[Clinical evaluation of otolithic function by the measurement of ocular cyclotorsion and skew deviation]

The ocular tilt reaction (OTR) consists in an association of an eye-head postural reaction, alteration of vertical perception, conjugated eye cyclotorsion, skew deviation and head tilt. We observed this condition following unilateral vestibular neurectomy and labyrinthectomy performed in patients suffering from severe Meniere's disease. All patients described postoperative vertical diplopia and vertical perception tilt. One illustrative case is reported in detail here. Changes in visual vertical were measured using a vertical frame with a pivoting pointer and the Maddox rod calibrated with a spirit level. The actual eye torsion was measured by a photography of eye-fundus. In the follow-up, it was found that vertical diplopia disappeared within a few days while conjugated eye cyclotorsion lasted weeks to months. Mechanisms involved in the OTR could be the consequence of a unilateral deafferentation of the utricular and saccular organs. We feel that the techniques of examination which we used with this patient might be a useful measurement for the clinical evaluation of unilateral otolithic dysfunction.