[Social cognition in Parkinson's disease dementia and behavioral variant of frontotemporal dementia]

To study the presence of alterations in social cognition in Parkinson's disease dementia (PDD) and behavioral variant frontotemporal dementia (bvFTD), to compare the levels of involvement, and to analyze their relevance as a tool to distinguish between both demential profile.

For this purpose, 34 patients diagnosed with PDD, 21 men and 13 women, with an average age of 70 years and 8 years of education, and 26 patients diagnosed with bvFTD, 9 men and 17 women, with an average age of 68 years and 6 years of education, were assessed. The control group consisted of 30 healthy subjects, with a mean of 66 years of age and 8 of schooling. Reading the Mind in the Eyes was use as an emotional Theory of Mind (ToM) test; First-Order False Belief as a cognitive ToM test; Faux Pas as mixed test, considering their emotional (FPec) and cognitive (FPcc) components; and Iowa Gambling Task for social decision-making.

Both groups of patients showed alterations in all tests compared to the control group. A significant difference between PDD and bvFTD was also observed for Reading the Mind in the Eyes test, Faux Pas total score, FPec and FPcc, with lower means and medians for PDD patients on all scores except for FPcc.

This findings suggests that emotional ToM would be most affected PDD patients, while the use of cognitive ToM and social decision-making tests would be restrain tools to differentiate between a type of dementia or another.