Cueing for freezing of gait in patients with Parkinson's disease: a rehabilitation perspective.

Freezing of gait (FOG) has been known to respond favorably to sensory tricks and cues. However, FOG is a complex phenomenon with various motor control deficits at play. In this review, we examined and summarized the currently available evidence for the effectiveness of cueing for FOG to determine its value as a clinical method. The results showed that the immediate effects of cues have no consistent impact but longer periods of cued training may be beneficial. The review also showed (1) the limited statistical power and methodological weakness of the studies involved; (2) measurement difficulties of FOG, and (3) the need to better understand its underlying causal factors. Overall, the findings suggest a smaller capacity for compensation in patients suffering from FOG. Especially when attention is overloaded, the therapeutic window and the practical applicability of cueing seem more limited. These aspects need to be incorporated in the development of future cueing programs designed to alleviate FOG.