Error analysis of limb and orofacial praxis in children with developmental motor deficits

Two models have been suggested to depict the relationship between disorders of limb and orofacial praxis. The first views apraxia as a unitary disorder in which the underlying mechanisms for each type are similar, while the second model suggests that there are two separate praxis systems: one for planning and controlling limb gestures and a second one for planning and controlling orofacial movements. The purpose of this study was to investigate whether a common mechanism may underlie deficits in limb and orofacial praxis in children. This was done by analyzing the types of praxis errors demonstrated by children with developmental motor deficits and normal controls when performing limb and orofacial gestures. Results indicated that there was consistency across modalities (i.e., limb, orofacial) in the types of praxis errors made by children with motor deficits, providing support for the idea that a common mechanism may underlie disruptions to limb and orofacial praxis in children. This study also examined developmental trends in gestural representation and in types of praxis errors. The findings revealed a striking developmental maturation in gestural ability between the ages of 6 and 11 years for all children. However, over this age range, children with developmental motor deficits were impaired relative to normal controls.