Staircase climbing is not solely a visual compensation strategy to alleviate freezing of gait in Parkinson's disease

Letter to the editors: In a recent case study by Janssen et al., the authors reported that Freezing of Gait (FOG) was alleviated in an individual with Parkinson’s disease (PD) when climbing stairs, an effect that was preserved when walking on a painted 3D staircase illusion. This is an important observation, as the clinical management of FOG remains challenging due in part to a lack of consensus regarding the underlying mechanisms driving effective compensation. The authors provided three hypotheses as to why 3D visual cues helped to alleviate FOG: enhanced visual feedback from 3D cues were thought to either: (1) force individuals to lift their feet higher; (2) perform larger lateral weight shifts; and/or (3) compensate for visuomotor deficits. Here, we refine these hypotheses by providing evidence that the compensatory mechanisms involved during staircase climbing in PD patients with FOG are not solely visual.