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.