Importance: Identifying cognitive or physical limitations that contribute to difficulties in instrumental activities of daily living (IADLs) is critical for adequate intervention with community-dwelling older adults with cognitive decline.
Objective: To establish the validity and responsiveness of an IADL scale based on the International Classification of Functioning, Disability and Health (the ICF–IADL) with respect to both cognitive and physical limitations.
Design: Cross-sectional study.
Setting: Multiple community care and senior centers.
Participants: Eighty-two older adults.
Intervention: Combination of physical exercise and cognitive training.
Measures: Five criterion measures—Lawton IADL Scale, Montreal Cognitive Assessment (MoCA), Digit Symbol Substitution Test (DSS), Word Lists Test (WLT), and Timed Up and Go Test (TUG).
Results: The ICF–IADL’s three summary scales—Disability Index (DI), Cognitive Disability Index (CDI), and Physical Disability Index (PDI)—had good concurrent validity with the Lawton IADL Scale. The DI and CDI had moderate to good associations with the MoCA. The DI’s and CDI’s predictive validity for scores on the Lawton IADL Scale, MoCA, and TUG was moderate to good and that of the PDI was fair. Responsiveness was large for the DI, moderate for the CDI, and small for the PDI.
Conclusions and Relevance: The ICF–IADL can be used to measure disability in IADLs related to cognitive and physical limitations. The DI and CDI were better than the PDI in predicting outcomes in general cognitive function and dynamic balance and were more responsive to change after intervention than the PDI.
What This Article Adds: The ICF–IADL addresses both cognitive and physical limitations and can be a valid assessment of IADLs. Occupational therapists can use it to determine difficulties in IADLs and causes of those difficulties, guide treatment planning, and monitor intervention effectiveness with community-dwelling older adults with cognitive decline.