Evaluation of Changes in Preoperative Cortical Excitability by Navigated Transcranial Magnetic Stimulation in Patients With Brain Tumor

Author(s)

Neville, Iuri Santana ^{[1, 2, 3]} ; dos Santos, Alexandra Gomes ^[2] ; Almeida, Cesar Cimonari ^{[2, 3]} ; Hayashi, Cintya Yukie ^{[2, 3]} ; Fontoura Solla, Davi Jorge ^[2] ; Galhardoni, Ricardo ^{[4, 2, 3]} ; de Andrade, Daniel Ciampi ^{[1, 2, 3]} ; Brunoni, Andre Russowsky ^[3] ; Teixeira, Manoel Jacobsen ^[2] ; Paiva, Wellingson Silva ^{[2, 3]}

Affiliation

^[1] Univ Sao Paulo, Inst Canc Estado Sao Paulo, Hosp Clin, Fac Med, Sao Paulo - Brazil

^[2] Univ Sao Paulo, Dept Neurol, LIM 62, Div Neurosurg, Fac Med, Sao Paulo - Brazil

^[3] Univ Sao Paulo, Hosp Clin, Inst Psiquiatria, Serv Interdisciplinary Neuromodulat, Fac Med, Sao Paulo - Brazil

^[4] Univ Cidade Sao Paulo UNICID, Sch Med, Sao Paulo - Brazil

• Document type: Journal article
• Source: FRONTIERS IN NEUROLOGY; v. 11, JAN 22 2021.
• Web of Science Citations: 0

Abstract

Background: This prospective study aimed to evaluate the cortical excitability (CE) of patients with brain tumors surrounding or directly involving the corticospinal tract (CST) using navigated transcranial magnetic stimulation (nTMS). Methods: We recruited 40 patients with a single brain tumor surrounding or directly involving the CST as well as 82 age- and sex-matched healthy controls. The patients underwent standard nTMS and CE evaluations. Single and paired pulses were applied to the primary motor area (M1) of both affected and unaffected cerebral hemispheres 1 week before surgery. The CE parameters included resting motor threshold (RMT), motor evoked potential (MEP) ratio for 140 and 120% stimulus (MEP 140/120 ratio), short-interval intracortical inhibition (SICI), and intracortical facilitation (ICF). Motor outcome was evaluated on hospital discharge and on 30-day and 90-day postoperative follow-up. Results: In the affected hemispheres of patients, SICI and ICF were significantly higher than in the unaffected hemispheres (p=0.002 and p=0.009, respectively). The 140/120 MEP ratio of patients' unaffected hemispheres was lower than that in controls (p=0.001). Patients with glioblastomas (GBM) had a higher interhemispheric RMT ratio than patients with grade II and III gliomas (p = 0.018). A weak correlation was observed among the RMT ratio and the preoperative motor score (R-2 = 0.118, p = 0.017) and the 90-day follow-up (R-2 = 0.227, p = 0.016). Conclusion: Using preoperative nTMS, we found that brain hemispheres affected by tumors had abnormal CE and that patients with GBM had a distinct pattern of CE. These findings suggest that tumor biological behavior might play a role in CE changes. (AU)

• FAPESP's process: 19/14687-4 - Neurophysiological evaluation of patients with brain tumor through transcranial magnetic stimulation
• Grantee: Alexandra Gomes dos Santos
• Support Opportunities: Scholarships in Brazil - Scientific Initiation