Varying intelligibility and linguistic complexity in sentence recognition in noise: Insights from older listeners

Abstract

Recognition of foreign-accented speech by older listeners with hearing loss has typically been examined with linguistically simple materials (words and short sentences), which may not capture the complexity of realistic speech experiences. In this study, older listeners with varying degrees of hearing acuity recognized simple (i.e., short, mono-clausal, canonical declarative syntax) and complex (i.e., longer, multi-clausal, non-canonical syntax, and/or passive voice) sentences in broadband noise at a signal-to-noise ratio of 5 decibels. Three talkers produced the sentences: one L1-English, one high-intelligibility and one low-intelligibility L2 English talkers (based on prior intelligibility testing with young, normal hearing listeners). As anticipated, sentence recognition accuracy dropped with decreasing talker intelligibility and increasing sentence complexity. However, the effect of linguistic complexity on recognition accuracy was modulated by talker intelligibility, as reflected in a robust interaction between the two variables. Namely, accuracy dropped with increasing linguistic complexity only for the native and high intelligibility talkers. This pattern persisted after accounting for the effects of working memory and degree of hearing acuity. These findings suggest that older listeners exhibit different listening strategies for low versus high intelligibility talkers, wherein recognition benefits attributable to linguistic simplicity only emerge for speech over a threshold of intelligibility.