The cooccurrence of attention deficits and motor incoordination or clumsiness was examined at the University of Goteborg in a population study of 400 seven-year-old children attending mainstream schools in Karlstad, Sweden. ADHD, developmental coordination disorder (DCD), and combined deficits in attention, motor control, and perception (DAMP) were found in 6.1%. Severe ADHD alone occurred in 2% and moderate ADHD in 5.4%. The boy:girl ratio was 2:1 for severe DAMP and 6.2:1 for severe ADHD alone. Considerable overlap of attention deficits and motor clumsiness was present. One half the children with ADHD had moderate motor incoordination (DCD), and one in 5 was severely affected. Similarly, children with DCD frequently met criteria for the diagnosis of ADHD. Findings were unchanged at follow-up examinations 8 months later. ’Soft signs’ were highly reproducible, with excellent agreement between neurologic exams and observations of motor dysfunction reported by physical education teachers. Parent reports of ADHD were confirmed by teacher observations in more than 90% of cases, whereas 40% of teacher diagnoses of ADD were not reported by parents in the home setting. DSM-III-R criteria for ADHD tended to exclude many ADD children with a high degree of classroom dysfunction. Those with subtype ADD or DAMP had higher classroom-dysfunction scores than those with mainly hyperactivity or ADHD. DAMP is a valid diagnostic subtype of ADHD. 
COMMENT. A neurologic examination to uncover soft signs, motor incoordination, and sensori-perception impairments (“minimal brain dysfunction“ or MBD) is an important part of the work-up of a child at risk of ADD. The omission of signs of impaired motor control and perception from the diagnostic criteria for ADHD excludes many ADD children with significant classroom dysfunction. A return to the former, more objective MBD criteria, in addition to the subjective, symptomatic criteria for ADHD, would lead to the earlier recognition of children with increased risk of classroom dysfunction sufficient to demand medical, psychological, and educational therapy. See Progress in Pediatric Neurology III. PNB Publ, 1997;pp204-205, for a review of previous Scandinavian reports of the DAMP syndrome and ADHD.
Huttenlocher PR (1990) and Millichap JG (1974) have emphasized the value of neurologic soft signs in the prediction of learning disabilities in preschool children and the correlation with hyperactive behavior and response to methylphenidate. (see Progress in Pediatric Neurology I. 1991;ppl67-8).