Post-ictal hyperfamiliarity syndrome in focal epilepsy

The recognition of familiar faces entails sequential cognitive processing. Initial encoding of face-specific information is followed by semantic association with previously learned information, which results in a subjective feeling of familiarity. We describe here a 32-year-old woman who post-ictally developed a sense of familiarity for previously unknown people and faces in the context of bilateral temporal seizures. We postulate that the delusion resulted from modality-specific indiscriminate association of all face-specific information with the affective label of familiarity. During this delusion, the step of semantic association was not required to generate the feeling of familiarity, which resulted in every face being labeled as familiar.