The Glasgow Benefit Plot: a new method for reporting benefits from middle ear surgery.

Conventionally, the results of middle ear surgery are reported in terms of postoperative closure of the air-bone gap or the improvement in air-conduction thresholds. While these are relevant in that they assess the technical success of the procedure and the lessening of monaural disability, they do not necessarily assess whether the patient has benefited. This is determined by many factors, not least of which is the hearing in the nonoperated ear.

Trial of flecainide acetate in the management of tinnitus.

A two-phase trial of flecainide acetate in the management of tinnitus has been carried out in 22 patients with severe long-term tinnitus resistant to other treatments. Although 5 (23%) patients reported some limited benefit the results are not conclusive but suggest that, for such patients, flecainide deserves a place as a drug worth considering as a last resort, with the prospect of it occasionally giving a worthwhile degree of relief.

A non-invasive, objective test of endolymphatic hydrops.

Our previous work has shown that auditory brainstem responses (ABRs) can be used to measure the basilar membrane travelling wave velocity (TWV). Based upon the hypothesis that increased pressure in the scala media will increase the stiffness of the basilar membrane and, hence, increase the speed of the travelling wave. ABRs have been used to provide a means of objectively testing for endolymphatic hydrops.

Frequency resolution as a function of hearing threshold level and age.

Frequency resolution ability was measured using a psychoacoustical tuning curve (PTC) or a notch-noise technique in two population samples. The first sample incorporated 1764 subjects with various degrees of sensorineural hearing impairment and ranging in age from 17-80 years. The second sample included 240 subjects aged between 50 and 75 years, carefully balanced in terms of impairment and age to avoid confounding between these two variables.

Early detection of hearing impairment: what role is there for behavioural methods in the neonatal period?

A survey of the use of behavioural methods for neonatal hearing screening in 1985 (1) concluded that the future for automated methods was quite promising. Since then several studies have assessed the two main automated behavioural tests: the Auditory Response Cradle (ARC) and the Crib-o-Gram (COG). As a screen targeted at neonatal intensive care unit (NICU) babies and other high risk groups (at present the most cost-effective form of neonatal hearing screening), the ARC is shown to have low sensitivity, even for severe hearing impairments, and the COG has an unacceptably low specificity.

Apparent travelling wave velocity changes in cases of endolymphatic hydrops.

This study attempted to develop a test which would be specific for endolymphatic hydrops. It is based upon the hypothesis that increased pressure in the scala media will alter the stiffness of the basilar membrane and hence increase the speed of the travelling wave. Auditory brainstem-derived responses were used to measure the basilar membrane travelling wave velocity in normals and to take the equivalent measures in Meniere's patients.

Interaural delay sensitivity to tones and broad band signals in the guinea-pig inferior colliculus.

We have measured the sensitivity of 243 low-frequency cells in the central nucleus of the guinea pig to the interaural time delay of best frequency (BF) tones, wideband noise and synthetic vowels. The highest rate of firing for the majority of cells occurred when the stimulus to the contralateral ear arrived 100-400 microseconds before that to the ipsilateral ear. The best delays for tones and noise measured in the same cell were highly correlated.

Determinants of self-reported disability in older subjects.

The effects of hearing threshold levels, age, personality, and IQ on indices of self-reported disability/handicap derived from the Hearing Performance Inventory and the Institute of Hearing Research Hearing Disability Questionnaire have been investigated in a sample of 240 individuals with bilateral, symmetric sensorineural hearing, which was efficiently balanced across hearing threshold level and age. The results show significant effects of age, IQ, and, in particular, personality on many aspects of reported disability/handicap, with different relative contributions for females and males. It is possible to account for between 42 and 50% of the variance in most of the disability/handicap indices.

The representation of the spectra and fundamental frequencies of steady-state single- and double-vowel sounds in the temporal discharge patterns of guinea pig cochlear-nerve fibers.

Psychophysical results using double vowels imply that subjects are able to use the temporal aspects of neural discharge patterns. To investigate the possible temporal cues available, the responses of fibers in the cochlear nerve of the anesthetized guinea pig to synthetic vowels were recorded at a range of sound levels up to 95 dB SPL. The stimuli were the single vowels /i/ [fundamental frequency (f0) 125 Hz], /a/ (f0, 100 Hz), and /c/ (f0, 100 Hz) and the double vowels were /a(100),i(125)/ and /c(100),i(125)/.

Modeling the perception of concurrent vowels: vowels with different fundamental frequencies.

If two vowels with different fundamental frequencies (fo's) are presented simultaneously and monaurally, listeners often hear two talkers producing different vowels on different pitches. This paper describes the evaluation of four computational models of the auditory and perceptual processes which may underlie this ability. Each model involves four stages: (i) frequency analysis using an "auditory" filter bank, (ii) determination of the pitches present in the stimulus, (iii) segregation of the competing speech sources by grouping energy associated with each pitch to create two derived spectral patterns, and (iv) classification of the derived spectral patterns to predict the probabilities of listeners' vowel-identification responses.

