Affective and cognitive theory of mind in Alzheimer's disease: The role of executive functions

Introduction: Although there are plenty of studies on affective or cognitive theory of mind (ToM) in Alzheimer's Disease (AD), few have investigated both these dimensions and even fewer have examined the ability to identify an emotion from context in relation to the executive function deficit. Thus, the purpose of this study was to examine the deficit of affective and cognitive ToM in AD patients in the light of their executive function deficit. We were especially interested in the ability to attribute emotions to a character from a context and the ability to recognize facial expressions and to understand social clumsiness. Method: Twenty-eight mild AD patients and 33 healthy participants completed two sessions, one involving neuropsychological tests evaluating the executive functions, and the other comprising three tasks (Facial Expression Attribution, Facial Expression Recognition, Faux Pas test) assessing affective and cognitive ToM. Results: Compared to the healthy participants, the AD patients were impaired in the recognition of shame, anger and the neutral expression. They had difficulties in inferring surprise and disgust from visual context in situations where no facial expression was available, and were also impaired in all aspects of the Faux Pas test. Globally, and independently of the Group factor, performance in the three ToM tasks was correlated with performance in the backward span test, and the significant proportion of variance in performance in the Facial Expression Recognition and Faux Pas test was explained by the performance in backward span test. However, separate analyses did not show any significant correlations for the AD patients. Conclusions: Our results suggest an impairment of affective and cognitive ToM in AD patients. This impairment is selective as it concerns only some emotions. Considering these results with caution, it is possible that, patients' working memory difficulties explain, at least in part, their difficulties in ToM tasks.