Abstract
An upcoming doorway has been shown to interfere with in parameters of gait and lead to freezing episodes (FOG), yet the mechanism underlying how perception of self-motion contributes to FOG is poorly understood. The objective of this study was to determine how FOG is affected by perception of self-motion through a doorway. Participants with PD (N=10) that experience FOG on a daily basis were recruited to participate in this study. Three conditions of walking through doorways in darkness were included: (i) walking through a doorway with only the door outline visible; (ii) both door outline visible and limbs illuminated with glow tape; (iii) complete darkness. As control conditions, participants walked away from the door into an open space in the dark and with limbs illuminated. A chi-square analysis of frequency of FOG identified a main effect of condition (x 2(4)=53.39, p<0.01). Wilcoxon tests were then used to determine how FOG occurrences differed across conditions. FOG episodes were lower when participants received information about their body position when passing through the doorway only. Step length was significantly decreased in the dark doorway condition in comparison to both control conditions. Cadence variability was statistically higher in the dark doorway condition compared to the dark no door condition, confirming an effect of the door. Results will be discussed in terms of sensory contributions to perceptual causes of FOG.
