Objective: This study examined the selective but overlapping roles of cognition and vision in gait in Parkinson’s disease (PD). To address this we studied; 1) saccade frequency during gait in PD in response to environmental challenge and dual task; and 2) the relationship between visual function, cognition, saccade frequency and gait in PD.

Background: Gait impairment is a core feature of PD with implications for falls risk and is difficult to treat due to its multi-factorial nature. It has been linked to cognitive and visual deficits through separate strands of research. Cognition and vision however are interrelated (termed visuo-cognition) confounding understanding of their roles. The separate and related influence on gait is of key interest to understand gait deficits, potential falls risk and develop targeted therapeutics.

Methods: Saccade frequency (proxy for visuo-cognition) was measured during walking in 56 PD participants and 40 age-matched controls using a mobile eye-tracker. Environmental challenge and dual task were tested; participants walked straight, through a door, and turned under single and dual task. Visual, cognitive and clinical assessments were conducted. Effect of environmental challenge and dual task were assessed using repeat measures ANOVAs. Relationships between saccade frequency, vision, cognition, and gait were explored using bivariate and multivariate analysis (e.g. structural equation modelling (SEM)).

Results: Saccade frequency increased through environmental challenge (p<.001) and decreased during dual task (p<.001) irrespective of group. In general saccade frequency was significantly reduced in PD during gait compared to controls. Attention related to saccade frequency, visual function and gait (ß=-.32, p=.012) in PD but not controls. Saccade frequency was associated with gait in controls, whereas saccade frequency and visual function were not directly related to gait in PD. However, SEM showed that attention facilitated an indirect relationship whereby saccade frequency (ß=.14, p=.011) and visual function (ß=-.15, p =.008) were both associated with gait in PD.

Conclusions: Attention facilitates the role of vision and visuo-cognition during gait in PD but not controls. This important relationship has to date not been explored in PD. Future research examining gait dysfunction and vision in PD must consider the role of attention. Understanding these complex features of gait control will help inform management.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/cognition-vision-and-visuo-cognition-in-gait-in-parkinsons-disease/