Threshold of Stimulation of the Horizontal Semi-Circular Canals in Man with Particular Reference to the Significance of the First Derivative of Angular AccelERATION AS A Stimulus

摘要

Records of responses to constant angular acceleration and to changes in angular acceleration were obtained. The indicator was the oculo-gyral illusion, and three types of responses were obtained: 'left movement', 'no movement', and 'right movement'. Fairly consistent relationships between the direction and amount of change in acceleration, as expressed in each of the three types of response were obtained. A threshold for change (mean change between four 20-second periods) in both positive and negative angular acceleration was determined to be about 0.12 degrees/sec/sec. It was also found that the reliability of response to constant acceleration decreased as the length of the period to which response referred increased beyond 20 seconds at near-threshold rates. It is possible to obtain a threshold for the effectiveness of the first derivative of acceleration, or the change in the rate of change in velocity. (Author)