Movement Difficulties in ADHD Affect Participation Most

What the research found

Fifteen of twenty children with ADHD screened positive for probable developmental coordination disorder. Among forty children of the same ages and sexes without ADHD, four did.

The comparison belongs to Rebeca Montes-Montes, Laura Delgado-Lobete and Sara Rodríguez-Seoane, whose case-control study of sixty Spanish children appeared in the journal Children in 2021. The twenty children in the ADHD group had a clinical diagnosis from a paediatrician, child neurologist or psychologist, no other diagnosed condition, and were recruited through two private rehabilitation centres. The forty controls attended seven elementary schools across three Spanish regions and were randomly matched for exact age and sex. Four fifths of the sample were boys, and the mean age was 8.9 years.

Developmental coordination disorder is the diagnostic name for motor coordination that develops well below what a child’s age predicts, persistently enough to interfere with dressing, handwriting, cutlery and ball games. Parents completed the Developmental Coordination Disorder Questionnaire, fifteen items on movement control, handwriting and general coordination, and a score at or below the fifteenth percentile for age marked probable DCD. That threshold covers one of the four diagnostic criteria, which is why the authors report probable DCD rather than the diagnosis itself. The odds of screening positive were twenty-seven times higher in the ADHD group, with a confidence interval running from 6.4 to 114.7.

Motor ability was measured a second way. The DCDDaily-Q asks parents about twenty-three ordinary activities covering self-care, fine motor tasks and gross motor play, and rates each one twice: how well the child performs the activity, and how much the child takes part in it. The authors are precise about why both are needed. A clinic task establishes what a child can do when seated at a table with a therapist. Performance and participation describe what happens at home on a Tuesday morning.

Children with ADHD scored worse on every subscale of both, at p below 0.01, with effect sizes between 0.9 and 1.4. The performance total reached 1.2, and the single widest difference in the study was the participation total, at 1.4.

What it means for you and your child

Participation on this questionnaire counts how often and how readily a child joins an activity. Slow, effortful dressing is described by the performance score. A child who has stopped asking to go to the park is described by the participation score, and that score moved further from the comparison group than the other.

Inside the ADHD group the two scores separated, in a comparison the design was too small to test. The fifteen children who screened positive for probable DCD performed worse on self-care and fine motor activities than the five who did not, while their participation totals were nearly identical, 42.5 against 42.0. The authors ran no statistical test on that comparison. The identical totals raise a possibility the study cannot test, that a child withdraws from everyday activities for reasons no motor score records, and five children are too few to take it further.

The deficit here is what it appears to be. Coordination difficulty screened positive in three quarters of the ADHD group on a validated instrument, and those same children did less of what their age-matched peers were doing. Skills that go unpractised do not improve on schedule, and the authors invoke a skill-learning gap to explain the drift, though the study was cross-sectional and tested no such sequence.

What the study can support is a referral. The authors report that DCD is widely unrecognised in Spain and that children with ADHD are rarely screened for coordination difficulties, and they recommend that occupational therapists and clinicians assess motor skills routinely after an ADHD diagnosis. Both questionnaires used here are completed by parents and take minutes. Neither requires a specialist appointment to fill in.

Two questions have specific answers in a school meeting or an occupational therapy assessment. The first is whether the child’s motor coordination has been screened with a validated instrument at any point since the ADHD diagnosis was made. The second is which activities the child has quietly stopped doing over the past year: the swimming lesson, the bicycle, the shoelaces handed over to an adult. That list is not in any clinical file, and you are the only person in the room who can produce it.