Objective measurement of motor activity during cognitive performance in adults with attention-deficit/hyperactivity disorder.

OBJECTIVE

This study investigates whether hyperactivity, i.e. an increased level of motor activity, can be observed in adults with attention-deficit/hyperactivity disorder (ADHD).

METHOD

An infrared motion-tracking system was used to measure motor activity in 20 unmedicated adults with ADHD and 20 matched healthy controls (HC) during a 1-back working memory task.

RESULTS

Motor activity was higher in ADHD. It increased with the duration of testing and co-varied with cognitive performance in ADHD only. Subjective and objective measurements of motor activity were related in HC, but not in ADHD.

CONCLUSION

Higher levels of motor activity in ADHD are objectively measurable not only in children, but in adults as well. It is linked to cognitive performance arguing against distinguishable diagnostic subtypes. The objective measurement of motor activity seems to extend the description of ADHD symptoms derived from rating scales and might thus help to bridge the gap between psychopathological symptom description and neurobiological alterations.