Theory of mind and executive functions in normal human aging and Parkinson's disease

Although the majority of research in theory of mind (TOM) has focused on yo ung children or individuals with autism, recent investigations have begun t o look at TOM throughout the lifespan and in other neurological and psychia tric populations. Some have suggested that TOM may represent a dissociable, modular brain system that is related to, but separable, from other brain f unctions including executive functions (EF). Recently, studies have shown t hat TOM performance can be compromised following an acquired brain insult ( e.g, damage to the right hemisphere). However, the relationship of such imp aired TOM performance to other brain functions in these cases has not been explored. This study investigated the effects of both normal human aging an d Parkinson's disease on TOM. The relationship of TOM performance and EF in these groups was also examined. The results suggested that although TOM pe rformance appeared compromised in the group of individuals with Parkinson's disease, the elderly control participants were relatively unimpaired relat ive to younger individuals. Significant relationships between several measu res of TOM and EF were also found. The implications of these findings, and also the finding that failure on one measure of TOM did not necessarily pre dict failure on all measures of TOM, are discussed.