This study examined early visual processing in 21 adults with ADHD vs. 24 neurotypical controls, measuring foveal contrast sensitivity (CS) across spatial frequencies (4–12 cpd) at 40 ms and 80 ms durations, spatial integration with enlarged stimuli, and perceptual noise exclusion.
Adults with ADHD showed overall lower contrast sensitivity than controls. A significant Group × Stimulus Size interaction at 40 ms indicated reduced spatial integration in ADHD (controls improved more with larger stimuli at 12 cpd). No significant group differences in external noise exclusion were found.
Small sample size (n=45 total) limits generalizability. The study only tested foveal CS and did not assess peripheral vision. Perceptual noise exclusion findings may lack power given the sample size.
Adults with ADHD may have subtle deficits in early visual processing — particularly spatial integration at high spatial frequencies and brief exposures — beyond executive dysfunction alone. Clinicians should be aware that visual processing differences may contribute to real-world perceptual challenges in ADHD.
