Short rapid steps to provoke freezing of gait in Parkinson's disease.

Freezing of gait (FOG) is both common and debilitating in patients with Parkinson's disease. Due to its episodic nature, it is a challenge to provoke FOG in clinical practice and in the research setting. Turning is most sensitive to provoke FOG, particularly when performed as rapidly as possible. Walking with short steps is an alternative approach to provoke FOG. Here, we assessed a modified version of this test, consisting of the instruction to make short steps as rapidly as possible. We evaluated what the diagnostic value of this new test is compared to rapid turning. 28 patients with Parkinson's disease participated, who all had objective FOG. Patients performed the following tasks two times: (1) normal walking, (2) walking as rapidly as possible, (3) walking with short steps, (4) walking with short steps as rapidly as possible and (5) making full rapid turns in both directions. FOG was provoked in 20 subjects (71 %). The most effective test to provoke FOG was rapid full turns (64 % of subjects). FOG occurred more often when patients walked with rapid short steps (50 %) compared to walking with short steps at normal speed (18 %). The combination of 'full rapid turns' and 'walking with short steps rapidly' yielded the highest sensitivity of provoking FOG (0.71, CI 0.51-0.86). The most sensitive way to provoke FOG is by asking patients to make full rapid turns, but if negative, walking with short steps as rapidly as possible can identify further subjects with FOG.