Associations between physical performance and executive function in older adults with mild cognitive impairment: Gait speed and the timed "Up & Go" test

Abstract

Background. Older adults with amnestic mild cognitive impairment (aMCI) areat higher risk for developing Alzheimer disease. Physical performance decline on gaitand mobility tasks in conjunction with executive dysfunction has implications foraccelerated functional decline, disability, and institutionalization in sedentary olderadults with aMCI.Objectives. The purpose of this study was to examine whether performance on2 tests commonly used by physical therapists (usual gait speed and Timed "Up & Go"Test [TUG]) are associated with performance on 2 neuropsychological tests ofexecutive function (Trail Making Test, part B [TMT-B], and Stroop-Interference,calculated from the Stroop Word Color Test) in sedentary older adults with aMCI.Design. The study was a cross-sectional analysis of 201 sedentary older adults withmemory impairment participating in a longitudinal intervention study of cognitivefunction, aging, exercise, and health promotion.Methods. Physical performance speed on gait and mobility tasks was measuredvia usual gait speed and the TUG (at fast pace). Executive function was measured withthe TMT-B and Stroop-Interference measures.Results. Applying multiple linear regression, usual gait speed was associated withexecutive function on both the TMT-B (β=-0.215, P=.003) and Stroop-Interference(β=-0.195, P=.01) measures, indicating that slower usual gait speed was associatedwith lower executive function performance. Timed "Up & Go" Test scores (inlogarithmic transformation) also were associated with executive function on both theTMT-B (β=0.256, P