Novel applications of social-personality measures to the study of dementia.

Despite the realization that personality change is a core feature of frontotemporal dementia (FTD), little work has been performed using personality as a diagnostic tool for this disease. Likewise, personality change in Alzheimer's disease (AD) has long been recognized, but generally has not been used for diagnostic purposes. We introduce novel social-personality measures (Big Five Inventory, Interpersonal Adjectives Scale and Interpersonal Measure of Psychopathy) in the differential diagnosis of AD and temporal subtypes of FTD, and integrate these measures with traditional behavioural and neuropsychological methods commonly used in diagnosing dementia. We present four cases: an FTD patient with predominantly left temporal degeneration, an FTD patient with predominantly right temporal degeneration and two patients with Alzheimer's disease (one with mild and the other with moderate impairment). Results show the diagnostic utility of these measures in differentiating among temporal subtypes of FTD and moderate AD. Right temporal FTD, in particular, shows profound shifts in personality and interpersonal behaviour, as well as a striking lack of insight into these shifts. In addition to diagnostic purposes, we discuss how measures of personality and interpersonal behaviour can be utilized as an important component of understanding disease susceptibility and risk, as well as offering insights into the neuroanatomical underpinnings of personality and social behaviour.