On the Functional State of Central Vestibular Structures in Monoaural Symptomatic Tinnitus Patients (BEAM-VbEP Study).

Clinical evidence suggests that overexcitation or disinhibition of structures in the brain occurs in tinnitus patients.1,2 Brain electrical activity mapping of vestibular evoked potentials (BEAM-VbEP method) provides an electrophysiologic approach of quantification of function in brain cortex. The effect of tinnitus on the BEAM-VbEP image was examined in two groups of acoustic tumor patient Group A (n = 24) reported tinnitus and Group B (n = 22) did not.  Statistically significant differences in the VbEP parameters have been identified between the two groups. The amplitude of the III/IV peak-to-peak component elicited by the rotation to the affected side, is higher (P < O.OS) in the tinnitus group than in the non-tinnitus group. Latencies of the late VbEP components (III, IV, and V) are shorter. In subgroup III, latency was 317.9 ± 37.5 ms in the tinnitus group versus 33S.S ± 30.9 ms in non-tinnitus group (p < O.OS); subgroup IV's component of 437.1 ± 3S.4 ms versus 470.9 ± 43.5 ms (p < 0.01), V 622.1 ± 32.6 versus 6SS.5 ± 46.6 ms (p < O.OS). Amplitude mapping of the most prominent VbEP component, subgroup III, demonstrates a well expressed negativity shift of the evoked brain electrical activity. The character of the electrophysiologic VbEP changes in the group of tinnitus patients is irritative. We consider the above described BEAM-VbEP images in tinnitus patients to reflect an electrophysiologic correlative of a state of cortical disinhibition, caused by either hyperactive or hypersensitive neural structures. Tinnitus is an aberrant p~rception of sound unrelated to an external source of acoustic stimulation; a dysynchrony within the auditory system.3-S