ERROR TYPES IN IDEOMOTOR APRAXIA - A QUALITATIVE-ANALYSIS

Seventeen brain-damaged subjects with dominant hemisphere pathology an d 24 matched control subjects were asked to perform simple familiar ge stures under four conditions: (1) verbal command (pantomime), (2) imit ation, (3) with the actual object, and (4) verbal command a second tim e. The subjects subsequently watched a video of an actor performing si mple movements and decided whether or not these were performed accurat ely. The gestural production task was videoed and analyzed for error t ype. Error type remained consistent over the four task conditions, alt hough subgroups of patients made different types of errors. One group of patients with Ideomotor Apraxia (IMA) made more errors but of the s ame type as the controls, i.e., movement-related errors and the use of ''body part as object'' (BPO). The second group made mainly substitut ed (i.e. unrelated) movements and perseverative errors. The second gro up of subjects was also poorer at discriminating incorrectly performed movements in the recognition task. BPO errors were commonly made by t he control group and they were also chosen as correct in the recogniti on task. This indicated that use of BPO may reflect a convention in sy mbolising gestures rather than pathology. The performance of the IMA s ubjects was discussed in relation to current theories of the mechanism s underlying apraxia. (C) 1994 Academic Press, Inc.