Effect of task context on reaching performance in children with spastic hemiparesis.

OBJECTIVE

To investigate the effect of task context on the quality of reaching movements in children with spastic hemiparesis.

DESIGN

Randomized controlled experimental trial.

SETTING

Institute for the Study of Education and Human Development (ISED).

SUBJECTS: Twelve children (8-14 years of age) with spastic hemiplegic cerebral palsy.

INTERVENTIONS: Subjects made fast reaching movements with the affected or nonaffected arm on a digitizer in three context conditions: (a) reach to press a light switch to turn on a red light (functional), (b) reach to press the light switch; no light (semi-functional), and (c) reach to a marker (nonfunctional).

MAIN OUTCOME MEASURES: Kinematics of reaching movements of affected and nonaffected arms: movement time (MT), peak velocity (PV), time to PV, percentage of MT where peak velocity occurred (PPV), and smoothness (i.e. number of movement units (MU)).

RESULTS

The functional condition elicited better quality of reaching for the nonaffected, but particularly the affected arm. Reaching of the affected arm was faster (larger MT; F = 10.21, p < 0.01), smoother (fewer MU; F = 19.95, p < 0.001), and better-controlled (right shift of PPV; F = 16.03, p < 0.001) compared with the semi- and nonfunctional condition. Reaching of the nonaffected arm was also faster (longer MT, F = 4.81, p < 0.05), and more smooth (fewer MU, F = 7.23, p < 0.05).

CONCLUSIONS

These findings suggest that providing a functional context to perform a task may enhance the quality of reaching movements of the affected arm in children with spastic hemiparesis.