Metacognition in the behavioral variant of frontotemporal dementia and Alzheimer's disease

Impaired self-awareness is characteristic of nearly all dementias, including Alzheimer's disease (AD), but the deficit is most severe in the behavioral variant of frontotemporal dementia (bvFTD). The prominence of frontal pathology in bvFTD suggests that failure of online monitoring, the process by which individuals monitor their own cognitive processing in real time, is an important contributor. Metacognitive research offers several approaches to measure self-assessment, some more and others less sensitive to online monitoring. The goal of this study was to assess metacognition in bvFTD using several approaches, and to compare the results with those in AD.

We examined metacognition in 12 patients with bvFTD, 14 with AD, and 35 healthy controls using feeling of knowing (FOK), ease of learning (EOL), judgment of learning (JOL), and retrospective confidence rating (CR) tasks, as well as response to feedback about performance.

BvFTD and AD were both impaired at FOK compared with controls, although AD showed some sparing. Both groups were similarly impaired at CR and neither group was impaired at JOL after accounting for memory performance. Most striking, bvFTD patients failed to appropriately adjust their predictions about future memory performance even after receiving explicit feedback that they had performed worse than they expected.

Both bvFTD and AD show deficits in online monitoring, although the deficit appears more severe in bvFTD. The insensitivity of bvFTD patients to overt feedback may point to unique mechanisms, possibly frontally mediated, that add to their severe lack of self-awareness.