Kimihisa Nomura

Comparison of Horizontal Nystagmus in Different Head Positions: A Study by Damped Pendular Rotation Test

Damped pendular rotation was given with the initial maximum speed of 180 degrees/s. The subjects head was tilted forward at an angle of 30 degrees from the upright position, or kept in the upright position, or tilted backward at 30 degrees from the upright position. Electronystagmography was used to evaluate the maximal slow-phase eye velocity (mx SPEV) of the horizontal nystagmus. Differences existed in mx SPEVs of the horizontal nystagmus for the head-tilted positions at 30 degrees forward or backward and that obtained in the upright position. The mx SPEV of the horizontal nystagmus in the upright position was higher than those acquired in the head-tilted positions.

Evaluation of the vertical semicircular canal function by the pendular rotation test : A study on patients with benign paroxysmal positional vertigo

The pendular rotation test (non-damped) in a head-tilted position, 60 degrees backward and then rotated 45 degrees either to the right or left, was performed in 6 patients with benign paroxysmal positional vertigo. The stimulus mode was amplitude = 360 degrees, frequency = 0.1 Hz, and the maximal speed = 114 degrees/s. By this test procedure, it was possible to evaluate the excitability of vertical semicircular canals. Using an infra-red CCD camera and a personal computer system, the evoked nystagmus was analysed. A statistically significant difference (p < 0.05) in the maximal slow-phase eye velocity of vertical nystagmus was found between those from the anterior semicircular canal and those from the posterior semicircular canal. The excitability of the posterior semicircular canal in the affected ear was found to be lower than that of the anterior semicircular canal.