Presentation
Search Abstracts | Symposia | Slide Sessions | Poster Sessions | Poster Slams
Word reading in autism shows enhanced activation of dorsal visual association cortex
Poster A49 in Poster Session A, Thursday, October 6, 10:15 am - 12:00 pm EDT, Millennium Hall
Cory McCabe1, Shannon Cahalan1, Melanie Pincus1, Mariam Mahboob1, Miriam Rosenberg-Lee1, William Graves1; 1Rutgers University
Previous studies have robustly shown that the neural correlates of word reading for the neurotypical (NT) population largely take place within a left-lateralized network of regions that include higher-order association cortices such as the visual word form area (VWFA), inferior frontal gyrus (IFG), supramarginal gyrus (SMG) as well as middle and superior temporal regions. For individuals with autism spectrum disorder (ASD), however, studies have observed an atypical involvement of sensory and sensory association cortices during word reading. One possibility is that such activation differences may relate to the developmental association of hyperlexia with autism. Hyperlexia is characterized by being able to read aloud beyond grade level, often without an equally advanced ability to comprehend what is being read. In this exploratory study, we examined neural responses to word reading among individuals on the autism spectrum with no obvious language delays and their neurotypical counterparts. If it is the case that reading in autism is associated with greater focus on word-form level processing compared to neurotypical readers, as would be predicted from a history of hyperlexic-style reading, then we predict greater levels of engagement in the visual or visual association regions in individuals with ASD as compared to neurotypicals. Participants were 35 English speaking neurotypical individuals (n = 19), and individuals with autism (n = 15) that were matched by age, IQ, and verbal IQ. The fMRI scanner task consisted of reading aloud 110 English words randomly intermixed with 110 pseudowords (pseudowords not analyzed here). There were no differences between groups their reading aloud pronunciation accuracy (ASD: M = 0.97, SD = .02; NT: M = 0.96, SD = .03, p = .44). Groups also did not significantly differ in their Wechsler Individual Achievement Test – Second Edition (WIAT-II) Word Reading subtest scores (ASD: M = 108.2, SD = 4.7; NT: M = 110.1, SD = 8.3, p = .39). Neural data were processed using AFNI software to contrast brain activations between groups in response to words. Results were thresholded at voxel-level p <.005, and cluster corrected to p<0.05. Individuals within both groups showed activation in response to words in standard reading-related areas described above (e.g., SMG and middle temporal cortex). When directly comparing ASD and NT groups, there was greater right-lateralized activation in response to words for individuals with autism as compared to neurotypicals with the activation peak occurring in the cuneus, a region of dorsal visual association cortex. Despite having no obvious language delays or differences in pronunciation accuracy and word reading ability, participants with autism exhibited greater activation in the right dorsal visual association cortex, specifically the cuneus, in response to words when compared to a neurotypical population. While this result is outside the canonical visual word form area, its occurrence in visual association cortex suggests a greater than typical association with visual form related-processing in the ASD group when reading. Whether this result indicates an adult vestige of hyperlexia will be the subject of future studies.
Topic Areas: Reading, Disorders: Developmental