AMPLITUDE AND LATENCY OF AUDITORY BRAINSTEM RESPONSES CORRELATE WITH IMPAIRMENT IN ACTIVITIES OF DAILY LIVING IN HEALTHY ELDERS

Abstract

There is increasing epidemiological evidence showing an association between presbycusis or age-related hearing loss and cognitive decline in elderly people. The Health ABC Study has shown that presbycusis subjects with audiometric hearing thresholds (PTA) worse than 40 dB are more likely to develop cognitive decline. Before the development of audiometric hearing loss, aged subjects could have communication problems, a clinical entity known as hidden hearing loss (HHL). The amplitudes and latencies of auditory brainstem responses (ABR) at supra-thresholds levels have been used as objective measures to detect HHL. Objective: To study whether supra-thresholds ABR responses are associated with impairment in activities of daily living (ADL) in healthy elders. 52 Persons from the ANDES study ≥65 years without dementia (MMSE>24) with normal hearing thresholds (PTA<20dB, n=13), with mild (PTA 20–39dB, n=29) or moderate presbycusis (PTA≥40dB, n=10), were evaluated with a comprehensive neuropsychological assessment, questionnaires of ADL and with auditory measurements including: PTA, and amplitudes and latencies of ABR waves I and V obtained at supra-thresholds levels. Neuropsychological and ADL data were compared between groups of hearing impairment, and lineal regressions between these data and different auditory assessment were performed. Those with moderate presbycusis (n=10) had more perseverative errors in the Wisconsin card sorting task (ANOVA, F(2)=3.4, p=0.04) than the other groups, without any other differences in the neuropsychological or ADL assessment (Table 1). Instrumental ADL impairments were correlated with latencies of bilateral ABR waves V: shopping (right: r=0.44, p=0.001; left: r=0.63, p<0.001), work (right: r=0.33, p=0.02; left: r=0.3, p<0.03) and house hold (right: r=0.29, p=0.04; left: r=0.39, p<0.006). Once excluding those with moderate presbycusis, we found significant correlations in the latencies of left wave V for house hold (r=0.38, p=0.013) and for communication (r=0.36, p=0.019). In addition, the amplitudes of wave I from the left ear were correlated with impairment in traveling (r=-0.40, p=0.013) and technology (r=-0.45, p=0.005). Supra-thresholds ABRs are good predictors of ADL impairments in elderlies without evident cognitive or hearing impairment. These results reinforce the study of other risk factors for cognitive decline in the elderly. Funded by Anillo ACT1403, Fondecyt 1140423, Fondecyt 1161155.