Comparing Longitudinal Behavior Changes in the Primary Progressive Aphasias.

Abstract

Differentiating between primary progressive aphasia (PPA) variants based on the profile of language deficits can be difficult in a proportion of patients. Further, little is presently know about the pattern of longitudinal changes in behavior in PPA variants. To determine the presence of behavioral changes in the main variants of PPA: semantic (sv-PPA), nonfluent/agrammatic (nfv-PPA), and logopenic (lv-PPA), and establish the course of these changes over time. We measured behavioral changes in 73 prospectively recruited PPA (30 sv-PPA, 22 nfv-PPA, and 21 lv-PPA), as well as 33 behavioral variant frontotemporal dementia (bv-FTD) and 31 Alzheimer's disease (AD) patients, at baseline and after 1 year, using the Cambridge Behavioural Inventory Revised. All included patients had mild dementia severity at baseline. Both at baseline and follow-up, sv-PPA exhibited significantly more behavioral disturbances of the type characteristic of bv-FTD compared with other PPA variants. 74% of sv-PPA patients with mild dementia severity exhibited at least one behavior disturbance at baseline, which increased to 84% during follow-up. Behavioral symptoms did not differ between nfv-PPA and lv-PPA groups at baseline. At follow-up, however, empathy loss was significantly more pronounced in nfv-PPA. The prevalence and course of behavioral symptoms in lv-PPA was similar to that found in AD. sv-PPA show more prominent FTD-like behavioral disturbances compared with other PPA variants which typically emerge already early in the disease course. Empathy loss may be an important factor that helps differentiating nfv-PPA from lv-PPA. Our results may allow improved prediction of likely progression in behavioral symptoms across the PPA variants.