Stages of mild cognitive impairment and Alzheimer's disease can be differentiated by declines in timed up and go test: A systematic review and meta-analysis

Motor dysfunction increases in the moderate and severe stages of dementia. However, there is still no consensus on changes in mobility during its early stages. This meta-analysis aimed to measure the level of single-task functional mobility in older subjects with mild cognitive impairment (MCI) and/or Alzheimer's disease (AD). In a search of the PubMed, ISI Web of Knowledge, and Scopus databases, 2728 articles were identified. At the end of the selection, a total of 18 studies were included in the meta-analysis. Functional mobility was investigated using the timed up and go (TUG) test in all studies. When compared to healthy elderly (HE) adults, the following mean differences (MD) in seconds were found for the investigated subgroups: no amnestic MCI (MD = 0.26; CI95% = -0.77, 1.29), amnestic MCI (MD = 0.86; CI95% = -0.02, 1.73), very mild AD (MD = 1.32; CI95% = 0.63, 2.02), mild AD (MD = 2.43; CI95% = 1.84, 3.01), mild-moderate AD (MD = 3.01; CI95% = 2.47, 3.55), and mild-severe AD (MD = 4.51; CI95% = 1.14, 7.88); for the groups, the following MD were found: MCI (MD = 0.97; CI95% = 0.51, 1.44) and AD (MD = 2.66; CI95% = 2.16, 3.15). These results suggest a transition period in motor capacity between healthy aging and dementia, wherein functional mobility analysis in a single-task (TUG) can contribute to the diagnosis and staging of predementia states and AD.