Cognitive deficits and reduced insight in primary progressive aphasia

Primary progressive aphasia (PPA) is a form of dementia caused by frontotemporal lobar degeneration. Unlike aphasia due to stroke, in which the association between particular aphasia profiles and insight has been well characterized, this relationship has not been investigated in PPA. Reduced insight is seen in other neurological conditions, but tends to involve right hemisphere damage, whereas PPA is predominantly a left hemisphere disorder. The aim of the current study was to examine whether fluent aphasia with less meaningful speech, is also associated with diminished insight in stroke, is also characteristic of PPA patients with reduced insight. Fourten PPA patients were studied. Results indicated that reduced information content in speech and poor performace on a nonlanguage test, the Pyramids and Palm Trees test, predicted insight. This study has implications for the anatomical network in insight and clinical implications in terms of selecting interventions apporpriate for individual patients with PPA.