,19耳反应阈为75dBnHL,7耳反应阈为65dBnHL。结论:根据进行性波动性听力减退、感音神经性聋在中耳功能正常的情况下出现低频骨气导差,ABR测试引出声诱发短潜伏期负反应及VEMP呈现高振幅低阈值的特征性提示,有助于临床医生得出LVAS的初步印象,可进一步行影像学检查以确诊。     

Vestibular evoked myogenic potentials are intact after sudden deafness

OBJECTIVE: To evaluate vestibular evoked myogenic potentials (VEMPs) in cases of sudden deafness, and to confirm the noncochlear origin of the VEMPs. STUDY DESIGN: Prospective study. VEMPs, which were evoked by short tone burst (95 dB nHL) stimulation, were recorded in 20 patients with unilateral, idiopathic sudden deafness. The results of the deaf ears were compared with those of the contralateral healthy ears and the normal control ears. The relations between VEMPs and the hearing level or caloric response were then investigated. RESULTS: All 20 of the deaf ears displayed normal biphasic VEMPs. The mean latencies of p13 and n23, as well as mean amplitude p13-n23, were 15.1 +/- 2.8 msec, 20.7 +/- 3.3 msec and 25.2 +/- 12.6 microV, respectively, not significantly different to either the contralateral healthy ears (p > 0.05) or the normal control ears (p > 0.05). Five deaf ears displayed canal paresis or absent caloric response, whereas the remaining 15 ears revealed normal caloric response. CONCLUSION: All the lesioned ears of patients with idiopathic sudden deafness exhibit normal biphasic VEMPs. Neither the hearing level nor the caloric response correlated to the VEMPs.     

Aportación del potencial vestibular miogénico evocado al estudio de la neuritis vestibular

IntroductionUntil recently, the only tests available to provide information about vestibular function were caloric and kinetic tests, which only give us information about the external semicircular canal and the superior vestibular nerve. In recent years the development of vestibular evoked myogenic potentials has allowed us to assess the saccule and the inferior vestibular nerve.Our aim is, by studying the caloric test results as well as the vestibular evoked myogenic potentials in patients with Vestibular Neuritis, to determine whether they have involvement of the superior, inferior or both vestibular nerves.Material and methodsRetrospective study of 9 patients with Vestibular Neuritis admitted to a tertiary care hospital. We studied them by means of anamnesis, otoneurological clinical examination, caloric test and vestibular evoked myogenic potentials. Their clinical progress after admission and any residual instability were also studied.ResultsWomen were more affected (66.6 %) than males. The mean age for presentation of the disease was 53.8 ± 14.0 years. Hospital stays lasted for 5.7 ± 3.2 days. After their crises, they suffered from instability for 122 ± 114 days. Four cases were diagnosed as Complete Vestibular Neuritis and five as Superior Vestibular Neuritis. P13 wave latency was normal in all cases. There were no differences between the groups in terms of the length of hospital stay nor residual instability.ConclusionsNowadays, vestibular evoked myogenic potentials make it possible to advance further in the study of Vestibular Neuritis. Complete and superior vestibular neuritis are much more frequent than inferior vestibular neuritis. Clinical behaviour is similar in the sub-types found.     

Assessment of vestibular function of infants and children with congenital and acquired deafness using the ice-water caloric test, rotational chair test and vestibular-evoked myogenic potential recording

CONCLUSIONS: The vestibular function can be assessed by ice-water caloric test, rotational chair test and VEMP recording in severely hearing impaired infants and young children, and 85% of these patients showed abnormal responses in these tests. OBJECTIVES: To evaluate the vestibular function of infants and young children with congenital and acquired deafness, we examined the semicircular canal and otolith function in their early childhood. MATERIALS AND METHODS: Our subjects were 20 children (11 boys, 9 girls; age range 31-97 months, mean age 54.2 months) with severe hearing impairment. Their vestibular functions were assessed by the ice-water caloric test, rotational chair test and vestibular-evoked myogenic potential (VEMP) recording. RESULTS: Among these 20 severely hearing impaired children, only 3 (15%) showed normal responses in the caloric test, rotational chair test and VEMP recording bilaterally. Seven (35%) showed responses asymmetrically in the caloric test despite normal responses in the rotational chair test and VEMP recording bilaterally. Five (25%) showed hyporeflexia or areflexia in the caloric test bilaterally, but showed normal responses in the rotational chair test and normal reproducible or decreased VEMPs. Five (25%) showed no responses at all in the caloric test, rotational chair test and VEMP recording.     

