The Birmingham Program has a high proportion of syndromic patients with complex medical problems. The fixture failure rate was found to be 14%. This included the multiple-fixture failures in children younger than 3 years old. There was 1 serious complication. The BAHA is a reliable and effective treatment for selected patients. Our program currently has 97% of its children wearing their BAHA on a daily basis with continuing audiologic benefit.

Objective-To determine the natural history and pathogenesis of hearing loss in children with acute bacterial meningitis. Design-Multicentre prospective study. Setting-21 hospitals in the south and west of England and South Wales. Subjects-124 children between the ages of 4 weeks and 16 years with newly diagnosed bacterial meningitis. Methods-Children underwent repeated audiological assessment with the first tests being performed within six hours of diagnosis. By using a combination of otoacoustic emissions, auditory brainstem responses, and tympanometry the diVerences between cochlear, neural, and conductive defects were distinguished. Results-Ninety two children (74%) had meningococcal and 18 (15%) had pneumococcal meningitis. All cases of hearing loss were apparent at the time of the first assessment. Three children (2.4%, 95% confidence interval (CI) 0.5 to 6.9%) had permanent sensorineural hearing loss. Thirteen children (10.5%) had reversible hearing loss of whom nine had an impairment that resolved within 48 hours of diagnosis. It is believed that this 'fleeting' hearing loss has not been reported previously. The cochlea was identified as the site of the lesion in both the permanent sensorineural and reversible impairments. Hearing loss was more common in children who had been ill for more than 24 hours (relative risk 2.72; 95% CI 0.93 to 7.98). Conclusions-Sensorineural hearing loss developed during the earliest stages of meningitis. Permanent deafness was rare but 10% of the patients had a rapidly reversible cochlear dysfunction. This may have progressed to permanent deafness if the patients had not been treated promptly. (Arch Dis Child 1997;76:134-138)

Transmission of intracranial pressure (ICP) to the perilymph of the cochlea may occur via the cochlear aqueduct and possibly other routes. Indirect measurement of perilymphatic pressure may be investigated by observing tympanic membrane (TM) displacement during stapedial reflex contraction. In a previous study we investigated the effects of changes in ICP on perilymphatic fluid pressure in three patients who underwent ventriculo/lumbar-peritoneal shunt operations. The TM displacement technique proved extremely sensitive and revealed marked changes in cochlear fluid pressure brought about by changes in ICP (Marchbanks et al., 1987). The study has been extended to 58 patients with hydrocephalus, intracranial tumours and other neurological conditions associated with abnormal ICP. Significant differences in the TM displacement were found between patients with raised and normal ICP. We have shown that changes in ICP can affect the hydrostatic pressure of the cochlea and influence the peripheral auditory system. The finding that ICP can be correlated with TM displacement strengthens the association between an abnormal TM displacement and abnormal cochlear hydrostatic status, irrespective of cochlear aqueduct patency. We suggest that the TM displacement technique provides a useful non-invasive method for the assessment of perilymphatic fluid pressure.

We have found the longer abutment to be very successful for the small proportion of patients with troublesome soft tissue overgrowth. We would advocate its use when topical management and surgical intervention have failed to control the skin reaction.

The patency of the cochlear aqueduct is a key factor in intra-cochlear hydromechanics. If patent, the cerebrospinal fluid (CSF) provides the reference pressure for the perilymph and also to a large extent the endolymph, since Reissner's membrane can only withstand a relatively small pressure differential. The aqueduct often becomes sealed as a natural process of ageing. In this instance the reference pressure is from a source, its position unknown, within the boundaries of the cochlea itself. Relatively large and rapid changes in the cerebrospinal fluid pressure may result from everyday events such as coughing (ca. 175 mm saline) and sneezing (ca. 250 mm saline). The resistive nature of the cochlear aqueduct and the mechanical compliance of the cochlear windows are probably important factors in limiting the amount of stress, and therefore possible damage, which may occur to the cochlea and cochlear windows for a given pressure change within the CSF system. A narrow aqueduct and compliant cochlear windows reduce the risk of structural damage. In practice, this should mean that the risk of structural damage will be increased by any process which reduces the compliance of one or both of the cochlear windows, for example, extremes of middle ear pressure perhaps brought about by Eustachian tube dysfunction or rapid barometric pressure changes. Techniques are now available which provide non-invasive indirect measures of perilymphatic pressure and CSF-perilymphatic pressure transfer. The tympanic membrane displacement measurement technique has been used to provide reliable measures of perilymphatic pressure and CSF-perilymphatic pressure transfer on an individual subject basis.(ABSTRACT TRUNCATED AT 250 WORDS)

The Birmingham bone-anchored hearing aid (BAHA) programme, since its inception in 1988, has fitted more than 300 patients with unilateral bone-anchored hearing aids. Recently, some of the patients who benefited extremely well with unilateral aids applied for bilateral amplification. To date, 15 patients have been fitted with bilateral BAHAs. The benefits of bilateral amplification have been compared to unilateral amplification in 11 of these patients who have used their second BAHA for 12 months or longer. Following a subjective analysis in the form of comprehensive questionnaires, objective testing was undertaken to assess specific issues such as ‘speech recognition in quiet’, ‘speech recognition in noise’ and a modified ‘speech-in-simulated-party-noise’ (Plomp) test.‘Speech in quiet’ testing revealed a 100 per cent score with both unilateral and bilateral BAHAs. With ‘speech in noise’ all 11 patients scored marginally better with bilateral aids compared to best unilateral responses. The modified Plomp test demonstrated that bilateral BAHAs provided maximum flexibility when the origin of noise cannot be controlled as in day-to-day situations. In this small case series the results are positive and are comparable to the experience of the Nijmegen BAHA group.

The Birmingham osseointegration programme began in 1988 and during the following 10 years there were a total of 351 bone-anchored hearing aid (BAHA) implantees. In the summer of 2000, a postal questionnaire study was undertaken to establish the impact of the bone-anchored hearing aid on all aspects of patients’ lives.We used the Glasgow benefit inventory (GBI), which is a subjective patient orientated post-interventional questionnaire especially developed to evaluate any otorhinolaryngological surgery and therapy. It is maximally sensitive to any change in health status brought about by a specific event: in this case the provision of a BAHA.A total of 312 bone-anchored hearing aid patients, who had used their aids for a minimum period of six months, were sent GBI questionnaires. Two hundred and twenty-seven questionnaires were returned and utilized in the study. The results revealed that the use of a bone-anchored hearing aid significantly enhanced general well being (patient benefit), improved the patient’s state of health (quality of life) and finally was considered a success by patients and their families.

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