An ICF-based evaluation for basic and instrumental ADL: a new method to measure daily functioning in mild cognitive disorders

Purpose: Current evaluations of activities of daily living (ADL) are inaccurate for differentiation between normal cognitive ageing (NC), Mild Cognitive Impairment (MCI) and Alzheimer’s Disease (AD). Based on the International Classification of Functioning Disability and Health (WHO, 2001), the evaluations for basic (b-) ADL according to Katz and instrumental (i-) ADL according to Lawton were adapted. This new evaluation focuses on individual slopes of functional decline and differentiates between underlying causes of limitation. The evaluation distinguishes a Global (DI), Cognitive (CDI) and Physical Disability Index (PDI). Methods: In order to investigate the psychometric properties, 100 community-dwelling participants (mean age 78.9; SD±7.31) were classified as (1) NC (n=33); (2) patients with MCI (n=27) and (3) with mild to moderate AD (n=40), based upon a standard clinical evaluation. Additionally, the new evaluation was administered. Results: This new tool showed good psychometrical properties. The inter-rater reliability was excellent for all indices (ICC ranging from .944 to .994). Regarding the construct validity, the CDI differed significantly between all groups (p<0.05). The DI and PDI were significantly different between the persons with NC and the patients (p<0.001). ROC curves showed good to excellent results for the DI and CDI in the diagnostic differentiation between HC, MCI and AD (AUC ranging from .609 to .998). Conclusions: This new evaluation allows a more straightforward and detailed assessment of ADL. It might offer a useful contribution to the identification and follow up