Cognitive functions and social cognition in multiple sclerosis: An overview.

Cognitive decline has been widely reported in patients with multiple sclerosis (MS) despite its clinical heterogeneity, at all stages and in all subtypes of the disease. Deficits are most commonly present in attention, processing speed, working memory, verbal fluency and executive function. However, MS patients also show decreased performance in tasks related to social cognition, i.e. mental operations thatdrive interpersonal skills such as social perception, empathy and theory of mind. Social cognitive deficits are an underestimated but important aspect of impairment in MS, reflecting how people process, store, and apply information in social interactions. Deficits in these domains have been associated with reduced social and psychological quality of life, even after controlling for severity and duration of the disease, age, and neurocognitive performance. Social cognition impairment is not entirely dependent on and parallel to general cognitive dysfunction, given that some patients experience disorganization of their social life before a significant or detectable cognitive impairment. The decrease in performance of social cognition tasks may reflect changes in brain activity and brain structure, either general or regional. Both subtle diffuse pathology and acute local lesions have at least partially independent effects on aspects of social cognition. The observed white matter damage contributes to a mechanism of disruption in the network of brain connections involved in social cognition. Undoubtedly, there is a wide variability in the relationship of social cognitionand neuroanatomical findings, not only due to the brain's complex connectivity, but also to the lack of a unique operative definition of these cognitive domains. Furthermore, it is difficult to compare study results, given the variability of clinical presentations in all stages of the disease.More research would contribute in understanding social cognition deficits better and in determining whether and what kind of training could be beneficial.