Executive functions in children with communication impairments, in relation to autistic symptomatology. 2: Response inhibition.

Although impairment in executive functions has been described in autism, there has been debate as to whether response inhibition is specifically affected. We compared four groups: high-functioning autism; pragmatic language impairment; specific language impairment; and control. Inhibition was assessed using two subtests from the Test of Everyday Attention for Children, one requiring a verbal response and the other a non-verbal response. Although we found evidence of inhibitory deficits, these were neither specific to autism, nor linked to particular aspects of autistic symptomatology. Rather, they appeared to be associated with poor verbal skills and inattention. It is suggested that future studies need to control for structural language skills and attention deficit when evaluating cognitive deficits in autism. Reliance on control groups matched solely on vocabulary level or nonverbal mental age may obscure the important role played by language skills in executive functions.