Three-dimensional modeling of static vestibulo-ocular brain stem syndromes

STATIC vestibule-ocular brain stem syndromes characterized by skew deviatio n, a vertical disconjugacy of the eyes, and ocular torsion are the result o f a vestibular tone imbalance in the frontal (roll) plane. Similar physiolo gical changes in static eye position, ocular counter-roll and conjugated de viations of vertical eye position, are caused by the influence of gravity m ediated by the utricles. These observations prompted our approach with the model described here: based on the known deviations of static eye position, we devised a three-dimensional mathematical model of otolith-ocular functi on including detailed brain stem anatomy. This model is able to explain and predict the differential effects of unilateral and bilateral peripheral or central vestibular lesions on static eye position in roll, pitch, and yaw planes. NeuroReport 9: 3841-3845 (C) 1998 Lippincott Williams & Wilkins.