突发性聋与前庭神经炎的前庭损伤差异性研究

目的　通过比较研究伴有前庭损伤的突发性聋和前庭神经炎,探讨两类疾病前庭损伤的差异。方法  2016-02-25～2016-07-20解放军总医院耳鼻咽喉头颈外科眩晕诊疗中心,突发性聋组55例,其中39例伴眩晕患者;前庭神经炎组46例。前庭双温冷热试验、头脉冲试验、颈性前庭诱发肌源性电位、眼性前庭诱发肌源性电位评价及比较突发性聋及前庭神经炎两组疾病前庭损伤差异性。结果　前庭双温冷热试验突发性聋组异常率25.45%,前庭神经炎组异常率97.82%,两组比较差异有统计学意义（χ2=54.01,P＜0.001）。头脉冲试验：突发性聋组异常率9.09%,前庭神经炎组异常率32.61%,两组比较差异有统计学意义（χ2=8.72,P =0.003）。颈性前庭诱发肌源性电位突 发性聋组异常率69.10%,前庭神经炎组异常率43.47%,两组比较差异有统计学意义（χ2=6.72,P =0.010）;眼性前庭诱发肌源性电位突发性聋组异常率54.55%,前庭神经炎组异常率63.04%,两组比较差异无统计学意义（χ2=0.745,P =0.388）。结论　突发性聋与前庭神经炎两组患者前庭损伤比较,突发性聋合并眩晕者更有可能为球囊/前庭下神经受累,损伤部位更多靠近神经终末端,损伤是低频段的;前庭神经炎的前庭损伤范围大,损伤是全频段的,高位可能性更大。     

Acute vestibulopathy with simultaneous bilateral involvement of the vestibulo-ocular reflex limited to the low-frequency range

We report a novel type of idiopathic bilateral vestibulopathy with acute simultaneous involvement of the vestibulo-ocular reflex limited to the low-frequency range. A 64-year-old female presented with dizziness, oscillopsia, and difficulty walking. She did not experience rotatory vertigo and did not show any nystagmus. Vestibular function tests showed absent caloric responses in both ears, while vestibulo-ocular reflex (VOR) gains in the video head impulse test (vHIT) were preserved in all six semicircular canals. Cervical and ocular vestibular evoked myogenic potentials in response to air-conducted sound were absent on both sides. Since the caloric test and vHIT measures low-frequency and high-frequency VOR, respectively, we diagnosed the patient as having a bilateral VOR deficit limited to the low-frequency range. During a 1-year follow-up with vestibular rehabilitation, the subjective symptom of dizziness gradually recovered while recovery of vestibular function was minimal.     

Vestibular evoked myogenic potentials versus vestibular test battery in patients with Meniere's disease.

OBJECTIVE: The present study was undertaken to assess the sensitivity of vestibular evoked myogenic potentials testing to side-of-disease in Meniere's disease patients and to test the hypothesis that information supplied by vestibular evoked myogenic potentials is complementary to that provided by a conventional vestibular test battery. STUDY DESIGN: Prospective cohort study. SETTING: Large specialty hospital, department of otolaryngology. SUBJECTS: Twenty consenting adults (9 men and 11 women) with unilateral Meniere's disease by American Academy of Otolaryngology-Head and Neck Surgery diagnostic criteria. INTERVENTIONS: All subjects underwent bilateral vestibular evoked myogenic potentials testing using ipsilateral broadband click and short-toneburst stimuli at 250, 500, and 1,000 Hz. All subjects also underwent electronystagmography and sinusoidal vertical axis rotation testing. MAIN OUTCOME MEASURES: Accuracy of side-of-disease assignment by vestibular evoked myogenic potentials, caloric asymmetry, and multivariate analysis. RESULTS: Side-of-disease assignment was most accurate using caloric asymmetry with a 5% interaural difference criterion, achieving 85% correct assignment. The next best method was vestibular evoked myogenic potentials using 250-Hz toneburst stimuli, achieving 80% correct assignment. The least accurate method was caloric asymmetry using a traditional 30% interaural difference limen, achieving 55% correct assignment. Comparison of 5% interaural difference criterion and vestibular evoked myogenic potentials using 250-Hz toneburst stimuli showed discordant results, but in no case did both 5% interaural difference criterion and vestibular evoked myogenic potentials using 250-Hz toneburst stimuli make an incorrect assignment. CONCLUSION: Vestibular evoked myogenic potentials threshold was shown to be highly sensitive to side-of-disease in unilateral Meniere's disease. We observed instances of discordance in side-of-disease assignment by caloric asymmetry and vestibular evoked myogenic potential methods but no case in which both methods were incorrect. This supports the hypothesis that vestibular evoked myogenic potentials supplies information complementary to that provided by other components of the vestibular test battery.     

