Elicitation of otolithic nystagmus by step and sinusoidal modes of linear acceleration (Gy) in humans.

The vestibular otolith organ, a sensor of linear acceleration, is known to be important not only for posture control and spatial orientation, but also for eye movement control. Niven et al. (1966) have reported that linear acceleration along the Y (left-right, interaural) head axis by using a linear track induces compensatory horizontal eye movements including nystagmus. This was confirmed by several authors using a linear accelerator and a parallel swing. We have already found that a step mode of Gy linear acceleration is useful to elicit otolithic nystagmus and that nystagmus have directional preponderance (DP) (Mori and Katayama, 1998). In the present report, we attempted to compare two modes of acceleration, step and sinusoidal, in nystagmic elicitation induced by linear acceleration.