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KMID : 0350519950480010313
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Journal of Catholic Medical College
1995 Volume.48 No. 1 p.313 ~ p.321
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Stretch Reflexes in Normal Korean Adults and Patients
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Abstract
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A sudden imposed movement of a limb gives rise to a complex reflex response in its muscle. If the movement stretches a muscle undergoing voluntary contraction, a series of bursts of electromyographic response is usually elicited. The early reflex
response(RI) is generally agreed to be the spinal stretch reflex since its latency is compatible with monosynaptic activation involving group Ia spindle afferents andγ-motor efferents, while the afferent fibers and the neuronal circuits
responsible for
the late reflex responses(R2 and R3) are still obscure.
Reflex electromyographic muscle responses were recorded from abductor pollicis brevis(APB) and tibialis anterior(TA) muscles of twenty four normal adults and twenty two patients with spastic hemiplegia. Responses in the muscles wereevoked during
voluntary muscle contraction(about 20% of maximal voluntary effort) by submaximal but suprathreshold electrical stimulation of the median(at the wrist) and common peroneal(at the neck of the fibula) nerves, respectively. Three EMG peaks(R1, R2
and
R3)
could be recorded after the direct muscle response(M).
The aims of this work were to analyse the reflex behaviour and to quantify the amplitude and latency of early and late reflex responses in normal adults and patients with spastic hemiplegia.
@ES The results were as follows :
@EN 1. The incidence of reflex responses in R1, R2 and R3 were 100.0%, 100.0%, 65.2% in APB muscle and 100.0%, 100.0% in TA muscle of normal adults, respectively.
2. The latency of reflex responses in R1, R2 and R3 were 27.6±2.4 msec, 48.4±8.4 msec, 65.5±6.5 msec in APB mucscle and 35.7±8.5 MESE, 53.9±11.0 msec, 70.5±10.8 msec in TA muscle of normal adults, respectively.
3. The amplitude of reflex responses in R1, R2 and R3 were 300.6±30.1μV, 137.5±16.8μV, 81.5±5.4μV in APB muscle and 156.3±15.6μV, 55.0±13.9μv, 43.8±2.7V, in TA muscle of normal adults, respectively.
4. There were not significant differences in the incidence, latency and amplitude of R1, R2 and R3 responses of unaffected limb of spastic hemiplegia, compared with those of normal adults.
5. In comparing the stretch reflex of APB and TA muscles in the spastic limb of hemiplegia with those in normal adults and unaffected limb of hemiplegia, the incidence rate of R2 response was low(P<0.05), whild the amplitude of R1 response was
increased(P<0.05), that of R2 response was decreased(P<0.05), significantly.
In conclusion, we obtained the normal values of latency and amplitude of R1, R2 and R3 response on stretch reflex, and suggested the changes of amplitude in R1 and R2 responses as useful indicators to evaluate the spasticity.
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KEYWORD
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