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

2021 ◽  
Vol 11 ◽  
Author(s):  
Iuri Santana Neville ◽  
Alexandra Gomes dos Santos ◽  
Cesar Cimonari Almeida ◽  
Cintya Yukie Hayashi ◽  
Davi Jorge Fontoura Solla ◽  
...  
Keyword(s):  
Brain Tumor ◽  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Cortical Excitability ◽  
Short Interval ◽  
Motor Evoked Potential ◽  
Biological Behavior ◽  
Navigated Transcranial Magnetic Stimulation ◽  
Resting Motor Threshold

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.

The effects of 30 Hz, 50 Hz AND 100 Hz continuous theta burst stimulation via transcranial magnetic stimulation on the electrophysiological parameters in healthy individuals

2021 ◽  
Vol 74 (1-2) ◽  
pp. 41-49
Author(s):  
Zeynep Ozdemir ◽  
Erkan Acar ◽  
Aysun Soysal
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Short Interval ◽  
Motor Evoked Potential ◽  
Individual Variability ◽  
Theta Burst Stimulation ◽  
Burst Stimulation ◽  
Resting Motor Threshold ◽  
Theta Burst ◽  
Continuous Theta Burst Stimulation

Transcranial magnetic stimulation is a non-invasive procedure that uses robust magnetic fields to create an electrical current in the cerebral cortex. Dual stimulation consists of administering subthre­shold conditioning stimulation (CS), then suprathreshold test stimulation (TS). When the interstimulus interval (ISI) is 1-6 msec, the motor evoked potential (MEP) decreases in amplitude; this decrease is termed “short interval intracortical inhibition” (SICI); when the ISI is 7-30 msec, an increase in MEP amplitude occurs, termed “short interval intracortical facilitation” (SICF). Continuous theta burst stimulation (cTBS), often applied at a frequency of 50 Hz, has been shown to decrease cortical excitability. The primary objective is to determine which duration of cTBS achieves better inhibition or excitation. The secondary objective is to compare 50 Hz cTBS to 30 Hz and 100 Hz cTBS. The resting motor threshold (rMT), MEP, SICI, and SICF were studied in 30 healthy volunteers. CS and TS were administered at 80%-120% and 70%-140% of rMT at 2 and 3-millisecond (msec) intervals for SICI, and 10- and 12-msec intervals for SICF. Ten individuals in each group received 30, 50, or 100 Hz, followed by administration of rMT, MT-MEP, SICI, SICF immediately and at 30 minutes. Greater inhibition was achieved with 3 msec than 2 msec in SICI, whereas better facilitation occurred at 12 msec than 10 msec in SICF. At 30 Hz, cTBS augmented inhibition and suppressed facilitation, while 50 Hz yielded less inhibition and greater inter-individual variability. At 100 Hz, cTBS provided slight facilitation in MEP amplitudes with less interindividual variability. SICI and SICF did not differ significantly between 50 Hz and 100 Hz cTBS. Our results suggest that performing SICI and SICF for 3 and 12 msec, respectively, and CS and TS at 80%-120% of rMT, demonstrate safer inhibition and facilitation. Recently, TBS has been used in the treatment of various neurological diseases, and we recommend preferentially 30 Hz over 50 Hz cTBS for better inhibition with greater safety and less inter-individual variability.

scholarly journals Low-Frequency Repetitive Transcranial Magnetic Stimulation for Stroke-Induced Upper Limb Motor Deficit: A Meta-Analysis

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Lan Zhang ◽  
Guoqiang Xing ◽  
Shiquan Shuai ◽  
Zhiwei Guo ◽  
Huaping Chen ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Upper Limb ◽  
Magnetic Stimulation ◽  
Cortical Excitability ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Meta Analysis ◽  
Low Frequency ◽  
Motor Evoked Potential ◽  
Motor Deficit ◽  
Resting Motor Threshold

