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 t he performance of four types of tasks. Method. Three groups of subject s 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 thre e groups of age-matched control subjects (i.e., children, young adults , older adults) were observed performing transitive intransitive, verb al command, and imitation tasks. Performance was scored on the basis o f the types of errors made. Errors were classified as conceptual (nonr elated unrecognizable sequencing) or production (omission, perseverati on, related, internal configuration, external configuration, incorrect movement, body part as object). Results. No significant difference wa s found between conceptual and production error patterns for any group . In addition, there was no significant difference between the dysprax ia and apraxia groups or among the control groups on the specific type s of production errors made. However, the dyspraxia and apraxia groups differed in the type of conceptual error made on the intransitive tas k. The body-part-as-object error was the most frequently made error on the transitive, verbal command, and imitation tasks, whereas the move ment error was the most frequently made error on the intransitive task s. Conclusion. Subjects with dyspraxia or apraxia make similar errors, suggesting that the praxis behaviors are similar.