Neural correlates of reading aloud on the autism spectrum

Individuals with autism can show intact decoding (i.e., ability to recognize and pronounce written words accurately). However, reading comprehension (i.e., ability to infer meaning from written text) in autistic individuals is often lower than expected based on age or grade level. Having intact decoding skills despite potentially atypical reading comprehension suggests altered reading pathways in autism, particularly when processing semantics (i.e., word meaning). To test for neural differences in word processing between autistic and non-autistic younger adults, we examined behavioral and neural responses to reading aloud words and pronounceable nonsense words (pseudowords). Additionally, we manipulated word imageability, word frequency, and word and pseudoword spelling-sound consistency as probes for different components (i.e., orthography, phonology and semantics) of the reading system. Behaviorally, the autistic group had a greater reduction in reaction time as word imageability increased. Neurally, pseudoword consistency effects, a probe of spelling-sound mappings without semantics, were only observed in the autistic group, where increased consistency was associated with decreased activity in bilateral intraparietal sulcus. Also compared to the non-autistic group, the autistic group showed greater effects of word consistency, where increasing word consistency was associated with increasing activation in the bilateral posterior superior temporal gyrus and ventral occipitotemporal cortex. Finally, the autistic group showed stronger effects of pseudoword consistency than the non-autistic group, that is increasing pseudoword consistency was associated with decreasing activation in the left ventral occipitotemporal cortex. Together, these results point to differences in how neural resources are used for reading, with more bilateral areas recruited during spelling-sound decoding in autistics to achieve comparable performance to non-autistics.