Event-related potentials to pitch and rise time change in children with reading disabilities and typically reading children.

OBJECTIVE: The purpose of the present study was to investigate whether children with reading disabilities (RD) process rise time and pitch changes differently to control children as a function of the interval between two tones.
METHODS: Children participated in passive oddball event-related potential (ERP) measurements using paired stimuli. Mismatch negativity (MMN), P3a and late discriminative negativity (LDN) responses to rise time and pitch changes were examined.
RESULTS: Control children produced larger responses than children with RD to pitch change in the P3a component but only when the sounds in the pair were close to each other. Compared to children with RD, MMN was smaller and LDN larger in control children in response to rise time change when the sounds in the pair were further apart. The non-overlap in ERP measures between the groups was 40-50%.
CONCLUSIONS: Problems in rapid processing of pitch change were reflected in a component associated with attention switching while amplitude envelope processing problems were reflected in components associated with stimulus detection or discrimination. SIGNIFICANCE: Children with RD process both rise time and pitch changes differently from control children thus providing evidence for the nature of amplitude envelope processing and rapid auditory processing deficits in dyslexia.