The Torsion Swing: A Simple Rotation Test

Abstract

A simple rotation test, the torsion-swing test, is used as a clinical method for the examination of the horizontal canals. By means of electronystagmography the per-rotatory horizontal nystagmus during movements of this swing is recorded. The difference between the total number of nystagmus beats to the left and the total number of beats to the right during the first ten swingings is expressed as a percentage of the total number of beats. The mean and standard deviation of this difference between left- and right-beating nystagmus in 80 normal subjects were calculated. A directional preponderance greater than 23% (double standard deviation) is an indication of pathology.