September 24, 2019
By Reuters Staff
NEW YORK (Reuters Health) - Gait impairment shows distinct patterns in Alzheimer's disease (AD) and Lewy body disease (LBD) patients, a new study suggests.
"Our findings provide initial evidence that Alzheimer's disease and Lewy body disease have unique signatures of gait impairment, which reflect profiles of cognitive impairment," Dr. Lynn Rochester of Newcastle University Institute of Ageing in Newcastle Upon Tyne, UK, and colleagues write in Alzheimer's and Dementia, online September 20.
"This supports the current theory that gait may act as a proxy for neuropathology, as gait-cognition relationships are different between subtypes, and more asymmetrical gait in Lewy body disease may reflect more asymmetrical neurodegeneration," they add.
Gait impairments appear in the prodromal phases of dementia, the authors note, and evidence is mounting that particular types of gait impairment are associated with impairment in distinct cognitive domains. However, they add, most studies have only measured gait speed.
The authors enrolled 45 individuals with mild cognitive impairment (MCI) or dementia due to LBD; 36 with AD; and 29 functionally independent controls without cognitive impairment or dementia diagnoses. The team used an instrumented walkway to analyze 16 different gait characteristics indicating five distinct domains: pace, rhythm, variability, asymmetry and postural control.
Patients with LBD had more impairments in asymmetry and variability than patients with AD, while both the LBD and AD groups had more impairment in pace and variability than controls.
Executive dysfunction accounted for 11% of variance in gait variability in LBD patients, while global cognitive impairment accounted for 13.5% of variance in in AD.
"Future work should follow the framework set out in Parkinson's disease to establish unique signatures of gait as proxy measures of disease-specific pathology; that is, use a validated gait model to explore the progressive relationship between gait, cognition, and pathology," Dr. Rochester and colleagues write.
"With a refined hypothesis that AD- and LBD-specific signatures of gait reflect discrete pathologies, future studies must examine the relationship between a validated model of gait with neural networks, using recognized biomarkers and postmortem follow-up," they conclude.
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