Odds of Demonstrating Auditory Processing Abnormality in the Average Older Adult: The Blue Mountains Hearing Study

Abstract

In Brief Objective: To determine, for the average older adult, the odds of demonstrating an auditory processing abnormality for each of seven speech-based measures of auditory processing and how these odds vary based on a number of independent subject variables. Design: Using a cross-sectional design, 1576 adults aged 55 years and older were assessed with speech measures of central auditory processing and questionnaires pertaining to health status, cognitive and perceived auditory function. The speech-based measures from which abnormal/normal outcomes were derived were (a) right ear Macquarie Synthetic Sentence Identification (MSSI) test maximum performance score (Rt MSSImax), (b) left ear MSSI test maximum performance score (Lt MSSImax), (c) right ear Macquarie Dichotic Sentence Identification (MDSI) test score (Rt MDSI), (d) left ear MDSI test score (Lt MDSI), (e) difference score for the right and left ear MDSI test (MDSI Diff score), (f) right ear MSSI test maximum performance score subtracted from the maximum performance score for monosyllabic word list materials in the same ear (Rt PB-MSSImax), and (g) left ear MSSI test maximum performance score subtracted from the maximum performance score for monosyllabic word list materials in the same ear (Lt PB-MSSImax). Results: The odds of demonstrating auditory processing abnormality for average older participants, increased by 4 to 9% per year of age. Men were approximately twice as likely as women to demonstrate this abnormality, but the gender difference was only evident with dichotic measures. With increasing hearing handicap, the odds of demonstrating auditory processing abnormality increased, but this was only evident for speech-in-noise measures. With subtle cognitive decline, the odds of demonstrating auditory processing abnormality also increased. Conclusions: This population-based study provides evidence of a link between perceived hearing handicap and outcomes on speech-in-noise measures as well as evidence of a gender difference that became apparent using dichotic tests. The contribution of central auditory processing abnormality to hearing health should therefore not be overlooked in the provision of auditory rehabilitation programs to older adults. An earlier report showed that auditory processing abnormality was common in 1576 older adult participants of the Blue Mountains Hearing Study (BMHS). In the present study, the odds of demonstrating this abnormality using abnormal/normal outcomes of speech-based measures and selected independent subject variables were calculated. Results showed that the odds a) increased for all speech measures with minor deterioration in scores on the selected screening test of cognitive function, b) increased with age in the majority of measures, c) were twice as high in men as in women when dichotic tests were used, and d) increased for speech-in-noise measures as hearing handicap increased. Therefore, the contribution of auditory processing abnormality to hearing health in a general older adult population should not be under-estimated.