Déjà vu phenomenon-related EEG pattern. Case report☆

BACKGROUND Déjà vu (DV, from French déjà vu - "already seen") is an aberration of psychic activity associated with transitory erroneous perception of novel circumstances, objects, or people as already known. OBJECTIVE This study aimed to record the EEG pattern of déjà vu. METHODS The subjects participated in a survey concerning déjà vu characteristics and underwent ambulatory EEG monitoring (12-16 h). RESULTS In patients with epilepsy, DV episodes began with polyspike activity in the right temporal lobe region and, in some cases, ended with slow-wave theta-delta activity over the right hemisphere. There were no epileptic discharges in healthy respondents during DV. CONCLUSION Two types of déjà vu are suggested to exist: "pathological-epileptic" déjà vu, characteristic of patients with epilepsy and equivalent to an epileptic seizure, and "nonpathological-nonepileptic" déjà vu, which is characteristic of healthy people and psychological phenomenon.