The Effects of Hippocampal Sclerosis on Autobiographical Memory Retrieval in Unilateral Temporal Lobe Epilepsy

Autobiographical memory, the memory of one’s own lived experiences, is enabled by a complex neural network in the brain. The hippocampus, within the medial temporal lobe, is considered part of the core autobiographical memory network. Existing literature presupposes a lateralization effect, indicating that the right and left hippocampi are involved differently in the construction and elaboration phases of autobiographical memory retrieval. This study assessed 23 individuals with unilateral temporal lobe epilepsy, exhibiting either right or left lateralized hippocampal sclerosis, for their performance on the Autobiographical and Public Memory Test, in comparison with 34 healthy controls. We aimed to observe both behavioural and structural differences between our groups. Results demonstrated that autobiographical memories are retrieved with greater specificity and sensation of recollection compared to public memories. While healthy control participants retrieved more specific memories than individuals with temporal lobe epilepsy, individuals with left hippocampal sclerosis reported memories with higher levels of experienced reliving, vividness, and emotional intensity than both control participants and individuals with right hippocampal sclerosis. Several explanations for this phenomenon are proposed and explored. Results from the structural analysis are also explored and discussed. The preliminary findings from this study support the lateralization of hippocampal involvement in autobiographical memory retrieval, inspiring future research and offering valuable insight for the clinical sphere.