Background and Purpose. This meta-analysis aimed to evaluate the therapeutic potential of low-frequency repetitive transcranial magnetic stimulation (LF-rTMS) over the contralesional hemisphere on upper limb motor recovery and cortex plasticity after stroke.Methods. Databases of PubMed, Medline, ScienceDirect, Cochrane, and Embase were searched for randomized controlled trials published before Jun 31, 2017. The effect size was evaluated by using the standardized mean difference (SMD) and a 95% confidence interval (CI). Resting motor threshold (rMT) and motor-evoked potential (MEP) were also examined.Results. Twenty-two studies of 1 Hz LF-rTMS over the contralesional hemisphere were included. Significant efficacy was found on finger flexibility (SMD = 0.75), hand strength (SMD = 0.49), and activity dexterity (SMD = 0.32), but not on body function (SMD = 0.29). The positive changes of rMT (SMD = 0.38 for the affected hemisphere and SMD = −0.83 for the unaffected hemisphere) and MEP (SMD = −1.00 for the affected hemisphere and SMD = 0.57 for the unaffected hemisphere) were also significant.Conclusions. LF-rTMS as an add-on therapy significantly improved upper limb functional recovery especially the hand after stroke, probably through rebalanced cortical excitability of both hemispheres. Future studies should determine if LF-rTMS alone or in conjunction with practice/training would be more effective.Clinical Trial Registration Information. This trial is registered with unique identifierCRD42016042181.

scholarly journals Cortical excitability varies across different muscles

2018 ◽  
Vol 120 (3) ◽  
pp. 1397-1403 ◽  
Author(s):  
Parvathi Menon ◽  
Matthew C. Kiernan ◽  
Steve Vucic
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Functional Organization ◽  
Cortical Excitability ◽  
Short Interval ◽  
Intracortical Inhibition ◽  
Body Regions ◽  
Threshold Tracking ◽  
Resting Motor Threshold ◽  
Limb Muscles

The aim of the present study was to determine whether significant differences in cortical excitability were evident across different body regions in healthy humans. Threshold tracking transcranial magnetic stimulation (TMS) was undertaken in 28 healthy controls. Short-interval intracortical inhibition [SICI between interstimulus intervals (ISI) 1–7 ms], intracortical facilitation (ICF, between ISI 10–30 ms), resting motor threshold (RMT), cortical silent period (CSP) duration (generated at stimulus intensity 150% RMT), and motor evoked potential amplitude were recorded from the abductor pollicis brevis (APB), tibialis anterior (TA), and trapezius muscles. These muscles were selected as they are frequently affected in neurodegenerative diseases, such as amyotrophic lateral sclerosis. SICI and ICF are measured as a percentage difference between conditioned and an unconditioned test response. SICI was significantly greater when recorded over the APB (9.9 ± 1.5%) and TA (8.6 ± 1.4%) muscles compared with the trapezius (4.5 ± 1.9%, P < 0.05). The CSP duration was significantly shorter (CSPtrapezius, 131.0 ± 6.3 ms; CSPTA, 175.7 ± 9.9 ms; CSPAPB, 188.3 ± 4.0 ms; P < 0.001) and ICF greater ( P < 0.01) in the trapezius muscle. There were no significant correlations between inhibitory and facilitatory processes recorded across the three muscles. The present study established significant differences in cortical excitability across three body regions, with evidence of more prominent inhibition and less facilitation in the limb muscles. NEW & NOTEWORTHY Cortical excitability of muscles with differing motor functions was assessed using threshold tracking transcranial magnetic stimulation. Significantly greater intracortical inhibition and less facilitation were evident over the limb muscles. These findings could relate to differences in the functional organization of the corticomotoneuronal system innervating different muscle regions.

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 ◽  
...  
Keyword(s):  
Brain Tumor ◽  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Cortical Excitability

CORTICAL EXCITABILITY AND REFRACTORY EPILEPSY: A THREE-YEAR LONGITUDINAL TRANSCRANIAL MAGNETIC STIMULATION STUDY

2012 ◽  
Vol 23 (01) ◽  
pp. 1250030 ◽  
Author(s):  
RADWA A. B. BADAWY ◽  
GRAEME D. JACKSON ◽  
SAMUEL F. BERKOVIC ◽  
RICHARD A. L. MACDONELL
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Refractory Epilepsy ◽  
Cortical Excitability ◽  
Focal Epilepsy ◽  
Idiopathic Generalized Epilepsy ◽  
Generalized Epilepsy ◽  
Effective Medication ◽  
Over Time

Transcranial magnetic stimulation was used to study the effect of recurrent seizures on cortical excitability over time in epilepsy. 77 patients with firm diagnoses of idiopathic generalized epilepsy (IGE) or focal epilepsy were repeatedly evaluated over three years. At onset, all groups had increased cortical excitability. At the end of follow-up the refractory group was associated with a broad increase in cortical excitability. Conversely, cortical excitability decreased in all seizure free groups after introduction of an effective medication.

scholarly journals Neuroplasticity Changes on Human Motor Cortex Induced by Acupuncture Therapy: A Preliminary Study

