Ictal déjà vu localization: what this review found

What was studied

This systematic review examined whether déjà vu, déjà vécu, dreamy states, and reminiscence during focal seizures can help identify the epileptogenic zone. The authors included 22 publications covering 597 patients. Each report had to provide enough clinical, anatomical, and electrical-recording information to assess the epileptogenic zone and the confidence of the reported association.

The review focused on interpreting these seizure symptoms during presurgical evaluation of people with drug-resistant focal epilepsy. The authors also assessed the quality and risk of bias of the included reports.

What they found

The reports with the highest confidence suggested that seizure-related déjà vu or dreamy states can be associated with epileptogenic zones in both anterior and posterior mesial temporal structures. Similar experiences have also been described with lateral temporal and insulo-opercular epileptogenic zones. Overall, these symptoms most commonly pointed to mesial temporal structures, but the findings had only moderate reliability and do not localize seizures with certainty.

Limits of the evidence

The included reports varied in quality, and the authors regarded the overall findings as having a moderate degree of reliability. Studies often pooled related experiences or used overlapping descriptions, making it difficult to determine whether each symptom has the same localization value. The abstract does not provide details about patient ages, individual study sizes, surgical outcomes, or how often each brain region was involved. The findings do not establish that a particular experience consistently arises from one specific area.

For families and caregivers

Déjà vu or a dream-like memory experience during a seizure may give an epilepsy team a clue about where seizures begin, particularly during evaluation for possible surgery. However, the symptom cannot identify the epileptogenic zone by itself and should be interpreted with electrical recordings, brain imaging, and other clinical findings.

What to watch next

Future studies should use more precise classifications and clinical descriptions of these experiences. Advanced imaging, broader use of stereo-EEG, and more well-documented cases with stronger evidence may improve understanding of their localization value.

Terms in this summary

Ictal

Happening during a seizure.

Focal epilepsy

Epilepsy in which seizures begin in a particular brain area or network.

Drug-resistant epilepsy

Epilepsy that continues despite treatment with seizure medicines.

Epileptogenic zone

The brain region considered responsible for generating seizures.

Mesial temporal structures

Structures deep within the temporal lobe that are involved in functions including memory and emotion.

Insulo-opercular region

Brain areas involving the insula and the nearby operculum.

Seizure semiology

The symptoms, sensations, and behaviors occurring during a seizure.

Stereo-EEG

A test using electrodes placed within the brain to record seizure activity.