Visual exploration during gait in Parkinson’s disease and its cognitive correlates Stuart S, Galna B, Lord S, and Rochester L Institute of Neuroscience/Newcastle University Institute of Ageing, Newcastle University http://research.ncl.ac.uk/bam |
@BAM_Research |
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[email protected]
Methods
Introduction Visual exploration of the environment is vital for safe and effective walking [1], and is influenced by cognitive and visual processes. Cognitive and visual impairments are common in Parkinson’s disease (PD) and likely affect visual exploration, and so contribute to walking impairment and falls risk.
A Dikablis mobile eye-tracker (Fig 1 and 2) was used to measure visual exploration (saccadic (fast) eye-movement frequency; number of saccades per second) during gait in 60 people with PD and 40 age-matched older adults (≥50 years) (controls). Clinical, cognitive and visual assessments were performed using a range of standardised tests. Participants then walked under varied environmental conditions (straight, through a door and turning) and attentional demand (single and dual-task) (Fig 3). A saccade was classed as an eye movement above a velocity threshold of ≥240 degrees/second (~5° amplitude) [2,3]. Cognitive and visual outcomes were correlated with saccade frequency, a proxy for purposeful visual attention.
This study describes visual exploration during walking in PD in response to environmental and attentional demand, and the association between visual exploration and cognition.
Straight walk
Straight walk through a door
40° turn
40° turn starting 10° off centre
2.5m
0.8m
Fig 3 Walking Conditions
Results • PD participants had significantly impaired cognition and vision compared to controls (Table 1) • PD participants took significantly longer to complete the walks (p=.009, Table 2) • PD participants made fewer saccades (p=.002, Table 2) than controls during all of the walks, particularly during a dual task (Fig 4) suggesting they explore the environment less • Saccade frequency significantly increased with environmental complexity (p
