EFFECTS OF OBJECT AFFORDANCES ON REACHING PERFORMANCE IN PERSONS WITHAND WITHOUT CEREBROVASCULAR ACCIDENT

Objective. This study investigated whether affording objects with diff erent levels of functional support would have an impact on reaching pe rformance in patients after cerebrovascular accident (CVA) and in adul ts who were neurologically intact Reaching performance was quantitativ ely analyzed, using several kinematic variables. Method. Two groups, 1 4 participants after CVA and 24 age-matched adults who were neurologic ally intact performed a food chopping task under two conditions: enric hed affordances and impoverished affordances. Enriched affordances inv olved reaching forward to a chopper and pushing down on the handle to chop fresh mushroom. Impoverished affordances involved reaching forwar d to a simulated chopper (i.e., a chopper covered with cardboard) with out anything in it and then pushing the handle down. Reaching movement was measured by a three-dimensional motion analysis system. Results. For the CVA group, the enriched condition of reaching to chop the mush room resulted in more efficient, direct, smooth, and preplanned moveme nt than the impoverished condition of reaching to push on the chopper handle. The neurologically intact group responded similarly except tha t the participants' movement was equally smooth, as measured by moveme nt unit, between the two testing conditions. Force generation as chara cterized by peak velocity was similar for both conditions for both gro ups. Conclusion. The finding that enriched affordances had a positive effect on movement kinematics in both CVA and neurologically intact gr oups suggests that providing natural objects for completing a task and providing national information on the objects may enhance the functio nal performance of persons who have had a CVA. These findings should b e replicated and extended to confirm the validity of these effects and allow for generalization.