Vestibular Evoked Potentials (VestEP) and Brain Electrical Activity Mapping - A Test of Vestibular Function - A Review (1990 - 1996).

Brain Electrical Activity Mapping of Vestibular Evoked Potentials (BEAM-VestEP) is a new technology for investigation of the spatial and temporal properties of a rotationally-induced brain electrical events. The method consists of multichannel EEG registration and mapping of the brain isoelectrical contours during short-lasting repetitive angular accelerations. A special data bank containing more than 400 BEAM-VestEP investigations on more than 300 persons, either symptom free volunteers or neurotological patients suffering from vertigo, tinnitus, sudden hearing loss, acoustic tumors, balance disorders, has been created for this study. The VestEP wave set consists of 5 - 7 positive/negative wave components, appearing within the time interval of 70 - 850 ms after the onset of the acceleratory step stimulus. The principle components analysis reveals that the shortest latencies and the highest amplitudes of the VestEPs can be registered from the central transversal line of electrodes, T3-C3-Cz-C4-T4. The later components are generated from the more frontally located cortical areas. The VestEP is a compound electrical phenomenon. The initial complex ( waves I - III) is related to the activation of specific (vestibular) cortical areas. The later complex (waves IV - VI) reflects the supramodal cortical proceedings with sensory information (cognitive components). INTRODUCTION Functional neuroimaging in neurootology with Brain Electrical Activity Mapping (BEAM) has been introduced to record cortical Vestibular Evoked Potentials (VestEP) in response to a rotatory stimulus. 14-18, 22, 34, 37, 38 Brain Electrical Activity Mapping (BEAM) is a special electrophysiological imaging procedure providing a graphic and quantitative recording of responses to a stimulus related electroencephalogram (EEG) event. This technique has particular application to neurootology for the investigation of sensation of: a) equilibrium; b) hearing; c) taste; d) smell. The technique has provided new insights into the origin and quality of complaints of Reprint requests: