The newly developed use of magnetic resonance imaging of the human inner ear, on a 3 Tesla scanner with intratympanically administered gadolinium, can now reliably distinguish perilymph from endolymph and visually confirm the presence or absence of endolymphatic hydrops. Transtympanic tone burst electrocochleography is an established, and under-utilised evoked response electrophysiological test for hydrops, but it relies on a symptom score to indicate the likelihood of hydrops being present. The current diagnostic criteria for Ménière's disease make no allowance for any in vivo test, making diagnostic errors likely. In this small pilot study of three patients undergoing tone burst electrocochleography, subsequent magnetic resonance imaging confirmed or excluded the hydrops that the electrocochleography predicted. Magnetic resonance imaging of the inner ear is a safe technique that can be performed in conjunction with imaging of the VIIIth cranial nerves. As this report comprised only three patients in a pilot study, rigorous clinical studies are required to define the possible role of magnetic resonance imaging in the diagnosis of Ménière's disease.

We aimed to investigate whether auditory brainstem response (ABR), assessed immediately after grommet insertion, was an accurate measure of hearing threshold.

Ten children were recruited (20 ears). Patients underwent transient evoked otoacoustic emission (TEOAE) and ABR tests before and after grommet insertion under general anaesthetic. A third assessment was conducted at a six-week review, without anaesthetic or sedation. The hearing threshold in dB and the presence of TEOAE were recorded by senior audiologists. The results of each investigation were compared. At review, only 15 ABR and 17 TEOAE tests, of a possible 20, were recorded.

Transient evoked otoacoustic emissions were recorded in 30 per cent of ears pre-operatively, 20 per cent of ears post-operatively and 82 per cent of ears at six-week review. The average ABR thresholds were 23.75 dB (range 10–45 dB) pre-operatively, 27.25 (range 15–40 dB) post-operatively and 15 dB (range 5–25 dB) at six-week review. Comparing pre- and post-operative assessment, decreased thresholds were seen in six ears and elevated thresholds in 11. Comparing the six-week review ABR with the post-operative ABR, 13 ears had decreased thresholds, by as much as 20 dB. Thresholds of 35 dB or greater were measured in six ears immediately after grommet insertion (maximum 40 dB). Threshold shifts of 15 dB or greater was observed in seven ears. The intra-subject variation was shown to be significant (p<0.001) when repeated measures analysis of variance was applied.

We conclude that there is evidence that ABR can be inaccurate after grommet insertion, overestimating hearing thresholds. We believe that the mechanism by which the error is realised is temporary threshold shift.

Objective: To formulate an alternative strategy for universal infants hearing screening in an Indian tertiary referral hospital with a high delivery rate, which could be extended to similar situations in other developing countries. The system should be able to diagnose, in a timely fashion, all infants with severe and profound hearing losses.

Methods: One thousand newborn were randomly selected. All underwent testing with transient evoked oto-acoustic emissions (TEOAE) in the first 48 hours of life. All TEOAE failures were followed up and repeat tests were performed at three weeks, three months and six months of age. Infants with acceptable TEOAE results at any of the four ages were discharged from the study. Infants with unacceptable TEOAE results at all the four ages underwent brainstem evoked response audiometry and oto-endoscopy. The ‘pass rate’ for TEOAE testing was calculated for all four ages. The time taken to perform TEOAE and brainstem evoked response audiometry was recorded for all subjects. These recordings were statistically analysed to find the most suitable strategy for universal hearing screening in our hospital.

Results: The pass rate for TEOAE was 79.0 per cent at ≤48 hours, 85.0 per cent at three weeks, 97.0 per cent at three months and 98.0 per cent at six months. The average time taken to perform the test was 12 minutes for TEOAE and 27 minutes for brainstem evoked response audiometry. Obstructed and collapsed external auditory canals were the two factors that significantly affected the specificity of TEOAE in infants ≤48 hours old.

Conclusion: The concept of screening all neonates within the first 48 hours of life is impractical because the specificity of TEOAE is lowest at that age. Many false positive results are generated, such that a larger number must undergo brainstem evoked response audiometry, wasting time and resources. This can easily be avoided by delaying TEOAE screening until three months of age, when it has a substantially lower false positive outcome. We expect that implementation of this alternative strategy in our hospital will maximise the benefits of such a programme.

Objectives: Sudden sensorineural hearing loss (SSHL) remains a challenge for the clinician. In the majority of cases, no definite cause can be found and the prognosis is variable.

Methods: The present study assessed 114 patients suffering from idiopathic SSHL, with regard to the prognostic value of demographic, epidemiologic, neurotologic and audiometric factors. In addition, the relationship between the identification of wave V in auditory brainstem responses and the final hearing outcome was investigated. All patients received 75 mg/day intravenous prednisolone, divided into three daily doses, for 10 days, with gradual tapering of the dose over the next 10 days.

