Factors that influence the benefit from amplification in the elderly

Abstract

Gatehouse S. Factors that influence the benefit from amplification in the elderly. Acta Otolaryngol (Stockh) 1991; Suppl. 476: 262—269.

Many factors have been proposed as potential determinants of the benefit that an individual receives from wearing a hearing aid. In this study, to quantify their relative importance, 54 individuals with symmetrical sensorineural hearing impairment were presented with and without simulated hearing aid characteristics on two measures of disability that were based on identifying words in sentences. Benefit was defined as the difference between the percentage of correct scores with and without the aid characteristics switched into the audio circuit. The factors investigated were age, various peripheral auditory functions, central auditory factors and non—auditory factors such as IQ and personality. Initial correlations suggested a strong relationship between the benefits of amplification and four types of variable: hearing threshold level, frequency resolution, aspects of central function, and the discrepancy in auditory threshold between two methods——a robust psychometric three alternative forced—choice procedure and a conventional audiometric procedure. When the effects of hearing threshold level were partialled out, there remained strong correlations with frequency resolution, co—modulation masking release, and the threshold discrepancy measure. Frequency resolution and threshold discrepancy accounted for a further 21.1 % of the variance over the 26.5% of the variance accounted for by hearing threshold level. There were no correlations in this sample of benefit with age, once other aspects had been accounted for. The results indicate a strong role for frequency resolution in the potential benefits from amplification, in addition to central factors such as co—modulation masking release. The threshold discrepancy may be interpreted as an index of the subject's own confidence in their hearing ability, with a relatively poor threshold from the clinical procedure (relative to the forced—choise procedure) indicating lower confidence. Given this interpretation, more “confident” individuals received greater benefit from amplification.

Key Words:

• benefit
• frequency resolution
• central function