Short tone burst-evoked myogenic potentials on the sternocleidomastoid muscle: are these potentials also of vestibular origin?

OBJECTIVES: To show that short tone bursts (STBs) evoke myogenic potentials from the sternocleidomastoid muscle (SCM) that are of vestibular origin. DESIGN: Evoked potential activity was recorded from the SCMs of normal volunteers and from patients with vestibulocochlear disorders. SETTING: This outpatient study was conducted at the Department of Otolaryngology, University of Tokyo, Tokyo, Japan. SUBJECTS: Nine normal volunteers and 30 patients (34 affected ears) with vestibulocochlear disorders were examined. INTERVENTION: Diagnostic. OUTCOME MEASURES: Sound-evoked myogenic potentials in response to STBs were recorded with surface electrodes over each SCM. Responses evoked by STBs in patients were compared with responses evoked by clicks. RESULTS: In all normal subjects, STBs (0.5, 1, and 2 kHz) evoked biphasic responses on the SCM ipsilateral to the stimulated ear; the same was true for clicks. Short tone bursts of 0.5 kHz evoked the largest responses, while STBs of 2 kHz evoked the smallest. In patients with vestibulocochlear disorders, responses to STBs of 0.5 kHz were similar to responses evoked by clicks. Thirty (88%) of the 34 affected ears demonstrated the same results with 0.5-kHz STBs and with clicks. Responses were present in patients with total or near-total hearing loss and intact vestibular function. Conversely, patients with preserved hearing but with absent or severely decreased vestibular function had absent or significantly decreased myogenic potentials evoked by STBs. CONCLUSIONS: Short tone bursts as well as clicks can evoke myogenic potentials from the SCM. Myogenic potentials evoked by STBs are also probably of vestibular origin.     

Frequency dynamics shift of vestibular evoked myogenic potentials in patients with endolymphatic hydrops.

OBJECTIVE: To measure the frequency dynamics of the vestibular evoked myogenic potential in patients with endolymphatic hydrops. STUDY DESIGN: A prospective study. SETTING: A university hospital. SUBJECTS: The endolymphatic hydrops group consisted of 28 affected ears of patients with definite unilateral Ménière's disease and a control group of 36 ears of 20 healthy volunteers. INTERVENTIONS: Vestibular evoked myogenic potentials generated by tone bursts at 250, 500, 700, 1,000, 1,500, 2,000, and 4,000 Hz were measured in both groups. Vestibular evoked myogenic potentials were also measured after furosemide administration in six patients in the endolymphatic hydrops group. MAIN OUTCOME MEASURE: The frequency sensitivity of vestibular evoked myogenic potential, as evaluated by p13-n23 normalized amplitude. RESULTS: Peak amplitudes were noted at 500 Hz in the control group and at 1,000 Hz in the endolymphatic hydrops group. After furosemide loading, peak amplitude shifted to a lower frequency in four of six ears. CONCLUSION: The peak amplitude of vestibular evoked myogenic potentials in the endolymphatic hydrops group was at a higher frequency than in the control group. The frequency of the saccule (nu) should be proportional to radical(tau/sigma), where tau is the tension of membrane and sigma is its density. We advocate the hypothesis that the shift in frequency dynamics of vestibular evoked myogenic potential in patients with endolymphatic hydrops originates from the morphologic features of the saccule, analogous to an expanded balloon.     

中国一家系凝血因子C同源物基因新突变携带者听力学及前庭功能特点

目的分析携带凝血因子C同源物（coagulation factor C homology，COCH）基因新突变的中国常染色体显性遗传非综合征型聋（autosomal dominant non-syndromic sensorineural hearing loss，DFNA）9家系成员的听力学及前庭功能特点。方法对家系成员进行纯音测听、听性脑干反应、耳蜗电图等听力学及计算机动态姿势描记、前庭诱发性肌源性电位、视眼动、前庭眼动等前庭功能检查。结果听力学检查提示该家系患者20～50岁出现以高频下降为主的进行性感音神经性聋，60～70岁进展为重至极重度全频听力损失。前庭功能检查提示随意抽取的家系中耳聋患者计算机动态姿势描记、视眼动、温度试验正常；前庭诱发性肌源性电位检查提示耳聋患者耳石功能异常；速度阶梯试验时间常数异常、正弦谐波试验增益和相位异常，提示耳聋患者水平半规管功能减弱。结论中国DFNA9家系的所有耳聋患者均无前庭功能损害的主诉，通过详尽的前庭功能检查提示位于COCH非胶原结构糖蛋白A型2结构域上的突变所导致的前庭功能损害明显轻于位于LCCL结构域上的突变。中国DFNA9家系的临床资料分析首次表明DFNA9存在基因型和表现型的相关性。     

