Authors :
First Author: Melissa Tsuboyama, MD – Boston Children's Hospital
Presenting Author: Adrianna Giuffre, PhD – Boston Children's Hospital / Harvard Medical School
Adrianna Giuffre, PhD – Postdoctoral Research Fellow, Neurology, Boston Children's Hospital; Song Dam, BSc – Neurology – Boston Children's Hospital; Ali Jannati, PhD – Boston Children's Hospital; Jingjing Liu, MD – Boston Children's Hospital; Paul MacMullin, BSc – Boston Children's Hospital; Alexander Rotenberg, MD, PhD – Neurology – Boston Children's Hospital
Rationale:
Resective surgery offers a curative option for people with refractory focal epilepsy, yet seizures persist in up to 70% of patients after epilepsy surgery. Identifying clinical and neurophysiologic characteristics that forecast optimal epilepsy surgery outcomes is a critical unmet need. Using transcranial magnetic stimulation (TMS), we tested whether the resting motor threshold (rMT), a metric of cortical excitability, contributes to seizure onset zone (SOZ) lateralization and the prediction of epilepsy surgery outcomes (i.e., Engel Score). Methods:
A single-center retrospective chart review was performed of patients with refractory focal epilepsy who received TMS motor mapping between 2013 and 2022 as part of their routine pre-surgical evaluation. Inclusion criteria were 1) age ≥4 years, 2) right-handed, 3) focal epilepsy, and 4) absence of corticospinal tract (CST) lesion. Patient demographics, neuropsychiatric comorbidities, and Engel scores were collected. rMT, recorded as electric field strength (V/m) and percent machine output (%MO), of the abductor pollicus brevis muscle (APB) was obtained on all participants in both hemispheres. Interhemispheric rMT differences were tested using paired t-tests. Multinomial and binomial logistic regression models were used to identify potential associations between rMT and either SOZ lateralization or Engel Scores. Results:
Of 179 patients who received TMS mapping, 123 met the inclusion criteria (age 12.5±4.3, 68 male), 85 of whom underwent epilepsy surgery (age 12.6±4.3, 47 male). Average follow-up duration after surgery was 804 days. Independent of seizure focus lateralization, rMT was lower in the left hemisphere (Lhem) (125.7±56.4 V/m, 60.9±20.1 %MO) compared to the right hemisphere (Rhem) (143.9±63.6 V/m, 64.0±21.0 %MO) (p < 0.042) across all participants.