円周歩行における半規管脊髄反射の研究

抄録

Electromyograms of both gastrocnemius muscles were recorded in 22 normal adults during circular walking under two conditions: with no caloric stimulation and immediately after irrigation of the right auditory canal with 20°C water for 20 seconds while the horizontal semicircular canal was in the vertical position. The subject was asked to walk at higher speed than usual with eyes closed in a circle 2 meters in diameter.
With no caloric stimulation, the activity of the gastrocnemius muscle was greater on the right side than on the left side during circular walking to the left and vice versa during circular walking to the right. Nystagmus towards the same side as the direction of the turning was simulataneously recorded by electronystagmography. Following irrigation of the right auditory canal the muscle activity was greater on the left side than on the right side during turning to the left, but no consistent difference in muscle activity was observed during turning to the right. Furthermore, the subject always complained of difficulty in walking to the stimulated side.
The results indicate that an ampullopetal lymphatic flow in the semicircular canal caused by circular walking increases the antigravity muscle tonus of the ipsilateral leg. This facilitates the ipsilateral leg to support the body weight which shifts to the inner side of circular walking.