Abstract
Conduction Limb Apraxia is defined as a deficit in imitation with preserved pantomime of gestures. The Conceptual Production Systems Model suggests that conduction apraxia could be caused by either an impaired ability to analyze visual gestural information (if the patient is also impaired on gesture identification) or by loss of the ability to use visual information in the control of movement (if gesture identification is intact). In both cases, the model predicts deficits in imitation of meaningless gestures. Our aim was to examine the frequency of such cases and to establish if in fact these patients have deficits in meaningless gestures imitation.
In review of our database of stroke patients with apraxia assessments, 74 right-handed patients had completed all four transitive tasks (pantomime, concurrent imitation, delayed imitation and gesture recognition) necessary to establish conduction apraxia. Ten patients suffered from conduction apraxia (deficits in both concurrent and delayed imitation, but preserved pantomime): one left hemisphere damage (LHD) patient also had gesture identification deficits and nine (6 LHD, 3 right hemisphere damage (RHD)) had no gesture identification deficits. Nine out of these 10 patients had deficits in both delayed and concurrent imitation of meaningless gestures, while one LHD patient had deficits in concurrent, but not delayed imitation.
Overall, these findings largely support the model, which predicts the occurrence of conduction apraxia should be associated with deficits in imitation of meaningless gestures. In addition, both left and right hemisphere damage caused this pattern suggesting that this process is bilaterally represented.
