Reliability and variability of physiotherapists scoring freezing of gait through video analysis.

Background: The "gold standard" marker for freezing of gait severity is percentage of time spent with freezing observed through video analysis.

Objective: This study examined inter- and intra-rater reliability and variability of physiotherapists rating freezing of gait severity through video analysis and explored the effects of experience.

Methods: Thirty physiotherapists rated 14 videos of Timed Up and Go performance by people with Parkinson's and gait freezing.