OBJECTIVE: To establish reference values for the Uppsala-Dalarna Dementia and Gait (UDDGait) Timed "Up & Go" dual-task (TUGdt) test variables in cognitively healthy adults and to assess these variables' test-retest reliability.
METHODS: For reference values, 166 participants were recruited with approximately equal numbers and proportions of women and men in the age groups 50 to 59, 60 to 69, 70 to 79, and 80+ (mean age = 70 years, age range = 50-91 years, 51% women). For reliability testing, 43 individuals (mean age = 69 years, age range = 50-89 years, 51% women) were recruited. Two dual-task tests were carried out: TUGdt naming animals and TUGdt months backward, representing 8 test variables: time scores, costs (the relative difference between single- and dual-task time scores), "number of animals", "number of months", "animals/10 s", and "months/10 s". Reference ranges for the variables were established by quantile regression in age- and sex-specific groups. For reliability, ICCs, standard error of measurement, minimal detectable change, and Bland-Altman plots were used.
RESULTS: Reference values for the TUGdt test variables are presented for the 2.5th and 97.5th percentile. The reliability of TUGdt time scores was excellent (ICCs between 0.85 and 0.86). "Number of animals" and "animals/10 s" as well as "months/10 s" showed fair to good levels of reliability (ICCs between 0.45 and 0.58), whereas the reliability for both cost measures and "number of months" was poor (ICCs between 0.34 and 0.39).
CONCLUSIONS: Normative reference values, potentially useful for clinical and research purposes, were presented in 4 age- and sex-specific groups from 50 years and above. Reliability for the test variables varied between poor and excellent, the lower estimates partly explained by some variables being the ratio of 2 other variables. In UDDGait, TUGdt tests are intended for diagnostic and predictive purposes, for which these tests are promising and require further investigations.
IMPACT: We present normative reference values and test-retest reliability results for the UDDGait TUGdt test variables. These results should be useful for both clinical and research purposes.
2021. Vol. 101, no 10, article id pzab179