EFFECTS OF TASK GOAL ON MOVEMENT KINEMATICS AND LINE BISECTION PERFORMANCE IN ADULTS WITHOUT DISABILITIES

Objective. This study investigated (a) whether the kinematic profile o f a reaching-for-an-object movement would differ depending on the goal of the reaching task and (b) the effect of task goal on attentional c arryover. Method. Twenty-four adults without disabilities performed a horizontal line bisection task under three conditions: (a) a natural c ondition (pressing the ringing lever of a desk bell), (b) an impoveris hed condition (touching the ringing lever of a desk bell), and (c) a c ontrol condition (bisecting a line only). Only the natural and impover ished conditions used the reaching task (i.e., pressing or couching th e ringing lever of the desk bell). The kinematic profile of reaching f or the bell was established with the OPTO-TRAK system, a quantitative kinematic analysis measure. The line bisection task was performed imme diately after the reaching task, which was located adjacent to the lef t of the line to be bisected. Results. The natural condition elicited better quality of reaching movement than did the impoverished conditio n. It produced significantly shorter movement time and higher peak vel ocity. A less impressive effect was found for percentage of reach wher e peak velocity occurs. Bisection performance under the two experiment al conditions was leftward biased relative to the control condition, a nd the magnitude of leftward bias in the natural condition was greater than that for the impoverished condition. Conclusion. Results support ed one core assumption of occupational therapy: goal-directed and func tional task can be used to enhance human performance. If the results h old for clinical populations, manipulations of functional goals may en hance movement performance of persons with disabilities and remediate left neglect often seen in clients who have had a stroke.