Action observation and motor imagery have no effect on balance and freezing of gait in Parkinson's disease: a randomized controlled trial.

The study included only people with Parkinson's disease at modified Hoehn and Yahr stages 1.5 to 3 who could walk 10 meters independently, so it may not apply to more advanced disease or people who need gait aids. Participants were recruited by convenience from previous project lists and active search, so they may not represent all people with Parkinson's disease. Only 39 of 44 randomized participants completed; 8 experimental-group and 2 control-group participants dropped out, and the analysis carried forward baseline scores for dropouts. The sample-size calculation was based on hip range of motion, not balance or freezing of gait. The experimental group had less sharp kinesthetic mental imagery at baseline than the control group. Assessment was only one day after the four-week intervention, with no longer-term follow-up. The trial did not control whether participants were assessed or trained under on or off medication conditions. Freezing of gait was measured with a questionnaire that does not account for different contexts, and participants had mild to moderate freezing.

Do not conclude that action observation and motor imagery are useless for Parkinson's disease. This trial tested one four-week protocol added to gait training and found no extra benefit over gait training alone; it did not test these methods by themselves, over a longer period, or in people with more severe freezing.