Pupil Size Tracks Attentional Performance In Attention-Deficit/Hyperactivity Disorder

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Science

Background:

• Current attention-deficit/hyperactivity disorder (ADHD) diagnosis relies on subjective symptom reporting, risking misdiagnosis.
• Objective biological markers are needed to improve ADHD diagnosis and understand its pathophysiology.
• Pupil size, reflecting arousal network activity linked to the norepinephrine system, is a potential objective cognitive marker.

Purpose of the Study:

• To investigate pupil size as a potential objective biomarker for ADHD.
• To explore the relationship between pupil size, cognitive performance, and medication in ADHD patients.

Main Methods:

• Pupil diameter was monitored in children with and without ADHD during a visuo-spatial working memory task.
• A subgroup of ADHD children repeated the task with and without methylphenidate.
• Pupil size was correlated with task performance and reaction time variability.

Main Results:

• Children with ADHD exhibited decreased pupil diameter during the working memory task compared to controls.
• Methylphenidate treatment normalized pupil diameter in ADHD patients.
• Pupil size correlated significantly with attention indicators like performance and reaction time variability.

Conclusions:

• Pupil size variations are linked to the noradrenergic system's involvement in attention.
• Pupil size shows promise as an objective biomarker for ADHD diagnosis and monitoring treatment effects.