Objective: The purpose of this study was to examine the extent to which executive cognitive dysfunction and frontally-mediated behavioral disturbances are associated with functional impairment in patients with mild-to-moderate Alzheimer disease (AD).
Methods: Patients with AD (N=45) completed the Mattis Dementia Rating Scale, and patients' caregivers completed the Frontal Systems Behavioral Inventory and a modified form of the Lawton and Brody Activities of Daily Living (ADLs) Questionnaire.
Results: Multiple-regression analyses revealed that executive cognitive dysfunction and apathy scores accounted for 44% of the variance in instrumental activities of daily living; executive cognitive dysfunction alone explained 17% of the variance in instrumental ADLs, and apathy scores explained an additional 27%. Executive dysfunction and frontal-behavioral impairment explained 28% of the variance in basic ADLs (BADLs), and, after accounting for executive dysfunction, apathy was the only symptom found to explain additional unique variance in BADLs.
Conclusion: These findings suggest that specific cognitive and behavioral symptoms are associated with functional impairment in patients with AD.