Augmented ocular vestibular evoked myogenic potentials to air-conducted sound in large vestibular aqueduct syndrome.

OBJECTIVE: To demonstrate the value of recording air-conducted ocular Vestibular Evoked Myogenic Potentials (oVEMP) in a patient with bilaterally enlarged vestibular aqueducts. DESIGN: Cervical VEMP and oVEMP were recorded from a patient presenting with bilateral hearing loss and imbalance, attributable to large vestibular aqueduct syndrome. The stimuli were air-conducted tone bursts at octave frequencies from 250 to 2000 Hz. Amplitudes and thresholds were measured and compared with the normal response range of 32 healthy control subjects. RESULTS: oVEMP reflexes demonstrated pathologically increased amplitudes and reduced thresholds for low-frequency tone bursts. Cervical VEMP amplitudes and thresholds were within normal limits for both ears across all frequencies of stimulation. CONCLUSIONS: This study is the first to describe the augmentation of AC oVEMPs in an adult with large vestibular aqueduct syndrome.

A Portrait of Menière's Disease Using Contemporary Hearing and Balance Tests.

OBJECTIVE: Menière's disease (MD) is characterized by recurrent vertigo and fluctuating aural symptoms. Diagnosis is straightforward in typical presentations, but a proportion of patients present with atypical symptoms. Our aim is to profile the array of symptoms patients may initially present with and to analyze the vestibular and audiological test results of patients with a diagnosis of MD. DESIGN: A retrospective study of patient files. SETTING: A tertiary, neuro-otology clinic Royal Prince Alfred Hospital, Sydney, Australia. METHOD: We identified 375 patients. Their history, examination, vestibular-evoked myogenic potentials (VEMP), video head-impulse test, canal-paresis on caloric testing, subjective visual horizontal (SVH), electrocochleography, ictal nystagmus, and audiometry were assessed. RESULTS: Atypical presenting symptoms were disequilibrium (n = 49), imbalance (n = 13), drop-attacks (n = 12), rocking vertigo (n = 2), and unexplained vomiting (n = 3), nonspontaneous vestibular symptoms in 21.6%, fluctuation of aural symptoms only (46%), and headaches (31.2%). Low velocity, interictal spontaneous-nystagmus in 13.3% and persistent positional-nystagmus in 12.5%. Nystagmus recorded ictally in 90 patients was mostly horizontal (93%) and of high velocity (48 ±â€Š34°/s). Testing yielded abnormal caloric responses in 69.6% and abnormal video head impulse test 12.7%. Air-conducted cervical VEMPs were abnormal in 32.2% (mean asymmetry ratio [AR] 30.2 ±â€Š46.5%) and bone-conducted ocular VEMPs abnormal in 8.8% (AR 11.2 ±â€Š26.8%). Abnormal interictal SVH was in 30.6%, (ipsiversive n = 46 and contraversive n = 19). Mean pure-tone averages 50 dB ±â€Š23.5 and 20 dB ±â€Š13 for affected and unaffected ears. CONCLUSION: Menière's disease has a distinctive history, but atypical presentations with normal vestibular function and hearing are a diagnostic challenge delaying treatment initiation.

Meniere's Disease.

This article reviews 3 aspects of Meniere's disease (MD), which have been recently revisited: namely, the pathologic mechanism causing the attacks of vertigo, the clinical diagnosis, and the medical and surgical treatments. The characteristic attacks of vertigo are unlikely to be due to membrane ruptures, so a hypothesis that the vertigo is caused by a volume of endolymph shifting suddenly from the cochlea into the pars superior is suggested. The definite diagnosis according to the American Academy of Otolaryngology HNS 1995 criteria [13] failed to exclude vestibular migraine sufficiently and a revision in 2015 [14] has partly addressed this problem but another method which stresses the interaction of the cochlear and vestibular symptoms is described. The treatment of MD has been updated, providing evidence for each popular therapy. Newer treatments using intratympanic medications including steroid solutions and gentamicin are discussed. Finally, the role of cochlear implants is mentioned.

Editorial: 'auditory neuropathy' and cochlear implantation - myths and facts.

