semantic dementia
Pronunciation: suh-MAN-tik duh-MEN-shuh
Progressive neurodegenerative condition characterized by gradual loss of semantic knowledge while other cognitive functions remain relatively preserved.
Full Definition
Semantic dementia is a variant of frontotemporal dementia characterized by progressive deterioration of semantic memory - the knowledge of word meanings, object concepts, and general facts about the world. Patients typically present with fluent but empty speech, word-finding difficulties, and progressive loss of understanding of word meanings, while maintaining relatively intact syntax, phonology, and episodic memory in early stages. The condition primarily affects the anterior temporal lobes bilaterally. Unlike Alzheimer's disease, patients with semantic dementia may retain good visuospatial skills and day-to-day memory for recent events until later in the disease course.
Usage
Usage note: Part of frontotemporal dementia spectrum. Also called semantic variant primary progressive aphasia (svPPA).
In Context
- "The patient's semantic dementia was evidenced by her inability to understand increasingly common words while maintaining fluent speech patterns." — Neuropsychological assessment
- "MRI findings showed bilateral anterior temporal atrophy consistent with semantic dementia." — Radiology report