Patterns of cognitive and emotional empathy in frontotemporal lobar degeneration

Objective: To examine the relationship between empathy and cognition in frontotemporal lobar degeneration (FTLD). Background: Theoretical models suggest empathy has multiple cognitive and affective subcomponents, and recent studies suggest that performance on specific cognitive tests may predict empathy. Qualitative behavioral studies of patients with FTLD suggest empathy loss may occur directly as a result of damage to frontal and temporal structures. Method: First-degree relatives used the Inter-personal Reactivity Index (IRI), a measure of cognitive and emotional empathy, to rate 18 patients with frontotemporal dementia (FTD), 19 patients with semantic dementia (SD), 16 patients with Alzheimer disease (AD), and 10 age-matched healthy control subjects (NC). Subjects also underwent cognitive testing. Results: Both FTD and SD groups showed significantly lower levels of empathy than either ADs or NCs. SDs showed disruption of both emotional and cognitive empathy, whereas FTDs showed only disruption of cognitive empathy. Regressions controlling for general cognitive impairment showed 32% of the variance in Perspective Taking score was predicted by Category Fluency (P < 0.001), and 25% of the variance in Fantasy score was accounted for by Phonemic Fluency (P < 0.001). Conclusions: Although cognitive empathy is at least partly reliant on frontal structures, the emotional components of empathy are likely mediated by structures in the temporal lobes.