The motor planning abilities of phonologically disordered children

The motor planning abilities of three subgroups of speech-disordered children were compared to normally speaking age- and comprehension-matched controls. There were 10 phonologically delayed children who used sound-pattern errors typical of chronologically aged younger children (delayed group); 10 children whose phonological system was characterised by the consistent use of non-developmental phonological processes (deviant consistent group); and 10 children whose production of specific lexical items and phonological features was variable (inconsistent group). The groups were compared on tasks that assessed simple and complex motor planning for hand movements and expressive and receptive novel-word learning. The groups did not differ on a simple task of motor planning for hand movements. However, the inconsistent group performed more poorly than all the other groups on a more complex, timed motor-planning task. Although the groups performed equally well on a task assessing receptive novel-word learning, the inconsistent group performed more poorly than all the other groups on an expressive novel-word learning task. The results provide support for the hypothesis that speech-disordered children with different surface error patterns have different underlying deficits in the speech-processing chain. Specifically, inconsistent error patterns are associated with a deficit in some aspects of fine motor planning.