Introduction: This study evaluates the effect of postoperative gliosis volume from anterior temporal lobectomy (ATL) on neurocognitive and psychological outcomes in patients with medically refractory mesial temporal lobe epilepsy (MTLE).
Methods: The data of 322 consecutive patients who underwent ATL for MTLE were retrospectively evaluated. 52 patients (24 L-ATL; 29 R-ATL) had complete follow-ups including seizure outcome, neuropsychological assessments, and = 3mo follow-up MRIs. Volumetric analysis of postoperative gliosis and resection cavities were carried out in the follow-up MRIs. Patients were categorized into high gliosis group (26) and low gliosis group (27). Changes in comprehensive neuropsychological test battery between preoperative and 1 year after surgery were compared between the side of surgery and gliosis volume groups.
Results: At 1-year follow-up, overall IQ scores showed improvement, except verbal IQ in L-ATL with high gliosis group had significant decline (p=0.001). Verbal memory impairment was seen more in L-ATL than R-ATL group regardless of gliosis volume but these batteries did not reach statistical significance among the groups. Non-verbal memory decreased significantly after R-ATL regardless of gliosis while L-ATL with low gliosis group produced some improvement (VR1 p=0.001; VR2 p=0.005). In language domain, L-ATL with high gliosis had significant decline in BNT (p=0.003) alone but no significant changes were observed in other language parameters. There was a suggestive trend in worsening of BAI (a psychological domain) in R-ATL with high gliosis (p=0.08), while BAI in L-ATL and R-ATL with low gliosis showed some improvements. There was no statistically significant difference between the volume of gliosis or volume of resection with respect to seizure outcomes (Engel I vs. Engel =II).
Conclusions: Postoperative ATL gliosis may predict changes in IQ, memory, language, and psychological outcomes. It was not predictive of seizure outcome class. Surgical technique minimizing the damage/ischemia to resection bed could benefit patients’ quality of life from neurocognitive perspectives.
Patient Care: The efficacy of ATL has traditionally been assessed solely based on seizure control rate in patients with MTLE. However, it has recently been realized that seizure frequency alone after surgery is not sufficient to judge whether a patient is in a favorable condition. Postoperative gliosis volume indicates damage done to the surrounding functional brain after surgery; however, surgeons rarely obtain follow-up MRIs several months after the surgery to evaluate such damage. This study elucidate whether damage to the surrounding brain as measured by gliosis volume predicts seizure outcome class or neurocognitive outcomes in ATL patients. Though there have been studies assessing neurocognitive outcomes after ATL, to authors’ knowledge none has addressed issue of volume of gliosis affecting these outcomes. The finding of this study may be used by surgeons in guiding choice of epilepsy surgical techniques.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the importance of evaluating neurocognitive and psychological outcome of anterior temporal lobectomy, 2) Discuss, in small groups what neurocognitive domains such as intelligence, verbal memory, nonverbal memory, language, and psychological aspects showed significant changes based on the side of surgery and volume of gliosis, 3) Identify an effective treatment of mesial temporal lobe epilepsy that can minimize the postoperative scar tissue/ gliosis to improve neurocognitive outcomes in patients undergoing surgical treatment of epilepsy.