Clinical and cognitive outcomes after laser interstitial thermal therapy for mesial temporal lobe epilepsy in adolescent patients

Introduction: Surgical treatment of medication-resistant Mesial temporal lobe epilepsy (MTLE) is associated with cognitive deficits. Laser interstitial thermal therapy (LITT) causes less damage to surrounding structures and has better cognitive outcomes in adults; however, cognitive outcomes research in pediatric patients is limited. Here, we present the clinical and cognitive outcomes in a series of adolescent patients who underwent LITT for MTLE.

Methods: After inclusion and exclusion criteria, six male adolescent (age range 17-20) patients were included. Half of patients had a left-sided, and half had a right-sided procedure. They received a preoperative and postoperative evaluation with a licensed neuropsychologist. Standardized assessments were performed, including the: Wechsler Intelligence Scales (WAIS-IV, WASI-2, WASI-4), Wide Range Assessment of Learning and Memory (WRAML2), Child and Adolescent Memory Profile (ChAMP), California Verbal Learning Test (CVLT-II), Delis-Kaplan Executive Function System (D-KEFS), Finger Tapping, and Grooved Pegboard. The Student’s t-test with repeated measures was used to compare pre-and post-operative with a significant p-value of 0.05.

Results: There were no statistically significant changes when comparing pre- and post-operative cognitive evaluations at the group level. A comparison of left-and right-sided procedures revealed an improvement in story memory encoding (p = 0.038) for patients who received right LITT. Phonemic fluency improved for patients who received right LITT (p = 0.01) but declined for patients who received left LITT (p = 0.01). Five patients (83%) underwent repeat LITT, and two patients (33%) underwent subsequent surgical resection after the second LITT. Engel classification postoperative seizure outcomes after repeat LITT and/or subsequent surgery were as follows: Engel I (3/6, 50%), Engel II (1/6, 16%), Engel III (1/6, 16%), and Engel IV (1/6, 16%).

Conclusion : Clinical outcomes were consistent with those reported in the literature, and we show that cognitive outcomes were grossly stable as well. This study shows that LITT is an effective treatment with minimal adverse neuropsychologic effects in pediatric patients.