Obstacle Avoidance amongst Parkinson Disease Patients Is Challenged in a Threatening Context

Abstract

We examined whether people with Parkinson disease (PD) have difficulty negotiating a gait obstruction in threatening (gait path and obstacle raised above floor) and nonthreatening (gait path and obstacle at floor level) contexts. Ten PD patients were tested in both Meds OFF and Meds ON states, along with 10 age-matched controls. Participants completed 18 gait trials, walking 4.7 m at a self-selected speed while attempting to cross an obstacle 0.15 m in height placed near the centre point of the walkway. Kinematic and kinetic parameters were measured, and obstacle contact errors were tallied. Results indicated that PD patients made more obstacle contacts than control participants in the threatening context. Successful crossings by PD patients in the threatening condition also exhibited kinematic differences, with Meds OFF PD patients making shorter crossing steps, with decreased initiation and crossing velocities. The findings from this study lend support to the theory that PD patients rely on directed attention to initiate and control movement, while providing indication that the motor improvements provided by current PD pharmacotherapy may be limited by contextual interference. These movement patterns may be placing PD patients at risk of obstacle contact and falling.

Pharmacological treatment in Parkinson's disease: Effects on gait

“…People with PD have a higher number of obstacle hits compared to healthy subjects [44, 45]. During obstacle crossing, people with PD are less stable than healthy subjects, reflected in more mediolateral movement of the CoM [46].…”

“…For example, the time needed to step over the obstacle is longer, resulting in more time spent standing on one leg [44, 47]. Also, the typical foot placement relative to the obstacle is smaller in PD patients than in healthy subjects, increasing the risk of collision [42, 44, 45]. …”

“…The ability to step over an obstacle during walking improved when using dopaminergic medication [45]. Success rates at avoiding obstacles changed in the ON state, with shorter and faster steps to cross the obstacle, suggestive of less cautious behavior [45, 64]. …”

A posturographic procedure assessing balance disorders in Parkinson's disease: a systematic review

“… 23 In most cases, the authors used an optoelectronic three-dimensional system with a walkway; 23 , 46 , 49 sometimes these systems were used together with a force platform, 45 , 48 but sometimes the force platform was used only with a walkway. 44 , 47 …”

“…Furthermore, in Doan et al, 47 the researchers tested patients with PD during stepping over an obstacle in a threatening context. Participants walked under two separate conditions: on the gait path with the obstacle raised above the floor and on the gait path with the obstacle at floor level.…”