Advanced search
Start date

Neurophysiological evaluation of patients with brain tumor through transcranial magnetic stimulation

Grant number: 19/14687-4
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): October 01, 2019
Effective date (End): November 30, 2020
Field of knowledge:Health Sciences - Medicine - Surgery
Principal Investigator:Iuri Santana Neville Ribeiro
Grantee:Alexandra Gomes dos Santos
Home Institution: Instituto do Câncer do Estado de São Paulo Octavio Frias de Oliveira (ICESP). Coordenadoria de Serviços de Saúde (CSS). Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil


Transcranial Magnetic Stimulation (EMT) is a noninvasive encephalic stimulation method that is based on the principle of electromagnetic induction. The variable magnetic field secondarily generates an electric field, which is capable of inducing changes in the transmembrane action potential in the neurons, triggering depolarization (action potentials). Examples of application of this concept are the mapping techniques of neoplastic lesions in the eloquent motor cortex region. The EMT navigation (nEMT) aims to study the neurophysiology of the cortex adjacent to the tumor, in order to delineate the lesion section limits, seeking compromise the patient's minimum motor functionality. Such resections were not associated with a significant new motor deficit and patients mapped with such a tool benefited from a longer survival. Another objective of nEMT is to study the measures of cortical excitability, and to verify its prognostic values. Our objective is to compare the cortical excitability of the cerebral hemisphere affected by neoplasia (diseased hemisphere) with the contralateral hemisphere (healthy hemisphere) through the following measurements obtained with EMT: resting motor threshold, short interval intracortical inhibition, intracortical facilitation, motor evoked potential supralaminar and Inter-hemispheric Ratio of resting motor threshold.This is an observational, cohort, prospective study that will include 40 patients with encephalic neoplasia followed at the ICESP in the department of Neurosurgery consecutively directed to microsurgery for resection of intracranial tumor. The inclusion criteria are: age between 18 and 80 years and the presence of neoplasia located in the frontal lobe and / or perirolandic region. Exclusion criteria are decompensated intracranial hypertension, uncontrolled epilepsy, quadriplegia, multiple brain lesions, formal contraindications to TMS, refusal to sign an EHIC or to participate in any of the stages of the study. The study was approved by the Research Center of ICESP and the Research Ethics Committee of the Faculty of Medicine of USP. Participants will be given the Free and Informed Consent Term. The following data will be collected: age; genre; Weight; stature; Body mass index; Karnofski Performance Scale (KPS); Eastern Cooperative Oncology Group (ECOG) Performance Scale; pathological diagnosis (categorized as: low-grade gliomas, high-grade gliomas, metastasis, and tumor grade according to the World Health Organization); (tumor location and dimensions, signs of intracranial hypertension, depth, involvement of primary motor area, degree of vasogenic edema) and postoperative (degree of tumor resection, presence of hematoma in the surgical bed, or ischemic events encephalic); use of medications; American Society of Anesthesiologists (ASA) Physical Status Classification; number of craniotomies (first surgery or reoperation); type of anesthesia (general or with the agreed patient); previous radiotherapy; complications resulting from surgery and clinical outcomes.For neurophysiological assessment through EMT we will use the MagPro X100 High Performance model (MagVenture A / S, Denmark). Simple pulses will be applied to measure the resting motor threshold (RMT) and obtain motor evoked potential (MEP). Paired pulses will be used to gauge other parameters of excitability of the motor cortex. The study will be divided into 3 stages: time 1: Preoperative evaluation (15 days before surgery), time 2: Early postoperative evaluation (between the 15th and the 30th postoperative day), time 3: Post evaluation late postoperative (90 days after surgery).Statistical analysis will be done through the IBM SPSS Statistical Package, version 21 (IBM, Armonk, NY, USA).