Friday, May 19, 2017

Dual-Gait Testing May Predict Dementia Risk for Patients With MCI

Dual-task gait testing—walking while simultaneously performing a cognitive test—can identify patients with mild cognitive impairment (MCI) who are at heightened risk of progression to dementia, according to a study published this week in JAMA Neurology.

Manuel M. Montero-Odasso, M.D., Ph.D., of the University of Western Ontario and colleagues found that low performance in dual-gait testing was significantly linked to a two- to three-fold increased risk of dementia, independent of age, sex, education, comorbidities, and baseline cognition.

As part of the Gait and Brain Study—an ongoing prospective cohort study of community-dwelling older adults—the researchers assessed cognitive changes in 112 patients with MCI (mean age 76 years; 55 women). Data were collected from July 2007 to March 2016, and participants were followed up to six years with biannual visits.

Researchers used a neuropsychological test battery to assess cognition, and recorded gait velocity under single-task and three separate dual-task conditions. Dual-gait cost was defined as the percentage change between single- and dual-task gait velocities, using an electronic walkway. For the dual tests, participants moved at their usual pace on the walkway, while doing the following cognitive tasks aloud: 1) counting backwards from 100 by ones, 2) subtracting serial sevens from 100, and 3) naming animals. 

Of the 112 participants in the study, 27 (24%) progressed to dementia. Of those 27 participants, 23 progressed to Alzheimer’s disease (85%), two to Lewy body dementia (7%), one to frontotemporal dementia (4%), and one to vascular dementia (4%). Those who progressed to dementia had a significantly lower dual-task gait velocity and a higher dual-task gait cost in the three test conditions. High dual-task cost in gait velocity while counting backward and naming animals was associated with dementia progression. Single-task velocity was not associated with dementia progression.

The dual-task gait testing served as a kind of “brain stress test” to detect impending cognitive decline in patients with subclinical damage, according to the authors, because brain circuits shared by both cognition and motor-gait performance can be impacted by aging and neurogenerative mechanisms.

MCI is known to increase risk of dementia. However, almost one-third of individuals with MCI remain clinically stable after the initial diagnosis or even revert to normal cognitive functioning—making it difficult to accurately predict those most likely to develop dementia, including Alzheimer’s disease. 

“Dual-task gait testing is easy to administer and may be used by clinicians to decide further biomarker testing, preventive strategies, and follow-up planning in patients with MCI,” the authors wrote. 

For related information, see the Psychiatric News article “Neuropsychiatric Symptoms Implicated in Conversion From MCI to Dementia.”

(Image: iStock/AzmanJaka)


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