The Neuropsychiatric Features of Behavioral Variant Frontotemporal Dementia.

Behavioral variant frontotemporal dementia (bvFTD) is a syndrome defined by a set of core clinical criteria, which include disinhibition; apathy or inertia; loss of sympathy or empathy; perseverative, stereotyped, or compulsive/ritualistic behavior; and hyperorality. The clinical features of bvFTD overlap substantially with those of psychiatric disease, particularly major depressive disorder and bipolar affective disorder. The similarities between bvFTD and primary psychiatric disease results in a significant diagnostic challenge for clinicians. Understanding the neuropsychiatric aspects of bvFTD may assist in differentiating bvFTD from a primary psychiatric disorder.

Neuroimaging in Frontotemporal Dementia: Heterogeneity and Relationships with Underlying Neuropathology.

Frontotemporal dementia encompasses a group of clinical syndromes defined pathologically by degeneration of the frontal and temporal lobes. Historically, these syndromes have been challenging to diagnose, with an average of about three years between the time of symptom onset and the initial evaluation and diagnosis. Research in the field of neuroimaging has revealed numerous biomarkers of the various frontotemporal dementia syndromes, which has provided clinicians with a method of narrowing the differential diagnosis and improving diagnostic accuracy. As such, neuroimaging is considered a core investigative tool in the evaluation of neurodegenerative disorders. Furthermore, patterns of neurodegeneration correlate with the underlying neuropathological substrates of the frontotemporal dementia syndromes, which can aid clinicians in determining the underlying etiology and improve prognostication. This review explores the advancements in neuroimaging and discusses the phenotypic and pathologic features of behavioral variant frontotemporal dementia, semantic variant primary progressive aphasia, and nonfluent variant primary progressive aphasia, as seen on structural magnetic resonance imaging and positron emission tomography.