Theory of Mind in mild cognitive impairment: Relationship with the default mode network (DMN)

Abstract

AbstractBackgroundIt has been well established that older adults presenting with amnestic Mild Cognitive Impairment (aMCI) are not only at a higher risk of developing dementia compared to individuals with non‐amnestic Mild Cognitive Impairment (naMCI) and older adult controls, but also demonstrate impairments in Theory of Mind (ToM) ability, which has been associated with smaller limbic structure volumes. In the present study, we sought to examine any alterations in resting‐state functional connectivity within the brain's default mode network (DMN) in a sample of adults with MCI previously reported to demonstrate poorer ToM abilities.Methods17 adults with aMCI, 26 adults with naMCI and 16 older adult controls completed the Reading the Mind in the Eyes Test, followed by resting‐state functional magnetic resonance imaging.ResultsAfter controlling for age and correcting for multiple comparisons, adults with aMCI demonstrating poorer ToM abilities revealed significantly decreased functional connectivity between the left lateral temporal cortex (LTC) and the right temporal pole (b = .07, t(23) = 3.73, p = .02), as well as between the left LTC and both the left (b = .06, t(23) = 3.32, p = .03) and right (b = .04, t(23) = 2.91, p = .049) temporoparietal junctions ,relative to adults with naMCI.ConclusionsOur findings suggest that deficits in connectivity across a more widely distributed network of brain regions such as the DMN may be contributing to ToM deficits in aMCI, beyond the previously identified changes in limbic structure volumes. Moreover, in a broader clinical sense, these results contribute to a growing body of evidence highlighting that it is important to include measures of social cognitive function in the routine clinical workup of individuals with suspected MCI.