- a language disorder associated with frontotemporal dementia, characterized by the gradual loss of a previously held ability to speak, write, sign, or understand language, and caused by a neurodegenerative disease: There are three subtypes of primary progressive aphasia, the first distinguished by fluent but semantically empty speech (fluent variant or semantic dementia ), the second by difficulty in finding words as well as by language consisting of content words but lacking grammatical elements (nonfluent variant ), and the third by preserved grammar but a difficulty in finding words when speaking (logopenic variant ).Abbreviation: PPA
