Associations and Dissociations among Phonological Processing Skills, Language Skills and Nonverbal Cognition in Individuals with Autism Spectrum Disorder

Aims: The purpose of this study was to examine the nature of phonological processing in individuals with autism spectrum disorder (ASD) as it pertains to their nonverbal cognitive and linguistic abilities. Methods: Twenty-one participants between the ages of 9 and 21 years were administered a nonverbal cognitive assessment (Raven test), a language measure that requires receptive and expressive knowledge of semantics, syntax and morphology, as well as the integration across these language domains (CELF-4), and a measure of phonological processing (CTOPP). Results: Results show that performance on nonword repetition (NWR) that reflects an aspect of phonological memory was significantly low, whereas performance on phoneme reversal, phoneme elision, blending words and memory for digits was within the normal range. Hierarchical regressions with age, nonverbal intelligence (Raven test) and receptive language (CELF) as predictors showed that for NWR and phoneme elision the receptive part of the CELF was the main significant -predictor, after controlling for age. For phoneme reversal and memory for digits, however, the Raven score was the significant predictor, suggesting that cognitive nonverbal ability is the main factor explaining variability in these tasks. Conclusions: A deficit in phonological memory characterizes individuals in the autistic population. This deficit may influence language acquisition in this population consistent with other populations of children with language impairments. Other tasks of phonological awareness, however, might be preserved especially when they do not involve memory for long phonological sequences and when the cognitive abilities are within the norm.