The mechanisms for adult-onset apraxia and developmental dyspraxia: an examination and comparison of error patterns.

OBJECTIVES The purpose of this study was to determine whether persons with developmental dyspraxia and apraxia make similar errors during the performance of four types of tasks. METHOD Three groups of subjects with dyspraxia or apraxia (i.e., children with learning disabilities and dyspraxia, young adults with learning disabilities and dyspraxia, older adults with left-hemisphere brain damage with apraxia) and three groups of age-matched control subjects (i.e., children, young adults, older adults) were observed performing transitive, intransitive, verbal command, and imitation tasks. Performance was scored on the basis of the types of errors made. Errors were classified as conceptual (nonrelated, unrecognizable, sequencing) or production (omission, perseveration, related, internal configuration, external configuration, incorrect movement, body part as object). RESULTS No significant difference was found between conceptual and production error patterns for any group. In addition, there was no significant difference between the dyspraxia and apraxia groups or among the control groups on the specific types of production errors made. However, the dyspraxia and apraxia groups differed in the type of conceptual error made on the intransitive task. The body-part-as-object error was the most frequently made error on the transitive, verbal command, and imitation tasks, whereas the movement error was the most frequently made error on the intransitive task. CONCLUSION Subjects with dyspraxia or apraxia make similar errors, suggesting that the praxis behaviors are similar.