Motor Control and Nonword Repetition in Specific Working Memory Impairment and SLI

Debate around the underlying cognitive factors leading to poor performance in the repetition of nonwords by children with developmental impairments in language has centered around phonological short-term memory, lexical knowledge, and other factors. The present study examined the impact of motor-control demands on nonword repetition in groups of school children with specific impairments in either language, working memory, or both.

Children repeated two lists of nonwords matched for motoric complexity either without constraint, or with a gummi bear bite block held between their teeth. The bite block required motoric compensation to reorganize the motor plan for speech production.

Overall, the effect of the biomechanical constraint was very small for all groups. When analyses focused only on the most complex nonwords, children with language impairment were found to be significantly more impaired in the motorically constrained nonword repetition task than the typically developing group. In contrast, working memory difficulties were not differentially linked to motor condition.

These findings add to the growing evidence that there is a motoric component to developmental language disorders. The results also suggest that the role of speech motor skill in nonword repetition is relatively modest.