Lateralization of Bilateral Temporal Lobe Epilepsy After Vagus Nerve Stimulation Surgery

Drug-resistant bilateral temporal lobe epilepsy is associated with poor outcomes following resective surgery because of the lack of a clearly lateralized focus. Vagus nerve stimulation (VNS) provides symptomatic benefit, but its potential role in facilitating surgical candidacy remains underrecognized. We describe a 32-year-old woman who developed drug-resistant bilateral temporal lobe epilepsy after herpes simplex virus encephalitis at age 13. Seizures included dialeptic, hypermotor, and generalized tonic-clonic events without consistent lateralizing features. Scalp electroencephalography showed bilateral independent temporal discharges, and magnetic resonance imaging revealed bilateral mesial temporal atrophy. At age 19, she underwent VNS implantation. Subsequent electroencephalography demonstrated progressive lateralization of interictal and ictal discharges to the right temporal lobe. At age 29, she underwent right anterior temporal lobectomy (ATL), resulting in Engel Class I seizure freedom. This case illustrates the potential of VNS not only as a palliative therapy but also as an inducer of lateralization of discharges, thereby enabling patients to undergo curative resective surgery.