Clinically relevant physiology of the vestibulo-ocular reflex.

This review attempts to explain those aspects of the physiology of the vestibulo-ocular reflex (VOR) which could be of future clinical value. The literature cited has been selected for its didactic worth to readers with limited time, preferring concise reviews to detailed reports wherever possible. Physiological data provide the background for the following possible improvements in clinical diagnosis: 1) In gaze analysis, coordination of the VOR with other motor patterns can be analyzed. 2) Precision of vestibular tests can be improved by selecting stimuli within the range of natural movements.3) Resolution of the caloric test can be imporved when the change of temperature at the semicircular canal mimics endolymph pressure changes during natural movements. 4) A direct test of the three neuron VOR pathways is possible, but not practicable. 5) Integration of the input signal (transformation from head acceleration to eye position information) can be directly tested. 6) Plasticity (the adaptation to visual requirements) of the VOR can be examined. 7) It is possible to quantify vestibular damage and detect the side of lesion in one test analyzing gain and binocular symmetry of the vertical VOR.