Theory of Mind in Neurodegenerative Diseases

BACKGROUND: Theory of Mind (ToM), defined as the ability to attribute mental states to one’s self and others, plays a key role in driving behaviour and social interactions. An issue under current debate is whether the behavioural problems usually reported in frontotemporal dementia (FTD) and, in a more subtle form, in other neurodegenerative diseases (e.g., motor neurone disease, MND), may at least partially be the result of an impairment in ToM. METHODS: The study investigated the attribution of social versus private intentions in small groups of FTD and MND patients, using a task in which participants had to choose the most appropriate endings for comic strips. The comic strips depicted: social interactions between characters; private actions performed by a single character; or causal links amongst objects, with no characters involved. RESULTS: Single case analysis showed the difficulty of some patients to attribute social (but not private) intentions to characters correctly. DISCUSSION: These findings suggest that attributing social intentions to others may require a cognitive integrity that is affected by these neurodegenerative diseases, leading to a difficulty in correctly interpreting and managing social interactions.