Jendrassik氏腱反射増強法のH波に及ぼす影響について

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  • Jendrassik シケンハンシャ ゾウキョウホウ ノ Hハ ニ オヨボス エイキョウ ニ ツイテ
  • The effect of the Jendrassik Maneuver on the H-reflex
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  • Original Article

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1) The amplitude of H-reflex was diminished by the procaine anesthesia of the tibial nerve, which blocked gamma fiber, and also by the use of a vibrator on the Achilles tendon, which caused the augmentation of the muscle spindle discharge. These diminished H-refiexes, inculuding that of the patients with parkinsonism, whose gamma system was pathologically hyperactive, showed a considerable enhancement by the Jendrassik maneuver. All these findings suggested that the Jendrassik maneuver had a direct effect on the excitability of the motoneurons. 2) Before a normal subject started the maneuver, having recognized the signal "on" the H-reflex showed marked facilitation. On the other hand, during the concentration of his attention to the signal lamp without muscular contraction, or during the anticipation to the signal, the H-reflex was not reinforced. It was reasoned that the impulses to the hands commanding to move, simultaneously hightened the motoneuron excitability of the lower extremities. 3) The facilitation was prominent during initial ca 300 msec of the exertion. Though the reinforcement diminished gradually, it persisted throughout the period of contraction as long as ten seconds. The less efficacy of the sustained contraction was conceived to be attributable to some feed back mechanism. 4) The reinforcement disappeared when the subject recognized the signal "off", even though the maneuver was not finished. After the finish of the maneuver, the H-reflex was kept within standard variance in normal subjects, but in the patients with hemiplegia, the H-reflex showed suppresion. This suppression was postulated to be caused by a defect of the mechanism to regulate the rebounding inhibitory effect. 5) Though the effect of the Jendrassik maneuver was not related to power or speed of the maneuver, the pushing button method was also effective as well as the classical maneuver.

This fact seemed to suggest that there might be something between the reinforcement and' the innervation ratio involving the motor cortex, or the difference of the phasic or tonic component of the maneuver.

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