title: Motor dual-task Timed Up & Go test better identifies prefrailty individuals than single-task Timed Up & Go test.
abstract: OBJECTIVE
  The present study investigated whether dual-task Timed Up & Go tests (TUG) could identify prefrail individuals more sensitively than the single-task TUG (TUGsingle ) in community-dwelling middle-aged and older adults.
  
  
  METHODS
  This cross-sectional study recruited adults aged 50 years and older who actively participated in local community programs. Time taken to complete single-task TUG and dual-task TUG, carrying a cup of water (TUGmanual ) or carrying out serial-3 subtraction (TUGcognitive ) while executing TUG, was measured. Prefrailty status was defined based on Fried's phenotypic definition.
  
  
  RESULTS
  Of the 65 participants (mean age 71.5±8.1 years), 33.3% of the 12 middle-aged (50-64 years) and 62.3% of the 53 older (≥65 years) adults were prefrail, mainly as a result of weak grip strength. The receiver operating characteristic curve analyses for differentiating prefrailty from non-frailty showed that the area under the curve (AUC) for TUGmanual (0.73, 95% CI 0.60-0.86) was better than that for TUGsingle (0.67, 95% CI 0.54-0.80), whereas the AUC value was not significant for TUGcognitive (0.60, 95% CI 0.46-0.74). The optimal cut-off points for detecting prefrailty using TUGsingle , TUGmanual and TUGcognitive were 7.7 s (sensitivity 68%), 8.2 s (sensitivity 83%), and 14.3 s (sensitivity 29%), respectively. After adjusting for age, logistic regression analyses showed that individuals with TUGmanual 8.2 s or slower were 7.2-fold more likely to have prefrailty than those with TUGmanual faster than 8.2 s.
  
  
  CONCLUSIONS
  TUGmanual is more valid and sensitive than TUGsingle in identifying prefrail individuals. The TUGmanual thus could serve as a screening tool for early detection of individuals with prefrailty in community-dwelling middle-aged and older adults.
authors.affiliation: School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan; Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan; Neurobiology and Cognitive Science Center, National Taiwan University Hospital, Taipei, Taiwan; Physical Therapy Center, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Pei-Fang
authors.initials: PF
authors.lastname: Tang
authors.forename: Hao-Jan
authors.initials: HJ
authors.lastname: Yang
authors.forename: Ya-Chi
authors.initials: YC
authors.lastname: Peng
authors.forename: Hui-Ya
authors.initials: HY
authors.lastname: Chen
mesh_terms: D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D016330:Frail Elderly; D015577:Geriatric Assessment / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D013647:Task Performance and Analysis
keywords: frail elderly; middle aged; mobility limitation; sensitivity and specificity