Can episodic memory tasks differentiate semantic dementia from Alzheimer's disease?
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Updated: Aug 13, 2026

Examining the Characteristics of Episodic Memory using Event-related Potentials in Patients with Alzheimer's Disease
Published on: August 30, 2011
V L Scahill1, J R Hodges, K S Graham
1MRC Cognition and Brain Sciences Unit, Cambridge, UK.
Abstract:
The performance of two groups of patients with semantic dementia (SD), with predominant right (SDR) and left temporal lobe atrophy (SDL), was contrasted with that of cases with probable Alzheimer's disease (AD) on a range of standard episodic memory tasks. While the SDL group achieved a good score on a composite visual, but not a verbal, episodic memory measure, the AD and SDR groups were equivalently impaired at visual and verbal memory. The SD, but not the AD, groups were, by definition, impaired on simple tests of semantic memory. Standard verbal episodic memory tests, therefore, failed to discriminate patients with SD from those with probable AD and even visual memory tests may result in misclassification of SDR cases.
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