A comparison of neuropsychological performance between US and Russia: preparing for a global clinical trial.
BACKGROUND: Understanding regional differences in cognitive performance is important for interpretation of data from large multinational clinical trials. METHODS: Data from Durham and Cabarrus Counties in North Carolina, USA and Tomsk, Russia (n = 2972) were evaluated. The Montreal Cognitive Assessment (MoCA), Trail Making Test Part B (Trails B), Consortium to Establish a Registry for Alzheimer's Disease Word List Memory Test (WLM) delayed recall, and self-report Alzheimer's Disease Cooperative Studies Mail-In Cognitive Function Screening Instrument (MCFSI) were administered at each site. Multilevel modeling measured the variance explained by site and predictors of cognitive performance. RESULTS: Site differences accounted for 11% of the variation in the MoCA, 1.6% in Trails B, 1.7% in WLM, and 0.8% in MCFSI scores. Prior memory testing was significantly associated with WLM. Diabetes and stroke were significantly associated with Trails B and MCFSI. CONCLUSIONS: Sources of variation include cultural differences, health conditions, and exposure to test stimuli. Findings highlight the importance of local norms to interpret test performance.
Hayden, KM; Makeeva, OA; Newby, LK; Plassman, BL; Markova, VV; Dunham, A; Romero, HR; Melikyan, ZA; Germain, CM; Welsh-Bohmer, KA; Roses, AD; TOMSK-DUKE Study Group Investigators,
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