BEHAVIORAL PHENOMENOLOGY IN ALZHEIMERS-DISEASE, FRONTOTEMPORAL DEMENTIA, AND LATE-LIFE DEPRESSION - A RETROSPECTIVE ANALYSIS

Often patients in the early stages of Alzheimer's disease (AD), fronto temporal dementia (FTD), and late-life depression can be difficult to differentiate clinically. Although subtle cognitive distinctions exist between these disorders, noncognitive behavioral phenomenology may pr ovide additional discriminating power. In 19 subjects with AD, 19 with FTD, 16 with late-life psychotic depression (LLPD), and 19 with late- life nonpsychotic depression (LLNPD), noncognitive behavioral symptoms were quantified retrospectively using the Schedules for Clinical Asse ssment in Neuropsychiatry (SCAN) and compared using both a one-way ANO VA and a multivariate stepwise discriminant analysis, which utilized a jackknife procedure. The FTD group showed the highest mean total SCAN score, while the AD group showed the lowest. ANOVA showed significant differences in the mean total SCAN scores between the four diagnostic groups (P < .0001). With the discriminant analysis,the four disorders demonstrated different clusters of behavioral abnormalities and were differentiated by these symptoms (P < .0001). A subset of 14 SCAN item group symptoms was identified that collectively classified correctly the following percentages of subjects in each diagnostic category: AD 94.7%, FTD 100%, LLPD 87.5%, and LLNPD 100%. These results indicate th at AD, FTD, LLPD, and LLNPD were distinguished retrospectively by the SCAN without using cognitive data. Better definition of the longitudin al course of noncognitive behavioral symptoms in different dementias a nd psychiatric disorders will be valuable both for diagnosis and to he lp define behavioral syndromes that are associated with selective neur oanatomic and neurochemical brain pathology.