Observation of social behavior in frontotemporal dementia.

Background: The most characteristic manifestations of behavioral variant frontotemporal dementia (bvFTD) are abnormalities in social behavior. However, distinguishing bvFTD based on social behavior can be difficult in structured clinical settings.

Methods: Using a Social Observation Inventory, 10 patients with bvFTD and 10 patients with Alzheimer's disease (AD) were compared to their caregiver interlocutors on 1-hour mealtime, in-home videotaped segments.

Results: Compared to caregivers and patients with AD, patients with bvFTD were significantly disturbed in social behavior. In contrast, patients with AD were indistinguishable from their caregivers. The lack of "you" comments and decreased tact and manners distinguished 92.6% of the patients with bvFTD from patients with AD and caregivers. The Social Observation Inventory scores correlated with scores on frontal-executive tests and socioemotional scales.

Conclusions: The systematic observation of social behavior during routine activities may be one of the best ways to distinguish patients with bvFTD from normal individuals and from patients with other dementias.