Abstract
Autism Spectrum Disorder is characterized by a unique, visual perceptual profile that is best defined by an often- superior ability to process non-social, or elementary, visual information when a local processing strategy is advantageous (Mottron et al. 2006, Behrmann 2006). Several studies suggest that locally-biased perception in ASD may originate at early stages of visual processing, reflected by an increased sensitivity to high-spatial frequency information (Keita, Guy et al. (in review), de Jonge et al. 2007, Jemel et al. 2010). The bulk of these studies, however, have been conducted in adults and older adolescents, neglecting the role of development. It is therefore unclear if locally-oriented perception in ASD emerges early in development and moreover, when exactly it manifests from childhood through to adulthood. The aim of the present study was therefore to examine the development of low-level visuo-spatial perception in ASD in school-aged children and adolescents. Spatial resolution was assessed across three different age groups (i.e. 6-9, 10-12 and 13-15 years), using luminance-defined, sinusoidal gratings defined by different spatial frequencies (0.5, 1, 2, 4, 8 & 16 cycles per degree). Detection thresholds were derived using a two-alternative temporal forced choice paradigm. Contrast sensitivity functions were then defined for each age group. Preliminary analyses failed to reveal a significant group difference in sensitivity. Only expected differences in sensitivity for SF condition and age group emerged. Our current findings indicate that group differences in sensitivity might only be apparent in late adolescence and early adulthood. These results warrant further exploration of the role of experience-dependent modification of neural mechanisms mediating the response properties of early visual processing in ASD.
Meeting abstract presented at VSS 2014