Executive dysfunction in Alzheimer disease

Background: Executive dysfunction (EDF) is common in Alzheimer disease (AD); however, its relationship to other symptoms is difficult to assess in patients with AD. Objectives: To determine the prevalence of EDF and study its relationship to cognitive, functional, and neuropsychiatric symptoms in patients with AD. Design, Setting, and Patients: A retrospective analysis of data from participants in the English Instruments Protocol of the Alzheimer's Disease Cooperative Study. Subjects were drawn from a sample of patients evaluated at tertiary referral centers. Results: A total of 64% of AD patients were classified as having EDF. Patients with EDF performed worse on tests of cognition (P<.001), dementia severity (P<.001), and activities of daily living (P = .01) and had more frequent symptoms of psychosis (P = .03) with greater emergence during the 12-month interval (P = .03) compared with patients with normal executive function. Less than 30% of the variance in executive function performance was explained by cognitive measures. Conclusion: These findings support the assessment of executive function in persons with AD and the importance of frontal lobe dysfunction in AD.