Neurodevelopmental study of writing disorders in middle childhood.

This study investigated patterns of neurodevelopmental dysfunction in children with writing disorders (WD). Records of children, ages 9 to 15 years, referred to a school problems clinic were examined. Using teacher questionnaire information, including ratings of writing legibility, mechanics, rate, linguistic sophistication, and spelling, 99 cases of WD were found. Sixty-three children without WD served as clinic controls. A cluster analysis revealed four discrete subtypes of WD and two non-WD control clusters. The four WD clusters were found to have different patterns of writing and reading characteristics. Neurodevelopmental tests discriminated among the clusters (F = 2.8, p less than .0001), and an examination of neurodevelopmental performance characteristics among the clusters showed different patterns of strengths and weaknesses. An empirically derived subtyping of WD is proposed: WD with fine motor and linguistic deficits, WD with visual-spatial deficits, WD with attention and memory deficits, and WD with sequencing deficits. This subtyping, if confirmed in a population study, may have important diagnostic and therapeutic implications.