Development, validity, and reliability of the General Activities of Daily Living Scale: a multidimensional measure of activities of daily living for older people

Objective: To propose and evaluate the psychometric properties of a multidimensional measure of activities of daily living (ADLs) based on the Katz and Lawton indices for Alzheimer's disease (AD) and mild cognitive impairment (MCI). Methods: In this study, 85 patients with MCI and 93 with AD, stratified by age (<= 74 years, > 74 years), completed the Mini Mental State Examination (MMSE) and the Geriatric Depression Scale, and their caregivers completed scales for ADLs. Construct validity (factor analysis), reliability (internal consistency), and criterion-related validity (receiver operating characteristic analysis and logistic regression) were assessed. Results: Three factors of ADL (self-care, domestic activities, and complex activities) were identified and used for item reorganization and for the creation of a new inventory, called the General Activities of Daily Living Scale (GADL). The components showed good internal consistency (> 0.800) and moderate (younger participants) or high (older participants) accuracy for the distinction between MCI and AD. An additive effect was found between the GADL complex ADLs and global ADLs with the MMSE for the correct classification of younger patients. Conclusion: The GADL showed evidence of validity and reliability for the Brazilian elderly population. It may also play an important role in the differential diagnosis of MCI and AD.