Evidence for higher reaction time variability for children with ADHD on a range of cognitive tasks including reward and event rate manipulations.

Abstract

Objective The purpose of the research study was to examine the manifestation of variability in reaction times (RT) in children with Attention Deficit Hyperactivity Disorder (ADHD) and to examine whether RT variability presented differently across a variety of neuropsychological tasks, was present across the two most common ADHD subtypes, and whether it was affected by reward and event rate (ER) manipulations. Method Children with ADHD-Combined Type (n=51), ADHD-Predominantly Inattentive Type (n=53) and 47 controls completed five neuropsychological tasks (Choice Discrimination Task, Child Attentional Network Task, Go/No-Go task, Stop Signal Task, and N-back task), each allowing trial-by-trial assessment of reaction times. Multiple indicators of RT variability including RT standard deviation, coefficient of variation and ex-Gaussian tau were used. Results Children with ADHD demonstrated greater RT variability than controls across all five tasks as measured by the ex-Gaussian indicator tau. There were minimal differences in RT variability across the ADHD subtypes. Children with ADHD also had poorer task accuracy than controls across all tasks except the Choice Discrimination task. Although ER and reward manipulations did affect children’s RT variability and task accuracy, these manipulations largely did not differentially affect children with ADHD compared to controls. RT variability and task accuracy were highly correlated across tasks. Removing variance attributable to RT variability from task accuracy did not appreciably affect between-group differences in task accuracy. Conclusions High RT variability is a ubiquitous and robust phenomenon in children with ADHD.

fMRI: blood oxygen level–dependent activation during a working memory–selective attention task in children born extremely preterm

“…4,5,7). Recent studies suggest that lack of attention in only Articles a few responses may be the cause of the overall prolonged RTs documented in children with attention-deficit hyperactivity disorder (31,32). This was a relevant possibility also for our preterm children, and a reason to add RT to our study design.…”

Data trimming procedure can eliminate bilingual cognitive advantage

“…This is problematic if long responses are most sensitive to the experimental manipulation and/or group differences, as in studies where group/condition differences only emerged in the tail of response distributions (e.g. Epstein et al, 2011;Hervey et al, 2006). In other words, if a difference resides in the tail of the response distribution, by trimming the tail one also trims the potential to observe an effect.…”

Lower white matter microstructure in the superior longitudinal fasciculus is associated with increased response time variability in adults with attention-deficit/hyperactivity disorder

“…Increased τ indicates more frequent excessively long RTs and is often attributed to lapses in attention. [7][8][9][10] Increased τ has consistently been found in patients with ADHD across tasks. [6][7][8][9][10][11][12][13][14] Compared with reports on τ, reports on alterations of μ and σ in patients with ADHD have been less consistent, and findings seem more taskdependent.…”