Association of Dual-Task Gait With Incident Dementia in Mild Cognitive Impairment Results From the Gait and Brain Study

IMPORTANCE Gait performance is affected by neurodegeneration in aging and has the potential to be used as a clinical marker for progression from mild cognitive impairment (MCI) to dementia. A dual-task gait test evaluating the cognitive-motor interface may predict dementia progression in older adults with MCI. OBJECTIVE To determine whether a dual-task gait test is associated with incident dementia in MCI. DESIGN, SETTING, AND PARTICIPANTS The Gait and Brain Study is an ongoing prospective cohort study of community-dwelling older adults that enrolled 112 older adults with MCI. Participants were followed up for 6 years, with biannual visits including neurologic, cognitive, and gait assessments. Data were collected from July 2007 to March 2016. MAIN OUTCOMES AND MEASURES Incident all-cause dementia was the main outcome measure, and single-and dual-task gait velocity and dual-task gait costs were the independent variables. A neuropsychological test battery was used to assess cognition. Gait velocity was recorded under single-task and 3 separate dual-task conditions using an electronic walkway. Dual-task gait cost was defined as the percentage change between single-and dual-task gait velocities: ([single-task gait velocity - dual-task gait velocity]/single-task gait velocity) x 100. Cox proportional hazard models were used to estimate the association between risk of progression to dementia and the independent variables, adjusted for age, sex, education, comorbidities, and cognition. RESULTS Among 112 study participants with MCI, mean (SD) age was 76.6 (6.9) years, 55 were women (49.1%), and 27 progressed to dementia (24.1%), with an incidence rate of 121 per 1000 person-years. Slow single-task gait velocity (<0.8 m/second) was not associated with progression to dementia (hazard ratio [HR], 3.41; 95% CI, 0.99-11.71; P=.05) while high dual-task gait cost while counting backward (HR, 3.79; 95% CI, 1.57-9.15; P=.003) and naming animals (HR, 2.41; 95% CI, 1.04-5.59; P=.04) were associated with dementia progression (incidence rate, 155 per 1000 person-years). The models remained robust after adjusting by baseline cognition except for dual-task gait cost when dichotomized. CONCLUSIONS AND RELEVANCE Dual-task gait is associated with progression to dementia in patients with MCI. 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.