Do sung speech and background noise affect sentence repetition in dyslexia?

Developmental dyslexia (DD) is typically associated with slow and laborious reading, but there is also evidence pointing to speech-in-noise perception difficulties and a deficit in rapid stimulus processing. We looked at sentence repetition in 56 adult participants, half of whom had a diagnosis of DD, using a mixed design with one between-subjects variable (group) and three within-subjects variables (presentation, noise level, and semantic content). More specifically, we investigated whether sung targets could facilitate sentence repetition in DD compared to spoken ones, drawing on the idea that singing has a slower presentation rate. Further, in light of difficulties in repeating semantically meaningless targets in DD and the mixed results regarding speech-in-noise perception in this population, we examined the effects of varying semantic content (story-like, news-like, semantically anomalous) on performance, presenting targets in quiet and in noise. Results showed a significantly poorer performance in DD in quiet relative to controls but not in noise. Semantic content came out non-significant, and sung targets did not statistically affect performance. Considering a previously documented dyslexia-amusia comorbidity, we screened all participants for amusia, and-in line with previous research-we found that approximately 29% of the DD sample met the diagnostic criteria for amusia. However, amusia did not significantly affect performance. The study suggests that sentence repetition is impaired in DD and naturalistic singing does not seem to confer an advantage. As we did not isolate presentation rate as a variable, the results cannot establish that a reduced presentation rate itself has no positive effects.