Measurements of the centre of pressure of individual legs reveal new characteristics of reduced anticipatory postural adjustments during gait initiation in patients with post-stroke hemiplegia
Ryo Onuma, T. Masuda, F. Hoshi, Tadamitsu Matsuda, Tomoko Sakai, Atsushi Okawa, Tetsuya Jinno
Abstract
OBJECTIVES: To determine whether individual measurements of the centre of pressure for the stance and stepping legs can reveal new characteristics of reduced anticipatory postural adjustments during gait initiation in post-stroke hemiplegic patients. METHODS: Subjects included 30 stroke patients and 10 healthy age-matched controls. The acceleration of the trunk, and the centre of pressure of each leg, were measured during gait initiation, 3 times each with the paretic and non-paretic legs leading. Anticipatory postural adjustments were characterized using trunk acceleration and centre of pressure displacement data. RESULTS: Latency of the posterior displacement peak of the paretic leg centre of pressure with either the paretic or non-paretic leg leading was significantly longer in stroke patients compared with controls, and was also longer than that of the non-paretic leg. The magnitude of the posterior displacement peak of the paretic leg centre of pressure was smaller than that of the non-paretic leg. Peak latency of the paretic stepping leg centre of pressure correlated with the clinical measures of motor dysfunction, postural balance, and gait ability. CONCLUSION: Measurements of the latency and magnitude of centre of pressure displacement peak individually for the paretic and non-paretic legs can help elucidate the mechanism behind reduced anticipatory postural adjustments. This information will be useful in designing new treatment strategies for stroke patients.