Improvement of visual field defects after focal resection for occipital lobe epilepsy: case report

Resection of an occipital lobe epileptogenic network resulting in improvement of a visual field deficit: illustrative case

BACKGROUND

Drug-resistant epilepsy leads to significant morbidity and mortality. Epilepsy surgery for resection of seizure foci is underused, particularly when a seizure focus is located in eloquent cortex. Epileptogenic networks may lead to neurological deficits out of proportion to a causative lesion. Disruption of the network may lead not only to seizure freedom but also reversal of a neurological deficit.

OBSERVATIONS

A 32-year-old male with new-onset generalized tonic-clonic seizure was found to have an occipital lobe cavernous malformation. On visual field testing, he was found to have a right-sided hemianopsia. He did not tolerate antiepileptic drugs and had a significant decline in quality of life. Resection was planned using intraoperative electrocorticography to remove the cavernous malformation and disrupt the epileptogenic network. Immediate and delayed postoperative visual field testing demonstrated improvement of the visual field deficit, with near resolution of the deficit 6 weeks postoperatively.

LESSONS

Epilepsy networks in eloquent cortex may cause deficits that improve after the causative lesion is resected and the network disrupted, a concept that is underreported in the literature. A subset of patients with frequent epileptiform activity and preoperative deficits may experience postoperative neurological improvement along with relief of seizures.

Auras in intractable frontal lobe epilepsy: Clinical characteristics, values, and limitations

Auras are essential in preoperative evaluation and can provide valuable information for delineating seizure onset zones. Frontal lobe epilepsy (FLE) is the second most common focal epilepsy, while a few studies have focused on auras in FLE. To better understand FLE, we analyzed the clinical characteristics, values, and limitations of auras in FLE. The incidence rate of aura in FLE was 37.9% in our study. We included 54 patients and 76 auras in 11 categories were reported. The rate of auras in the decreasing order are as follows: autonomic aura; emotional aura; somatosensory aura; psychic aura; cephalic aura; abdominal aura; whole-body sensory aura, visual aura; auditory aura; and vestibular and unclassified aura. A significant number of aura types can be reported by FLE patients; autonomic aura was the most frequent category and somatosensory auras are most likely associated with the contralateral motor areas.