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Yi Yang ◽  
Ines Eisner ◽  
Siqi Chen ◽  
Shaosong Wang ◽  
Fan Zhang ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Acupuncture Therapy ◽  
Motor Cortex ◽  
Magnetic Stimulation ◽  
Primary Motor Cortex ◽  
Motor Evoked Potential ◽  
Interhemispheric Inhibition ◽  
Human Motor Cortex ◽  
Interhemispheric Competition ◽  
Resting Motor Threshold

While neuroplasticity changes measured by transcranial magnetic stimulation have been proved to be highly correlated to motor recovery and have been tested in various forms of interventions, it has not been applied to investigate the neurophysiologic mechanism of acupuncture therapy. The aim of this study is to investigate neuroplasticity changes induced by a single session of acupuncture therapy in healthy adults, regarding the excitability change on bilateral primary motor cortex and interhemispheric inhibition. Ten subjects took a 30-minute acupuncture therapy and the same length relaxing phase in separate days. Transcranial magnetic stimulation measures, including resting motor threshold, amplitudes of motor-evoked potential, and interhemispheric inhibition, were assessed before and 10 minutes after intervention. Acupuncture treatment showed significant changes on potential amplitude from both ipsilateral and contralateral hemispheres to acupuncture compared to baseline. Also, interhemispheric inhibition from the contralateral motor cortex to the opposite showed a significant decline. The results indicated that corticomotoneuronal excitability and interhemispheric competition could be modulated by acupuncture therapy on healthy subjects. The following question about whether these changes will be observed in the same way on stroke patients and whether they correlate with the therapeutic effect on movement need to be answered by following studies. This trial is registered with ISRCTN13074245.

Probing Modifications of Cortical Excitability During Stroke Recovery With Navigated Transcranial Magnetic Stimulation

2012 ◽  
Vol 19 (2) ◽  
pp. 182-192 ◽  
Author(s):  
Pantelis Lioumis ◽  
Satu Mustanoja ◽  
Rozaliya Bikmullina ◽  
Anne-Mari Vitikainen ◽  
Dubravko Kičić ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Cortical Excitability ◽  
Stroke Recovery ◽  
Navigated Transcranial Magnetic Stimulation

Cortical dysfunction underlies disability in multiple sclerosis

2011 ◽  
Vol 18 (4) ◽  
pp. 425-432 ◽  
Author(s):  
Steve Vucic ◽  
Therese Burke ◽  
Kerry Lenton ◽  
Sudarshini Ramanathan ◽  
Lavier Gomes ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Cortical Excitability ◽  
Short Interval ◽  
Motor Evoked Potential ◽  
Intracortical Inhibition ◽  
Progressive Multiple Sclerosis ◽  
Conduction Time ◽  
Cortical Function ◽  
Resting Motor Threshold ◽  
Cortical Dysfunction

Background: Gray matter atrophy has been implicated in the development of secondary progressive multiple sclerosis (SPMS). Cortical function may be assessed by transcranial magnetic stimulation (TMS). Determining whether cortical dysfunction was a feature of SPMS could be of pathophysiological significance. Objectives: Consequently, novel paired-pulse threshold tracking TMS techniques were used to assess whether cortical dysfunction was a feature of SPMS. Methods: Cortical excitability studies were undertaken in 15 SPMS, 25 relapsing–remitting MS patients (RRMS) and 66 controls. Results: Short interval intracortical inhibition (SPMS 3.0 ± 2.1%; RRMS 12.8 ± 1.7%, p < 0.01; controls 10.5 ± 0.7%, p < 0.01) and motor evoked potential (MEP) amplitude (SPMS 11.5 ± 2.2%; RRMS 26.3 ± 3.6%, p <0.05; controls 24.7 ± 1.8%, p < 0.01) were reduced in SPMS, while intracortical facilitation (SPMS -5.2 ± 1.9%; RRMS -2.0 ± 1.4, p < 0.05; controls -0.9 ± 0.7, p < 0.01) and resting motor threshold were increased (SPMS 67.5 ± 4.5%; RRMS 56.0 ± 1.5%, p < 0.01; controls 59.0 ± 1.1%, p < 0.001). Further, central motor conduction time was prolonged in SPMS (9.1 ± 1.2 ms, p < 0.001) and RRMS (7.0 ± 0.9 ms, p < 0.05) patients compared with controls (5.5 ± 0.2 ms). The observed changes in cortical function correlated with the Expanded Disability Status Scale. Conclusion: Together, these findings suggest that cortical dysfunction is associated with disability in MS, and documentation of such cortical dysfunction may serve to quantify disease severity in MS.

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