R. R. A. Coles

A clinical study of tinnitus maskers

This report describes a three-centre study of the effectiveness of tinnitus maskers, combination instruments (masker plus hearing aid), and hearing aids in the management of tinnitus. Some 472 patients entered the study with 382 reaching the first evaluation session after a minimum period of 6 months from fitting, and 206 reaching the second evaluation not less than 6 months after the first. The study included two control groups, by which to assess the comparative benefit to be derived solely from the investigation and counselling of such patients. The principal results were as follows: thorough investigation and careful counselling do much to help the patient; much further benefit is given by tinnitus masking instruments of various kinds; maskers are more often effective than hearing aids, although the latter are frequently the most appropriate first treatment of those patients who have substantial (but not yet treated or insufficiently treated) hearing difficulties as well; there is no evidence of masking having any harmful effect on hearing. None of the audiometric or tinnitus tests currently employed can be regarded as predictive, either of tinnitus severity, or of the eventual outcome of masking therapy, however certain measurements may help as a guide to patient management.

Research note: Patterns of exposure of schoolchildren to amplified music

The amplified-music listening habits and the hearing status of 1443 comprehensive schoolchildren have been surveyed by questionnaire. In a stratified sample of them (n = 25), the levels at which they would listen to a personal cassette player (PCP) in various circumstances were measured. The main conclusion drawn was reassuring: that these children seem to be more conservative in their music-listening habits than young people are commonly given credit for. Nevertheless, music may sometimes make a small contribution to socioacusis and to the total noise dosage of those exposed to noise occupationally. Some recommendations are made for manufacturers of PCPs, and for some restrictions on the use of PCPs in occupational noise.

The results of cortical electric response audiometry in medico-legal investigations

Cortical ERA was conducted in a consecutive series of 118 medicolegal cases (467 threshold determination in 209 ears). In organic cases, the distribution of subjective (manual pure tone audiometry)/objective (CERA) discrepancies was normal and centred on 0 dB, with only 3.2% of the discrepancies exceeding + 15 dB. Averaged over 3 or more test frequencies in one ear, only 4.4% of the discrepancies exceeded + 7.5 dB, as compared to 95.1% exceeding + 7.5 dB in those suspected of having a non-organic overlay. The pattern of non-organic overlay superimposed on noise-induced hearing loss is expected and demonstrated to produce a flattening of the dip in the audiogram. It is argued that such flattening is very rarely the end product of noise exposure.

Asymmetric sensorineural hearing thresholds in the non‐noise‐exposed UK population: a retrospective analysis

Objectives:  To estimate the distribution of inter‐aural sensorineural hearing threshold level differences in the non‐noise‐exposed adult population of the UK.

Efficiency of tests used to screen for cerebello-pontine angle tumours: A prospective study

With increasing use of imaging in the investigation of cerebello-pontine angle (CPA) tumours, the role of audio-vestibular and electrophysiological testing has changed. Field performance data on the efficiencies of these tests to screen for CPA tumours are lacking, but must be known to choose an appropriate testing strategy. A prospective observational study of 237 patients attending a neuro-otology clinic for audio-vestibular investigation was carried out. The aim was to provide field performance data on which to base an effective protocol to screen for CPA tumours. All patients presenting at the ENT department and meeting any of the following criteria were referred to the neuro-otology clinic and included in the study: (1) asymmetrical sensorineural hearing loss, (2) unexplained asymmetrical tinnitus with normal bearing thresholds, (3) unilateral bearing difficulties with normal hearing thresholds and (4) other neurological indications. In addition to audio-vestibular and auditory brainstem response (ABR) investigation, every patient underwent computed tomography (CT), with magnetic resonance imaging (MRI) in cases having marginal results on CT, to exclude or confirm the presence of a tumour. Pass or fail on each test was based on a priori criteria from other studies. Eighteen patients were found to have CPA tumours. ABR testing was the only effective procedure for screening, but had some limitations. A contingent protocol using ABR in all cases except those with asymmetrical tinnitus and normal bearing thresholds, those with severe hearing loss, and those with neurological signs, was retrospectively defined: the exceptions would go straight to CT. This protocol would have missed two of the 18 tumour patients. CT scanning alone would have missed one small intra-canalicular tumour, which was picked up on MRI triggered by abnormal ABR. Based on the results from the present study we conclude there is no effective screening protocol for detecting CPA tumours, as MRI scanning with gadolinium enhancement will identify virtually all tumours. Where MRI is available but waiting lists are long, the described strategy using ABR to select priority referrals for MRI scanning is recommended.

