Minor neurological dysfunction in children with dyslexia.

AIM: to improve understanding of brain function in children with severe dyslexia in terms of minor neurological dysfunctions (MNDs).
METHOD: one hundred and four children (81 males, 23 females; age range 7-12y; mean age 9y 7mo, SD 1y 2mo;) with severe dyslexia (the presence of a Full-scale IQ score of ≥ 85, retardation in single-word or text reading of ≥2y), assessed in a department of dyslexia of a third-level regional psychiatric centre, underwent a neurological examination according to Touwen and a multidisciplinary child psychiatric assessment. Special attention was paid to severity and type of MND. Data were compared with neurological morbidity data of children in the general population.
RESULTS: most children had MND (87%): 43% had simple MND, 44% complex MND. The incidence of MND was significantly higher (p<0.001) in the children with dyslexia than in the general population (simple MND 15%, complex MND 6%). Children with dyslexia showed especially fine manipulative disability and - to a lesser extent - mild dysfunction in muscle tone regulation and excessive presence of associated movements. A comorbid psychiatric syndrome was diagnosed in 66 children (63%): emotional disturbances (27%), adjustment disorder (42%), hyperkinetic disorder (15%), autism spectrum disorder (3%), specific disturbances of childhood not otherwise specified (13%). The neurological findings of children with dyslexia with and without psychiatric comorbidity were similar.
INTERPRETATION: our results demonstrate the importance of neurological and child psychiatric assessment in children with severe dyslexia. Our findings suggest that dysfunction of cortical structures plays a dominant role in dyslexia.