頭部動揺の角加速度成分に関する研究

Abstract

Angular of head movement was measured with the Watson angular accelerometer which is based on piezoelectric vibrating beam technology. The angular accelerometer fixed on the head can detect the action of the 3 semicircular canals, measuring movement in the coronal plane (right and left direction : R-L), sagittal plane (anterior and posterior direction : A-P), and axial plane (horizontal direction : HOR) of the head.In static postures, angular registrography is greatly influenced by the pulse in sitting and Romberg positions. In normal subjects, averaged amplitude was larger when blindfolded than with eyes open, and larger in unstable than in stable postures. According to the direction measured, averaged amplitude was larger on the HOR than A-P plane and larger on the A-P than R-L plane. Averaged frequency was lower when blindfolded than with eyes open, and lower in unstable than in stable postures except in the one leg position It was significantly lower on the HOR than R-L or A-P plane. In artificial disequilibrium models, averaged amplitude increased as the frequency of nystagmus increased under caloric stimulation and with the eyes blindfolded, it also increased when galvanic stimulation was either on or off. Averaged frequency decreased as averaged amplitude increased. Angular registrography as used in this study detected dysfunction of the semicircular canals more clearly than did linear registrography reported previously.Angular registrography was also measured during stepping. The parameter was amplitude of angular acceleration which was significant angular of the head toward the opposite site when one leg was elevated. In normal subjects, amplitude of specified angular with left leg elevation was almost equal to that with right leg elevation. It seemed that specified angular acted on the semicircular canals, and this modulated bilateral muscle tension in the legs to make stepping performance smoother. In artificial disequilibrium models, a significant difference in the amplitude of specified angular between right and left was seen in proportion to stimulation intensity similar to the deviation of body sway. These findings suggest that the function of the right and left semicircular canals can be demonstrated by this difference.