Freezing of Gait in People with Parkinson's Disease: Nature, Occurrence, and Risk Factors.

Background: Freezing of gait (FOG) is a common symptom of Parkinson's disease (PD) which can result in falls and fall related injuries, poor quality of life and reduced functional independence. It is a heterogeneous phenomenon that is difficult to quantify and eludes a unified pathophysiological framework.

Objective: Our aim was to document the occurrence and nature of freezing, cognitive stops and stumbles in people with PD during walks with varying cognitive loads and conditions designed to elicit FOG.