Within-subject variability during spatial working memory in children with ADHD: an event-related potentials study.

Area of Science:

• Neuroscience
• Developmental Psychology
• Cognitive Science

Background:

• Attention deficit/hyperactivity disorder (ADHD) is associated with working memory (WM) deficits and increased variability.
• The electrophysiological basis of this variability in ADHD, especially considering developmental trajectories, remains poorly understood.

Purpose of the Study:

• To investigate behavioral and electrophysiological within-subject variability in children with ADHD during a visuo-spatial WM task.
• To examine developmental aspects of this variability and its relationship with task performance.

Main Methods:

• Multichannel (31) event-related potentials (ERPs) were recorded from 44 children (8-16 years) performing one-back (BM1) and two-back (BM2) visuo-spatial tasks.
• Behavioral parameters, motor response variability, and ERP amplitude variability were analyzed and compared between ADHD and control groups.
• Age-related changes in variability were assessed in both groups.

Main Results:

• Children with ADHD committed more errors, particularly on the more demanding BM2 task.
• While motor response variability did not differ, ADHD patients exhibited higher ERP amplitude variability, especially in the BM2 task.
• ADHD patients showed a delayed maturation of ERP amplitude variability, with a slower decrease in variability with age compared to controls.

Conclusions:

• ADHD is characterized by impaired visuo-spatial WM processing, evidenced by increased ERP amplitude variability.
• Findings suggest a delayed cortical maturation of WM circuits in ADHD.
• The correlation between amplitude variability and commission errors differs between ADHD and control groups, underscoring distinct neural mechanisms.