Dichotic listening performance under high and low lexical work load in subtypes of developmental dyslexia.

This study examined dichotic listening performance in different subtypes of developmental dyslexia under high and low verbal work load conditions. Free recall tests of digits and words were administered to 320 dyslexic children from grade 3 to grade 10 and their matched controls. Results indicate significant differences within subtypes. Surface dyslexics manifested extreme ear neglect or total performance collapse but only under high verbal work load conditions. Phonological dyslexia was distinguished by poor total performance both under high and low work load levels. Visuo-motor dyslexics, however, did not differ in any measure from their controls. These results lend support to the contention that the main neuropsychological factor impeding reading acquisition varies according to dyslexia subtype.