Internal Cognitive Load Differentially Influences Acoustic and Lexical Context Effects in Speech Perception: Evidence From a Population With Attention-Deficit/Hyperactivity Disorder.

BACKGROUND:To overcome variability in spoken language, listeners utilize various types of context information for disambiguating speech sounds. Context effects have been shown to be affected by cognitive load. However, previous results are mixed regarding the influence of cognitive load on the use of context information in speech perception. PURPOSE:We tested a population characterized by an attention-deficit/hyperactivity disorder (ADHD) to better understand the relationship between attention (or internal cognitive load) and context effects. METHOD:The use of acoustic versus lexical properties of the surrounding signal to disambiguate speech sounds was examined in listeners with ADHD and neurotypical listeners. RESULTS:Compared to neurotypicals, individuals with ADHD relied more strongly on lexical context for speech perception; however, reliance on acoustic context information from speech rate did not differ. CONCLUSION:These findings confirm that cognitive load impacts the use of high-level but not low-level context information in speech and imply that speech recognition deficits in ADHD likely arise due to impaired higher order cognitive processes.