Inflectional morphology in high-functioning autism: Evidence for speeded grammatical processing.

Autism is characterized by language and communication deficits. We investigated grammatical and lexical processes in high-functioning autism by contrasting the production of regular and irregular past-tense forms. Boys with autism and typically developing control boys did not differ in accuracy or error rates. However, boys with autism were significantly faster than controls at producing rule-governed past-tenses ( slip-slipped , plim-plimmed , bring-bringed ), though not lexically dependent past-tenses ( bring-brought , squeeze-squeezed , splim-splam ). This pattern mirrors previous findings from Tourette syndrome attributed to abnormalities of frontal/basal-ganglia circuits that underlie grammar. We suggest a similar abnormality underlying language in autism. Importantly, even when children with autism show apparently normal language (e.g., in accuracy or with diagnostic instruments), processes and/or brain structures subserving language may be atypical in the disorder. [ABSTRACT FROM AUTHOR]