Journal of Vestibular Research

This article presents operational diagnostic criteria for benign paroxysmal positional vertigo (BPPV), formulated by the Committee for Classification of Vestibular Disorders of the Bárány Society. The classification reflects current knowledge of clinical aspects and pathomechanisms of BPPV and includes both established and emerging syndromes of BPPV. It is anticipated that growing understanding of the disease will lead to further development of this classification.

BACKGROUND: Linear acceleration generally gives rise to translation perception. Centripetal acceleration during centrifugation, however, has never been reported giving rise to a radial, inward translation perception.

OBJECTIVE: To study whether centrifugation can induce a radial translation perception in the absence of visual cues.

METHODS: To that end, we exposed 12 subjects to a centripetal acceleration with eyes closed. To avoid confounding with angular motion perception, subjects were fist rotated on-axis, and were shifted out fast and slow only after rotation sensation had vanished. They were asked for translation direction and velocity right after the shift-out, as well as after about 60 seconds of constant centrifugation.

RESULTS: Independent of fast or slow shift-out, the vast statistically significant majority of trials yielded an inward radial translation perception, which velocity was constant after 60 seconds of constant centrifugation.

CONCLUSIONS: We therefore conclude that during centrifugation, an inward radial translation perception does exist in humans, which perception reaches a constant, non-zero value during constant rotation, lasting for at least one minute. These results can be understood by high-pass filtering of otolith afferents to make a distinction between inertial and gravitational acceleration, followed by a mere integration over time to reach a constant velocity perception.

Self-motion perception, which partly determines the realism of dynamic driving simulators, is based on multisensory integration. However, it remains unclear how the brain integrates these cues to create adequate motion perception, especially for curvilinear displacements. In the present study, the effect of visual, inertial and visuo-inertial cues (concordant or discordant bimodal cues) on self-motion perception was analyzed. Subjects were asked to evaluate (externally produced) or produce (self-controlled) curvilinear displacements as accurately as possible. The results show systematic overestimation of displacement, with better performance for active subjects than for passive ones. Furthermore, it was demonstrated that participants used unimodal or bimodal cues differently in performing their activity. When passive, subjects systematically integrated visual and inertial cues even when discordant, but with weightings that depended on the dynamics. On the contrary, active subjects were able to reject the inertial cue when the discordance became too high, producing self-motion perception on the basis of more reliable information. Thereby, multisensory integration seems to follow a non-linear integration model of, i.e., the cues' weight changes with the cue reliability and/or the intensity of the stimuli, as reported by previous studies. These results represent a basis for the adaptation of motion cueing algorithms are developed for dynamic driving simulators, by taking into account the dynamics of simulated motion in line with the status of the participants (driver or passenger).

BACKGROUND: The ocular vestibular myogenic potentials (oVEMP) can be elicited by monaural air-conducted sound stimulation, and are usually recorded from the contralateral eye. In clinical setting a binaural stimulation would save time and require less effort from the subjects.

OBJECTIVE: We evaluated the differences between monaural and binaural stimulation, and the possible effect of age and gender on oVEMP parameters.

METHODS: Air-conducted oVEMP were recorded by binaural and by monaural stimulation in a group of 54 normal subjects, aged from 12 to 83 years, and in 50 vestibular patients. From each side, we measured the latency of the N1 component, and the peak-to-peak N1-P1 amplitude. For both parameters we also computed the asymmetry ratio.

RESULTS: In normal subjects binaural stimulation produced slightly larger responses than monaural stimulation; detectability, latency and amplitude ratio were the same for the two techniques. We found no differences related to gender, and the age-induced amplitude decline was likely to be negligible.

oVEMP recorded not in an acute phase of their disorder, proved to be abnormal in about 20% of the patients, and the normal or abnormal findings obtained either with monaural or with binaural stimulation were always concordant.

CONCLUSIONS: The oVEMP obtained after binaural and monaural stimulation are very similar, and they are largely independent from age and gender.

AIMS: The purpose of this study is to compare the test-retest reliability of cervical vestibular evoked myogenic potential (cVEMP) parameters between monaural sequential (mSEQ) cVEMP and binaural simultaneous (bSIM) cVEMP recordings.

MATERIALS AND METHODS: Twenty two volunteers aged 22 from 38 years were enrolled. Two different methods of cVEMP measurement were performed in the subjects. The two methods were (1) monaural sequential (mSEQ) measurement and (2) binaural simultaneous (bSIM) measurement. After a mean test-retest interval of 7.1 ± 2.8 days, the second run of the cVEMP measurement was performed in a random order. To compare the test-retest reliability of mSEQ and bSIM cVEMP responses, Intraclass correlation coefficient (ICC) and Spearman correlation were applied.

RESULTS: Both p13 and n23 latencies did not show a statistically significant difference between the two cVEMP recording methods. Also, there were no significant differences in the inter-peak amplitude (IPA) and interaural amplitude difference (IAD) ratio between the two methods. The test-retest reliability of inter-peak amplitude (IPA) demonstrated a positive correlation for both mSEQ and bSIM cVEMP methods. The IAD ratio of bSIM cVEMP response demonstrated a statistically significant test-retest reliability (ICC = 0.691, p= 0.015). However, the IAD ratio of mSEQ cVEMP response did not demonstrate a statistically significant test-retest correlation.

