ADHD in Children
Visual Abstract
Evidence for higher reaction time variability for children with ADHD on a range of cognitive tasks including reward and event rate manipulations
ADHD and Response Time Variability
Jeffery N Epstein , Joshua M Langberg , Paul J Rosen , Amanda Graham , Megan E Narad , Tanya N Antonini , William B Brinkman , Tanya Froehlich , John O Simon , Mekibib Altaye
Summarized by:
May 31, 2023
study source
Neuropsychology
Jul 2011
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What they studied
Researchers wanted to examine how ADHD affects response time variability.
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What they found
Those with ADHD had a wider range of response times across a variety of cognitive tests.
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What this means
Response time variability may be a fundamental effect of ADHD.
Evidence for higher reaction time variability for children with ADHD on a range of cognitive tasks including reward and event rate manipulations
Objectives
ADHD has been linked to cognitive challenges in addition to its effects on attention and hyperactivity.
One of the most robust links has been with reaction time variability. On cognitive tests, those with ADHD tend to have a broader range of response times. Those with ADHD can take much longer to respond to some questions while taking less time for others.
This study wanted to examine whether this phenomenon was consistent across different tests. They also wanted to see whether the ADHD subtype and different test scenarios affected reaction time variability.
Study Quote
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 ...
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Methods
This study compared children with ADHD and matched controls without ADHD on several standardized tasks designed to test reaction time variability under different conditions.
Study Quote
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 as...
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Results
The results showed that children with ADHD had much more variability in the response times than children without ADHD.
Those with ADHD had a wider range of response times on various tests covering working memory, attention, and response inhibition.
These results suggest that response time variability is a core effect of ADHD, consistent with previous studies on response time.
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Consistent with predictions, children with ADHD demonstrated significant elevations in RT variability compared to controls. Increased variability among children with ADHD was evident across a range of cognitive tasks assessing a variety of cognitive skills (i.e., working memory, response inhibition, and attention).
The results also showed that higher event rates tended to reduce response times for those with ADHD but did not reduce variability in response times.
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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.
Study Quote
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 ta...
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Conclusions
Researchers concluded that response time variability is vital to ADHD based on its effects across different tests and conditions.
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The robust nature of RT variability elevations observed in children with ADHD suggests dysfunction in a core cognitive process that is utilized across cognitive skills and is not consistently affected by experimental manipulations that attempted to target arousal.
Study Quote
High RT variability is a ubiquitous and robust phenomenon in children with ADHD.