Differences in Auditory Perception Between Young and Older Adults When Controlling for Differences in Hearing Loss and Cognition

Abstract

This study was designed to examine age effects on various auditory perceptual skills using a large group of listeners (155 adults, 121 aged 60-88 years and 34 aged 18-30 years), while controlling for the factors of hearing loss and working memory (WM). All subjects completed 3 measures of WM, 7 psychoacoustic tasks (24 conditions) and a hearing assessment. Psychophysical measures were selected to tap phenomena thought to be mediated by higher-level auditory function and included modulation detection, modulation detection interference, informational masking (IM), masking level difference (MLD), anisochrony detection, harmonic mistuning, and stream segregation. Principal-components analysis (PCA) was applied to each psychoacoustic test. For 6 of the 7 tasks, a single component represented performance across the multiple stimulus conditions well, whereas the modulation-detection interference (MDI) task required two components to do so. The effect of age was analyzed using a general linear model applied to each psychoacoustic component. Once hearing loss and WM were accounted for as covariates in the analyses, estimated marginal mean thresholds were lower for older adults on tasks based on temporal processing. When evaluated separately, hearing loss led to poorer performance on roughly 1/2 the tasks and declines in WM accounted for poorer performance on 6 of the 8 psychoacoustic components. These results make clear the need to interpret age-group differences in performance on psychoacoustic tasks in light of cognitive declines commonly associated with aging, and point to hearing loss and cognitive declines as negatively influencing auditory perceptual skills.

Keywords: aging; cognition; principal component analysis; psychoacoustics; working memory.

Figure 1.

Median hearing thresholds of the test ear (filled circles) and interquartile ranges (dotted lines without symbols) for the older adults.

Figure 2.

Average thresholds for the younger and older listeners are shown for 7 different psychoacoustic tasks. Error bars represent the standard errors of the mean.

Figure 3.

Principal component (PC) scores for younger and older listeners on the PC analyses for 8 psychoacoustic tasks. Average PCA values are plotted for young and older listeners as black and gray bars, respectively, with standard errors indicated. The top panel plots mean PC scores for the two groups, whereas the bottom panel plots estimated marginal means from a GLM treating PTA4 and WM as covariates. Significant effects at the p < 0.05 level are indicated with asterisks.

Figure 4.

Schematic illustration of the results of the two-stage principal-component analyses for the data from the 121 older adults in this study. The numerical values adjacent to each arrow represent the component weights showing the loading of each measure on a given component. For the first stage of the analyses, oblique rotation was used and the numerical values were drawn from the pattern matrix of PC loadings for that solution.