The efficacy of auditory brainstem responses (ABRs), middle-latency responses (MLRs), and slow cortical potentials (SCPs) has been evaluated in 40 patients with multiple sclerosis (MS). ABRs and MLRs were averaged to clicks and SCPs to 1-kHz tone bursts of 70-dB nHL intensity. ABR, MLR, and SCP abnormalities were detected in 65.0, 42.5, and 30.0% of the sample, respectively. The combined sensitivity of ABRs and MLRs amounted to 80.0%, of ABRs and SCPs to 75.0%, and of MLRs and SCPs to 60.0%. The joint aptitude of all three responses equalled 87.5%. All three responses were capable to detect MS in seven of nine patients, failing to display neurological signs of brainstem lesion. The responses were also abnormal in three of five subjects with negative magnetic resonance imaging. It is concluded that the combined application of ABRs, MLRs, and SCPs promotes both detecting and confirming MS loci.

Auditory brainstem responses (ABRs), middle latency responses (MLRs), and slow cortical potentials (SCPs) were registered in normal-hearing adults to trains of low-frequency signals delivered binaurally on a background of a continuous masking noise. Two stimulus conditions, labelled as S0M0 and S pi M0 paradigms, respectively, were systematically compared. In the S0M0 paradigm, both the signals and the masker were in-phase at two ears. In the S pi M0 paradigm, the signals were out-of-phase at two ears, while the masker was in-phase. The psychoacoustic release from masking in S pi M0 vs. S0M0 paradigms was regularly accompanied by an increase in amplitudes and a shortening in peak latencies of the SCPs. In contrast, no differences were evidenced between the S0M0 and the S pi M0 paradigms with respect to the ABRs and the MLRs. Considering the generation loci of the studied electric responses, it is concluded that the binaural psychoacoustic phenomenon, referred to as the masking level difference, is operated primarily at the cortical level.

ABR recordings were made on 31 normal-hearing subjects and 253 patients with sensorineural hearing loss (86 patients with unilateral hearing loss, 61 patients with asymmetrical hearing loss, 34 patients with symmetrical hearing loss, 55 patients with noise-induced hearing loss and 17 patients in the late chronic stage of Menière's disease). In the patient group with unilateral hearing loss, the mean interpeak interval (IPI) I-V was significantly shorter than in normal-hearing subjects. The interaural IPI differences provide a sharp criterion for early detection of acoustic neuroma. The calculation of the 95%-limits (means + 1.96 SD) showed that in patients with normal hearing or with unilateral or symmetrical hearing loss an interaural difference in the IPII-V greater than 0.2 ms has to be considered as an indication of a neuroma or any other brainstem abnormality. In patients with asymmetrical or with noise-induced hearing loss, the limit is 0.3 ms. In contrast to the frequently recommended interaural wave V latency difference criterion, the interaural IPI difference criterion requires no correction for audiogram differences.

Auditory brainstem responses, middle-latency responses, and slow cortical potentials (ABRs, MLRs, SCPs) were recorded in 21 epileptic patients before and during treatment with carbamazepine (CBZ). The peak-latencies, interpeak intervals, and amplitudes were estimated and evaluated statistically. CBZ monotherapy resulted in prolongation of peak latencies of ABR waves I, III, and V as well as of interpeak intervals I-III and I-V. A significant increase in the peak-latencies of MLR components Na, Pa, and Nb and of interpeak intervals V-Pa and Na-Nb was also observed along with the systematic NaPa amplitude reduction. CBZ also prolonged the peak-latencies of SCP components P1 and N1. Based on the obtained results, we suggest that CBZ exerts suppressive influences both on modally specific (lemniscal) and modally nonspecific (extralemniscal) auditory structures.

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Parameters of the brainstem auditory evoked potentials (BAEPs) to high-intensity clicks of initial rarefaction (R) and condensation (C) phases differed. The amplitudes of Waves I, II and IV were greater with R clicks, while that of Wave V was greater with C clicks. The peak-latencies of Waves I and VI were shorter with R clicks and those of the remaining components tend to shorten with C clicks. At low stimulus intensities the preserved BAEP components (Waves III, V and VI) did not change noticeably with click phase inversion.

The effects of the preceding (conditioning) click on the evoked otoacoustic emission (EOAE) to the following (test) click were investigated in normally hearing adults. To overcome distortions due to superimposition of the test EOAE on the EOAE to the conditioning click, a special stimulation and response subtraction procedure was utilized. The conditioning stimulus was found to suppress the test EOAE. The suppression lessened with a decrease in the conditioning stimulus level and an increase in the time interval between the conditioning and the test stimuli. Nevertheless, the influence was traced even with the level of the conditioning stimulus as low as 5 dB SL, and lasted for the interval between the conditioning and the test stimuli, as long as 7.5 ms. An attempt at theoretical comprehension of the obtained results is made and their usefulness in differentiation of EOAEs from acoustic reflections is proposed.

<b><i>Objective:</i></b> To assess the relationship between ocular (oVEMPs) and cervical (cVEMPs) vestibular evoked myogenic potentials and audiometrically determined clinical stage in Ménière’s disease (MD). <b><i>Methods:</i></b> Thirty-four unilateral MD patients and 30 healthy volunteers were included in the study. Pure-tone hearing levels, oVEMPs, cVEMPs, and videonystagmography results were analyzed and compared between the groups. <b><i>Results:</i></b> Both oVEMPs and cVEMPs were highly reproducible in the control group. At the early stages of MD, cVEMPs were particularly disturbed, while at the advanced stages both oVEMPs and cVEMPs were altered pathologically. In the study group, oVEMP and cVEMP amplitudes and interaural amplitude difference (IAD) statistically differed from those in the control sample. oVEMPs were absent in 7.7% of stage III and in 44.5% of stage IV MD patients, while cVEMPs were absent in 15.4% of stage III and in 54.5% of stage IV MD patients, respectively. In stage III and IV MD patients in whom oVEMPs and cVEMPs were obtained, IADs were increased. Caloric asymmetry was found in 64.7% of MD patients. Caloric weakness was more prominent in cases with advanced MD. <b><i>Conclusion:</i></b> VEMPs can be used for objective validation of the stage of MD.