Is there correlation between cognition and functionality in severe dementia? the value of a performance-based ecological assessment for Alzheimer's disease.

OBJECTIVE: Besides significant cognitive decline, patients in later stages of Alzheimer's disease (AD) also present global functional impairment, usually reported by their caregivers. This study searched for preserved activities of daily living by investigating correlations among specific instruments for severe dementia with a performance-based functional scale. METHOD: A sample of 95 moderate to severe AD patients and their caregivers underwent a neuropsychological battery consisting of screening tools, the Functional Assessment Staging Test (FAST), the Severe Mini-Mental State Examination (MMSEsev) and a performance-based ecological scale, the Performance Test of Activities of Daily Living (PADL). RESULTS: Consistent findings emerged from the comparisons among tests. PADL showed significant statistical correlation with MMSEsev (ρ<0.001), according to FAST subdivisions. CONCLUSION: Upon suspicion of unreliable caregiver reports, ecological scales may be useful for disease staging. Variable degrees of functionality and cognition may be present even in later stages of AD, requiring proper assessment.