Sequencing versus nonsequencing working memory in understanding of rapid speech by older listeners.

The goal of this study was to identify specific neurocognitive deficits that are associated with older listeners' difficulty understanding rapid speech. Older listeners performed speech recognition tests comprised of time-compressed sentences with and without context, and on a neurocognitive battery aimed specifically at testing working memory, processing speed, and attention. A principle component analysis identified three main cognitive components as follows: a sequencing working memory (WM-S) component, a nonsequencing working memory (WM-NS) component, and a processing speed (PS) component. Each of the cognitive component scores was divided into high, mid, and low categories. Sentence performance of the cognitive subgroups was compared within each component. The results showed that, with hearing loss and age accounted for, the cognitive score groups differed similarly on the sentence condition scores also at 50 and 60% time compression, particularly on the subgroups of the WM-S component. The results suggest that deficits in a separate working memory function identified as sequencing were associated with differences in ability to understand time-compressed speech in this study.