Luminance- and Texture-Defined Visual Perceptual Processing in Children and Adolescents with Asd; Comparison with Other Neurodevelopmental Conditions
Objectives: Thepresent study (i) assessed visuo-perceptual profiles (processing of static and dynamic stimuli of varying complexity) in youth with ASD and other NDCs, and (ii) explored the extension of the CS hypothesis to a non-adult ASD population.
Methods: This study employed a single interval, two alternative (spatial) forced-choice orientation-discrimination paradigm to assess the processing of luminance- (simple) and texture-defined (complex) gratings presented in both static and dynamic states for 101 children and adolescents (aged 5 to 17 years). Participant groups either had a primary diagnosis of ASD (n=32), a non-ASD NDC (i.e., ADHD, ID and LD; NDC; n=26) or were typically developing (TD; n=43); groups were matched for mental age (MA), (p=.10), defined by an assessment of cognitive ability using the Wechsler Abbreviated Scale of Intelligence (WASI-II). Orientation-discrimination thresholds (luminance- and contrast-modulation thresholds) were calculated for each condition across groups; performance was assessed in relation to MA.
Results: The performance of the ASD group was comparable to the TD group, whereas the NDC group demonstrated reduced performance for second-order dynamic stimuli, suggesting that the CS hypothesis can define perceptual abilities of younger individuals with a non-ASD NDC. While results are not consistent with the adult-based CS hypothesis, significant correlations were found between MA and ASD perceptual discrimination thresholds in all conditions: r [-.49, -.41, -.55], with the exception of the luminance-defined, dynamic information condition.This relationship, demonstrating that discrimination thresholds decrease with increasing mental age, suggests the visuo-perceptual profile of individuals with ASD changes with MA.
Conclusions: This study provides valuable information regarding the respective maturation of both dynamic and static early perceptual abilities across childhood and adolescence in ASD compared to MA-matched NDC and TD groups. Findings extend the literature by evaluating the integrity of the dorsal and ventral visual streams in clinical groups, and contribute to the developmental and condition-specific conceptualization of visuo-perceptual processing in ASD. Overall, the results support the applicability of the CS hypothesis to other NDCs, and highlight the relationship between visuo-perceptual profiles and overall cognitive abilities (i.e., MA) in ASD. Future research should assess perceptual abilities in ASD and other NDCs within a developmental context.