Fifty two patients with positioning nystagmus were studied with the V.N.G. three-dimentional device of ULMER. In benign paroxysmal positional vertigo (BPPV) the torsionnal component is not pure: a vertical and a less important horizontal components also exist. They are not of the same amplitude on both eyes. The torsionnal and horizontal components are more important on the eye ipsilateral to the BPPV. The vertical component is more important on the contralateral eye. The horizontal canal B.P.V. (2% of the cases of B.P.V.) is so defined by the absence of vertical and torsionnal components. Three-D Eye Movement Analysis is helpful for differential diagnosis with the positional protocol described. The characteristics of central and peripheral paroxysmal positional nystagmus are given. The head Tilt and the ocular counter rolling reflex (O.C.R.) can be quantified with this device. It will be useful in the future to better explore the inferior root of the eighth nerve and the otolith organ. For clarity we propose to describe the torsionnal nystagmus so that the results are expressed with respect to the patient: clockwise nystagmus (in reference to the patient) would thus be also right rotatory nystagmus while left rotatory nystagmus would be also anticlockwise.