Indications for aspirin as a palliative for tinnitus caused by SOAEs: A case study

This paper explores the effect of aspirin on the tinnitus of one patient for whom two contralateral spontaneous otoacoustic emissions (SOAEs) caused binaural tinnitus. The relation between the SOAEs and tinnitus was explored during a preliminary testing session, after which the SOAEs were measured for 7 days. During days 1, 2, 5, 6 and 7 of the trial, a placebo (two 50-mg tablets of ascorbic acid) was administered four times per day. During days 3 and 4, a drug (two 300-mg tablets of aspirin) was administered four times per day. During day 2, the right ears SOAE was low level and labile, sometimes disappearing into the noise floor. The effect of aspirin on an emission which is not consistently observed, cannot be assessed so this report focuses primarily on the left ear. During days 1 and 2, the SOAE in the left ear was present and the tinnitus was audible. By day 3 (after 2.4 g of aspirin), the SOAE in the left ear had been abolished, and the tinnitus was not audible. On the fifth day (24 hours after the last aspirin), both the SOAE and the tinnitus in the left ear had returned. There were no reported side-effects of the aspirin. Thus, aspirin seemed to provide an acceptable palliative for this patients SOAE-caused tinnitus.

Comparative study of four noise spectra as potential tinnitus maskers

Ten experienced tinnitus-masker uses compared four widely different noise bands as potential maskers in a laboratory environment. No reliable individual preferences could be found, and most of the noises were acceptable to most of the subjects. A wide-band noise was marginally most frequently preferred. In this sample, there was no indication that individual tailoring of the frequency spectra of tinnitus maskers is required to achieve acceptable masking. Subjects also underwent tests of hearing, tinnitus matching and tinnitus masking. Most subjects chose noise levels for therapeutic masking that only partially masked their tinnitus. This suggests prescription or trial of tinnitus maskers even for patients who have high minimal masking levels.

Tinnitus Information: A Study by Questionnaire

The aim of the present study was to improve the information for patients with tinnitus. The investigation consists of three parts: a pilot study where 24 slightly informed tinnitus patients as well as 17 well-informed tinnitus patients and 9 audiological professionals suggested contents for a tinnitus information pamphlet. The second part consisted of scoring of the 74 most common suggestions by 36 of the original 50 people. The answers were graded according to importance. Three available tinnitus information folders from Sweden, Germany and the USA were also studied and taken into account in preparing recommendations on content and size for a tinnitus information pamphlet. This should probably not exceed 2500 words, and 35 items of information.

Guidelines for quantification of noise‐induced hearing loss in a medicolegal context

Guidelines published in 2000 by the authors are widely used by medical and legal professionals in the UK for diagnosis of noise‐induced hearing loss in a medicolegal context. However, they cannot be used for quantification of the noise‐induced hearing loss, which is required in most cases. This requirement is addressed.

Assessment of hearing disability: discussion paper.

Early in 1982, a member of the British Association of Otolaryngologists (BAOL) drew attention to the current confusion in medicolegal reports caused by the use of a considerable variety of British and American formulae for relating hearing threshold level to disability. He asked the Association to consider the matter and to recommend a method for use by otologists whenever they were not required to employ some other particular statutory or out-of-court settlement scheme. Accordingly a subcommittee was set up by the BAOL, together with the British Society of Audiology (BSA), to consider this matter in the light of current scientific evidence and medicolegal needs, with the following main objectives: (1) to provide a formula by which measurements of hearing impairment (normally as airconduction pure-tone hearing threshold level, dB HTL) may be used to give an estimate of hearing disability (normally on a scale of percentage loss of normal ability to perceive speech); (2) to give guidance on factors influencing hearing handicap (the degree of *restriction of personal activity in the individual case) and on various other matters that arise in medicolegal assessment of hearing. This paper, by members of the subcommittee, outlines the philosophical, medical and scientific rationales underlying many of the details of the method of assessment recommended. The method itself is published elsewhere (BAOL/BSA 1983).