Relative and absolute reliability of functional performance measures for adults with dementia living in residential aged care

Abstract

ABSTRACTBackground:This pilot investigation aimed to assess the relative and absolute test–retest reliability of commonly used functional performance measures in older adults with dementia residing in residential aged care facilities.Methods:A total of 12 participants were tested on the Short Physical Performance Battery (SPPB), the Balance Outcome Measure for Elder Rehab (BOOMER), hand grip strength, anthropometric measures and Bio-electric Impedance Analysis (BIA). This study utilized a seven-day test–retest evaluation. Intra-class Correlation Coefficients (ICC) were used to assess relative reliability, Typical Error of Measurement (TEM) was used to assess the absolute reliability, and Bland–Altman plots were used to assess group and individual levels of agreement.Results:With the exception of Standing Balance (ICC = 0.49), 2.4-m walk (ICC = 0.68), functional reach (ICC = 0.38), and static timed standing (ICC = 0.47), all measures demonstrated acceptable (>0.71) ICCs. However, only the anthropometric measures demonstrated acceptable levels of absolute reliability (>10% TEM). Bland–Altman analysis showed non-significant (p > 0.05) mean differences, and eight out of the 17 measures showing wide Limits of Agreement (LoA).Conclusions:Current measures of functional performance are demonstrably inappropriate for use with a population of older adults with dementia. Authors suggest aligning current measurement strategies with Item Response Theory as a way forward.