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

The APOE {varepsilon}4 gene is associated with increased risk of developing sporadic Alzheimers Disease (AD). Several studies have focused on declarative memory, where episodic memory deficits are reported in {varepsilon}4 carriers, while semantic memory has received much less attention. To clarify whether the impact of APOE {varepsilon}4 on declarative memory is specific to episodic memory, we administered a novel measure of autobiographical memory, the Semantic Autobiographical Interview (SAI). Thirty-eight healthy older adults were recruited, 19 {varepsilon}4 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 {varepsilon}4 carriers 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 {varepsilon}4 carriers. In contrast, carriers had 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 AD than episodic memory. Public Significance StatementPeople at risk for Alzheimers Disease struggle with recalling memories from specific events (episodic memory), but it remains unclear whether they also have difficulties with personal and general knowledge (semantic memory). We used a new measure, the Semantic Autobiographical Interview, to evaluate these forms of memory. Compared to control participants, people at risk for Alzheimers Disease produced a reduced number of episodic details, but a similar amount of semantic knowledge.