Pupillary unrest is attenuated in attention deficit hyperactivity disorder (ADHD)

Area of Science:

• Neuroscience
• Psychiatry
• Ophthalmology

Background:

• Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder.
• Pupillary unrest, or pupil oscillations, has been explored as a potential indicator of cognitive and neurological states.
• Previous research suggests altered pupil dynamics in individuals with ADHD during active tasks.

Purpose of the Study:

• To investigate pupillary unrest in adults with ADHD compared to neurotypical controls.
• To determine if pupillary oscillation power differs between ADHD and control groups under passive and resting conditions.
• To explore the potential of pupillary unrest as a biomarker for ADHD.

Main Methods:

• The study included 76 adult participants (34 with ADHD, 42 controls) aged 18-40.
• Pupillary unrest was measured by analyzing low-frequency pupil oscillations.
• Measurements were taken under two conditions: a passive condition with minimal distraction and a resting condition with no distraction.

Main Results:

• Individuals with ADHD exhibited significantly reduced power in low-frequency pupillary oscillations compared to controls.
• This reduction in pupillary unrest was observed in both passive and resting conditions.
• The findings suggest a background suppression of general catecholaminergic activity in individuals with ADHD.

Conclusions:

• Reduced pupillary unrest in ADHD is independent of visual tasks or cognitive effort.
• This phenomenon supports previous findings of reduced pupil dilation in ADHD during active tasks.
• Pupillary unrest may serve as a valuable psychophysical biomarker for ADHD evaluation and classification.