Abstract #80: Assessment of cortical excitability with Transcranial Magnetic Stimulation in patients with brain tumor

2019 ◽  
Vol 12 (2) ◽  
pp. e28
Author(s):  
Cintya Hayashi ◽  
Iuri S. Nevile ◽  
Cesar C. Almeida ◽  
Priscila Rodrigues ◽  
Ricardo RG. Galhardoni ◽  
...  
2021 ◽  
Vol 11 ◽  
Author(s):  
Iuri Santana Neville ◽  
Alexandra Gomes dos Santos ◽  
Cesar Cimonari Almeida ◽  
Cintya Yukie Hayashi ◽  
Davi Jorge Fontoura Solla ◽  
...  

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 (R2 = 0.118, p = 0.017) and the 90-day follow-up (R2 = 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.


2021 ◽  
Vol 11 (4) ◽  
pp. 432
Author(s):  
Fiorenzo Moscatelli ◽  
Antonietta Messina ◽  
Anna Valenzano ◽  
Vincenzo Monda ◽  
Monica Salerno ◽  
...  

Transcranial magnetic stimulation, since its introduction in 1985, has brought important innovations to the study of cortical excitability as it is a non-invasive method and, therefore, can be used both in healthy and sick subjects. Since the introduction of this cortical stimulation technique, it has been possible to deepen the neurophysiological aspects of motor activation and control. In this narrative review, we want to provide a brief overview regarding TMS as a tool to investigate changes in cortex excitability in athletes and highlight how this tool can be used to investigate the acute and chronic responses of the motor cortex in sport science. The parameters that could be used for the evaluation of cortical excitability and the relative relationship with motor coordination and muscle fatigue, will be also analyzed. Repetitive physical training is generally considered as a principal strategy for acquiring a motor skill, and this process can elicit cortical motor representational changes referred to as use-dependent plasticity. In training settings, physical practice combined with the observation of target movements can enhance cortical excitability and facilitate the process of learning. The data to date suggest that TMS is a valid technique to investigate the changes in motor cortex excitability in trained and untrained subjects. Recently, interest in the possible ergogenic effect of non-invasive brain stimulation in sport is growing and therefore in the future it could be useful to conduct new experiments to evaluate the impact on learning and motor performance of these techniques.


2020 ◽  
Vol 47 (4) ◽  
pp. 427-434
Author(s):  
Mohammed S. El-Tamawy ◽  
Moshera H. Darwish ◽  
Saly H. Elkholy ◽  
Engy BadrEldin S. Moustafa ◽  
Shimaa T. Abulkassem ◽  
...  

BACKGROUND: Cortical reorganization between both cerebral hemispheres plays an important role in regaining the affected upper extremity motor function post-stroke. OBJECTIVES: The purpose of the current study was to investigate the recommended number of contra-lesion low frequency repetitive transcranial magnetic stimulation (LF-rTMS) sessions that could enhance cortical reorganization post-stroke. METHODS: Forty patients with right hemiparetic subacute ischemic stroke with an age range between 50–65 yrs were randomly assigned into two equal groups: control (GA) and study (GB) groups. Both groups were treated with a selected physical therapy program for the upper limb. Sham and real contra-lesion LF-rTMS was conducted for both groups daily for two consecutive weeks. Sequential changes of cortical excitability were calculated by the end of each session. RESULTS: The significant enhancement in the cortical excitability was observed at the fourth session in favor of the study group (GB). Sequential rate of change in cortical excitability was significant for the first eight sessions. From the ninth session onwards, no difference could be detected between groups. CONCLUSION: The pattern of recovery after stroke is extensive and not all factors could be controlled. Application of LF-rTMS in conjugation with a selected physical therapy program for the upper limb from four to eight sessions seems to be efficient.


Epilepsia ◽  
2014 ◽  
Vol 55 (2) ◽  
pp. 362-369 ◽  
Author(s):  
Katja Menzler ◽  
Anke Hermsen ◽  
Katharina Balkenhol ◽  
Caroline Duddek ◽  
Hannes Bugiel ◽  
...  

2021 ◽  
Author(s):  
JeYoung Jung ◽  
Stephen Williams ◽  
Faezeh Sanae Nezhad ◽  
Matthew Lambon Ralph

Abstract The effect of repetitive transcranial magnetic stimulation can vary considerably across individuals, but the reasons for this still remain unclear. Here, we investigated whether the response to continuous theta-burst stimulation (cTBS) – an effective protocol for decreasing cortical excitability – related to individual differences in glutamate and GABA neurotransmission. We applied cTBS over the anterior temporal lobe (ATL), a hub for semantic representation, to explore the relationship between the baseline neurochemical profiles in this region and the response to this stimulation. Our experiments revealed that non-responders (subjects who did not show an inhibitory effect of cTBS on subsequent semantic performance) had higher excitatory-inhibitory balance (glutamate + glutamine/GABA ratio) in the ATL, which led to up-regulated task-induced regional activity as well as increased ATL-connectivity with other semantic regions compared to responders. These results disclose that the baseline neurochemical state of a cortical region can be a significant factor in predicting responses to cTBS.


Author(s):  
Javier Caballero-Villarraso ◽  
Francisco Javier Medina ◽  
Begoña M. Escribano ◽  
Eduardo Agüera ◽  
Abel Santamaría ◽  
...  

: Transcranial magnetic stimulation (TMS) is widely used in neurophysiology to study cortical excitability. Research over the last few decades has highlighted its additional value as a potential therapeutic tool in the treatment of a broad range of psychiatric disorders. More recently, a number of studies have reported beneficial and therapeutic effects for TMS in neurodegenerative conditions and strokes. Yet despite its recognised clinical applications and despite considerable research using animal models, the molecular and physiological mechanisms through which TMS exerts its beneficial and therapeutic effects remain unclear. They are thought to involve biochemical-molecular events affecting membrane potential and gene expression. In this aspect, the dopaminergic system plays a special role. This is the most directly and selectively modulated neurotransmitter system, producing an increase in the flux of dopamine (DA) in various areas of the brain after the application of repetitive TMS (rTMS). Other neurotransmitters, such as glutamate and gamma-aminobutyric acid (GABA) have shown a paradoxical response to rTMS. In this way, their levels increased in the hippocampus and striatum but decreased in the hypothalamus and remained unchanged in the mesencephalon. Similarly, there are sufficient evidences that TMS up-regulates the gene expression of BDNF (one of the main brain neurotrophins). Something similar occurs with the expression of genes such as c-Fos and zif268 that encode trophic and regenerative action neuropeptides. Consequently, the application of TMS can promote the release of molecules involved in neuronal genesis and maintenance. This capacity may mean that TMS becomes a useful therapeutic resource to antagonize processes that underlie the previously mentioned neurodegenerative conditions.


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