"I remember it as if it were yesterday": memory for recent events in patients with semantic dementia

Patients with semantic dementia (SD), who have an incontrovertible deficit in semantic memory, are reported to show good day-to-day memory for recent events; but experimental evidence on their anterograde episodic memory/new learning is somewhat sparse and does not always tell a consistent story. We describe the performance of five SD patients, relative to controls, on (a) a range of semantic memory measures that predictably revealed substantial impairment, and (b) a newly designed naturalistic and incidental episodic task, which included information regarding the items and context of the semantic tasks. As a group, the patients' episodic memory for these natural events was good, even after a 24-h delay, although case-by-case analysis revealed some heterogeneity in performance. These findings are discussed with regard to the neural substrate of episodic memory and psychological models of long-term memory.