Walking along circular trajectories in Parkinson's disease.

We hypothesized that gait capacities would be more stressed in patients with Parkinson's disease (PD) when walking along curved than straight trajectories, owing to the complex adaptations required for this walking task. Twenty on-phase patients with PD and 20 healthy subjects walked eyes-open along straight and curved trajectories for 1 minute at self-paced cadence and velocity. Step frequency along straight and curved trajectories was computed from video-recordings of the lower limbs. Step frequency was not affected by trajectory shape in either patients with PD or healthy subjects. Distances run by the patients were shorter than normal under both conditions. However, in PD, distances were relatively shorter during curved than straight walking; therefore, decreased distances in PD were connected with decreased mean step length (as the ratio between distance and step number). No correlation was found between the above mentioned variables and the severity or duration of the disease or the frequency of falls. Walking along curved trajectories can highlight impaired gait control in on-phase patients with PD, and can be suitable for the routine evaluation of possible walking disorders when straight walking is not significantly affected.