[Lewy bodies dementia and Primary progressive aphasias: current diagnostic criteria].

The spectrum of neurodegenerative diseases that primarily affect cognition and behavior ranges from asymptomatic preclinical disease to very mild cognitive impairment and frank dementia. This article reviews the current criteria for the diagnosis of Lewy body dementia, the second most common cause of neurodegenerative dementia in people over 65 years of age after Alzheimer's disease (AD) and Primary progressive aphasias, which are characterized by early and isolated impairment of linguistic functions, and whose evolution develops a complex syndrome characterized, in addition to language impairment, by the presence of progressive cognitive impairment, behavioral disorders and motor system involvement. They can also be the presentation syndrome of an atypical variant of Alzheimer's disease (AD), but mixed or uncharacterizable forms are not rare.