A review of current opinion concerning 'auditory neuropathy' is presented. It is suggested that electrophysiological tests, including electrocochleography, auditory brainstem responses and electrically evoked auditory brainstem responses, together with imaging, can provide information regarding the site of the underlying pathological conditions that may produce the combination of otoacoustic emissions in the absence of auditory brainstem responses in children with hearing loss. It is suggested that in 75% of cases auditory neuropathy can merely be a result of surviving outer hair cells when inner hair cell function is compromised. The remaining cases of auditory neuropathy may have dysfunction of the afferent neural synapse, cochlear nerve, cochlear nucleus, auditory brainstem tracts and central auditory system. Rather than continuing to use a blanket and often misleading term, we are now in a better position to describe each individual case exhibiting this phenomenon according to the correct site of lesion.

Meningitis resulting in hearing loss and labyrinthitis ossificans - does the causative organism matter?

Our aim was to demonstrate whether one causative agent of meningitis is more likely to cause profound hearing loss and labyrinthitis ossificans. We obtained data from the New South Wales health department for cases of meningitis between 1995 and 2005 (1568 cases) and the Sydney Cochlear Implant Centre for cochlear implant patients with hearing loss secondary to meningitis from 1984 to 2005 (70 ears in 59 patients). The aetiological agents were compared with regard to their ability to cause profound hearing loss and cochlear ossification. Neisseria meningitidis resulted in 56.9% of cases of meningitis and 11.4% of the cases of profound hearing loss resulting in cochlear implantation (incidence of profound hearing loss of 0.4%). Streptococcus pneumoniae, however, caused 41.1% of meningitis but 85.7% of cochlear implantation (incidence of 4.6%). Labyrinthitis ossificans was more common after infection with Streptococcus pneumoniae but there was no statistically significant difference between Streptococcus pneumoniae, Haemophilus influenzae or Neisseria meningitidis for labyrinthitis ossificans (p = 0.45, chi-squared test). In conclusion Neisseria meningitidis meningitis carries a very low risk of profound hearing loss but Streptococcus pneumoniae meningitis a significantly higher risk.

Trans-tympanic electric auditory brainstem response (TT-EABR): the importance of the positioning of the stimulating electrode.

Trans-tympanic electric auditory brainstem response (TT-EABR) is an established pre-operative investigation in cochlear implantation surgery. Various techniques have been employed to obtain electrical responses but there has been no universal agreement on the exact positioning of the stimulating electrode on the medial wall of the mesotympanum. The authors investigate the relationship of the positioning of the electrode and the brainstem response.

Cochlear implantations in children with Waardenburg syndrome: an electrophysiological and psychophysical review.

Waardenburg syndrome presents with dystopia canthorum, pigmentary abnormalities of hair, iris and skin (often a white forelock and heterochromia iridis) and sensorineural deafness. The authors review the electrophysiological and psychophysical findings of implanted children with Waardenburg syndrome at the Sydney Cochlear Implant Centre. Twenty children with Waardenburg syndrome received cochlear implants between 1985 and 2001. Electrical auditory brainstem response (EABR) was performed in all of these patients intra-operatively as part of the routine investigations. Only 13 of these patients were assessed one year or more post-operatively by means of the Melbourne Categories (0-7). Four patients (20%) were found to have abnormal EABR recordings. The mode of Melbourne Categories in this group (n = 3) was 1 at one year post-operation. The other 16 patients were found to have normal EABR and the mode of Melbourne Categories in this group (n = 10) was 7. A poor outcome after cochlear implantation was associated with abnormal EABR recordings (a 'true' auditory neuropathy) and was found in a significant proportion of patients with Waardenburg syndrome.

Cochlear Implant Outcomes in Cochlea Nerve Aplasia and Hypoplasia.

OBJECTIVE: To assess cochlear implant (CI) outcomes, and factors affecting outcomes, for children with aplasia/ hypoplasia of the cochlea nerve. We also developed a new grading system for the nerves of the internal auditory meatus (IAM) and cochlea nerve classification. STUDY DESIGN: Retrospective patient review. SETTING: Tertiary referral hospital and cochlear implant program. PATIENTS: Children 0 to 16 years inclusive with a CI who had absent/hypoplastic cochlea nerve on magnetic resonance imaging (MRI). INTERVENTION: Cochlear implant. MAIN OUTCOME MEASURES: MRI, trans-tympanic electrical auditory brainstem response, intraoperative electrical auditory brainstem response, Neural Response Telemetry, Categories of Auditory Perception score, Main mode of communication. RESULTS: Fifty CI recipients (26 males and 24 females) were identified, 21 had bilateral CIs, 27 had developmental delay. MRI showed cochlea nerve aplasia in 64 ears, hypoplasia in 25 ears, and a normal nerve in 11 ears. Main mode of communication was analyzed for 41 children: 21 (51%) used verbal language (15 speech alone, 5 speech plus some sign, 1 bilingual in speech and sign), and 20 (49%) used sign language (10 sign alone, 9 sign plus some speech, 1 tactile sign). Seventy-three percent of children used some verbal language. Cochlea nerve aplasia/ hypoplasia and developmental delay were both significant factors affecting main mode of communication. Categories of Auditory Performance scores were available for 59 CI ears; 47% with CN Aplasia (IAM nerve grades 0-III) and 89% with CN hypoplasia (IAM nerve grade IV) achieved Categories of Auditory Performance scores of 5 to 7 (some verbal understanding) (p = 0.003). CONCLUSION: Our results are encouraging and useful when counselling families regarding the likelihood of language outcomes and auditory understanding.

