Efficacy of cervical and ocular vestibular-evoked myogenic potentials in evaluation of benign paroxysmal positional vertigo of posterior semicircular canal

Abstract

Benign paroxysmal positional vertigo (BPPV) constitutes a major proportion of the population with peripheral vestibulopathies. Although the freely floating otoconia within the semicircular canals is responsible for the symptoms of BPPV, the source of the otoconia debris is mainly believed to be the otolith organs. Therefore, the pathology in either or both the otolith organs appears a logical proposition. Cervical and ocular vestibular-evoked myogenic potentials (cVEMP and oVEMP), being the tests for functional integrity of the otolith organs, appear promising for investigating otolith involvement in BPPV. While recent evidences are suggestive of equivocal findings for cVEMP, there are only a few studies on oVEMP. Additionally, both these potentials have never been explored in the same set of individuals with BPPV. Therefore, the present study aimed to evaluate the functional integrity of the otolith organs through cVEMP and oVEMP in individuals with posterior canal BPPV. Thirty-one individuals with unilateral posterior canal BPPV and 31 age- and gender-matched healthy controls underwent 500 Hz tone-burst-evoked cVEMP and oVEMP. The results demonstrated no significant group difference on any of the cVEMP parameters (p > 0.05). A similar trend was noticed for the latency-related parameters of oVEMP. However, the peak-to-peak amplitude was significantly smaller in the affected ears of individuals with BPPV than their unaffected ears and the ears of healthy controls (p < 0.05). The BPPV group showed significantly higher inter-aural amplitude difference ratio than the healthy controls (p < 0.05). Further, the sensitivity and specificity of oVEMP were also found to be far superior to those of cVEMP. Thus, the outcome of the present study revealed involvement of utricle rather than saccule in posterior canal BPPV, and therefore, oVEMP appears to be better suited to clinical investigation than cVEMP in individuals with posterior canal BPPV.

Utility of the Frequency Tuning Measure of oVEMP in Differentiating Meniere’s Disease from BPPV

“…The oVEMP being a utricular response, it could be useful in identifying utricular involvement in BPPV. This was indeed confirmed by the results of some of the recent studies that demonstrate utricular involvement in BPPV (Nakahara et al, 2013;Seo et al, 2013;Singh and Barman, 2015;Singh and Apeksha, 2016). While these studies reported reduced oVEMP amplitudes in the ears with BPPV, Seo et al (2013) and Singh and Barman (2015) also reported the finding of augmented oVEMP amplitude in the affected ears of individuals with BPPV.…”

Optimum Response Filter Setting for Air Conduction–Induced Ocular Vestibular Evoked Myogenic Potential

“…This is a further testimony to the outcomes of phase I of the study which showed that 0.1-1000 Hz was a better band-pass filter than the 1-to 1000-Hz one and should, therefore, be considered optimum for clinical recording of oVEMP. Similar better response detection could be a probability in some of the individuals suffering from clinical conditions such as Meniere's disease or benign paroxysmal positional vertigo (BPPV), which are known to result in amplitude reduction of oVEMP or cause its absence in several cases (Singh and Barman, 2015;2016a,b;Singh and Apeksha, 2016), which, however, can be confirmed only after experimental evidence from future studies in this regard. Here, it would be important to mention a word of caution that two of 20 ears represent a small sample and require more controlled studies to further assert the findings.…”

Vestibular-Evoked Myogenic Potential Testing in Vestibular Localization and Diagnosis

“…76,77 Similar results have also been reported for oVEMPs in the unaffected ear and for cVEMPs, suggesting that both sides and both otoliths may be affected by the same otoconial deterioration. Abnormality rates tend to be higher in oVEMPs than cVEMPs, 73,74 but AC oVEMPs are more sensitive to disease in general and recruitment bias is likely to be an important factor. In VN, patients with saccular dysfunction are less likely to present with BPPV, since this signifies involvement of the inferior division and thus posterior canal dysfunction, which would result in failure of dislodged otoconia to produce vertigo when they fall into the posterior canal.…”

“…However, many studies have now demonstrated a higher than expected rate of VEMP abnormalities in patients with BPPV. 73,74 This is likely to occur for two reasons. First, some patients may develop BPPV following another vestibular disease (e.g., VN) or direct damage to the otoliths (e.g., head trauma).…”

“…Second, the VEMP abnormalities may reflect the deterioration in otoconial membrane that is thought to precipitate BPPV. Several studies have found elevated rates of absent or small oVEMPs compared with age-matched controls after excluding patients with other neuro-otological diagnoses: amplitudes tend to be smaller in affected ears, [73][74][75] and abnormalities more frequent in patients with recurrent symptoms. 76,77 Similar results have also been reported for oVEMPs in the unaffected ear and for cVEMPs, suggesting that both sides and both otoliths may be affected by the same otoconial deterioration.…”