BODY RESPONSE TO BINAURAL MONOPOLAR GALVANIC VESTIBULAR STIMULATION IN HUMANS

We investigated the possibility of obtaining an anteroposterior body r esponse to galvanic vestibular stimulation (GVS) by applying an equiva lent stimulus to both sides of the vestibular apparatus. An original ' double fronto-mastoidal' stimulation was used on eight subjects standi ng with their head facing forwards. Both the onset and the cut-off of the current did induce an anteroposterior body tilt, without any later al component. The amplitude of the tilt increased as a function of sti mulus intensity. GVS evokes anteroposterior or lateral sway of similar spatio-temporal features according to the stimulation configuration. We suggest that the central nervous system makes use of the discrepanc y between the left and right vestibular activity to orientate the resp onse: equivalent afferent flows would result in an anteroposterior bod y response whereas lateral sway is obtained with discrepant ones. (C) 1998 Elsevier Science Ireland Ltd.