Neck muscle vibration alters visually-perceived roll after unilateral vestibular loss

Unilateral sternocleidomastoid muscle vibration was applied to 21 normal an d six unilateral vestibular deafferented (uVD) human subjects at head erect and during 30 degrees left and right whole body roll-tilt. In normal subje cts, neck vibration had no effect upon the settings of a visual bar to subj ective visual horizontal (SVH) in any roll-tilt condition. In uVD subjects settings to SVH were significantly altered by neck vibration, with ipsilesi onal neck vibration increasing the SVH bias at head erect. Further, during contralesional roll-tilt, ipsilesional neck vibration in uVD subjects signi ficantly increased the E-effect. These results suggest that compensation af ter vestibular loss allows cervical signals to influence visual perception of roll-tilt. (C) 2000 Lippincott Williams & Wilkins.