Foveal crowding and segmentation effects in adults with ADHD

Area of Science:

• Neuroscience
• Cognitive Psychology
• Ophthalmology

Background:

• Visual crowding, the difficulty identifying targets among distractors, is well-researched in peripheral vision.
• Its impact on central (foveal) vision in adults with Attention-Deficit/Hyperactivity Disorder (ADHD) is less understood.

Purpose of the Study:

• To investigate foveal crowding and segmentation effects in adults with ADHD compared to neurotypical controls.
• To explore how visual crowding manifests in central vision for ADHD adults.

Main Methods:

• 45 participants (22 ADHD, 23 controls) performed a computerized visual task identifying a central target letter ('E') under crowded and uncrowded conditions.
• A subset also completed a segmentation task with a red target and black flankers.
• Accuracy and response times were measured across various stimulus durations (30-240 ms).

Main Results:

• Adults with ADHD showed significantly increased foveal crowding effects and slower response times compared to controls.
• Segmentation improved performance in both groups, with salient cues enhancing target distinctiveness.
• Enhanced crowding in ADHD suggests impaired filtering of irrelevant visual information and larger integration fields.

Conclusions:

• Perceptual alterations in ADHD extend to fundamental central vision processes.
• Impaired filtering and increased susceptibility to crowding in ADHD impact daily visual tasks like reading and driving.
• Salient visual cues can mitigate crowding effects by improving target differentiation.