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The aim of this study was the determination of the incidence of symptoms of audio-vestibular dysfunction and of abnormalities on audio-vestibular testing in patients found to have a unilateral meningioma of the cerebello-pontine angle (CPA). The case notes of 25 patients diagnosed with unilateral, sporadic and histologically proven CPA meningioma were retrospectively reviewed. The age range of this series was 31–71 years, with a mean age of 50 years. Two patients were male (eight per cent) and 23 were female (92 per cent). The mean length of history was 44.7 months. The distribution of tumour size was skewed toward larger tumours, with 15 cases (60 per cent) having tumours with a maximum diameter greater than 3.5 cm on imaging. Pure tone audiometry was normal in five cases (20 per cent), and no patients exhibited the high frequency sensorineural hearing loss that is characteristic of vestibular schwannoma. Speech audiometry was normal in 50 per cent of cases. Caloric testing was abnormal in 77 per cent of the 18 cases tested, whilst auditory brainstem responses (ABR) were abnormal in 100 per cent of the 18 cases who had sufficient hearing for this test to be possible. The presence of normal audiometry in patients with a proven CPA lesion indicates that, if in a protocol for investigation, asymmetry of hearing is mandatory then some pathology will be missed. Any suspicion of a CPA lesion warrants investigation even in the absence of hearing loss.The investigation of choice for the identification of CPA lesions has become magnetic resonance imaging (MRI). If this technique is not available then this study indicates that ABR is a suitable and sensitive investigation. It should be borne in mind however that the data in this study has been derived from a series of predominantly large tumours, and the sensitivity of ABR to smaller CPA meningiomata may fall, as is the case for vestibular schwannoma.

We report a case of a cerebellopontine angle cholesteatoma whose initial sign was benign paroxysmal positional vertigo (BPPV). Positional vertigo caused by a central pathology is extremely rare and is usually accompanied by other suspicious features. In this case, there were no additional neurotologic symptoms or signs. The only abnormalities were seen on Dix-Hallpike testing, but because they were not consistent with a diagnosis of BPPV, the decision was made to proceed to imaging. Diagnostic rigor is required when evaluating positional vertigo, as with all symptoms of imbalance, if such cases are not to be overlooked.

The objective of this study was to determine the findings on magnetic resonance imaging (MRI) in patients identified as having central vestibular abnormalities on electronystagmography (ENG) testing, to discuss the issue of ‘gold standard’ in the investigation of central oculo-vestibular system diseases and to present a model for understanding this area. A retrospective review of the case notes of patients (n = 23) found to have central ENG findings at vestibular assessment and for whom MRI scanning data was available was undertaken. Each patient underwent a full ENG evaluation, including gaze, ocular-motor and caloric testing, and MRI. Only seven of the patients with central ENG findings had abnormal MRI scans. Thus, the incidence of the identification of structural abnormality on MRI in patients with central ENG findings is low. These investigations are complementary in the investigation of balance disorder patients.

Tinnitus retraining therapy has been heralded as a major advance in the alleviation of tinnitus perception. A cornerstone of this technique is to use white noise produced by a white noise generator (WNG) over a period of several months in order to assist the patient to habituate to their tinnitus. There are three factors which influence the frequency spectrum of the perceived noise such that the perception of white noise from a WNG is unlikely. These factors are the actual spectrum of the emitted noise, the ear canal resonance of the patient and the hearing sensitivity of the patient.Advocates of tinnitus retraining therapy state that white noise is the optimal stimulation to assist habituation of tinnitus. This paper demonstrates that this optimal situation is unlikely to be achieved and that this may account for the long periods needed for patients to achieve benefit from the technique. The development of devices that allow for the above factors to be countered is suggested.

The investigation and treatment of vestibular schwannomas is an increasingly specialized area in which major advances have been seen over recent years. The effect of these advances on the referral patterns to a centre specializing in such surgery is reviewed. The proportion of referrals with a known diagnosis has increased substantially, allowing the specialist centre to focus on appropriate management rather than diagnosis. The vast majority of vestibular schwannomas are referred by otolaryngologists. The caseload referred by neurologists or neurosurgeons have different presenting symptoms. The incidence of vestibular schwannoma in the Cambridge district is found to be 1 per 50,000 population per year. This is a higher incidence than that recorded in other studies. This may be due to a tight diagnostic strategy and the high level of clinical awareness of the local general practitioners.

Decibel scales are a very important but potentially confusing subject for the clinician. Misunderstanding can, at worst, lead to inappropriate management which is detrimental to the patient. This paper sets out, from the viewpoint of an acoustician, the calibration and meaning of the various decibel scales in common use, shows how they are applied to the clinical setting, and explains their limitations.