Abstract:Magnetic pules stimulation was carried out for the peripheral nerve of the forearm of five healthy adults by using the magnetic stimulation device. Dorsiflexion movement of the wrist was measured using a digital goniometer under the following stimulus conditions. Magnetic field strength : 3 stage. Stimulation frequency 10 Hz to 50 Hz. Stimulation time : 0.5 to 2 sec. According to the stimulation conditions, wide range in bending angle of the wrist over 100 degree was observed.
“…Various stimulus intensity has been used in NMES (Table ). We stimulated at a rate of 30 Hz for 2 sec, because greater movements were obtained at 30 Hz than 10 or 20 Hz in a previous study and 2 sec is the maximum on time in our system. However, the optimum intensity of magnetic stimulation should be investigated in the future.…”
“…Various stimulus intensity has been used in NMES (Table ). We stimulated at a rate of 30 Hz for 2 sec, because greater movements were obtained at 30 Hz than 10 or 20 Hz in a previous study and 2 sec is the maximum on time in our system. However, the optimum intensity of magnetic stimulation should be investigated in the future.…”
“…Our previous study has confirmed the linear relationship between stimulus intensity and pulsed magnetic field intensity adjacent to the coil, what stimulus frequency can be adjusted in 2.5 Hz increments to any value within the range of 10–50 Hz. 20 – 22 Figure 1 Stimulus instruments. …”
Section: Methodsmentioning
confidence: 99%
“…For both devices, the stimulus frequency was set at 30 Hz. 20 , 24 The stimuli were administered a total of 4 times at each intensity for a duration of 2 s each, with intervening 8 s breaks. Although the nature of the devices did not permit the use of an identical pulse width, the pulse widths were set as close to equivalent as possible, 350 µs for rPMS and 300 µs for TES.…”
Section: Methodsmentioning
confidence: 99%
“…Our previous study has confirmed the linear relationship between stimulus intensity and pulsed magnetic field intensity adjacent to the coil, what stimulus frequency can be adjusted in 2.5 Hz increments to any value within the range of 10-50 Hz. [20][21][22] Electrical stimulation was delivered using a transcutaneous electrical current stimulator (Espurge, Ito CO., Ltd, Saitama, Japan) and a 50 × 50 mm electrode band (PALS Platinum, Axelgaard Manufacturing, Fallbrook, CA, USA). The main unit measured 151 mm high × 84 mm wide × 23.5 mm deep and weighed approximately 230 g. The maximum output current was 31 mA ± 20% (effective value), maximum output voltage was 40 V ± 20% (peak value, 500-Ω load), and maximum output frequency was 400 Hz ± 10% (Figure 1 right).…”
Purpose
Both repetitive peripheral magnetic stimulation (rPMS) and transcutaneous electrical current stimulation (TES) could elicit the limb movements; it is still unclear how subjective sensation is changed according to the amount of limb movements. We investigated the pain and discomfort induced by newly developed rPMS and TES of peripheral nerves in the dorsal forearm.
Methods
The subjects were 12 healthy adults. The stimulus site was the right dorsal forearm; thus, when stimulated, wrist dorsiflexion was induced. The rPMS was delivered by the new stimulator, Pathleader at 10 stimulus intensity levels, and TES intensity was in 1-mA increments. The duration of each stimulation was 2 s. The analysis parameters were subjective pain and discomfort, measured by a numerical rating scale. The rating scale at corresponding levels of integrated range of movement (iROM) induced by rPMS or TES was compared. The subjective values were analyzed by two-way repeated measures ANOVA with the stimulus conditions (rPMS, TES) and the seven levels of iROM (20–140 ºs).
Results
In the rPMS experiments, stimuli were administered to all subjects at all stimulus intensities. In the TES experiments, none of the subjects dropped out between 1 and 16 mA, but there were dropouts at each of the intensities as follows: 1 subject at 17 mA, 20 mA, 22 mA, 23 mA, 27 mA, 29 mA and 2 subjects at 21 mA, 24 mA, 26 mA. The main effects of the stimulus conditions and iROM were significant for pain and discomfort. Post hoc analysis demonstrated that pain and discomfort in rPMS were significantly lower compared to TES when the iROM was above 60 ºs and 80 ºs, respectively.
Conclusion
New rPMS stimulator, Pathleader, caused less pain and discomfort than TES, but this was only evident when comparatively large joint movements occurred.
“…Thus, increased intensity of exogenous electrical stimulation can increase pain, and long-time application of electrical stimulation may become unpleasant or difficult 7 , 8 ) . Repetitive peripheral magnetic stimulation (rPMS) is less painful, increasing its clinical applications 9 ) . rPMS acts on intramuscular motor axons, which evoke muscle contraction 10 ) .…”
[Purpose] This study evaluated the effects of repetitive peripheral magnetic stimulation
of the soleus muscle on spinal cord and peripheral motor nerve excitability. [Subjects and
Methods] Twelve healthy adults (mean age 22 years) who provided written informed consent
were administered repetitive peripheral magnetic stimulation for 10 min. Pre-and
post-stimulation latencies and amplitudes of H- and M-waves of the soleus muscle were
measured using electromyography and compared using paired t-tests. [Results] Pre- and
post-stimulation latencies (28.3 ± 3.3 vs. 29.1 ± 1.3 ms, respectively) and amplitudes
(35.8 ± 1.3 vs. 35.8 ± 1.1 mV, respectively) of H-waves were similar. Pre-stimulation
latencies of M-waves were significantly higher than post-stimulation latencies (6.1 ± 2.2
vs. 5.0 ± 0.9 ms, respectively), although pre- and post-stimulation amplitudes were
similar (12.2 ± 1.4 vs. 12.2 ± 1.3 mV, respectively). Motor neuron excitability, based on
the excitability of motor nerves and peripheral nerve action, was increased by M-waves
following magnetic stimulation. [Conclusion] The lack of effect of magnetic stimulation on
the amplitude and latency of the H-reflex suggests that magnetic stimulation did not
activate sensory nerve synapses of α motor neurons in the spinal cord. However, because
motor nerves were stimulated together with sensory nerves, the increased H-wave amplitude
may have reflected changes in peripheral rather than in α motor nerves.
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