Diagnostic validity of the Alzheimer's disease functional assessment and change scale in mild cognitive impairment and mild to moderate Alzheimer's disease

Abstract

Background: The Alzheimer's Disease Functional Assessment and Change Scale (ADFACS) is a functional assessment instrument widely used in clinical research.

Aims: To test the diagnostic and concurrent validity of the Spanish version of this scale and to describe the functional deficit pattern for mild cognitive impairment (MCI) and Alzheimer's disease (AD) dementia.

Methods: The ADFACS, the Interview for Deterioration in Daily Living Activities in Dementia (IDDD), and the Mini Mental State Examination (MMSE) were administered to 146 control subjects (CS) and 165 patients (67 MCI and 98 AD). Nonparametric tests were used to compare the diagnostic groups. Cronbach's α and correlations with the MMSE and the IDDD were calculated. Sensitivity, specificity and predictive values were studied.

Results: The ADFACS had a high internal consistency (α = 0.95). Three cutoff points of 1, 4, and 17 were provided to separate CS and MCI patients, MCI and mild AD patients, and mild AD and moderate AD patients, respectively. The ADFACS strongly correlated with functional (IDDD, 0.927) and cognitive (MMSE, 0.747) measures. A similar pattern of dysfunction, but in different grades, was found for the MCI and AD groups.

Conclusion: The ADFACS is a reliable, valid, and sensitive instrument to assess functional abilities; it is useful in dementia assessment for elderly populations.