Head and trunk rotation during walking turns in Parkinson's disease.

Head and trunk axial rotation during walking to align with a new path are integral components of direction change (turning). Turning is problematic in people with Parkinson's disease (PD), who appear to move en-bloc when turning and when walking straight. Axial rotation has been little investigated in this group. Accordingly, head, thorax, and pelvis rotation relative to the laboratory axes (global rotation) was investigated in 10 patients with PD and 10 matched comparison subjects when walking straight and when turning 60 and 120 degrees . Data were selected at three footfalls before and three after a pole denoting the corner. Although rotation was reduced overall in patients with PD, final differences were minimized by rotation commencing at an earlier step in the patient group. When rotation was measured at various distances relative to the corner, the patient group demonstrated greater rotation than their peers. In support of clinical observations, patients constrained thorax and pelvis closely together around the corner, while control subjects maintained a pattern of reciprocal oscillation when turning. Stride length reduction appears to contribute more to inefficient turning in PD than under-scaled amplitude of rotation.