Abstracts

Rationale: We describe a case study of a 19 year-old, right-handed, bilingual patient with a history of epilepsy for five years with a 9mm lesion in his left superior temporal gyrus. Semiology includes a sudden inability to talk lasting for seconds with an alert mental status; secondary generalization was rare. Following failed trials of multiple AEDs, and daily seizures despite three medications, he was referred for epilepsy surgery.The overarching goal of this case study was to investigate the relationship between stereotactic electroencephalography (SEEG) language mapping results with awake language mapping and functional outcome in this 19 year old man with refractory epilepsy.  Methods: SEEG electrodes were places perilesionally, with one anterior and one posterior to the lesion.  In addition, electrodes were placed in the left amygdala, hippocampus, posterior temporal lobe and orbital frontal area.  Typical seizures were captured with his medication lowered.In order to best localize functional language area and epileptogenic cortices, the patient underwent a cortical stimulation mapping (CSM) while SEEG was implanted. Mapping yielded multiple sites where an aura was felt, as well as areas resulting in impaired language comprehension. Following SEEG explantation, the patient underwent intraoperative language mapping in an effort to spare eloquent cortex. Mapping procedures included assessment of basic language fluency, repetition, basic and complex auditory comprehension, as well as auditory and visual naming.  Results: Seizure onsets were found in the electrodes anterior and posterior to the lesion; both electrodes were slightly inferior to the lesion.  The patient’s typical aura of a sensation of an oncoming seizure with language comprehension difficulties were elicited with low current stimulation of the perilesional electrodes (see Figure 1).  In addition, the patient had difficulty with visual naming and repetition.  The contacts were located in Heschl’s gyrus and the medial portion of the superior temporal gyrus (see Figure 2).  Of note, more pronounced language findings were elicited in the posterior temporal depth.Awake language mapping revealed similar interruptions during auditory comprehension tasks.  These were not consistent and the patient was able to complete the task intermittently. The lesion was resected along with the surrounding cortices, including the seizure onset zone, as well as brain tissue which, when stimulated, evoked the patient’s typical aura and subtle language hits (both during the SEEG CSM and awake mapping).The patient’s language was entirely intact directly after surgery.  Conclusions: SEEG is relatively new and we have limited experience with the results of brain mapping.  Deficits found during SEEG mapping should not be considered an absolute contraindication to resection. As Heschl’s gyrus and medial superior temporal gyrus are not the typical area for language, it is possible that the patient’s seizure network contained parallel function (as his aura was in the same electrodes) which did not result in a deficit when removed. Funding: None