Persistent déjà vu associated with hyperperfusion in the entorhinal cortex

Area of Science:

• Neurology
• Neuroscience
• Epileptology

Background:

• Déjà vu is a common phenomenon, but its occurrence as a seizure manifestation in temporal lobe epilepsy (TLE) is significant.
• The precise etiology of déjà vu in TLE remains largely unknown, necessitating further investigation into its underlying mechanisms.

Observation:

• A case study documented persistent déjà vu in an epilepsy patient, characterized by a sensation of reliving past experiences.
• Functional neuroimaging using blood perfusion single-photon-emission computed tomography (SPECT) was performed during the déjà vu episodes.

Findings:

• SPECT revealed hyperperfusion in the left medial temporal area during persistent déjà vu.
• The hyperperfused region was precisely identified as the entorhinal cortex in the left temporal lobe through 3D SPECT-MRI co-registration.
• Discontinuation of the déjà vu sensation correlated with the resolution of the hyperperfused area on SPECT.

Implications:

• This case supports theories linking recognition memory dysfunction in the parahippocampal area to déjà vu.
• Findings suggest that epileptic activity within the entorhinal cortex may be a direct trigger for déjà vu experiences in TLE.
• Highlights the potential of neuroimaging in understanding the neural correlates of subjective ictal phenomena.