Motor control in children with ADHD and non-affected siblings: deficits most pronounced using the left hand

• Published in: Journal of child psychology and psychiatry 2007-11, Vol.48 (11), p.1071-1079
• Main Authors: Rommelse, Nanda N.J., Altink, Marieke E., Oosterlaan, Jaap, Buschgens, Cathelijne J.M., Buitelaar, Jan, De Sonneville, Leo M.J., Sergeant, Joseph A.
• Format: Article
• Language: English
• Subjects: ADHD; Adolescent; Adult; Attention Deficit Disorder with Hyperactivity - diagnosis; Attention Deficit Disorder with Hyperactivity - epidemiology; Attention Deficit Disorder with Hyperactivity - genetics; Attention Deficit Disorders; Attention deficit disorders. Hyperactivity; Attention deficit hyperactivity disorder; Biological and medical sciences; Brain Hemisphere Functions; Child; Child clinical studies; Child psychology; Child, Preschool; Children; Cognition Disorders - diagnosis; Cognition Disorders - epidemiology; Communication; Control Groups; endophenotype; Female; Functional Laterality; Genetics; Handedness; Heritability; Humans; Hyperactivity; Male; Medical sciences; Motor ability; motor control; Motor performance; Motor Skills Disorders - diagnosis; Motor Skills Disorders - epidemiology; Neuropsychological Tests; non-affected sibling; Pathology; Phenotype; Psychiatry; Psychology. Psychoanalysis. Psychiatry; Psychomotor Skills; Psychopathology. Psychiatry; Risk; Severity of Illness Index; Siblings; Social Behavior; Surveys and Questionnaires; Task Analysis
• ISSN: 0021-9630; 1469-7610
• DOI: 10.1111/j.1469-7610.2007.01781.x

Background:  Attention‐deficit/hyperactivity disorder (ADHD) is strongly influenced by heritability. Identifying heritable vulnerability traits (endophenotypes) that mark a relatively high risk of developing the disorder can contribute to the identification of risk genes. A fruitful area for the search for such endophenotypes may be motor control in children with ADHD, since the disorder is frequently accompanied by motor problems. Method:  The current study used a large sample of 350 children with ADHD, 195 non‐affected siblings and 271 normal controls aged 5–19 years. Children were administered two computerised motor control tasks in which they had to trace a path between two circles (Tracking task) and follow a randomly moving target (Pursuit task). Both tasks were performed with both the right and the left hand. Results:  Children with ADHD were less precise and stable than controls. Non‐affected siblings also deviated from controls, but only on the Tracking task. Group differences were modulated by the use of the right versus the left hand: no group differences emerged when the right hand was used, yet group differences did emerge when the left hand was used. Performance on both tasks was significantly familial. Conclusions:  Imprecision and instability of movements in children with ADHD and in their non‐affected siblings as measured by the Tracking task might be suitable endophenotypic candidates: these deficits are familially present in children having ADHD as well as in their non‐affected siblings. Motor performance might be best assessed in children using their left hand, because motor control deficits are most pronounced using the left hand. This might relate to right hemispheric brain pathology in children with ADHD (and possibly in their non‐affected siblings) that is related to the control of the left hand and/or relate to differential effects of daily life practice on both hands, which may be smaller on the left hand.