A diffusion-model analysis of timing deficits among children with ADHD

Area of Science:

• Cognitive Neuroscience
• Neurodevelopmental Disorders
• Psychiatry

Background:

• Timing perception deficits are hypothesized as a cause of Attention-Deficit/Hyperactivity Disorder (ADHD) cognitive and behavioral issues.
• Previous research on timing deficits in ADHD has yielded inconsistent results due to methodological limitations.
• A diffusion model approach is employed to dissect timing into component processes, overcoming limitations of single-performance indices like reaction time (RT) or accuracy.

Purpose of the Study:

• To investigate timing deficits in children with ADHD using a diffusion model approach.
• To differentiate between internal clock speed and decision-making speed in ADHD.
• To explore the implications of timing deficits for understanding ADHD pathophysiology.

Main Methods:

• Fifty children diagnosed with ADHD and 32 non-ADHD controls, aged 8-12, participated.
• Participants completed a temporal bisection procedure, a validated timing task.
• A diffusion model was applied to analyze timing task performance.

Main Results:

• Diffusion model analysis revealed slower internal clock speed and decision-making speed in children with ADHD compared to controls.
• Evidence strongly indicated that slowed decision-making speed was a more significant deficit than a slower internal clock.
• The findings highlight a domain-general deficit in evidence accumulation during decision-making in ADHD.

Conclusions:

• Slower evidence accumulation during decision-making represents a domain-general deficit in ADHD.
• This slowing aligns with adaptive-gain theories, suggesting a suboptimal neural signal-to-noise ratio in ADHD.
• The study provides novel insights into the temporal processing deficits underlying ADHD.