Altered pre-stimulus alpha dynamics index sustained attention difficulties in ADHD.

Area of Science:

• Neuroscience
• Cognitive Psychology
• Psychiatry

Background:

• Sustained attention deficits are a core feature of Attention-Deficit/Hyperactivity Disorder (ADHD).
• The underlying neural mechanisms of these attention difficulties, especially over time, are not fully understood.
• Prestimulus posterior alpha power is a neural marker of attentional engagement.

Purpose of the Study:

• To investigate time-on-task effects on prestimulus posterior alpha power in adults with and without ADHD.
• To examine neural dynamics of attentional preparation during a reaction time task.
• To explore the relationship between neural attention measures and behavioral performance in ADHD.

Main Methods:

• EEG data analyzed from adults with ADHD (n=24) and controls (n=20) during a slow-paced 2-choice reaction time task.
• Examined time-on-task effects on prestimulus posterior alpha power.
• Analyzed temporal dynamics of alpha power within the pre-stimulus interval and its relation to reaction times.

Main Results:

• Both groups showed increased alpha power over time, but the ADHD group exhibited a more pronounced increase, indicating greater attentional decline.
• Adults without ADHD showed decreased alpha power over time, signifying increased attentional readiness, which was not sustained by the ADHD group.
• Lower alpha power predicted faster reaction times in controls, but this link was absent in adults with ADHD, suggesting a neural-behavioral decoupling.

Conclusions:

• Adults with ADHD demonstrate a dynamic failure to regulate attentional states over time.
• ADHD is associated with a persistent difficulty in translating anticipatory attention into motor performance.
• Time-on-task analyses and neural measures are crucial for understanding sustained attention deficits in ADHD.