Postural instability in adult ADHD - A pilot study

Abstract

Background: Apart from inattention, hyperactivity and impulsivity, ADHD in childhood presents with an impairment of motor coordination and balance functions. Until now, literature is scarce about sensorimotor deficits in adult ADHD. This is a pilot study that identifies and quantifies the role of sensory, motor, and central adaptation mechanisms for adult ADHD patients' sensorimotor deficits in a systematic way, using postural control.

Methods: We analyzed spontaneous and externally perturbed stance in ten adult patients suffering from ADHD. Findings were compared to data from ten matched healthy subjects.

Results: Spontaneous sway amplitudes and velocities were larger in ADHD patients compared to healthy subjects. Furthermore, body excursions as a function of platform tilts were abnormally large in ADHD patients, specifically in the low frequency range. Based on simple feedback model simulations, we found that ADHD patients showed a larger time delay between platform tilts and body response, and a lower value of the integral part of the neural controller, which affects the long-term control of their posture. These postural abnormalities correlated well with the hyperactivity and impulsivity dimensions of the individual ADHD symptoms.

Conclusion: We conclude that adult ADHD patients' major postural deficit consists of an impairment of a stable, long-term sensorimotor behavior, which fits very well to the concept of impulsivity and hyperactivity.

Keywords: ADHD; Motor control; Neuropsychiatry; Sensory system; Vestibular system.