Content area
Full text
Frontotemporal dementia (FTD) is thought to account for between 12% and 20% of all dementia cases and is a common cause of presenile dementia. 1, 2 Misdiagnosis is common, and FTD is often mistaken for Alzheimer's disease (AD). Consensus guidelines for FTD emphasise early behavioural change as a feature of the disease, along with disinhibition, impulsive or inappropriate behaviour, difficulty in modulating behaviour, and other large departures from premorbid personality. In addition, patients are noted to show little insight or self awareness regarding these changes. The psychiatric nature of patients' symptoms is another cause for misdiagnosis: one study showed that seven of 12 patients with FTD were first evaluated by psychiatrists for their condition. 3 This stands in stark contrast to AD, in which early memory difficulties, rather than extreme personality change, tend to be the hallmark of diagnosis. Indeed, patients with AD often maintain socially appropriate behaviour and can be adept at covering up memory losses, suggesting a preservation of insight that is lacking in patients with FTD. 4
Personality tends to be stable in middle and later life, 5 and profound changes in personality often reflect an underlying neurological disease. Because of this, measures of personality can be used to examine the complex changes in self image, insight, and interpersonal interaction that are the hallmarks of FTD. Previous research has shown a quantitative difference in the degree and type of personality change in FTD compared with other forms of dementia. Patients with FTD who have predominantly frontal disease show dramatically increased social submissiveness and introversion compared with patients with AD. 6 However, no quantitative study of personality self awareness exists for this patient population, despite the evidence from clinical observation that lack of insight into personality change is a key feature of FTD. Given that loss of insight remains one of the primary diagnostic criteria for FTD, it is crucially important that we improve our ability to quantify this behavioural feature objectively so that diagnostic accuracy can be improved.
Although there is a large body of literature studying lack of insight in patients with AD, this research has focused on deficits in disease awareness (anosognosia) and unawareness of cognitive and overt behavioural deficits, rather than on awareness of personality. Compared with patients with...