Semantic dementia is typically associated with which brain region?

• A. Anterior temporal area
• B. Left posterior frontal and insular areas
• C. Left temporoparietal area
• D. Left hippocampus

Answer: (A)

Semantic dementia reflects a breakdown of semantic knowledge—the stored meanings of words, objects, and concepts—due to degeneration in the anterior temporal lobes, especially on the left. This region serves as a hub for semantic representations across modalities, so as it atrophies, people lose understanding of word meanings and object concepts even when other language abilities remain relatively intact. The other regions listed are linked to different language or memory functions: the hippocampus with episodic memory, the temporoparietal area with certain aspects of language comprehension and semantic processing, and the posterior frontal/insular areas with speech production and syntax. Thus, the anterior temporal area best accounts for semantic dementia.