Displacement of electrodes of a cochlear implant into the vestibular system: intra- and postoperative electrophysiological analyses.

A cochlear implant device is normally inserted into the scala tympani via a posterior tympanotomy and cochleostomy. There has been no previous report of displacement of the array into the vestibular part of the labyrinth. The authors present and discuss the audiological and electrophysiological measurements of a case in which part of the array herniated through into the vestibule.

Pediatric cochlear implantation: associated with minimal postoperative pain and dizziness.

OBJECTIVE: To prospectively document the surgical pain, assessing analgesia use as a proxy, and postoperative dizziness in children over the first week after cochlear implantation. STUDY DESIGN: Prospective. SETTING: Tertiary referral hospital and cochlear implant program. PATIENTS: Children aged 0 to 16 years inclusive undergoing cochlear implant surgery, who returned to see the primary surgeon for the postoperative 1-week follow-up appointment. INTERVENTIONS: One-week postoperative collection of data via direct questioning of parents and children. MAIN OUTCOME MEASURES: Analgesia use, duration of analgesia use and dizziness (nil, slight, or moderate), type of surgery, and radiologic findings. RESULTS: Data were available for 61 of 98 children aged 5 months to 15 years. Children underwent first side implant (n = 27), sequential second side implant (n = 15), bilateral simultaneous (n = 16), and explant reimplantation (n = 3). On average, children used paracetamol for only 1.9 days after discharge from the hospital. Longer average paracetamol use was associated with bilateral simultaneous surgery (3.3 d after discharge from the hospital) and also the younger age group of 0 to 12 months (3.2 d). Slight dizziness was reported by 8% of all children at 1 week postsurgery.No child had marked dizziness or unsteadiness. Four children had large vestibular aqueducts on radiology scans, two (50%) of these children has slight unsteadiness at 1 week postoperatively. CONCLUSION: Our study shows cochlear implant surgery is well tolerated by children. This information enables better counseling of families and children considering cochlear implantation.

CHARGE syndrome and Cochlear implantation: difficulties and outcomes in the paediatric population.

OBJECTIVES: CHARGE syndrome is a complex cluster of congenital abnormalities, these children may have absent or hypoplastic auditory nerves. Our objective was to assess preoperative factors and outcomes for paediatric cochlear implant recipients with CHARGE syndrome, to enable better surgical preparation and family counselling. METHODS: The Sydney Cochlear Implant Centre database was searched for children with CHARGE syndrome who had received a cochlear implant at ages 16 and less. Data were collected regarding clinical history; hearing assessments; MRI and CT scan findings; preoperative transtympanic electrical Auditory Brainstem Response (ABR); intraoperative findings and intraoperative electrical ABR and Neural Response Telemetry; and language outcomes in terms of main language used and Categories of Auditory Performance scores (0-7 ranking). RESULTS: Ten children were identified. All seven prelingual profoundly deaf children with CHARGE syndrome had hypoplastic or absent auditory nerves bilaterally on MRI scans. Middle ear anatomy was often abnormal, affecting surgical landmarks and making identification of the cochlea very difficult in some cases. Three cases required repeated surgery to obtain successful cochlear implant insertion, one under CT scan image guided technique. All seven children used sign language, or simpler gestures, as their main mode of communication. Two children of of these children, who were implanted early, also attained some spoken language. CAP scores ranged from 0 to 6. The three children with CHARGE syndrome and progressive sensorineural hearing loss had a normal auditory nerve in at least one ear on MRI scans. All had preoperative verbal language, with CAP scores of 6, and continued with CAP scores of 6 following receipt of the cochlear implant. CONCLUSION: Children with CHARGE and congenital profound hearing loss all had hypoplasia or absent auditory nerves, affecting their outcomes with cochlear implants. They often had markedly abnormal middle ear anatomy and CT image guided surgery can be helpful. These children should be offered a bilingual early intervention approach, using sign language and verbal language, to ensure best language outcomes. Children with CHARGE syndrome and progressive profound hearing loss did well with cochlear implants and continue to be able to use verbal language.

