Table 1.
Clinical characteristics of semantic dementia and Alzheimer’s disease.
| Semantic dementia (SD) | Alzheimer’s disease (AD) | |
|---|---|---|
| Predominant brain atrophy | Lateral temporal Left > Right | Medial temporal Bilateral |
| Cognitiona | ||
| Executive function | Intact | + – ++ |
| Orientation | Intact | ++ |
| Recent episodic memory | Intactb | +++ |
| Remote episodic memory | +++ | + |
| Semantic knowledge | +++ | ± |
| Word comprehension | +++ | ± |
aFunctions are relatively intact in the early stages of the disease; bcontingent on the nature of test materials used; +, mild deficits; ++, moderate deficits; +++, severe deficits; ±, variable deficits.