Working memory, processing speed, and set-shifting in children with developmental coordination disorder and...

Area of Science:

• Neuroscience
• Developmental Psychology
• Pediatrics

Background:

• High comorbidity exists between attention-deficit-hyperactivity disorder (ADHD) and developmental coordination disorder (DCD).
• A common underlying neurocognitive mechanism is hypothesized for ADHD and DCD comorbidity.

Purpose of the Study:

• To investigate shared neurocognitive deficits in working memory, set-shifting, and processing speed between children with DCD and ADHD.
• To determine if executive functioning tasks reveal common underlying mechanisms for ADHD and DCD.

Main Methods:

• 195 children (aged 6.5–14.1 years) participated: controls, DCD group, ADHD-inattentive group, and ADHD-combined group.
• Participants completed three executive functioning tasks assessing working memory, set-shifting, and processing speed.

Main Results:

• Children with DCD exhibited significant slowness across all tasks, confirming a timing deficit.
• Children with ADHD generally performed similarly to controls, with few exceptions.
• Motor deficits are crucial for understanding performance on timing-dependent tasks.

Conclusions:

• The study suggests that motor deficits, specifically timing impairments in DCD, are more prominent than executive function deficits in ADHD when examining these specific tasks.
• Findings underscore the necessity of considering motor skill deficits when evaluating children on tasks with a timing component.