Relationship between reaction time variability and motor skill development in ADHD

Abstract

Slower and more variable reaction times to computerized tasks have been documented in children diagnosed with attention deficit/hyperactivity disorder (ADHD). Recent research supports a role for attentional lapses in generating abnormally variable and slow responses. However, given the association between ADHD and impairments in motor control, we hypothesized that slower or more variable reaction times might also correlate with motor development. The aim of this case-control study was to explore the relationship between motor function, reaction speed and variability, and ADHD. After comprehensive educational and clinical assessments, motor skill development was evaluated in 35 children ages 9 to 14 (19 with ADHD) using the Physical and Neurological Examination for Subtle Signs (PANESS) test battery. Finger-sequencing speed and variability were quantified with goniometers. Reaction times were measured with 20 trials each of computerized simple and choice (binary) tasks. Compared to healthy controls, children with ADHD had slower and more variable reaction times, and these findings correlated with impaired motor development (PANESS) and slow and variable finger sequencing (goniometers). Further studies of motor development in ADHD may identify factors influencing speed and variability of reaction times.

Keywords:

• Reaction time variability
• Motor development
• Children
• Attention deficit/hyperactivity disorder
• Goniometer
• PANESS

Acknowledgments

We acknowledge Ms. Amanda Lewis, Ms. Erica Kao, and Ms. Natalia Carvalho for assistance gathering and processing data in this study, and Stewart M. Mostofsky for insight and technical assistance.

Steve W. Wu receives research support from the Tourette Syndrome Association, Genzyme Corporation, and Otsuka Pharmaceuticals. Donald L. Gilbert has received honoraria from the Tourette Syndrome Association/Centers for Disease Control, the Movement Disorder Society, the American Academy of Neurology, and the American Academy of Pediatrics. He serves on the medical advisory board for the Tourette Syndrome Association, writes board review questions for PREP SA (American Academy of Pediatrics) and has received research support from the NIH (NIMH R01 MH078160 [co-I], NIMH R01 MH08185 [co-I], and NINDS NS056276 [co-I]), Cincinnati Children's Hospital Research Foundation, the University of Cincinnati, the Tourette Syndrome Association, Otsuka Pharmaceuticals, and Psyadon Pharmaceuticals.

Funding: University of Cincinnati Medical Student Summer Research Program, Cincinnati Children's Hospital Medical Center Division of Neurology Summer Research Program, and NIH R01 MH078160.