Effects of listeners' working memory and noise on speech intelligibility in dysarthria.

The purpose of this study was to investigate the effects of listeners' working memory (WM), types of noise and signal to noise ratios (SNRs) on speech intelligibility in dysarthria. Speech intelligibility was judged by using a word transcription task. A three-way mixed design (2 × 3 × 2) was used with the WM group (high/low group) as a between-subject factor and the types of noise (multi-talker babble/environmental noise) and SNRs (0, +10 and +20 dB) as within-subject factors. The dependent measure was the percentage of correctly transcribed words. The results revealed that the high WM group performed significantly better than the low WM group and listeners performed significantly better at higher levels of SNRs on the speech intelligibility test. The findings of this study suggested that listeners' cognitive abilities and SNRs should be considered as important factors when evaluating speech intelligibility in dysarthria.