Temporal processing in speech perception of dyslexics.

Abstract

Numerous studies show that a phonological deficit causes dyslexia, but the origin of this deficit remains a controversial issue. The present study examines whether perceptual phonological deficit in dyslexics can be explained by a temporal processing deficit with a design that controls the demands of the task and linguistic complexity and temporal contrasts between speech sounds. Thirteen dyslexics with phonological deficits (9-11 years) and 13 age-matched normal readers were assessed on tasks of temporal order judgment tasks (TOJ) and same-different discrimination tasks (I-D). The tasks are based on contrasts of the syllables / ba / -/da / and / fa/-/ la /. We analyze the effects of the complexity of the stimuli (similar versus no similar) and the task (temporal order judgment versus discrimination tasks). Dyslexic’s children showed lower performance than normal readers in both pairs of syllables. The performance of dyslexics in the TOJ task was significantly lower than controls but no differences between groups in the same-different task were found. The findings are discussed in terms of temporal processing problems in speech perception in dyslexic children.