SIGNIFICANCE 

Attention-deficit/hyperactivity disorder (ADHD) has been commonly associated with alterations in visual perception. However, the individual behavior of visual perceptual skills and its relationship with different comorbidities remain unknown.

PURPOSE 

The purpose of this study was to examine whether visual perceptual skills are impaired in children with ADHD, as well as to test the possible mediating role of comorbidities.

METHODS 

Thirty-five nonmedicated ADHD (20 pure and 15 with comorbidities) and 35 age-matched controls completed the performance-based Test of Visual Perceptual Skills.

RESULTS 

The analysis between total ADHD and controls favored the alternative hypothesis (greater values for children with ADHD) for visual memory, spatial relationships, sequential memory, and all the composite measures (Bayes factor [BF] range, 4.26 to 366.85). The analysis between pure ADHD and controls showed that data are more likely under the alternative hypothesis for spatial relationships, sequential memory, overall, basic, and sequencing (BF range, 3.82 to 21.71), whereas the comparison between ADHD with comorbidities and controls additionally favored the alternative hypothesis for visual discrimination (BF = 5.37). Lastly, data from the comparison between pure ADHD and ADHD with comorbidities were insensitive for favoring the null or alternative hypotheses in any subtest or composite scaled score (BF range, 0.33 to 0.66).

CONCLUSIONS 

Our results suggest that some specific patterns of visual perception are altered in ADHD, especially for the total ADHD group. The current findings also evidence that comorbidities play an important role in the association between ADHD and visual perceptual skills. Future studies should address the mediating role of each specific type of comorbidity.