Alzheimer disease and frontotemporal dementias. Behavioral distinctions.

BACKGROUND: Frontotemporal dementia (FTD) is a syndrome produced by lobar degeneration of the temporal and/or frontal lobes.

OBJECTIVES: To quantify the behavioral disturbances of FTD and compare them with behavioral changes observed in Alzheimer disease (AD).

DESIGN: Cross-sectional comparison of 2 groups defined by research diagnostic criteria and single photon emission computed tomography. Behaviors were assessed using a standardized rating scale-Neuropsychiatric Inventory. Groups were matched for dementia severity.

SETTING: Patients were seen at 2 university-based outpatient dementia clinics and a Veterans Affairs medical center.

PARTICIPANTS: Twenty-two patients with FTD and 30 patients with AD.

RESULTS: Patients with FTD had significantly greater total Neuropsychiatric Inventory scores than patients with AD and exhibited more apathy, disinhibition, euphoria, and aberrant motor behavior. The Neuropsychiatric Inventory accurately assigned 77% of patients with FTD and 77% of patients with AD to the correct diagnostic group using disinhibition, apathy, and depression. Patients with FTD had higher levels of disinhibition and apathy with relatively lower levels of depression compared with patients with AD.

CONCLUSIONS: The Neuropsychiatric Inventory provides a behavioral profile that differentiates patients with FTD from patients with AD. Patients with FTD are more behaviorally disturbed but are often less depressed than patients with AD relative to their level of apathy.