The evidence base for the application of contralateral bone anchored hearing aids in acquired unilateral sensorineural hearing loss in adults.

. Acquired unilateral sensorineural hearing loss reduces the ability to localize sounds and to discriminate in background noise. . Four controlled trials attempt to determine the benefit of contralateral bone anchored hearing aids over contralateral routing of signal (CROS) hearing aids and over the unaided condition. All found no significant improvement in auditory localization with either aid. Speech discrimination in noise and subjective questionnaire measures of auditory abilities showed an advantage for bone anchored hearing aid (BAHA) > CROS > unaided conditions. . All four studies have material shortfalls: (i) the BAHA was always trialled after the CROS aid; (ii) CROS aids were only trialled for 4 weeks; (iii) none used any measure of hearing handicap when selecting subjects; (iv) two studies have a bias in terms of patient selection; (v) all studies were underpowered (vi) double reporting of patients occurred. . There is a paucity of evidence to support the efficacy of BAHA in the treatment of acquired unilateral sensorineural hearing loss. Clinicians should proceed with caution and perhaps await a larger randomized trial. . It is perhaps only appropriate to insert a BAHA peg at the time of vestibular schwanoma tumour excision in patients with good preoperative hearing, as their hearing handicap increases most.

The effect of mental alerting on gaze-evoked nystagmus.

OBJECTIVES: To determine whether mental alerting (MA) makes a significant difference to nystagmus recorded during gaze testing using electronystagmography (ENG). DESIGN: A prospective study, blinded interpretation of test results, alternate order of testing sequence. SETTING: Vestibular assessment clinic in a tertiary referral centre. PARTICIPANTS: A total of 80 patients were seen by the authors (R.L.H., K.F.L.M.) for vestibular assessment, between August 2002 and February 2004. Patients cognitively unable to perform MA tasks or with limited English were omitted. Patients all underwent gaze-testing using ENG. Each patient was tested twice, once without MA and once with an MA task, in an alternate test order. MAIN OUTCOME MEASURES: Slow-phase velocity values of recorded nystagmus, number of patients with clinically significant nystagmus (slow-phase velocity > or = 6 deg/s). RESULTS: A total of eight patients had significant gaze-evoked nystagmus when tested without MA and a total of six patients when tested with MA. Only four of these patients were common to both groups. When all nystagmus values (regardless of significance) were considered, no statistically significant differences between nystagmus measured with and without alerting were found (Wilcoxon signed rank test, P > 0.05). CONCLUSIONS: Mental alerting during gaze testing did not result in a significant difference in nystagmus and is just as likely to result in an exacerbation as a reduction in slow-phase velocity. In addition, MA is likely to result in a noisy (and therefore difficult to interpret) recording and increases the impact of the test on the patient. In view of these findings, we propose that MA is contraindicated during the gaze-testing component of the vestibular test battery.

Referral patterns in vestibular schwannomas --10 years on.

Diagnostic imaging techniques, symptom awareness and education of local sources of referral in vestibular schwannomas, including general practitioners, have all improved in the last 10 years. The referral patterns in vestibular schwannomas in Cambridgeshire in the period 1981-1993 has been reported.(1) A direct comparison was made with regard to referral patterns seen in the last 10 years paying particular emphasis to source of referral, diagnosis at referral and symptoms/size at presentation. The incidence of vestibular schwannomas in the region is compared and discussed. Patients' managed by the 'watch and wait' policy were particularly scrutinized, as they were not discussed previously. Retrospective analysis of computerized database was used. We have demonstrated an increase in the proportion of referrals with known vestibular schwannoma to 90% of all referrals. No significant change in length of history prior to referral, source of referral or principal presenting symptom were found. An overall decrease in tumour size was found but an increase in the percentage with larger tumours (>4.5 cm). We attribute the significant findings to an increase in availability of magnetic resonance (MR) scanners in the country during the past 10 years. It appears that some tumours would still present with no symptoms until late and therefore will elude identification until large in spite of a low threshold for MR scanning.

Hyperventilation in the vestibular clinic: use of the Nijmegen Questionnaire.

The objective of the present study was to determine the prevalence of hyperventilation syndrome in patients seen for vestibular assessment and to assess the clinical utility of the Nijmegen Questionnaire in this group. The Nijmegen Questionnaire and Dizziness Handicap Inventory (DHI) were administered prospectively to a consecutive series of 100 patients identified as candidates for vestibular assessment within the University Hospital Neuro-otology practice. Twenty-three per cent of patients seen for vestibular assessment were diagnosed with hyperventilation syndrome using the Nijmegen Questionnaire. Seventeen of these (74%) would have remained undetected had the Nijmegen questionnaire not been used. No relationship was found between vestibular assessment results and either Nijmegen or DHI scores. A significant correlation was found between DHI scores and Nijmegen Questionnaire scores (rho = 0.348, P = 0.0005). In conclusion, the Nijmegen Questionnaire is a quick, easy to administer and low-impact assessment tool for hyperventilation syndrome and is a useful adjunct to the otological consultation. Diagnosed patients can then be offered breathing control exercises as part of a vestibular rehabilitation programme.

Head-shaking nystagmus in patients with a vestibular schwannoma.

The aim of this study was to calculate the sensitivity of the head-shake test for peripheral and central vestibular dysfunction associated with unilateral sporadic vestibular schwannoma and to discuss the feasibility of using the head-shake test as a screening test. The study group consisted of 102 patients with unilateral sporadic vestibular schwannomas, who were seen consecutively for preoperative vestibular assessment, including the head-shake test. The sensitivity of the head-shake test for vestibular schwannoma was found to be 22%, and the sensitivity and specificity of the head-shake test for canal paresis (>/=25%) were found to be 27% and 88%, respectively. Patients with abnormalities in the central vestibular system and with a greater canal paresis were more likely to have head-shake nystagmus, although, even for severe canal paresis, the sensitivity of the test remained low at 36%. The direction of nystagmus was found to be contra-lateral to the side of the tumour in 86% of patients. It was concluded that the head-shake test is of insufficient sensitivity to be used as a screening test either for vestibular schwannoma or for vestibular-system abnormalities associated with vestibular schwannoma. The deduction is made that the head-shake test is of insufficient sensitivity or specificity to be of clinical value as a screening test for vestibular dysfunction in a general population with symptoms of imbalance.

Convergent validity of the tinnitus handicap inventory and the tinnitus questionnaire.

For research into tinnitus to be robust and credible, the use of well-validated instruments of self-perceived tinnitus handicap as outcome measures is essential. The tinnitus handicap inventory (THI) and the tinnitus questionnaire (TQ) are two such instruments which are in widespread use. Both questionnaires were administered by mail to 100 consecutive new patients of the Cambridge Tinnitus Clinic, and completed in randomized order. These patients had been referred by the otolaryngology team and had not undergone any tinnitus therapy. The response rate was 78 per cent, neither questionnaire being more acceptable to patients than the other. The convergent validity of the instruments was high, with total and subscale scores all being significantly correlated at the five per cent level (Spearman correlation coefficients). A number of subscale scores were not significantly correlated at the one per cent level however. In particular, the sleep disturbance element of the TQ was demonstrated to have some discriminant validity from the THI and from other elements of the TQ at the one per cent significance level. The THI and TQ have been demonstrated to have high convergent validity and are both suitable for tinnitus outcome studies involving the quantification of self-perceived tinnitus handicap. For research that aims to determine the specific effect of an intervention on tinnitus-related sleep disturbance, the TQ sleep subscale has potential utility. The hypothetical constructs of tinnitus handicap underlying the psychologist-developed TQ and the audiologist-developed THI have been shown to be convergent.