Assessing Episodic and Semantic Autobiographical Recall in Healthy Older APOE ε4 Carriers

The APOE E4 gene is associated with increased risk of developing sporadic Alzheimer's Disease. Several studies have focused on declarative memory, where episodic memory deficits are reported in E4 carriers, while semantic memory has received much less attention. To clarify whether the impact of APOE E4 on declarative memory is specific to episodic memory, we administered a novel measure of autobiographical memory, the Semantic Autobiographical Interview (SAI). Thirty-eight health older adults were recruited, 19 E4 carriers and 19 non-carriers, matched in age, education, and gender. The groups did not significantly differ in any neuropsychological tests except for recognition memory, where E4 carries showed reduced performance. On the original Autobiographical Interview (AI), results revealed a reduced number of episodic details (internal details and external events) in carriers. Together, these results suggest a reduction of episodic specificity in E4 carriers. In contrast, carriers has very similar semantic production to non-carriers, whether it was for off-task (external) semantic details in the AI, or on-task general and personal semantic details produced in the SAI. These results suggest that older adults retain the gist of their personal experience and that the semanticization of their autobiographical narratives is robust and less sensitive to risk for Alzheimer's Disease than episodic memory.