Motor Incoordination Response to Methylphenidate in Children with ADHD

Abstract

Source: Flapper BCT, Houwen S, Schoemaker MM. Fine motor skills and effects of methylphenidate in children with attention-deficit hyperactivity disorder and developmental coordination disorder. Dev Med Child Neurol. 2006;48:165–169; doi:10.1017/S0012162206000375The manual dexterity subtests of the Movement Assessment Battery for Children and handwriting and computerized graphomotor tasks were used to compare motor skills in a group of 12 children (11 males) with attention-deficit hyperactivity disorder (ADHD) and developmental coordination disorder (DCD) to those in 12 controls at University Medical Centre Groningen, the Netherlands. ADHD-DCD children had more severely impaired fine motor abilities than control children: they made more errors and were slower in completing manual dexterity tests (P=.001), their handwriting was poorer (P=.002), and on a flower trail graphomotor task, they drew more rapidly and fluently but were less accurate than controls (P=.002). When treated with methylphenidate, manual dexterity in the ADHD-DCD group was improved (P=.003), handwriting quality improved (P=.042), and lines on the graphomotor task were less fluent (P=.028) but more accurate (P=.01). It is estimated that 50% of children with ADHD have comorbid DCD.Dr. Millichap has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of a commercial product/device. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device.The prevalence of incoordination and other ”subtle” or ”soft” neurologic abnormalities in children with ADHD was recognized by a National Institutes of Health task force in 1966, when the term “minimal brain dysfunction” (MBD) was coined for the syndrome.1 Subtle abnormal neurological signs include motor impersistence (inability to maintain a motor behavior such as closing the eyes on request), response inhibition deficit (inability to look at an object without picking it up (“he cannot keep his hands to himself”), dyspraxia (loss of dexterity in purposeful moments, as in using scissors), dysgraphia (inability to write or print words and numbers despite normal hand muscle power, essentially a dyspraxia of the hands), synkinesia (mirror movements), incoordination (clumsiness), and graphanesthesia (inability to recognize traced numerals, a cortical sensory deficit). Some of these neurologic signs are now described as part of DCD. These signs were used as outcomes in early controlled trials of methylphenidate in the treatment of ADHD (MBD).2 Improvements in coordination, handwriting, and visual perception, in addition to attention and activity, were documented that were similar to the results obtained in the current report. In the DSM criteria3 for the diagnosis of ADHD, reference to impaired motor performance, clumsiness, and incoordination has been omitted, despite the frequency of these findings. The early concept of an organic or neuro-biologic syndrome4 has been rejected in favor of a symptom diagnosis for ADHD.In Scandinavia, the syndrome of DAMP (deficits in attention, motor control and perception) emphasizes the association of neurologic signs of motor dysfunction, perceptual dysfunction, and attention deficits.5 An overlap of ADHD and DAMP, and the presence of DAMP among children with neurodevelopmental disorders, are also recognized. ADHD, when complicated by incoordination and other symptoms of DCD, may increase the risk of learning and especially language and reading problems.6 The inclusion of questions and tests for incoordination and perceptual dysfunction in the criteria for ADHD would allow a more objective diagnosis and lead to earlier recognition and effective treatment. Perhaps the term “attention deficit hyperactivity & coordination disorder (ADH&CD)” would be more appropriate.ADHD, DCD, ADHD-DCD, DAMP, MND, ADH & CD – this article tested our ability to attend to multiple acronyms! Nonetheless, it did not dampen our interest in monitoring for fine motor improvement in children with ADHD, which may well be a good marker of response to therapy.