Dual-Task Gait Test Predicts Progression to Dementia

By Will Boggs MD

NEW YORK—Performance on the dual-task gait test predicts progression to dementia in people with mild cognitive impairment (MCI), according to results from the Gait and Brain Study.

"Although we expected that dual-task gait can predict incident dementia, we were surprised about the magnitude of its predictive ability, that seems to be better or higher than cognitive testing, which may suggest that dual-task gait, as a test evaluating motor-cognitive interaction, is capturing some subtleties that global cognitive tests may not grasp,” Dr. Manuel M. Montero-Odasso from Parkwood Institute, London, Ontario, Canada told Reuters Health by email.

MCI is associated with a 10-fold increase risk of progression to dementia, yet nearly a third of individuals with MCI remain clinically stable or revert to normal cognitive functioning.

Dr. Montero-Odasso and colleagues examined the longitudinal association between dual-task gait performance and the incidence of dementia during six years of follow-up in 112 participants of the Gait and Brain Study.

During the dual-task tests, participants walked at their usual pace while doing one of three cognitive tasks aloud: counting backwards from 100 by ones; subtracting serial sevens from 100; and naming animals.

At baseline, single-gait velocity was normal in all participants, but those who went on to progress to dementia had significantly slower dual-task gait velocity and higher dual-task gait cost (percentage of original velocity lost) than those who did not progress in all three test conditions.

Single-gait velocity did not predict dementia, according to the May 15th JAMA Neurology online report.

Dual-task gait tests (velocities and costs), however, accurately predicted progression to dementia, except for dual-task gait cost in serial sevens subtractions.

When analyzed as dichotomous variables, high dual-task costs in gait velocity while counting backward (hazard ratio, 3.79) and naming animals (HR, 2.41) were both associated with dementia progression, and when groups were divided into quartiles by performance, the highest risk of progression to dementia was seen in the lowest quartiles of the dual-task gait velocity while counting backward (HR, 13.39) and while naming animals (HR, 9.89).

“Simple motor tests as gait velocity and dual-task gait can serve as a screening test to select which patients may need further assessments,” Dr. Montero-Odasso said. “Importantly, we believe that functional tests, like this one, may guide physicians to know which patients may benefit the most from more invasive or expensive testing, including biological and imaging biomarkers.”

“Translating research findings to clinical practice is always challenging,” he explained. “However, due to the simplicity of dual-task gait test, we believe it would be easily incorporated in specialist clinics as part of the comprehensive assessments of older people with cognitive complaints. On the other hand, we also believe that primary care clinicians can use dual-task tests as a screening test, since we found potential applicable cut-offs; it appears that a dual-task cost, slowing dual-task speed while doing a cognitive challenge, of more than 20% can detect patients highly vulnerable to future decline.”

“Future studies should confirm whether adding dual-task gait testing to the clinical and cognitive evaluation of patients with MCI can improve dementia prediction,” the researchers add. “Cross-validation of this approach in other MCI cohorts would further support the clinical applicability.”

Dr. Rebecca K. MacAulay from the University of Maine in Orono, who recently investigated the sensitivity of dual-task gait speed assessment for detecting MCI, told Reuters Health by email, "The finding that cognitive load dual-task gait assessment reveals deficits not evident in normal walking is important. These findings provide further support for the relationship between cognitive load dual-task gait assessment and executive function and attention processes, even when other relevant risk factors are assessed and also supports the use of measuring decrements between normal and dual-task conditions.”

“The feasibility aspect is actually an interest of mine,” she said. “Notably, the GAITRITE system, which is currently the gold-star measure, used in this study is an expensive piece of equipment ($26,000-30,000) and also requires a space for the mat to be placed (with space being a challenge in most clinical settings). Thus, there is currently the need to develop more affordable and portable products that can accurately measure different aspects of gait.”

“Overall, there is a growing consensus supported by multidisciplinary research with converging results that use of dual-task gait assessment can increase the sensitivity by which older adults at risk of dementia are detected,” Dr. MacAulay concluded. “In this respect, the addition of dual-task gait assessment to routine clinical screener measure may provide a cost-effective, quick, and sensitive measure to evaluate brain-behavior relationships. Gait assessment can be easily integrated into clinical practice by use of a simple timer and well demarcated areas.”

SOURCE: https://bit.ly/2ro1mXB

JAMA Neurol 2017.

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