Separated center-of-pressure measurements reveal new characteristics of reduced anticipatory postural adjustments during gait initiation in patients with Parkinson's disease.

BACKGROUND AND OBJECTIVE

Accelerations, ground reaction force data, and other quantitative data obtained from kinematic analyses of gait initiation serve as measures of dyskinesia in patients with Parkinson's disease. The objective of this study was to determine whether a separate center of pressure information could reveal new characteristics of reduced anticipatory postural adjustments in patients with Parkinson's disease.

METHODS

Ten healthy elderly subjects and 10 patients with Parkinson's disease participated in this study. Motions at gait initiation in response to a light signal to begin the task were analyzed. Anticipatory postural adjustments were characterized using trunk acceleration data and center of pressure displacement data.

RESULTS

The separated center of pressure in patients with Parkinson's disease showed longer peak latency ( < .01) and larger peak magnitude ( < .01) in the stance leg than in the stepping leg. In patients with Parkinson's disease, the displacement peak latency of the stance leg center of pressure correlated negatively with the Timed Up and Go time ( = -0.46, < .05), while displacement peak latency of the stepping leg center of pressure correlated negatively with Unified Parkinson's Disease Rating Scale (=  -0.47, < .05), and positively with Berg Balance Scale score ( = 0.50, < .05).

CONCLUSIONS

Patients with Parkinson's disease experience asymmetry between the stance leg and stepping leg at gait initiation. These findings may help clinicians understand the changes to motor function in patients with Parkinson's disease and suggest strategies for improved rehabilitation training.