Cognitive Deficits and Reduced Insight in Primary Progressive Aphasia

isolated dysfunction in the perisylvian language regions to involve other cortical and subcortical regions, insight appears to concurrently diminish.5 Additionally, PPA is a fairly heterogeneous condition, with various language profiles represented among affected individuals who may also display differing lev-els of insight. As such, PPA provides a compelling model with which to investigate the relationship between language symptoms, other cognitive symp-toms, and reduced insight. As numerous definitions of insight exist,6 in this article we will take the broad def-inition “awareness of symptoms or characteristics of a disease process.” The specific characteristics of the language dis-order in PPA differ among patients. Numerous attempts have been made to subgroup PPA patients based on prominent linguistic characteristics such as speech fluency.4,7 In patients with aphasia from stroke, those with fluent, grammatically correct but empty speech and poor naming appear to be less aware of their impairments,8 although they rarely lose insight entirely.9 Those with nonfluent, gram-matically impaired but informative speech and rela-tively preserved naming appear to be aware of and, as a result, depressed by their deficits. In PPA, the fluent–nonfluent distinction is difficult due to the fact that the disease is progressive and most patients Primary progressive aphasia (PPA) is caused byneurodegenerative disease that leads to an ini-tially isolated breakdown of language abilities.1-3 PPA is part of a wider spectrum of neurodegenerative disorders caused by frontotemporal lobar degeneration (FTLD),3,4 which also includes another clinical condi-tion, behavioral variant frontotemporal dementia (bvFTD). BvFTD is characterized by initial changes in behavior and loss of insight into these changes, with relative preservation of other cognitive functions. In PPA, the few studies completed on this topic thus far indicate that insight is not entirely intact and that it tends to diminish with progression of the disease. As the disease progresses neuroanatomically from initia