Evidence for surviving outer hair cell function in congenitally deaf ears.

OBJECTIVES/HYPOTHESIS: The hypotheses of the study were that congenital hearing impairment in infants can result from the isolated loss of inner hair cells of the cochlea and that this is shown by the presence of abnormal positive summating potentials on round window electrocochleography. The objectives were to establish the proportion of infants with hearing loss affected, the nature of the cochlear lesion, and its etiology. And to highlight the important implications for otoacoustic emissions testing and universal neonatal screening. STUDY DESIGN: A prospectively conducted consecutive cohort study with supplemental review of notes was performed. METHODS: Four hundred sixty-four children underwent round window electrocochleography and auditory brainstem response testing under general anesthesia to assess suspected hearing loss. The presence of abnormal positive potentials was recorded. Otoacoustic emissions data were collected separately and retrospectively. RESULTS: Three hundred forty-two children had significant bilateral congenital hearing loss. All results were from hearing-impaired children. Abnormal positive potentials were recorded in 73 of 342 children (21%). Eighty-three percent of children with otoacoustic emissions also had abnormal positive potentials, but only 14% of children without otoacoustic emissions had abnormal positive potentials (P <.001). In the neonatal intensive care unit setting, 43% of infants were found to have abnormal positive potentials, whereas only 10% had abnormal positive potentials if not in the neonatal intensive care unit setting (P <.001). Abnormal positive potentials were present in 63% of infants born before 30 weeks gestation and in 14% of infants born at term (P <.001). Abnormal positive potentials were identified in 57% of infants with documented hypoxia and 11% of children with no episodes (P <.001). Otoacoustic emissions were present in 48% of infants from the neonatal intensive care unit, despite their hearing loss. CONCLUSION: Both otoacoustic emissions and abnormal positive potentials may originate from outer hair cell activity following inner hair cell loss. This may occur in more than 40% of hearing-impaired children in the neonatal intensive care unit setting. Chronic hypoxia is the most likely cause. Otoacoustic emissions testing may not be a suitable screening tool for such infants.

Role of auditory stimulation in maturation of the auditory pathway.

OBJECTIVE: To compare the maturation of the auditory pathway, as shown by electrical brainstem auditory potentials (EABRs), in ears with and without prior auditory stimulation. MATERIAL AND METHODS: Electrophysiological data were collected prospectively from ears which had received cochlear implants. Implant-evoked (Imp)EABRs were recorded. Thirty children, implanted after January 2000, were selected according to a strict inclusion/exclusion protocol. All the children had received a 22-channel Nucleus cochlear implant (CI24 series). Intraoperatively, ImpEABRs were recorded using the Medelec Synergy Evoked Response system in conjunction with Nucleus Neural Response Telemetry software. The ImpEABR latencies of waves eII, eIII and eV and the morphology of wave eV were assessed. RESULTS: ImpEABRs alter during the first 12 months of life. The latency becomes shorter during this period and the morphology of wave eV alters from a broad shape to a more distinct waveform. This appears to occur independently, even in the absence of auditory stimulation. CONCLUSION: The development of electrical brainstem auditory potentials is not dependent on auditory stimulation.

The role of the promontory stimulation test in cochlear implantation.

To date, 290 adults have been implanted in the cochlear implant programme in Sydney (Australia), where the promontory stimulation test (PST) is routinely used to assess implant candidacy. There has been much controversy over the exact role and value of this test. Pre- and postoperative speech comprehension tests of 150 implantees were analysed, and scores were compared with preoperative PST performances. Eighty-nine per cent of the patients perceived sound when the promontory was stimulated electrically. This group of implantees scored 81% on CID speech tests at 12 months postoperatively, compared to the minority who lacked preoperative promontory stimulability, who scored 42%. The PST is therefore predictive of greater speech benefits after implantation. It also provides an important psychophysical experience of hearing electrical sound.

Impedance, neural response telemetry, and speech perception outcomes after reimplantation of cochlear implants in children.

