Calibrating limitation features and dependence levels in basic activities of daily living among individuals with dementia: an item response theory-based analysis

Abstract Background Evaluating basic activities of daily living (BADL) is essential for monitoring disease progression and determining appropriate care plans for individuals with dementia. Existing dementia-specific BADL scales emphasize specific limitations without adequately depicting the spectrum of dependence. Discrepancies in how these limitations and the required assistance are described and interpreted across scales highlight the urgent need for a standardized approach to accurately map limitation features to their appropriate levels of dependence. Methods This was a cross-sectional study. Participants with dementia were enrolled between May and September 2022 from a 274-bed dementia unit at a nursing home in Guangzhou, China. Limitation features were classified into eight categories from “no limitations” to “resistance to care”. Dependence was rated on an 11-point scale, from complete independence (0) to complete dependence (10). The calibration of limitation features and dependence levels was based on item response theory (IRT) analysis. Results In total, 215 subjects were included (mean age 85.2 ± 7.4; 70.7% female). Hierarchically, the average measures (logit) increased from “no limitations” (-3.6 to -1.8), “initiation deficits” (-2.7 to -0.6), “planning deficits” (-2.2 to 0), “organizational deficits” (-1.6 to 0.4), “partial execution deficits” (-1.2 to 0.8), “inability with cooperation” (0.3 to 1.3), to “complete inability” (1.4 to 2.1). IRT location parameters revealed that deficits in initiation, planning, and organization fell within mild dependence (average θ: -1.1 to 0) across most of the items, although organizational deficits in grooming aligned more closely with moderate dependence. Partial execution deficits and inability with cooperation corresponded to moderate (average θ: -0.4 to 0.5) and severe dependence (average θ: 0.3 to 0.8), respectively. “Resistance to care” was disordered and fell between “inability with cooperation” and “complete inability”. The item characteristic curves supported these mappings. Conclusions The findings offer valuable insights into the hierarchical nature of dementia-specific BADL limitations and gradation of dependence in BADL of persons with dementia.