Can proprioception influence gait abnormalities in Parkinson’s disease?

Freezing of gait (FOG), clinically defined as the transient inability to move one’s feet off the ground, is a symptom of Parkinson’s disease (PD) associated with changes to gait parameters. Since proprioception is impaired in PD, relying on proprioception alone to guide locomotion, when walking in the dark for example, may lead to greater gait impairments such as FOG and gait variability. To date, no study has demonstrated whether differences in the accuracy of proprioception in participants who experience FOG (‘freezers’) can influence gait impairment when walking in the dark. This study aimed to identify a correlation between the degree of proprioception impairment and frequency of freezing episodes to determine whether improving proprioception could improve FOG. In this study, freezers performed walking trials in both dark and lit conditions. FOG severity, step variability, and proprioception (joint position matching of the upper limbs) were measured. Participants were divided into two groups, classified as either ‘high’ or ‘low’ proprioception error, using a median split of error scores on the joint position matching task. High error and low error groups were not significantly different in step time variability, FOG episode duration, or FOG frequency in dark walking trials. However, there was a significant group by condition interaction effect (p=0.02). This suggests that having better proprioception can mitigate the effects of a proprioceptive processing challenge while walking, which may have clinical applications in PD.