It is now established that disturbances in social cognition are frequent in neurology and that they contribute to the development of social conduct disorders. Their assessment is therefore essential, particularly in order to propose early and adapted care. However, this assessment remains limited today. A new serious game-type test, REALSoCog, has been developed to address the shortcomings of current tools and to highlight disturbances in social behaviors. The latter are not always observed in consultation although they are often reported by caregivers. The objective of this research is therefore to validate the REALSoCog task in a pathological population (currently being standardized in the general population: CER-U, IRB N°: 00012020-115). The clinical interest of this task will be tested with a group of patients suffering from a neurodegenerative disease (Alzheimer's disease (AD), dementia with Lewy bodies (DCL), fronto-temporal lobar degeneration (FTD)) in order to assess its sensitivity and specificity in the detection of social-cognitive disturbances, and in particular in terms of social behaviors (detection of social behavioral disorders reported in daily life). The objective is also to document the socio-cognitive profiles in the mentioned diseases thanks to a more ecological test, and to better understand the links between socio-cognitive processes on the one hand, and individual characteristics on the other hand (e.g. mood and social participation).