Impairment of phonetic reading in dyslexia and its persistence beyond childhood--research note.

A previous analysis of the historical development of writing towards progressive phonetisation gave rise to the hypothesis that disorders of reading arise from a defective processing of spoken sounds. Sixteen adolescent and adult dyslexic patients were studied, 10 of whom had been followed up from childhood. A newly devised test of phonetic reading proved superior to the Schonell reading test in distinguishing dyslexics from normals, and mirrored the original severity of the disorder. A phonetic writing test was less useful. The findings support the view that dyslexia is due to a defect of verbal processing which may persist beyond childhood.