井林 賢志

OBJECTIVE: Patients with temporal lobe epilepsy (TLE) suffer from epileptic seizures and memory decline. While focal resection eliminates seizures in 60-70% of patients, surgery carries the risk of further compromising memory. We hypothesized that hippocampal neurofeedback (NF) will induce targeted brain activity associated with memory function. METHODS: Patients with intracranial electrodes implanted in bilateral hippocampi performed a memory NF task, developed specifically for this project. The NF task involved real-time analysis of hippocampal activity using the electrode in the less-affected hippocampus while conducting a memory task. Changes in theta activity and task performance were assessed. RESULTS: The NF task was conducted in seven TLE patients. In five patients, theta activity increased significantly in the targeted hippocampus (Mann-Kendall test; p < 0.05). Mixed linear model analysis across all sessions revealed a significant increase in theta activity in the targeted hippocampus (p = 0.0032), with no significant change contralaterally (p = 0.19). Three additional TLE patients underwent random NF to assess if theta activity was induced merely by the encoding process, but none of them showed significant changes in theta activity. CONCLUSION: Memory NF task effectively induced targeted hippocampal activity in TLE patients. SIGNIFICANCE: Hippocampal NF may enhance memory function in TLE patients prior to focal resection.

BACKGROUND: Redo awake surgery is ideal for recurrent malignant gliomas in the language-dominant hemisphere, but it may not always be optimal because of inadequate awake mapping. In this report, the authors describe a case of recurrent language-dominant frontal glioma in which a super-selective Wada (ssWada) test and super-selective cone-beam CT angiography (ssCBCTA) enabled successful tumor removal under general anesthesia after awake surgery. OBSERVATIONS: A woman in her 30s underwent awake surgery for left frontal glioma recurrence 2 years after the initial resection. Three years after another recurrence, the ssWada test and ssCBCTA revealed that the tumor-supplying artery did not perfuse the functional cortex, allowing safe and maximal resection under general anesthesia. Postoperatively, she had mild motor aphasia but recovered quickly with minimal sequelae. LESSONS: The combined use of the ssWada test and ssCBCTA enables precise preoperative language mapping and safe tumor resection. Originally developed for epilepsy surgery, the ssWada test is valuable for functional mapping and, when paired with ssCBCTA, provides a 3D understanding of the lesions. This combination serves as a critical preoperative tool for tumors in the language-dominant hemisphere. https://thejns.org/doi/10.3171/CASE25384.

BACKGROUND: Chronic inflammation of the thorax, as in tuberculosis-related pyothorax, can cause secondary malignant lymphomas. However, primary malignant lymphoma of the central nervous system, specifically of the dura mater, developing after intracranial infection or inflammation has rarely been reported. Herein, the authors describe a case of primary dural lymphoma that developed secondary to subdural empyema, with an initial presentation mimicking a chronic subdural hematoma. OBSERVATIONS: A 51-year-old man had undergone single burr hole drainage for subdural empyema 2 years prior. The patient subsequently underwent multiple craniotomy and drainage procedures, with successful remission of the subdural empyema. He was subsequently referred to the authors' hospital approximately a year after his initial treatment because of a recollection of subdural fluid, which was suspected to be recurrent empyema. After another single burr hole drainage, which revealed only a subdural hematoma, a histopathological diagnosis of B-cell lymphoma of the dural/subdural membrane was made. Subsequent radiation therapy was completed, with good local control and no recurrence of the subdural hematoma confirmed at 2 months posttreatment. LESSONS: Intracranial lymphoma triggered by chronic inflammation is rare but should be considered a differential diagnosis in subdural hematomas for which the background pathology is unclear. https://thejns.org/doi/10.3171/CASE24153.

The efficacy of surgical treatment for drug-resistant epilepsy has been proven based on accumulated evidence, such as several randomized controlled trials. There are emerging treatment modalities, including less invasive surgical techniques and neuromodulation devices, which have also been proven to benefit patients by improving seizure control. A recent methodological shift from subdural electrocorticography recordings to stereo-encephalography recordings for intracranialelectroencephalography (iEEG) monitoring has also positively impacted clinical decision-making. Although some of these newer modalities are yet to be implemented in Japan, this article provides updated evidence and a summary of the currently available options for surgical treatment of patients with drug-resistant epilepsy. We hope that this summary will widen the treatment opportunities for patients with this highly impactful disease.

OBJECTIVE: Endovascular electroencephalography (evEEG) uses the cerebrovascular system to record electrical activity from adjacent neural structures. The safety, feasibility, and efficacy of using the Woven EndoBridge Aneurysm Embolization System (WEB) for evEEG has not been investigated. METHODS: Seventeen participants undergoing awake WEB endovascular treatment of unruptured cerebral aneurysms were included. After WEB deployment and before detachment, its distal deployment wire was connected to an EEG receiver, and participants performed a decision-making task for 10 minutes. WEB and scalp recordings were captured. RESULTS: All patients underwent successful embolization and evEEG with no complications. Event-related potentials were detected on scalp EEG in 9/17 (53%) patients. Of these 9 patients, a task-related low-gamma (30-70 Hz) response on WEB channels was captured in 8/9 (89%) cases. In these 8 patients, the WEB was deployed in 2 middle cerebral arteries, 3 anterior communicating arteries, the terminal internal carotid artery, and 2 basilar tip aneurysms. Electrocardiogram artifact on WEB channels was present in 12/17 cases. CONCLUSIONS: The WEB implanted within cerebral aneurysms of awake patients is capable of capturing task-specific brain electrical activities. Future studies are warranted to establish the efficacy of and support for evEEG as a tool for brain recording, brain stimulation, and brain-machine interface applications.