Results: The results (after one year follow up) revealed the following factors to be related to a better hearing outcome: younger age; male sex; less time elapsed between the onset of hearing loss and the beginning of treatment; and an upward-sloping or cupeloid audiogram contour. The detection of wave V early in recovery and within the first month of medical treatment might also constitute a significant favourable factor in respect to hearing recovery.

Conclusions: The present study revealed that there are certain factors that affect prognosis in idiopathic SSHL. This is very important in counselling patients and may affect current clinical practice.

In this study 22 patients (44 ears) with noise-induced permanent hearing loss were audiologically evaluated using transient-evoked otoacoustic emissions (TEOAE) and auditory brain-stem response (ABR). Twenty-one normal subjects (42 ears) without exposure to occupational noise were used as controls. Based upon the hearing loss at 4, 3, 2 and 1 kHz on the pure-tone audiogram, they were classified into four groups. In group 1 (eight ears), emissions were present in all ears but their TEOAE-noise level and their reproducibility (percentage) proved to be weak. The auditory brain-stem response (ABR) indicated that the I/V amplitude ratio, the latency values of wave V and the I–V intervals fell within the normal range in all ears. In Group 2 (14 ears), 40 per cent had no emissions, whereas the remaining ears showed weak emissions. The ABR revealed that in all ears the I/V amplitude ratio became small while wave V peak latency as well as I–V intervals were within the normal range. In Group 3 (10 ears), emissions were absent in 50 per cent, while in the other ears the emissions were very weak. The ABR revealed that the I/V amplitude ratio, which could be calculated in the 60 per cent in which wave I was present, was smaller than in Group 2. Wave V latency as well as I–V intervals were within the normal range. In Group 4 (12 ears), none of the ears showed emissions. The ABR indicated that the I/V amplitude ratio was much smaller when wave I was present (27 per cent) as well as I–V interval values being within the normal range. Wave V absolute latency value (δV index) indicated a positive index in 17 per cent of this group (two ears) when wave I was absent. In the present study a dynamic process from cochlear outer hair cells to cochlear neurons was seen, correlating with an increasing hearing loss.

The temporal bone pathology of a 74-year-old female affected by vestibular schwannoma was compared with findings of auditory brainstem response and electrocochleography. At age 71, she complained of hearing loss in the left ear in which pure tone audiometry revealed threshold elevation in the middle- and high-frequency range. Temporal bone CT scanning revealed a medium-sized cerebellopontine angle tumour in the left ear. ABR showed no response in the left ear, but the electrocochleography showed clear compound action potentials. Three years later, at age 74, she died of metastatic lung cancer and sepsis. The left temporal bone pathology consisted primarily of a large vestibular schwannoma occupying the internal auditory meatus. The organ of Corti was well preserved in each turn. In the modiolus, the numbers of spiral ganglion cells and cochlear nerve fibres in each turn were decreased. These histological findings suggest that clear compound action potentials were recorded from the distal portion of the cochlear nerve in spite of the presence of the vestibular schwannoma, but ABR could not be detected because of the blockade of the proximal portion of the cochlear nerve by the vestibular schwannoma.

Multiple sclerosis is known to affect the myelin of the auditory pathway resulting in acute hearing loss. Two cases of sudden deafness due to multiple sclerosis have been evaluated by conventional audiometry, brainstem auditory evoked response audiometry and transtympanic electrocochleography. The abnormalities of the compound action potential in both patients (enhanced latency, abnormal adaptation using fast stimulus rate) and the normal receptor potentials (cochlear microphonic, summating potential), as well as the absence of brainstem responses suggest a disturbance of synchronization at the level of the first auditory neurone. The electrocochleography provides valuable information for the topodiagnosis of this and other neural hearing losses, especially in the absence of reliable brainstem responses.

The records of 94 consecutive developmentally retarded children with speech retardation and suspected hearing loss who underwent auditory assessment by both conventional behavioural observation audiometry (BOA) and brain stem evoked response audiometry (BERA) were analysed. In 54 children (57.4 percent) there was good agreement between the results of both techniques leading to a clearcut diagnosis. In 22 children a diagnosis was possible only by the results of BERA as the results of BOA were inconclusive. Of the remaining 18 children, two groups could be identified whose results posed a dilemma. Group 1 (n = 7) consisted of children whose BOA test results differed considerably from their BERA results. Group 2 (n = 11) consisted of children in whom there was no discernible response by BERA while the response by BOA was either inconsistent (n = 5) or not elicitable (n = 6). The specific strategies to be adopted for hearing assessment in these situations are discussed.