Figure 4 - available via license: Creative Commons Attribution 4.0 International
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A simulated biphasic waveform of an MEP. The different parameters of the signal represents the main issues defining the influence on cortico-spinal excitability. The initial negative phase of the MEP (left side) is not considered in this calculation.
Source publication
Background:
Brain stimulation motor-evoked potentials (MEPs) are transient signals and not periodic signals, and thus, they differ significantly in their properties from classical surface electromyograms. Unsuitable pre-processing of MEPs due to inappropriate filter settings leads to distortions. Filtering of extensor carpi radialis MEPs with tran...
Context in source publication
Context 1
... line hum was largely reduced due to shielding and power supply to the measuring apparatus by DC. The examination of MEPs serves for the quantitative estimation of the corticospinal excitability (Fig- ure 4). Under optimal stimulation conditions, biphasic responses to the TMS can be measured. ...
Citations
... The amplifier has a bandwidth of 1 Hz-1000 Hz, a × 1000 amplification, and an input impedance of 10 gΩ. A Butterworth 1st-order high-pass filter with a cut-off frequency of 1 Hz [25,26] was used to remove movement artifacts in the EMG. ...
Background: The reduction of muscular hypertonia is important in the treatment of various diseases or rehabilitation. This study aims to test the efficacy of a 5 Hz mechanical muscle stimulation (tapotement massage) in comparison to a 5 Hz repetitive peripheral magnetic stimulation (rPMS) on the neuromuscular reflex response. Methods: In a randomized control trial, 15 healthy volunteers were administered with either 5 Hz rPMS, tapotement massage, or rPMS sham stimulation. The posterior tibial nerve was stimulated with rPMS and sham stimulation. The Achilles tendon was exposed to a mechanically applied high-amplitude 5 Hz repetitive tendon tapotement massage (rTTM). The tendon reflex (TR) was measured for the spinal response of the soleus muscle. Results: After rPMS, there was a reduction of the TR response (−9.8%, p ≤ 0.034) with no significant changes after sham stimulation. Likewise, TR decreased significantly (−17.4%, p ≤ 0.002) after Achilles tendon tapotement intervention. Conclusions: These findings support the hypothesis that both afferent 5 Hz sensory stimulations contributed to a modulation within the spinal and/or supraspinal circuits, which resulted in a reduction of the spinal reflex excitability. The effects could be beneficial for patients with muscle hypertonia and could improve the functional results of rehabilitation programs.
