The effect of mild dementia on speech perception in quiet and noise

Abstract

Difficulty understanding speech, particularly in background noise, is a common complaint of older adults. In quiet, speech perception is often assumed to be relatively automatic. In background noise, however, additional cognitive abilities likely play a more substantial role in successful communication (Koeritzer et al., 2018; Rönnberg et al., 2013). We used a word identification task in quiet and two levels of speech-shaped noise ( + 6 and + 3 SNR), to examine the impact of mild dementia on speech perception. In addition to noise, the number of similar sounding words (i.e., number of neighbors) also influences spoken word recognition — words with high neighborhood density (many competitors) are more difficult to perceive compared to low-density words (Luce and Pisoni, 1998). We predicted that individuals with dementia would perform significantly worse in conditions with the highest cognitive demands (high-density words, least favorable SNR). Preliminary results revealed that identification scores were significantly lower for conditions with more background noise and that, even after controlling for hearing loss, individuals with dementia had significantly reduced performance in all conditions. These results suggest that after accounting for differences in hearing, individuals with mild dementia still struggle with speech understanding, even in the absence of background noise.