Memory-guided force output is associated with self-reported ADHD symptoms in young adults

Abstract

Attention-Deficit/Hyperactivity disorder (ADHD) is the most commonly diagnosed mental health disorder in childhood and persists into adulthood in up to 65% of cases. ADHD is associated with adverse outcomes such as the ability to gain and maintain employment (Kessler et al. 2009; Kupper et al. 2012), and is associated with an increased risk for substance abuse (Groenman et al. 2013; Upadhyaya 2008; Wilens et al. 1995), obesity (Albayrak et al. 2013; Cortese et al. 2008; Nazar et al. 2012; Nazar et al. 2014), workplace injuries (Breslin and Pole 2009; Hodgkins et al. 2011; Swensen et al. 2004), and traffic accidents (Barkley and Cox 2007; Barkley et al. 1993; Jerome et al. 2006a; Jerome et al. 2006b; Merkel et al. 2013). A majority of diagnosed children have motor deficits, however few studies have examined motor deficits in young adults. This study provides a novel examination of visuomotor control of grip force in young adults with and without ADHD. Participants were instructed to maintain force production over a 20-second trial with and without real-time visual feedback about their performance. The results demonstrated that when visual feedback was available, adults with ADHD produced slightly higher grip force than controls. However, when visual feedback was removed, adults with ADHD had a faster rate of decay of force, which was associated with ADHD symptom severity and trait impulsivity. These findings suggest that there may be important differences in the way that adults with ADHD integrate visual feedback during continuous motor tasks. These may account for some of the motor impairments reported in children with ADHD. These deficits could result from (1) dysfunctional sensory motor integration and/or (2) deficits in short-term visuomotor memory