Effects of task goal and personal preference on seated reaching kinematicsafter stroke

Background and Purpose-Current theories of motor control in rehabilitation focus on how the nervous system responds to many types of external and inte rnal constraints to execute motor behavior to accomplish a task. However, t he dynamic interplay between these 2 constraints remains unclear. This stud y examined the impact of some aspects of internal and external constraints an motor performance in persons with stroke. Methods-Twenty-seven persons with stroke used the uninvolved arms to perfor m an upper-extremity reaching task under 4 experimental conditions, formed by the crossing of functional goals and personal preferences. For the highe r level of a functional goal, subjects took a drink from a can of beverage. For the lower level of a functional goal, subjects brought the can to the mouth without drinking. The level of personal preferences was determined; b y interview, by the degree of predilection for particular beverages. Results-Significant and large effects of functional goals and personal pref erence were found in the variables of movement time and reaction time. Howe ver, the data trend of the 4 testing conditions varied according to presenc e of visuospatial neglect and side of lesion. Conclusions-Offering choices for the treatment activities and incorporating functional goals to therapeutic tasks might enhance response rate or movem ent efficiency, depending on the side of the lesion and presence of visuosp atial neglect. The findings suggest that the consideration of the neglect p henomenon is a necessity when rehabilitative treatment planning incorporate s constraint factors.