Chronic unilateral loss of otolith function revealed by the subjective visual vertical during off center yaw rotation.

摘要: Assessing the subjective visual vertical, SVV, in a static upright position is an easy clinical test which deviation of some 10 degrees from true vertical indicates acute loss unilateral (otolithic) vestibular function on side to SVV tilted. Because this compensated during following months, patients with chronic do no longer differ normal subjects. This study presents experimental set-up that allows for clear detection otolithic by testing SVV. 21 normals and 17 unilaterally deafferentiated (UVD) (vestibular neurectomies) were first rotated human centrifuge about earth yaw axis through midsagittal plane head (240 degrees/s). induced tilts gravito-inertial force (GIF) vectors, differed at two inner ears 8 degrees. During constant velocity rotation, subjects moved pseudo-randomized steps laterally up 16 cm apart rotation axis, inducing roll GIF vectors Normal set their pre-centrifugation values positions close while UVD indicated 5.9 +/- 2.5 paramedian intact ear. Tilts shifted gain 0.70 only 0.32 patients. Roll gains directed relative ear did not medially The observed lower than those body or eccentric larger radius, might be least partially due conflicting stimulation between extra-vestibular cues.