OBJECTIVE: To compare mean impedance levels, neural response telemetry (NRT), and auditory perception after initial and explant-reimplant pediatric cochlear implants. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral hospital and cochlear implant program. PATIENTS: Children 0 to 16 years inclusive who have undergone explant-reimplant of their cochlear implant. INTERVENTION: Impedance levels, NRT, and speech perception performance. MAIN OUTCOME MEASURES: Impedance, NRT, and auditory perception at switch on, 3 months, 12 months, 3 years, and 5 years after initial cochlear implant and reimplantation. RESULTS: The explant-reimplant group receiving Cochlear contour array had significantly (p < 0.001) raised impedance at switch on, 3 months, 12 months, and 3 years, compared with their initial implant. The explant-reimplant group receiving Cochlear straight array had marginally significant (p = 0.045) raised impedance at switch on, 3 months, 12 months, and 3 and 5 years. Infection was associated with greater increases in impedance in the reimplant Contour group. NRT was increased in the explant-reimplant group but not significantly (p = 0.06). Auditory perception returned to preexplant levels within 6 months in 61% of children. CONCLUSION: Impedance is higher after explant-reimplant and remains increased for years after explant-reimplant with Cochlear contour and to a lesser degree the straight array device.

Cochlear implants and magnetic resonance scans: A case report and review.

OBJECTIVE AND IMPORTANCE: Traditionally, magnetic resonance imaging (MRI) was contraindicated for patients with cochlear implants (CIs), due to concern about device displacement, overheating of the device or tissues, or direct damage to the device electrode. In addition, image artifact from the device magnet gave poor imaging information in the cranial and upper cervical spine region. Today, MRI is increasingly required in patients who have undergone cochlear implantation, and CI design and MRI protocols have therefore changed to allow implanted patients to safely enter the MRI field, in some cases without removal of the CI internal magnet. CLINICAL PRESENTATION: We present a patient with bilateral CIs who required MRI to investigate new neurological symptoms. Despite tight head bandaging applied according to our protocol, MRI at 1.5 T led to bilateral skin reactions and displacement of the magnet on the left. Both magnets were subsequently removed to allow the skin reactions to settle and for further imaging without artifact. The functioning of the patient's implants was not affected. CONCLUSION: The final decision to recommend that a patient with a CI undergoes MRI, with or without removal of the internal magnet, requires close cooperation between the CI team, the physician requiring the scan, and the radiology team involved in the patient's care. The case study we present highlights the need for patients to be fully informed of the risks involved.

Pediatric cochlear implants: additional disabilities prevalence, risk factors, and effect on language outcomes.

OBJECTIVE: To determine the prevalence of additional disabilities in a pediatric cochlear population, to identify medical and radiologic conditions associated with additional disabilities, and to identify the effect of additional disabilities on speech perception and language at 12 months postoperatively. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center and cochlear implant program. PATIENTS: Records were reviewed for children 0 to 16 years old inclusive, who had cochlear implant-related operations over a 12-month period. INTERVENTIONS: Diagnostic and rehabilitative. MAIN OUTCOME MEASURES: Additional disabilities prevalence; medical history and radiologic abnormalities; and the effect on Categories of Auditory Performance (CAP) score at 12 months postoperatively. RESULTS: Eighty-eight children having 96 operations were identified. The overall prevalence of additional disabilities (including developmental delay, cerebral palsy, visual impairment, autism and attention deficit disorder) was 33%. The main conditions associated with additional disabilities were syndromes and chromosomal abnormalities (87%), jaundice (86%), prematurity (62%), cytomegalovirus (60%), and inner ear abnormalities including cochlea nerve hypoplasia or aplasia (75%) and semicircular canal anomalies (56%). At 12 months postoperatively, almost all (96%) of the children without additional disabilities had a CAP score of 5 or greater (speech), compared with 52% of children with additional disabilities. Children with developmental delay had a median CAP score of 4, at 12 months compared with 6 for those without developmental delay. CONCLUSION: Additional disabilities are prevalent in approximately a third of pediatric cochlear implant patients. Additional disabilities significantly affect the outcomes of cochlear implants.

Assessment of intracochlear trauma caused by the insertion of a new straight research array.

