Early Signs of Aging in Auditory Function Reflected in the Event-Related Potentials

Background: Speech perception requires a balanced interplay between the bottom-up sensory and top-down cognitive processes. The differential impact of aging on the bottom-up and top-down processes in the auditory system has been debated.<br> Purpose: The primary aim of this study was to use auditory event-related potentials (ERPs) including the cortical auditory evoked potential (CAEP), mismatch negativity (MMN), and the P300 in young and upper-middle-aged adults to determine early effects of aging on auditory processing at the preattentive and attentive levels. The secondary aim of this study was to determine the correlations between ERPs and subjective evaluation of hearing as well as cognitive function.Research Design: ERPs were recorded in response to an oddball stimulus paradigm under passiveand attentive listening conditions, respectively. The frequency discrimination (FD) test, the five-itemSpeech Spatial and Qualities of Hearing Scale (SSQ) questionnaire, and computerized cognitive testswere also administered.<br> Study Sample: A total of 20 young adults (Young group aged 20–30 years; mean ¼ 23.01 6 1.43 years) and 10 upper-middle-age adults (Upper-middle-age group aged 50–60 years; mean ¼ 53.67 6 2.83 years) without hearing impairment participated in the study. They were recruited in the Greater Cincinnati area through advertisements for this study.<br> Data Collection and Analysis: The amplitude and latency of ERP peaks (N1 and P2 of the CAEP, MMN, and P300), the FD threshold, reaction time of cognitive tests, and SSQ scores were collected from each participant. Statistical analyses were performed to investigate the effects of aging on all these outcomes and the correlations between ERPs and other measures.<br> Results: Compared to the Young group, the Upper-middle-aged group showed a larger amplitude and shorter latency in the CAEP peak components and a smaller amplitude and longer latency in the MMN and P300 peaks. Despite the fact that the Upper-Middle-aged group had poorer averaged hearing thresholds, different ERP measures, and poorer cognitive performance, their FD threshold did not differ from that of the Young group.<br>Conclusions: Early signs of aging in the auditory system can be shown in preattentive and attentive ERPs. <br> Clinical Relevance Statement: ERPs provide objective measures of early signs of age-related changes in auditory function.