Background: Loss of insight is a core diagnostic criterion for frontotemporal dementia (FTD), whereas failure to recognise cognitive deficits and unawareness of disease (anosognosia) are well established findings in Alzheimer's disease (AD). However, self awareness of personality has not been quantified in these patient groups.
Methods: Twenty two patients (12 with frontal variant FTD; 10 with early AD) and 11 older adult normal controls completed self report questionnaires (the Interpersonal Adjectives Scales) describing their current personality. First degree relative informants completed two questionnaires, one describing the subject's current personality, the other retrospectively describing the subject's personality before disease onset. Differences between subject and informant reports of current personality were used to measure the accuracy of self awareness.
Results: Discriminant function analysis showed significant differences in self awareness among the three groups, with those in the FTD group showing the greatest magnitude of error in the largest number of personality dimensions (dominance, submissiveness, cold heartedness, introversion, and ingenuousness). Despite personality changes over time, patients with AD showed accurate self awareness in all personality dimensions except submissiveness and extraversion. Normal controls showed a pattern of underestimating positive qualities, whereas patients with FTD exaggerated positive qualities and minimised negative qualities. For the personality facets showing impaired insight, the self reports of patients with FTD and AD most closely matched their premorbid personalities, suggesting a failure to update their self image after disease onset.
Conclusions: This study operationalises research criteria for loss of insight in FTD.