Behavioral Assessment to Distinguish Alzheimer's Disease from Frontotemporal Dementias (pp. 35-49)
Authors: (Sandro Misciagna and Annalisa Barbier)
Abstract: Alzheimer‘s disease (AD) is a progressive dementia disorder mainly characterized by decline of cognitive functions with particular involvement of memory. Moreover, many behavioural disorders such as anxiety, depression, delusions and hallucinations and other psychiatric symptoms may affect patients with AD. Cognitive and behavioural disorders may be observed in patients affected by AD or other types of dementia, such as Frontotemporal Dementias (FTD). Frontotemporal Lobe Degeneration is a clinically and neuropathologically heterogeneous condition which includes different syndromes, sharing focal neurodegeneration in anterior brain regions. The most widely accepted clinical subtypes are Frontal Variant, also called frontal lobe dementia (FLD), primary nonfluent progressive aphasia (PPA) and Semantic Dementia (SD). Differential diagnosis between AD and frontotemporal dementias must include not only a neuropsychological examination but also a behavioural assessment.
We describe a study conducted on three groups of patients affected respectively, by AD (n = 13), FLD (n = 19) and PPA (n = 7), in which we assessed both cognitive deficits and behavioural disorders. Neuropsychological assessment included tasks of visual and verbal memory, executive functions, abstract reasoning and praxis abilities. Behavioural features were assessed by means of a retrospective interview on early cognitive and behavioural disorders and other informant-based interviews such as the Neuropsychiatric Inventory (NPI)  and the Informant Based Behavioural Questionnaire (IBBQ) .
Cognitive assessment showed that AD patients performed worse than the other groups on tasks involving episodic memory, while PPA patients performed worse than the other patients in language tasks, mostly involving verbal fluency and naming.
Behavioural assessment showed a prevalence of neuropsychiatric disorders in patients affected by FLD such as social behaviour disturbances (e.g. social avoidance,