Speech-in-noise recognition abilities are associated with vocal pitch perception abilities in controls but not in high-functioning autism spectrum disorder
The ability to recognise auditory speech in a noisy environment is critical for successful communication in everyday situations. There is evidence that in autism spectrum disorder (ASD), speech perception is reduced under noisy conditions (Alcantara, Weisblatt, Moore, & Bolton, JChildPsycholPsyc, 2004; Groen et al., JAutismDevDisord, 2009). Currently it is unclear, whether difficulties in speech-in-noise perception are associated with difficulties in perceiving basic acoustic features of voices that are relevant for speech-in-noise perception. A key acoustic feature for speech-in-noise perception is the fundamental frequency which is perceived as vocal pitch (Anderson & Kraus, JAmAcadAudiol, 2010). Here we investigated speech-in-noise recognition abilities and its relation to vocal pitch perception abilities in a group of adults with high-functioning ASD (n = 16) and typically developed individuals (n = 16; matched pairwise on age, gender, and IQ). The ASD group has been previously shown to have difficulties in vocal pitch perception but intact non-vocal pitch perception abilities (Schelinski, Roswandowitz, & von Kriegstein, AutismRes, 2017). In the speech-in-noise recognition test, we investigated the individual thresholds for speech recognition when speech was presented with different levels of speech-shaped noise. The ASD group showed significantly higher thresholds as compared to the control group, i.e. typically developed individuals understood speech in higher noise levels. Within the control group, performance in the speech-in-noise recognition test correlated with performance in vocal pitch, but not non-vocal pitch perception. Within the ASD group, there were no correlations between speech-in-noise recognition and vocal or non-vocal pitch perception abilities. This indicated that in controls better speech-in-noise recognition abilities were associated with better vocal pitch perception, but not in the ASD group. Our results suggest that perceptual impairments, i.e. difficulties in vocal pitch perception, might contribute to speech-in-noise recognition difficulties in ASD. In line with our previous results on vocal emotion recognition this implies that communication difficulties in ASD might not only be based on higher-level cognitive difficulties, but also on impaired basic perceptual processing.