Seizure Localization in Patients with Multiple Tubers: Presurgical Evaluation in Tuberous Sclerosis
The patient was a 30-year-old woman who had history of epilepsy since 3-year-old. She was transferred to our epilepsy clinic for the video-electroencephalography (VEEG) monitoring for presurgical evaluation. She was right handed, high school graduate, and unemployed. Physical examination revealed shagreen patch on her right lumbar region and few hypomelanotic macules on her back. Neurological examination revealed no remarkable neurological deficit. She reported to have monthly psychic and, or abdominal aura which often evolves to complex partial seizure, while on valproate, topiramate, carbamazepine, and pregabalin. Caregivers reported that she fumbles her right fingers and shows lip smacking during her seizures, and does not respond to questions. She reported only one episode of generalized tonic clonic seizure which occurred before taking anti-epileptic drugs. Caregivers also reported the change in the personality. She became aggressive and violent, mostly addressed to caregivers.\nIntellectual assessment revealed IQ score of 83 which indicates low average level. Her neuropsychological test indicated bilateral frontal lobes and right temporal lobe dysfunction. Beck’s depression inventory score was 33 and Beck’s anxiety inventory score was 34, indicating severe depressive and anxious state.\nAn 8-day Video-EEG monitoring study demonstrated frequent interictal epileptiform activity localized to right frontotemporal region. Five seizures and one aura were recorded. Semiology was psychic, and, or abdominal aura which evolves to automotor seizure with right hand fumbling. Ictal EEG exhibited two seizures with maximum amplitude over the right frontotemporal electrodes, and three were obscured by artifacts. Remarkably, all five seizures had theta range rhythm build up at right frontotemporal electrodes (). The brain magnetic resonance imaging (MRI) study revealed multiple cortical tubers including a prominent on right anterior temporal cortex with loss of normal gray-white differentiation, and other scattered cortical tubers are located at right middle, and superior frontal gyri, right insula, left medial frontal and Lt parietal regions.\nRadiotracer for ictal SPECT was injected at 24 seconds from the onset of 56 second duration habitual seizure. Ictal single photon emission computed tomography (SPECT) findings were concordant to the localization of ictal EEG onset. The hyperperfusion was regionalized to right anterior temporal area. This also anatomically correlated with cortical tuber seen at the right anterior temporal pole. Furthermore subtracted ictal-interictal SPECT co-registered with MRI (SISCOM) revealed hyperperfusion at the right temporal pole and anterior temporal region (). Other cortical tubers seen in the brain MRI shows no definite regional perfusion changes. The ictal EEG at the timing of injection was rhythmic 5 Hz theta rhythm in right frontotemporal region. Brain 18F-fludeoxyglucose positron emission tomography (FDG-PET) reveals right anterior to posterior temporal regions hypometabolism, especially involving mesial temporal area (). The genetic test confirms the gene mutation in TSC1 (c.2389C>T). Further evaluation for other symptoms of tuberous sclerosis including abdominal and thoracic CT scan were unremarkable.