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Dual‐task gait as a differential marker of dementia disease subtype: Considering a declarative memory task

Mc Ardle, R., Galna, B.ORCID: 0000-0002-5890-1894, Thomas, A.J. and Rochester, L. (2020) Dual‐task gait as a differential marker of dementia disease subtype: Considering a declarative memory task. Alzheimer's and Dementia, 16 (S5). e039348.

Link to Published Version: https://doi.org/10.1002/alz.039348
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Abstract

Background
Dual-task (DT) gait involves walking while concurrently engaging with a cognitively-demanding task. It may be useful to identify dementia and differentiate cognitive subtypes [Montero-Odasso etal., 2019]. Gait performance deteriorates under DT conditions due to added attentional demand. The majority of studies employ attentional DTs, limiting our understanding of the impact of alternative cognitive domains (e.g. memory or visuospatial abilities). Different dementia subtypes have unique cognitive profiles. Applying cognitive DTs related to these discrete profiles may improve the discriminatory ability of DT gait. This study aimed to assess the feasibility and efficacy of employing a concurrent declarative memory test on gait performance to differentiate Alzheimer’s disease (AD) and Lewy body disease (LBD).

Method
110 participants were recruited. This included 29 people with cognitive impairment due to AD (Age:77±9; sMMSE:24±4), 31 due to LBD (Age:75±6; sMMSE:25±3) and 29 similarly-aged controls (Age:74±9; sMMSE:29±1). Gait was assessed using an instrumented walkway (GAITRite) under single-task (ST) and DT conditions (performing a story recall task). Gait outcomes in ST and DT conditions included measures of pace, variability, rhythm, asymmetry and postural control. Kruskall Wallis tests with Mann Whiney U post-hocs assessed group differences.

Result
89 participants successfully completed both conditions. The declarative task was too difficult for 21 participants (AD:7; LBD:14). There were no differences in gait performance between disease groups during the DT. During ST, the LBD group showed greater step length variability (p=.035) and stance time asymmetry (p=.037) compared to AD. Both disease groups demonstrated impaired gait compared to controls (p≤.05) in both conditions. There were no significant differences between disease groups on performance of the story recall task in either condition, but performance was significantly worse (p≤.001) compared to controls.

Conclusion
This study demonstrated limited feasibility for people with cognitive impairment to complete a declarative memory DT. This particular DT was not as useful as ST gait for differentiating dementia subtypes. It is important to understand how feasible and effective different cognitive tasks are when using DT gait as a clinical tool. Future research should consider the efficacy of this task to predict dementia in “at-risk” groups, such as those with genetic risk factors.

Item Type: Journal Article
Publisher: Wiley
Copyright: © 2020 the Alzheimer’s Association
URI: http://researchrepository.murdoch.edu.au/id/eprint/62665
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