OBJECTIVE: To assess the degree of intracochlear trauma using the Cochlear™ Straight Research Array (SRA). This electrode has recently been released by Cochlear™ on the CI422 implant. BACKGROUND: Electroacoustic stimulation (EAS) enables recipients to benefit from cochlear implantation while retaining their natural low-frequency hearing. A disadvantage of short EAS electrodes is that short electrodes provide limited low-frequency stimulation. Thus, loss of the residual hearing may require reimplantation with a longer electrode. In order to overcome this problem, the slim diameter SRA with increased length (20-25 mm) has been designed to provide a deeper, yet non-traumatic insertion. METHODS: Two insertion studies into temporal bones were undertaken. The first involved dissection of the cochlea to gain a view into the scala vestibuli and insertion of the SRA and control electrodes with a microactuator for a surgeon-independent yet controlled insertion. High-speed photography was used to record data. The second study involved a high-resolution X-ray microcomputed tomography (microCT) study to assess electrode placement and tissue preservation in surgeon-implanted bones. RESULTS: The SRA had a smooth insertion trajectory. The average angular insertion depth was 383° when inserted until resistance was encountered, and 355° if inserted to a predetermined mark for EAS use. In addition, microCT data showed that this caused no significant trauma or distortion of the basilar membrane up to 20 mms depth. CONCLUSION: Temporal bone studies show that the SRA appears to cause no intracochlear trauma if used as an EAS electrode up to 20 mm depth of insertion.

On the differential diagnosis of Ménière's disease using low-frequency acoustic biasing of the 2f1-f2 DPOAE.

We have cyclically suppressed the 2f1-f2 distortion product otoacoustic emission (DPOAE) with low-frequency tones (17-97 Hz) as a way of differentially diagnosing the endolymphatic hydrops assumed to be associated with Ménière's syndrome. Round-window electrocochleography (ECochG) was performed in subjects with sensorineural hearing loss (SNHL) on the day of DPOAE testing, and from which the amplitude of the summating potential (SP) was measured, to support the diagnosis of Ménière's syndrome based on symptoms. To summarize and compare the cyclic patterns of DPOAE modulation in these groups we have used the simplest model of DPOAE generation and modulation, by assuming that the DPOAEs were generated by a 1st-order Boltzmann nonlinearity so that the magnitude of the 2f1-f2 DPOAE resembled the 3rd derivative of the Boltzmann function. We have also assumed that the modulation of the DPOAEs by the low-frequency tones was simply due to a sinusoidal change in the operating point on the Boltzmann nonlinearity. We have found the cyclic DPOAE modulation to be different in subjects with Ménière's syndrome (n = 16) when compared to the patterns in normal subjects (n = 16) and in other control subjects with non-Ménière's SNHL and/or vestibular disorders (n = 13). The DPOAEs of normal and non-Ménière's ears were suppressed more during negative ear canal pressure than during positive ear canal pressure. By contrast, DPOAE modulation in Ménière's ears with abnormal ECochG was greatest during positive ear canal pressures. This test may provide a tool for diagnosing Ménière's in the early stages, and might be used to investigate the pathological mechanism underlying the hearing symptoms of this syndrome.

The vestibular evoked-potential profile of Ménière's disease.

OBJECTIVE: To define the ocular and cervical vestibular evoked myogenic potential (oVEMP and cVEMP) profile in Ménière's Disease (MD), we studied air-conducted (AC) sound and bone-conducted vibration (BCV)-evoked responses in 77 patients and 35 controls. METHODS: oVEMPs were recorded from unrectified infra-orbital surface electromyography (EMG) during upward gaze. cVEMPs were recorded from rectified and unrectified sternocleidomastoid EMG during head elevation against gravity. Responses to AC clicks delivered via headphones and BC forehead taps delivered with a mini-shaker (bone-conduction vibrator) and a triggered tendon-hammer were recorded. RESULTS: In clinically definite unilateral MD (n=60), the prevalence of unilateral VEMP abnormalities was 50.0%, 10.2% and 11.9% for click, minitap and tendon-hammer evoked oVEMPs, 40.0%, 22.8% and 10.7% for click, minitap and tendon-hammer evoked cVEMPs. The most commonly observed profile was abnormality to AC stimulation alone (33.3%), followed by abnormalities to both AC and BCV stimuli (26.7%). Isolated abnormalities to BCV stimuli were rare (5%) and limited to the minitap cVEMP. The prevalence of abnormalities for each of the AC VEMPs was significantly higher than for any one BCV VEMP. For click cVEMP, click oVEMP and minitap cVEMP, average Reflex Asymmetry Ratios (AR) were significantly higher in MD compared with controls. Test results for AC cVEMP, AC oVEMP, minitap cVEMP and caloric asymmetry were significantly correlated with hearing loss. CONCLUSIONS: Predominance of abnormalities in oVEMP and cVEMP responses to AC sound is characteristic of MD and indicative of saccular involvement. SIGNIFICANCE: This pattern of VEMP abnormalities may enable separation of Ménière's disease from other peripheral vestibulopathies.