ABSTRACT
All rating scales for attention deficit hyperactive disorder (ADHD) include items that inquire to evaluatemotor hyperactivity. Although these ratings can be confounded by aggression, oppositionality, and reduced impulse control, the motor aspect of ADHD is an important one, since a general motor hyperactivity is the most apparent symptom of ADHD in young children. Further, theworking groupofGillberg described asDAMPsyndromeagroup of children with deficits in attention, motor control, and perception (1). This combination is often found in ADHD children, particularly of the combined subtype. Themotor activity in children with ADHD is not only quantitatively increased compared to healthy children but, especially in waiting situations (2), movements start earlier compared to their peers and this movement is disorganized, poorlymodulated, shows problems in goal direction and cannot
be inhibited properly (3). Also, some studies found that children with ADHD are not only more active during daytime than age-matched controls but even during sleep (4-6) indicating that locomotor hyperactivity is a primary symptom. Further, Rothenberger (7) and Yordanova et al. (8) demonstrated that ADHD children (registration of brain electrical activity using event-related potentials) seem to have a deficit of motor control in the primary motor cortex as well as of the frontal lobe. This view is supported by Mostofsky et al. (9) who, on the basis of MRI findings, suggested that the clinical picture of ADHD encompasses dysfunctions attributable to anomalous development of both premotor and prefrontal cortices. ADHD children do not regulate the neuronal networks responsible for voluntary motion with selective activation and sufficient precision. This possibly applies even more for spontaneous movements, which are poorly under voluntary control in ADHD children. Hence, as one example, their tendency for associative mirror movements may be better clarified by using specific experimental tasks such as transcranial magnetic stimulation (TMS). Unfortunately, in a preliminary study, Barker et al. (10) did not find a significant correlation between mirror movements and the ipsilateral silent period evoked by TMS, although they could show an abnormal transcallosal inhibition in children with ADHD.
