Neuropsychiatric symptoms in primary progressive aphasia: phenomenology, pathophysiology, and approach to assessment and treatment.

Primary progressive aphasia (PPA) is a neurodegenerative syndrome characterized by insidious and progressive loss of language. Current diagnostic criteria require symptoms to be largely restricted to language dysfunction for at least the first 2 years of the syndrome. However, as the disorder progresses - and sometimes even in the early stages - patients with PPA may exhibit neuropsychiatric symptoms. In this article, we review the phenomenology and frequency of neuropsychiatric symptoms in PPA. Among the few studies of this topic that have been performed, there is consistent agreement that neuropsychiatric symptoms are not uncommon among PPA patients. In some cases, particularly the semantic variant of PPA, symptoms are similar to those found in the behavioral variant of frontotemporal dementia. We further review the approach to assessment of behavioral symptoms in PPA and their possible management strategies, and speculate regarding their potential neurobiological substrates.