To evaluate the spasticity and electrophysiologic effects of applying extracorporeal shock wave therapy (ESWT) to the gastrocnemius by studying F wave and H-reflex.
Ten healthy adults and 10 hemiplegic stroke patients with ankle plantarflexor spasticity received one session of ESWT on the medial head of the gastrocnemius. The modified Ashworth scale (MAS), tibial nerve conduction, F wave, and H-reflex results were measured before and immediately after the treatment. The Visual Analogue Scale (VAS) was used during ESWT to measure the side effects, such as pain.
There were no significant effects of ESWT on the conduction velocity, distal latency and amplitude of tibial nerve conduction, minimal latency of tibial nerve F wave, latency, or H-M ratio of H-reflex in either the healthy or stroke group. However, the MAS of plantarflexor was significantly reduced from 2.67±1.15 to 1.22±1.03 (p<0.05) after applying ESWT in the stroke group.
After applying ESWT on the gastrocnemius in stroke patients, the spasticity of the ankle plantarflexor was significantly improved, with no changes of F wave or H-reflex parameters. Further studies are needed to evaluate the mechanisms of the antispastic effect of ESWT.
Citations
The characteristics of the surface recorded F responses including minimal latency, mean latency, amplitude, duration, area and shape were investigated in the posterior tibial nerves of rabbits. During a train of 100 stimuli, each F wave was divided by the recurrence of shape into repeaters and nonrepeaters. There was no significant difference between the parameters of repeaters and nonrepeaters such as mean latency, minimal latency, amplitude and area. These findings suggest that the associated discharges of motor neurons generating the repeaters of F wave represented no definite distinctions from that of nonrepeaters in the aspect of the neuron size or the number of neurons contributing to each parameters of F wave. After the sciatic nerve was exposed, it was minimally injured by compression and then F responses were studied. Mean latency and minimal latency were prolonged, and amplitude and area were diminished in post-injured group. The frequency of repeater waves was increased but was not a useful parameter in the assessment of injury model due to a wide range of normal value.
The effect of electrical nerve stimulation are controversial because of the inconsistent variables of stimulating current and electrophysiologic study. The purposes of this study are to reconfirm the electrophysiolgic changes by electrical stimulation of the peripheral nerve that had been reported in 1993, and to monitor how long they will be maintained. In this study, the following conditioning stimulations were applied to 20 healthy volunteers; interferential current(frequency: 80∼100 Hz, intensity: 27∼34 mA) on the sacral paraspinal area. The H reflex, the F response, and the somatosensory evoked potential(SEP) of the tibial nerve were evaluated as the electrophysiologic study before, immediately after, 30 minutes, 60 minutes, and 120 minutes after the above conditioning stimulation. The following results were obtained;
1) Latencies of the H reflex, the F response and the SEP(P1), and the F wave conduction time, the F wave conduction velocity and the F ratio in the tibial nerve conduction study were increased by conditioning stimulation of the proximal peripheral nerves(P＞0.01).
2) Changes of the amplitude of the H reflex, the H/M ratio, and the amplitude(P1N1) of the tibial SEP were not significant in the same conditioning stimulation(P＞0.05).
3) Prolongations of the latencies of H reflex, F response and P1 SEP of the tibial nerve were the most significant immediately after conditioning stimulation and sustained for 45 minutes after conditioning on average (P＜0.01).
The above results suggest that certain conditional electrical stimulation of the peripheral nerves causes reversible changes in the conduction of the H reflex, the F response and the SEP and they may be inhibitory effect of the proximal conduction via the spinal cord.
First
Prev