CONCLUSION: Results implicate that bSIM cVEMP not only saves time, but it also has an advantage of a more reliable test-retest outcome.

OBJECTIVE: The aims of the study are to determine the intra-, interobserver, and the test re-test reliability of the cervical and ocular vestibular evoked myogenic potentials (VEMPs).

METHODS: Twenty healthy subjects underwent acoustically and forehead tap elicited cervical and ocular VEMPs. The measurements were repeated one week later.

RESULTS: The intra- and interobserver reliability of both ocular and cervical VEMPs is excellent. The test re-test reliability of the raw p13n23 peak-to-peak amplitudes of the cervical VEMPs is excellent (ICC: 0.76, 0.87) and the p13 latencies show a good reliability (ICC: 0.56, 0.73). The raw n1p1 peak-to-peak amplitudes of the ocular VEMPs show a fair-to-good test re-test reliability (ICC: 0.51, 0.64) and the n1 and p1 latencies show a poor reliability (ICC: -0.17 ≤ x ≤ 0.44).

CONCLUSIONS: The intra- and interobserver reliability of the cervical and ocular VEMPs is excellent. The raw ocular and cervical VEMP peak-to-peak amplitudes are the most reliable parameters, followed by the cervical VEMP latencies. The ocular VEMP latencies shows a poor test re-test reliability. The individual VEMP results, however, remained within normal limits despite the test re-test variability.

OBJECTIVE: We investigated the neuro-otological findings, including nystagmus, and the clinical course of patients with the horizontal canal variant of benign paroxysmal positional vertigo (HC-BPPV), who showed spontaneous inversion of nystagmus without a positional change. Furthermore, we speculated on the possible mechanism of spontaneous inversion of nystagmus without a positional change.

PATIENTS AND METHODS: The characteristics of spontaneous inversion of positional nystagmus without a positional change were analyzed in 7 patients with HC-BPPV.

RESULTS: All patients were diagnosed as having HC-BPPV. During the positional test, the spontaneous inversion of nystagmus was observed in the same head position in all patients. Spontaneous inversion was observed on both sides in 5 patients, and only on 1 side in 2 patients. All patients presented with geotropic nystagmus in the first phase, and ageotropic nystagmus in the second phase.

CONCLUSIONS: The coexistence of cupulolithiasis and canalolithiasis appears to be a possible mechanism of the spontaneous inversion of positional nystagmus.

OBJECTIVE: This study adopted an inner ear test battery comprising audiometry, and ocular vestibular-evoked myogenic potential (oVEMP), cervical VEMP (cVEMP) and caloric tests to assess inner ear function in patients with long term exposure to organic solvents.

METHODS: Eighteen patients exposed to organic solvents and another 18 non-exposed controls from the same environment were enrolled in this study. Each subject underwent an inner ear test battery.

RESULTS: The percentages of abnormalities identified by the oVEMP test, cVEMP test, audiometry and caloric test for the exposed group were 85%, 54%, 50% and 33%, respectively, which showed significant differences when compared with the respective 8%, 8%, 6% and 0 for the non-exposed group. Additionally, a significantly declining trend of inner ear deficits from the utricle to the saccule, cochlea, and semicircular canals was noted in the exposed group, but not in the non-exposed group.

CONCLUSION: Ototoxicity was identified in those exposed to organic solvents, with the sequence of abnormal inner ear function from the utricle to the saccule, cochlea, and semicircular canals.

BACKGROUND: Vestibular rehabilitation (VR) improves symptoms and function in some but not all patients with bilateral vestibular hypofunction (BVH).

OBJECTIVE: The purpose of this retrospective study was to examine change following vestibular rehabilitation and to identify factors associated with rehabilitation outcome in patients with BVH.

METHODS: Data from 69 patients with BVH were analyzed. Factors studied included patient characteristics, subjective complaints and physical function. Outcome measures included symptom intensity, balance confidence, quality of life, gait speed, fall risk, and dynamic visual acuity. Bivariate correlations were used to examine relationships of patient characteristics and baseline measures with outcome measures. One-way ANOVAs were used to compare outcomes in patients with BVH versus unilateral vestibular hypofunction (UVH).

RESULTS: As a group, patients with BVH improved in all outcome measures except disability following a course of vestibular rehabilitation (VR); however, only 38-86% demonstrated a meaningful improvement, depending on the specific outcome measure examined. Several factors measured at baseline - age, DGI score, gait speed and perceived dysequilibrium - were associated with outcomes. For example, greater age was related to higher DVA scores at discharge; lower initial DGI scores were related to higher Disability scores at discharge. Compared to patients with UVH, reported previously [9], a smaller percentage of patients with BVH improve and to a lesser extent.

CONCLUSION: Consideration of baseline factors may provide guidance for setting patient goals. Further research is needed determine what factors predict outcome and to develop more effective treatment strategies for those patients who do not improve.