ADHD Research Today is a free monthly online journal that collates and summarizes the latest research about ADHD, including details on attention-deficit hyperactivity disorder, drugs, treatment, symptoms. | ||||||||
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Motor flexibility problems as a marker for genetic susceptibility to attention-deficit/hyperactivity disorder.Slaats-Willemse D, de Sonneville L, Swaab-Barneveld H, Buitelaar J Academic Center for Child and Adolescent Psychiatry Oost-Nederland, University Medical Center St. Radboud, Reinier Postlaan 12, 6525 GC Nijmegen, The Netherlands. dorine.slaats@skjpon.nl BACKGROUND: Since many children with attention-deficit/hyperactivity disorder (ADHD) have fine visuomotor problems that are already evident at a young age, motor dysfunctioning is investigated in family-genetic perspective. We hypothesized that if fine motor problems may be a marker for genetic susceptibility to ADHD, nonaffected siblings of ADHD probands would experience motor problems similar to those of their ADHD siblings. METHODS: Twenty-five carefully phenotyped ADHD probands with a family history of ADHD, their nonaffected siblings (n = 25), and 48 normal control subjects (aged 6 to 17) completed a motor fluency task and a motor flexibility task. The motor fluency task involved completion of a familiar, automatized trajectory, whereas the motor flexibility task required continuous adjustment of movement to complete an unpredictable random trajectory. RESULTS: On the motor fluency task, the performance of the nonaffected children was significantly better than that of the ADHD probands; strikingly, on the motor flexibility task, they performed as well as their ADHD siblings. CONCLUSIONS: Nonaffected siblings experience complex motor problems similar to their ADHD siblings but only in nonautomatized movements that require controlled processing. The results suggest that higher-order controlled motor deficits in ADHD may be associated with genetic susceptibility for ADHD. Published 8 August 2005 in Biol Psychiatry, 58(3): 233-8.
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