fMRI during word processing in dyslexic and normal reading children

THE present study addresses phonological processing in children with develo pmental dyslexia. Following the hypothesis of a core deficit of assembled p honology in dyslexia a set of hierarchically structured tasks was applied t hat specifically control for different kinds of phonological coding (assemb led versus addressed phonological strategies). Seventeen developmental dysl exics and 17 normal reading children were scanned during four different tas ks: (1) passive viewing of letter strings (control condition), (2) passive reading of non-words, (3) passive reading of legal words, and (4) a task re quiring phonological transformation. Statistical analysis of the data was p erformed using statistical parametric mapping (SPM96). Comparison of patter ns of activation in dyslexic and normal reading children revealed significa nt differences in Broca's area and the left inferior temporal region for bo th, non-word reading and the phonological transformation task. The present data provide new evidence for alteration of the phonological system in dysl exic children, and in particular, the system that mediates assembled phonol ogical coding. NeuroReport 10:3459-3465 (C) 1999 Lippincott Williams & Wilk ins.