Conversational Laughter in the Behavioral Variant of Frontotemporal Dementia (P6.248)

Objective: We hypothesized that those with behavioral variant frontotemporal dementia (bvFTD) would laugh less during or after their own speech during conversations than controls, Alzheimer’s disease (AD) or the semantic variant of primary progressive aphasia (svPPA). Within bvFTD, we hypothesized that the proportion of laughter of this kind would correlate with grey matter volume in the right anterior insula. Background: Behavioral variant frontotemporal dementia (bvFTD) is associated with changes in social interaction, including a loss of appropriately embarrassed behavior. Laughter is an important social signal that can signal embarrassment when directed at the self. Both bvFTD and laughter have been associated with anterior insular function. Methods: Patients with bvFTD (n=26), svPPA (n=27), and eoAD (n=11) engaged in a brief conversation in a semi-naturalistic setting with a control companion (n=68). The number of people who laughed, percentage of the conversation spent laughing, and total amount of speech were compared between groups. Among those who laughed, laughs were categorized by occurrence during or shortly after the participant’s vocalization (“self” context) or the partner’s vocalization (“other” context). The proportion of laughs in the participant context was compared between groups and included in voxel-based morphometric analysis. Results: There was no significant between-group difference in the total number of people who laughed or percentage of the conversation spent laughing. The proportion of laughter in the “self” context was found to be significantly less in the bvFTD compared to either controls or svPPA. Among bvFTD patients, the probability of laughing in the “self” context correlated with grey matter volume in the right anterior insula. Conclusions: A lack of laughter at oneself in conversation may be a useful measure of behavior change in bvFTD. Study Supported by: the American Brain Foundation, grant numbers P50AG023501, P01AG019724, and 5R01NS050915-11 from the NIH National Institute on Aging. Disclosure: Dr. Pressman has nothing to disclose. Dr. Simpson has nothing to disclose. Dr. Mandelli has nothing to disclose. Dr. Spinelli has nothing to disclose. Dr. Shdo has nothing to disclose. Dr. Miller has nothing to disclose. Dr. Merrilees has received research support for activities with Quest Diagnostics. Dr. Gorno Tempini has received personal compensation in an editorial capacity for Co-Editor, Neuroimage Clinical. Dr. Levenson has nothing to disclose.