Abstracts

Rationale: In focal epilepsy, seizure related auditory aura may suggest involvement of Heschl’s gyrus. The Heschl’s or transverse temporal gyrus is located on the Sylvian surface of the superior temporal gyrus and provides a challenging surgical target. Resection is challenging due to its involvement in verbal functioning and access to deeper insular targets may require bifurcation of the superficial sylvian vein. Additionally, localization of the seizure foci can be challenging with difficulty in correlating the sequence of clinical semiology of seizure with the auditory aura.


Methods:
Two patients with refractory focal epilepsy, both with auditory aura as part of typical seizure semiology, evaluated by the University of Kentucky Epilepsy Comprehensive Epilepsy Program and reviewed retrospectively using the online electronic health system. We describe these cases in which there was a unique auditory aura, reproduced during electrical stimulation of Heschl’s gyrus. They underwent subsequent responsive neurostimulation which resulted in reduction in seizure burden, provided further information about the seizure foci, and informed further surgical management.




Results:
Both patients underwent stereotactic electroencephalography (SEEG) due to suspicion of foci in the left temporal region. The first patient was a 44-year-old female with auditory “helicopter blade” aura, which could be reproduced with low voltage stimulation of the contralateral Heschl’s gyrus. She underwent RNS placement with two trans-occipital longitudinal depth leads, targeting hippocampus and Heschl’s gyrus. The RNS data was able to assist in further localization and subsequent plan for resection. She underwent resection along the first two electrode contacts in the STG up to the temporal pole, which were identified to be the seizure onset zone. Post operatively she had 1-2 seizures per day in the week following surgery, but no seizures or other complications after that at one month follow up. The second patient was a 28-year-old male with similar auditory aura, reproduced with stimulation. He underwent identical RNS placement as the first patient and has had an approximate 75% reduction in seizure frequency at the time of follow-up. In the past he also had progression to focal aware status epilepticus, which has not recurred since RNS placement.




Conclusions:
Responsive neurostimulation has both therapeutic and diagnostic value in patients with suspicion of focal epilepsy, particularly in targets such as the Heschl's gyrus which are challenging surgical targets for resection.




Funding: No funding was utilized as part of the study.