Self-awareness and self-monitoring of cognitive and behavioral deficits in behavioral variant frontotemporal dementia, primary progressive aphasia and probable Alzheimer's disease

Abstract

Lack of insight is a core diagnostic criterion for behavioral variant frontotemporal dementia (bvFTD), and is believed to be intact in the early stages of primary progressive aphasia (PPA). In other neurological conditions, symptom-specific insight has been noted, with behavioral symptoms appearing especially vulnerable to reduced insight. Different components of insight, self-awareness and self-monitoring, are also often considered separate phenomena. The current study compared insight in patients with PPA, bvFTD, and probable Alzheimer's disease (PrAD) and a group of cognitively intact control subjects. Additionally, differences in insight for the domains primarily affected by the three types of dementia, namely, Behavior, Naming, and Memory, were assessed, and self-awareness and self-monitoring were compared. A total of 55 participants were enrolled. Participants were asked to complete self-estimate scales demonstrating their perceived ability immediately prior to, and immediately following a test in each domain of interest. Results indicated that PPA and normal control groups performed very similarly on control (Weight and Eyesight) and cognitive domains, whereas bvFTD and PrAD patients were unable to accurately assess Memory. All three diagnostic groups failed to accurately assess their behavioral symptoms, suggesting that this domain is vulnerable to loss of insight across diagnoses. Naming ability, in contrast, was either accurately assessed or underestimated in all groups. Finally, there were no notable differences between self-awareness and self-monitoring, potential explanations for this are examined.

Figure 1. An example of the procedure taken from a 62 year-old male with a diagnosis of PrAD

Note: When asked to complete the visual analog scale initially, he considers his naming ability to be quite good, indicating this with a mark that is 83% of the way up the line. His actual BNT score is poor (T=14). This difference between pretest estimate and actual performance suggests self-awareness was poor. However, he realized that he should have known some of the words he missed, and this is reflected on the post-estimate, where his mark is just 33% from the bottom of the line. Thus, in this case, self-monitoring was judged more intact than self-awareness.

Figure 2. Boxplot demonstrating spread of SAS and SMS scores for each domain, by group

Note: The line at zero represents a perfect estimate of performance. Anything below the line represents underestimation of deficit (i.e., poor self-awareness or self-monitoring). Boxes for each domain are filled in different shades of the same color, lighter for SAS and darker for SMS.