Ipsilateral and contralateral vestibular schwannomas in unilateral long-term deaf ears

In the past decade, we have encountered two patients with unilateral long-term deaf ear having vestibular schwannoma. One was on the deaf ear in a 53 years’ woman and the other was on the contralateral hearing ear in a 62 years’ woman. These two patients had total deafness on the right ear since childhood, associated with absent auditory brainstem response (ABR) and caloric responses, whereas normal ABR and caloric responses were shown on the left ear. Although similar physiological findings were disclosed on the deaf ears, MRI scan demonstrated vestibular schwannoma on the different side, that is, one in deaf ear and the other in hearing ear. For the former, absent ABR and caloric results indicate that the tumor originates from the superior vestibular nerve. In contrast with the latter, normal ABR and caloric responses, but absent vestibular-evoked myogenic potentials on the hearing ear imply that the tumor originates from the inferior vestibular nerve. The ipsilateral tumor on the deaf ear underwent intracranial surgical excision, followed by radiosurgery due to tumor recurrence 10 years later, while the contralateral one on the only hearing ear received radiosurgery only. Both patients were rather well, 3 years after last treatment.     

全聋型突发性耳聋患者的预后与前庭症状及前庭功能关系的回顾性分析

目的 探讨全聋型突发性耳聋患者的预后与前庭症状及前庭功能的关系。 方法 回顾性分析52例单侧全聋型突发性耳聋患者的前庭症状,以及眼肌前庭诱发肌源性电位(oVEMP)、颈肌前庭诱发肌源性电位(cVEMP)、视频头脉冲试验(vHIT)和冷热试验结果,观察这些患者的听力结果与前庭症状及前庭功能的关系。 结果 在52例单侧全聋型突发性耳聋患者中,有前庭症状、前庭功能异常的全聋型患者与无前庭症状者、功能正常者相比疗效差异有统计学意义。oVEMP、cVEMP、vHIT和冷热试验四项结果异常的全聋型患者显示出更低的治疗总有效率,oVEMP、cVEMP、vHIT和冷热试验正常的突发性耳聋患者有更高的听力恢复数值。 结论 有前庭症状、前庭功能异常的全聋型突发性耳聋患者疗效较差,oVEMP、cVEMP、vHIT和冷热试验正常的全聋型突发性耳聋患者有更好的听力恢复。前庭功能异常提示突发性聋患者的内耳病变范围较大、程度较重。     

Extent of lesions in idiopathic sudden hearing loss with vertigo: study using click and galvanic vestibular evoked myogenic potentials

OBJECTIVE: To clarify the extent of the vestibular lesions in idiopathic sudden hearing loss with vertigo using vestibular evoked myogenic potentials (VEMPs) in response to click (click-VEMP) and galvanic (galvanic-VEMP) stimulation, as well as caloric tests. DESIGN: Retrospective study. SETTING: University hospital. PATIENTS: We enrolled 22 patients with idiopathic sudden hearing loss with vertigo in this study. All patients underwent audiometry and click-VEMP and caloric tests. Eight patients underwent a galvanic-VEMP test. RESULTS: Among the 22 patients, 17 (77%) showed an absence of click-VEMPs on the affected side. In response to caloric testing, 10 patients (45%) showed a decreased response on the affected side. All 8 patients who underwent galvanic-VEMP testing showed normal responses. Most patients with decreased caloric responses (9 [90%] of 10 patients) showed an absence of click-VEMPs, whereas 9 (53%) of the 17 patients who showed abnormal click-VEMPs showed decreased caloric responses. Initial hearing level and hearing outcome significantly correlated with abnormalities on the vestibular test results. CONCLUSIONS: The lesion site of vestibular disorders in idiopathic sudden hearing loss with vertigo appeared to be within the labyrinth on the basis of galvanic-VEMP findings. Results of the click-VEMP and caloric tests suggested that the saccule could be involved more frequently than the semicircular canals. The combined use of click-VEMP and caloric tests is useful for evaluating vestibular functions in idiopathic sudden hearing loss with vertigo because the extent of vestibular abnormalities correlated well with hearing outcome.     

