Working memory, processing speed, and set-shifting in children with developmental coordination disorder and attention-deficit–hyperactivity disorder

Authors


* Correspondence to first author at School of Psychology, Curtin University of Technology, GPO Box U1987, Perth 6845, Western Australia. E-mail: j.piek@curtin.edu.au

Abstract

It has been suggested that the high levels of comorbidity between attention-deficit-hyperactivity disorder (ADHD) and developmental coordination disorder (DCD) may be attributed to a common underlying neurocognitive mechanism. This study assessed whether children with DCD and ADHD share deficits on tasks measuring working memory, set-shifting, and processing speed. A total of 195 children aged between 6 years 6 months and 14 years 1 month (mean 10y 4mo [SD 2y 2mo]) were included in this study. A control group (59 males, 79 females), a DCD group (12 males, six females), an ADHD-predominantly inattentive group (16 males, four females), and an ADHD-combined group (15 males, four females), were tested on three executive functioning tasks. Children with DCD were significantly slower on all tasks, supporting past evidence of a timing deficit in these children. With few exceptions, children with ADHD did not perform more poorly than control children. These findings demonstrate the importance of identifying children with motor deficits when examining tasks involving a timing component.

List of abbreviations
ADHD

Attention-deficit-hyperactivity disorder

DCD

Developmental coordination disorder

DSM-IV

Diagnostic and Statistical Manual of Mental Disorders

GNT

Goal neglect task

MABC

Movement Assessment Battery for Children

MN

Mean time

NC

Number correct

RTcr

Reaction time to correct responses

RTicr

Reaction time to incorrect responses

SWAN

Strengths and Weakness of the ADHD-symptoms and Normal-behavior

TMUT

Trail-making/memory updating task

VIT

Visual inspection time

Ancillary