Abstracts

Rationale: Temporal lobe epilepsy is a common cause of focal epilepsy and resection frequently leads to seizure freedom1. However, resection of the hippocampus ipsilateral to verbal memory dominance frequently results in severe memory deficits. In adult patients with seizures arising from the mesial temporal lobe, multiple hippocampal transections (MHT) have been documented to result in excellent seizure outcome with preservation of verbal memory2. We report the first detailed report of a child undergoing MHT for mesial temporal epilepsy. Methods: A 13 year-old right-handed male began having seizures at 7 years of age. Seizures consisted of epigastric discomfort evolving to unresponsiveness and chewing automatisms lasting 1 minute 2-3 times per week. Seizures did not typically generalize, but there was a history of six generalized tonic-clonic seizures. He failed four antiepileptic drugs and had poor seizure control on levetiracetam. Neurological exam was normal and he had normal developmental milestones with no epilepsy risk factors. Video EEG showed: 1. Left temporal sharp waves every 5-10 seconds during sleep, maximum FT9. 2. Left temporal spikes every second for 5-8 seconds, maximum FT9. 3. Intermittent left frontotemporal slowing lasting 2-8 s, 30% of the record. 4. Epileptic seizures off AED: a. Dialepsis followed by right head version followed by generalized tonic-clonic seizure, EEG onset unclear. [18F] flurodeoxyglucose-PET provided no lateralization. MRI at 1.5 Tesla showed volume loss of the right amygdala and hippocampus head without signal abnormality. Neuropsychological evaluation showed average to above average cognitive abilities with mild weakness in memory and verbal IQ suggestive of left TL dysfunction. After a discussion at a comprehensive epilepsy surgery conference, a SEEG investigation was performed using eight electrodes to sample multiple regions potentially involved in seizure onset (Figure 1A) that demonstrated spikes exclusively in the hippocampus, amygdala, and temporal pole. He had multiple typical seizures with clinical onset several seconds after SEEG ictal activity in the anterior mesial temporal region that quickly spread across the hippocampal head, body and tail. The temporal pole and amygdala were resected en bloc and MHT performed with eight transections as shown (Figure 1B). Results: A comprehensive battery of standardized neuropsychological tests 4 months before and 6 months after the surgery showed a significant decline in confrontational naming but no other abnormalities after the operation (Table 1). Notably, there was no significant change in verbal memory compared with preoperative testing. Eight years later, he has remained seizure free with no antiepileptic medication and is attending college. Conclusions: In children with established hemispheric dominance suffering from mesial temporal lobe epilepsy, MHT may be an option with excellent memory outcome and seizure freedom. Funding: none