A short latency vestibular evoked potential (VsEP) produced by bone-conducted acoustic stimulation.
In this paper data are presented from an experiment which provides evidence for the existence of a short latency, acoustically evoked potential of probable vestibular origin. The experiment was conducted in two phases using bone-conducted acoustic stimulation. In the first phase subjects were stimulated with 6-ms, 500-Hz tone bursts in order to obtain the threshold V(T) for vestibular evoked myogenic potentials (VEMP). It was confirmed that the difference between bone-conducted auditory and acoustic vestibular thresholds was slightly over 30 dB. The estimated threshold was then used as a reference value in the second part of the experiment to stimulate subjects over a range of intensities from -6 to +18 dB (re: V(T)). Averaged EEG recordings were made with eight Ag/AgCl electrodes placed on the scalp at Fpz, F3, F4, F7, F8, Cz, T3, and T4 according to the 10-20 system. Below V(T) auditory midlatency responses (MLRs) were observed. Above V(T) two additional potentials appeared: a positivity at about 10 ms (P10) which was maximal at Cz, and a negativity at about 15 ms (N15) which was maximal at Fpz. Extrapolation of the growth functions for the P10 and N15 indicated a threshold close to V(T), consistent with a vestibular origin of these potentials. Given the low threshold of vestibular acoustic sensitivity it is possible that this mode may make a contribution to the detection of and affective responses to loud low frequency sounds. The evoked potentials may also have application as a noninvasive and nontraumatic test of vestibular projections to the cortex.
Todd
Neil P McAngus
NP
Department of Psychology, University of Manchester, Manchester M13 9PL, United Kingdom. todd@psy.man.ac.uk
Rosengren
Sally M
SM
Colebatch
James G
JG
D000161:Acoustic Stimulation; D001309:Auditory Threshold / Q000502:physiology; D001844:Bone Conduction / Q000502:physiology; D002540:Cerebral Cortex / Q000503:physiopathology; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory / Q000502:physiology; D006801:Humans; D009334:Neck Muscles / Q000294:innervation*; D010037:Otolithic Membrane / Q000503:physiopathology*; D011930:Reaction Time / Q000502:physiology*; D012018:Reflex / Q000502:physiology; D012815:Signal Processing, Computer-Assisted; D015837:Vestibular Diseases / Q000175:diagnosis* / Q000503:physiopathology; D014724:Vestibular Function Tests; D014726:Vestibular Nuclei / Q000503:physiopathology*