Comodulation masking release as a function of bandwidth and test frequency.

Comodulation masking release (CMR) was investigated as a function of signal frequency (0.5-4.0 kHz) and the total bandwidth of noise centered on the signal frequency.

Factors influencing consultation for management of hearing disability.

The aim of this study was to compare individuals referred to an Audiology Clinic (consulters) with hearing-impaired individuals in the population who have never sought advice (non-consulters) in order to identify factors which lead some individuals with hearing problems to seek management while others with apparently similar impairments do not seek advice. Two hundred and sixty nine consulters referred to the Audiology Clinic at Glasgow Royal Infirmary were compared with 289 individuals identified in the MRC National Study of Hearing who had never sought advice as an adult about hearing problems. Age, sex, socio-economic group and better-ear hearing threshold were controlled for in all analyses.

The Chief Scientist reports ... hearing research at the Medical Research Council Institute of Hearing Research (Scottish Section).

In addition to conducting research with the Section's own resources from the MRC and the Scottish Home and Health Department, the Section stimulates collaborative clinical research with the University and Health Service Departments. This work would be unlikely to take place without the existence of the Scottish Section of the MRC Institute of Hearing Research. Its presence has contributed to the continuing recognition of the Royal Infirmary Departments as an attractive centre for postgraduate training by both British and overseas graduates, leading in time to a substantial body of clinical research in ENT.

Response times to speech stimuli as measures of benefit from amplification.

The benefits of management of hearing disability, in particular by provision of a hearing aid, are traditionally assessed by the percentage improvement in performance on a speech identification task. To provide precise and stable results, such procedures require more time than is available in most clinical settings. In any stressed performance, e.

A procedure for measuring auditory and audio-visual speech-reception thresholds for sentences in noise: rationale, evaluation, and recommendations for use.

The strategy for measuring speech-reception thresholds for sentences in noise advocated by Plomp and Mimpen (Audiology, 18, 43-52, 1979) was modified to create a reliable test for measuring the difficulty which listeners have in speech reception, both auditorily and audio-visually. The test materials consist of 10 lists of 15 short sentences of homogeneous intelligibility when presented acoustically, and of different, but still homogeneous, intelligibility when presented audio-visually, in white noise. Homogeneity was achieved by applying phonetic and linguistic principles at the stage of compilation, followed by pilot testing and balancing of properties.

Magnitude of diotic summation in speech-in-noise tasks: performance region and appropriate baseline.

The diotic summation effect is one of the three types of binaural advantage for perceiving speech-in-noise. Using a within-subject design in normally-hearing subjects having no significant noise exposure, we examined its magnitude. The average advantage was +5%, at an overall performance level of 70-80% rising to +9% when an appropriate control was used to exclude order effects introduced by the within-subject design.

Strengths and Weaknesses of Procedures for Separating Simultaneous Voices.

Two signal-processing procedures for separating the continuously-voiced speech of competing talkers are described and evaluated. With competing sentences, each spoken on a monotone, the procedures improved the intelligibility of the target talker both for listeners with normal hearing and for listeners with moderate-to-severe hearing losses of cochlear origin. However, with intoned sentences, benefits were smaller for normal-hearing listeners and were inconsistent for impaired listeners.

Strengths and weaknesses of procedures for separating simultaneous voices.

Two signal-processing procedures for separating the continuously-voiced speech of competing talkers are described and evaluated. With competing sentences, each spoken on a monotone, the procedures improved the intelligibility of the target talker both for listeners with normal hearing and for listeners with moderate-to-severe hearing losses of cochlear origin. However, with intoned sentences, benefits were smaller for normal-hearing listeners and were inconsistent for impaired listeners.

Quality estimation of click-evoked oto-acoustic emissions.

The Fsp statistic used by Elberling & Don (1984) as a quality estimator for averaged ABR recordings has been applied to averaged click-evoked oto-acoustic emissions. This statistic is akin to signal-to-noise ratio. The sampling distribution of Fsp under the null hypothesis that no signal is present has been determined by using no-stimulus trials.

Algorithms for separating the speech of interfering talkers: evaluations with voiced sentences, and normal-hearing and hearing-impaired listeners.

Two signal-processing algorithms, derived from those described by Stubbs and Summerfield [R.J. Stubbs and Q.

Occupational noise and demographic factors in hearing.

The effects of age, sex, socioeconomic background and noise exposure on hearing were examined in a population sample. Subjects, aged between 17 and 80 years, were selected from the electoral register using a stratified random sampling technique based on age and reported hearing difficulty. Exposure to occupational, social and gunfire noises was estimated retrospectively from a structured interview.

Whole blood viscosity and red cell filterability as factors in sensorineural hearing impairment in the elderly.

Deficiencies in blood supply can lead to impairments in cochlear function. We have reported significant associations of both measures of whole blood viscosity and derived measures of red cell rigidity with hearing threshold levels in individuals with sensorineural hearing impairments. This paper describes direct measures of red cell filterability in a group balanced across the variables of hearing threshold level and age to facilitate dissociation of the effects of factors correlated with age.