title: A comparison of neuropsychological performance between US and Russia: preparing for a global clinical trial.
abstract: 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.
authors: Department of Psychiatry, Joseph and Kathleen Bryan ADRC, Duke University Medical Center, Durham, NC, USA. Electronic address: khayden@duke.edu.
authors: Kathleen M
authors: KM
authors: Hayden
authors: Center for Clinical Trials, Nebbiolo LLC, Tomsk, Russia.
authors: Oksana A
authors: OA
authors: Makeeva
authors: Duke Clinical Research Institute, Durham, NC, USA; Department of Medicine, Duke University Medical Center, Durham, NC, USA.
authors: L Kristin
authors: LK
authors: Newby
authors: Department of Psychiatry, Joseph and Kathleen Bryan ADRC, Duke University Medical Center, Durham, NC, USA.
authors: Brenda L
authors: BL
authors: Plassman
authors: Center for Clinical Trials, Nebbiolo LLC, Tomsk, Russia.
authors: Valentina V
authors: VV
authors: Markova
authors: Duke Clinical Research Institute, Durham, NC, USA.
authors: Ashley
authors: A
authors: Dunham
authors: Department of Psychiatry, Joseph and Kathleen Bryan ADRC, Duke University Medical Center, Durham, NC, USA.
authors: Heather R
authors: HR
authors: Romero
authors: Center for Clinical Trials, Nebbiolo LLC, Tomsk, Russia.
authors: Zarui A
authors: ZA
authors: Melikyan
authors: Department of Psychiatry, Joseph and Kathleen Bryan ADRC, Duke University Medical Center, Durham, NC, USA.
authors: Cassandra M
authors: CM
authors: Germain
authors: Department of Psychiatry, Joseph and Kathleen Bryan ADRC, Duke University Medical Center, Durham, NC, USA.
authors: Kathleen A
authors: KA
authors: Welsh-Bohmer
authors: Zinfandel Pharmaceuticals, Durham, NC, USA.
authors: Allen D
authors: AD
authors: Roses
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000150:complications; D003071:Cognition / Q000502:physiology*; D003072:Cognition Disorders / Q000175:diagnosis* / Q000209:etiology; D003431:Cross-Cultural Comparison; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D012426:Russia; D011795:Surveys and Questionnaires; D014177:Translations; D014481:United States
keywords: Alzheimer's disease; Cross-cultural comparison; Neuropsychological tests; Primary prevention delay of onset of MCI due to Alzheimer's disease