P 115. Effects of rTMS in conversion paralysis
2
Citation
1
Reference
10
Related Paper
Citation Trend
Keywords:
Conversion disorder
Silent period
Evoked potential
Cite
Citations (10)
During exercise, changes occur at many sites in the motor pathway, including the muscle fiber, motoneuron, motor cortex, and “upstream” of the motor cortex. Some of the changes result in fatigue, which can be defined as a decrease in ability to produce maximal muscle force voluntarily. Transcranial magnetic stimulation (TMS) over the human motor cortex reveals changes in both motor evoked potentials (MEPs) and the silent period during and after fatiguing voluntary contractions in normal subjects. The relationship of these changes to loss of force or fatigue is unclear. However, during a sustained maximal contraction TMS evokes extra force from the muscle and thus demonstrates the development of suboptimal output from the motor cortex, that is, fatigue at a supraspinal level. In some patients with symptoms of fatigue, the response to TMS after exercise is altered, but the changed MEP behavior is not yet linked to particular symptoms or pathology. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 18–29, 2001
Muscle Fatigue
Silent period
Cite
Citations (178)
Evoked potential
Cite
Citations (81)
Silent period
Muscle Fatigue
Brain stimulation
Cite
Citations (0)
Silent period
Evoked potential
Interstimulus interval
Cite
Citations (37)
Evoked potential
Cite
Citations (75)
Measurements of motor cortex inhibition and excitability can provide useful insights when assessing pathological damage as well as neuronal recovery from injuries. PURPOSE: The aim of this study was to determine the reliability of single pulse transcranial magnetic stimulation (TMS) measures in men and women. METHODS: Nine (5 female) healthy college age participants were tested at three time points, each separated by one week. Single pulse TMS was delivered to the contralateral motor cortex of the dominant first dorsal interosseous. Resting motor threshold (RMT) and the peak-to-peak amplitude of motor evoked potentials (MEP) at 120% RMT were used to quantify motor cortex excitability. The duration of the cortical silent period (CSP), evoked at 120% RMT while participants maintained a contraction at 50% of maximum force, was used to quantify motor cortex inhibition. Reliability was assessed with the intraclass correlation coefficient (ICC 2,1). RESULTS: There was no significant difference across time (p=0.82; p=0.83; p=0.70) or between sexes (p=0.83; p=0.68; p=0.36) for RMT, MEP, or CSP, respectively. Also, there was no significant sex by time interaction (p≥0.34) for any of the measures. Reliability across days was strong for RMT (R=0.69), and very strong for MEP (R=0.87) and CSP (R=0.95). CONCLUSIONS: These results support the use of single pulse TMS measurements to reliably assess and track motor cortex physiological function in men and women.
Silent period
Evoked potential
Cite
Citations (0)
Transcranial magnetic stimulation (TMS) is a noninvasive and painless technique used to stimulate the human motor cortex. The resulting motor evoked potential (MEP) can be recorded from a target muscle with conventional electromyography. Preservation of the MEP in the first hours after stroke predicts a favorable outcome, whereas absence of the MEP predicts poor outcome. Many stroke patients, in particular those with motor neglect, show a lengthening of the TMS evoked silent period, indicating enhanced cortical inhibition. TMS mapping provides evidence that motor representations in the affected motor cortex expand and shift during motor recovery. These various TMS applications improve outcome prediction and enhance our understanding of the mechanisms underlying reorganization after stroke. Complementary to the clinical examination, TMS may be used soon to monitor and guide rehabilitative strategies in stroke patients.
Stroke
Silent period
Evoked potential
Motor System
Cite
Citations (10)
Aim:To investigate the effects of low frequency repetitive transcranial magnetic stimulation (rTMS) on the excitability of the motor cortex in Parkinson′s disease (PD) and to study mechanism of PD from the eletrophysiology. Methods:30 patients with PD were performed by 1Hz rTMS therapy to 10 days, 15 patients were performed sham stimulation, 15 normal volunteers were enrolled as control. Excitability of the motor cortex were assessed by rest threshold (RT), central motor conduction time (CMCT), central silent period (CSP) and amplitude of motor evoked potential(MEP). Results:①Patients with PD were treated by rTMS, the results of RT, CMCT and CSP decreased or shortened significantly compared with control, but MEP amplitudes were not changed. In the treatment group, RT increased, CMCT and CSP prolonged, they were closed to normal subjects after treatment, but these changes were not observed in sham group. ②The four indexes were not different in patients with marked tremor or marked rigidity. ③ Patients were divided into mild, moderate and grievous groups by Unified Parkinson′s Disease Rating Scale (UPDRS). The results of the three groups were not significant different by comparing the four indexes. Conclusion An increased motor cortical excitability in PD was observed in our study. Low frequency rTMS may to some extent inhibit the enhanced cortical excitability. But rTMS is not so sensible to detect the excitability of early PD,and more work needs to be done.
Silent period
Evoked potential
Cite
Citations (0)