Dual-Task Gait and Alzheimer’s Disease Genetic Risk in Cognitively Normal Adults: A Pilot Study

Article type: Research Article

Authors: Whitson, Heather E.^{a; b; c; *} | Potter, Guy G.^{b; d; e} | Feld, Jody A.^f | Plassman, Brenda L.^{b; d; e} | Reynolds, Kelly^b | Sloane, Richard^b | Welsh-Bohmer, Kathleen A.^{b; d; e}

Affiliations: [a] Department of Medicine (Geriatrics), Duke University School of Medicine, Durham, NC, USA | [b] Center for the Study of Aging and Human Development, Duke University School of Medicine, Durham, NC, USA | [c] Durham VA Geriatrics Research Education and Clinical Center (GRECC), Durham, NC, USA | [d] Joseph and Kathleen Bryan Alzheimer’s Disease Research Center, Duke University School of Medicine, Durham, NC, USA | [e] Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, NC, USA | [f] Department of Orthopedic Surgery, Doctor of Physical Therapy Division, Duke University School of Medicine, Durham, NC, USA

Correspondence: [*] Correspondence to: Heather E. Whitson, MD, MHS, Department of Medicine (Geriatrics), Duke University School of Medicine, DUMC 3003, Durham, NC 27710, USA. Fax: +1 919 684 8569; E-mail: [email protected]

Abstract: Background:Dual-task paradigms, in which an individual performs tasks separately and then concurrently, often demonstrate that people with neurodegenerative disorders experience more dual-task interference, defined as worse performance in the dual-task condition compared to the single-task condition. Objective:To examine how gait-cognition dual-task performance differs between cognitively normal older adults with and without an APOE ɛ4 allele. Methods:Twenty-nine individuals ages 60 to 72 with normal cognition completed a dual-task protocol in which walking and cognitive tasks (executive function, memory) were performed separately and concurrently. Fourteen participants carried APOE ɛ4 alleles (ɛ3/ɛ4 or ɛ2/ɛ4); fifteen had APOE genotypes (ɛ2/ɛ2, ɛ2/ɛ3, or ɛ3/ɛ3) associated with lower risk of Alzheimer’s disease (AD). Results:The two risk groups did not differ by age, sex, race, education, or gait or cognitive measures under single-task conditions. Compared to low risk participants, APOE ɛ4 carriers tended to exhibit greater dual-task interference. Both the memory and executive function tasks resulted in dual-task interference on gait, but effect sizes for a group difference were larger when the cognitive task was executive function. In the dual-task protocol that combined walking and the executive function task, effect sizes for group difference in gait interference were larger (0.62– 0.70) than for cognitive interference (0.45– 0.47). Discussion:Dual-task paradigms may reveal subtle changes in brain function in asymptomatic individuals at heightened risk of AD.

Keywords: Aging brain, cognitive performance, cognitive reserve, dementia, diagnosis, early detection, motor interference, phenotype, risk, stress test

DOI: 10.3233/JAD-180016

Journal: Journal of Alzheimer's Disease, vol. 64, no. 4, pp. 1137-1148, 2018