Three Derivations in Electronystagmography

Abstract

In order to be able to detect in the simplest possible manner and in part also to analyse the changed direction of nystagmus, three derivations for recording nystagmus have been introduced. Three bipolar leads are connected to three electrodes. The magnitude of the electric effect in one derivation is directly proportional to the corneoretinal potential; in the second inversely proportional to the square of distance of the lead points from the rotating dipole; both are corrected by calibration. The third magnitude of the electric effect is in direct proportion to the cosine of the deflection angle which exists between the rotating dipole and the line of derivation. It is thus possible to mark in an isoceles for each derivation the amplitude of the deflection of the eye from the central point.