Impacts of freezing of gait on forward and backward gait in Parkinson's disease.

Freezing of gait (FOG) is a major risk factor for falls and fall-related injuries in patients with Parkinson's disease (PD). The characteristics of gait in PD patients with FOG have been studied but remain controversial. To investigate gait characteristics of FOG in PD, this study analyzed the forward and backward walking of patients with PD. Twenty-six patients with PD were recruited [age: 71.0 ± 6.2 years, Hoehn and Yahr stage: 2-3 (median 2.5)]. Based on responses to the New Freezing of Gait Questionnaire, we classified patients into either the "freezer" or "non-freezer" group. Spatiotemporal and kinematic analyses of forward and backward walking were completed using a three-dimensional motion analysis system over an 8 m walkway in the defined "off" state. There was no difference in demographic and clinical characteristics between the freezers (n = 10) and non-freezers (n = 16). Analysis of forward walking revealed no between-group differences, except for faster walking speed among the non-freezers. During backward walking, the freezers exhibited slower walking speed, shorter stride length, and increased asymmetry of step length. Kinematic analysis of backward walking revealed smaller range of motion in hip and ankle joints and lower step height in freezers. Further investigations of backward walking might expand our understanding of the pathophysiology of FOG in patients with PD.