Screening for auditory dysfunction in infants by evoked oto-acoustic emissions

Auditory threshold using auditory brain-stem responses (ABR) was determined in 30 ears from normally-hearing infants and 16 ears from infants with sensorineural deafness. In the same population, evoked oto-acoustic emissions (EOAEs) in response to a click of 20-dB hearing level were recorded. The presence of EOAEs was correlated with ABR thresholds. Evoked oto-acoustic emissions were always present when ABR wave V threshold was equal to or below 30-dB hearing level. On the contrary, infants with ABR thresholds higher than 40-dB hearing level never had EOAEs. As the recordings of EOAEs could be obtained more rapidly than ABR thresholds (average duration: five minutes vs 40 minutes), EOAEs could hold some promise as an objective, easy, and noninvasive test for screening auditory dysfunction in infants.     

Vestibular evoked myogenic potentials show altered tuning in patients with Ménière's disease.

OBJECTIVE: Acoustic stimulation of the saccule gives rise to a vestibulocollic reflex, the output of which can be measured in the neck as inhibition of activity in the ipsilateral sternocleidomastoid muscle. This vestibular evoked myogenic potential has been promoted as a means of assessing integrity of saccular function. In this study, we test the hypothesis that the cochleosaccular hydrops of Ménière's syndrome leads to alterations in saccular motion that change the dynamics of the vestibular evoked myogenic potential. STUDY DESIGN: Prospective cohort study. SETTING: Large specialty hospital, department of otolaryngology. SUBJECTS: Fourteen normal adult volunteers and 34 consecutive consenting adult patients with unilateral Ménière's disease by American Academy of Otolaryngology-Head and Neck Surgery diagnostic criteria. INTERVENTIONS: All subjects underwent vestibular evoked myogenic potential testing using ipsilateral broadband click and short tone-burst stimuli at 250, 500, 1,000, 2,000, and 4,000 Hz. MAIN OUTCOME MEASURES: Threshold, amplitude, and latency of vestibular evoked myogenic potential responses in normal and Ménière's affected and unaffected ears. RESULTS: Vestibular evoked myogenic potential was present in all ears tested. Normal subjects show a frequency-dependent vestibular evoked myogenic potential threshold, with best response ("frequency tuning") at 500 Hz. Compared with normal subjects and unaffected ears of Ménière's subjects, affected Ménière's ears had significantly increased vestibular evoked myogenic potential thresholds. Affected Ménière's ears showed threshold shifts at all frequencies and there was less tuning apparent at 500 Hz. Unaffected ears of Ménière's subjects also showed significantly elevated vestibular evoked myogenic potential thresholds compared with normal subjects. Analyses of vestibular evoked myogenic potential thresholds for effects of age, hearing loss, and audiometric configuration showed no significant differences. CONCLUSIONS: Ménière's ears display alterations in vestibular evoked myogenic potential threshold and tuning, supporting our hypothesis of altered saccular motion mechanics arising from hydropic distention. Unaffected ears of unilateral Ménière's subjects show similar changes, though to a lesser degree. This finding may be because of occult saccular hydrops in the asymptomatic ear or binaural interactions in the vestibular evoked myogenic potential otolith-cervical reflex arc.     

Click-evoked myogenic potentials recorded on alert guinea pigs

The aim of this study was to establish an animal model of acoustically evoked vestibulo-collic reflex using guinea pigs. A special clamp was applied to restrain the head and body of the guinea pigs, but leaving its four legs free. Each animal underwent vestibular evoked myogenic potential (VEMP) and caloric tests using clip electrode method without general anesthesia or decerebrate surgery. The response rates for the myogenic potentials on the neck of guinea pigs using 100, 90, 80 and 70 dB monaural acoustic stimulation with unilateral recording were 100%, 62%, 50% and 0%, respectively. The mean latencies of the positive and negative peaks for the myogenic potentials were 7.24+/-0.49 and 9.15+/-0.47 ms, 7.09+/-0.43 and 9.28+/-0.42 ms, as well as 7.03+/-0.59 and 9.14+/-0.56 ms, when elicited by 100, 90 and 80 dB acoustic stimulation, respectively. The median (minimum-maximum) peak-to-peak amplitudes were 11.93 (6.14-16.86), 10.99 (5.28-19.40), and 11.17 (5.02-20.72) microV, when elicited by 100, 90 and 80 dB acoustic stimulation, respectively. We found no significant relationship between the stimulus intensity and the mean latencies or peak-to-peak amplitude of the myogenic potentials in guinea pigs. For those treated with gentamicin unilaterally, all guinea pigs showed absent caloric responses on the lesion side, and absent myogenic potentials on the neck when using ipsi-lesional acoustic stimulation, while the hearing was preserved. Hence, the use of gentamicin-treated animals, along with normal controls and auditory brainstem responses, results in convincing results that the recorded myogenic potentials are in fact of vestibular origin.