Editorial: Impacts of VEMP and VHIT on the diagnosis of vestibular diseases

COPYRIGHT © 2023 Tarnutzer, Seo, Fujimoto, Straumann and Murofushi. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Editorial: Impacts of VEMP and VHIT on the diagnosis of vestibular diseases

With the introduction of quantitative testing of both the angular (i.e., the semicircular canals) and linear (utriculus and sacculus) acceleration sensors in the inner ear and their neural afferents, vestibular mapping has become broadly available [e.g. (1)]. Important milestones were laid by Colebatch et al. (2), who introduced cervical vestibular-evoked myogenic-potentials (cVEMPs) for assessing saccular function, and about a decade later, when the basics of ocular VEMPs (oVEMPs) for assessing utricular function were described by Rosengren et al. (3). Likewise, with the development of a lightweight high-resolution video head impulse testing (vHIT) device, the Sydney team led by Curthoys, Halmagyi, MacDougall, McGarvie, and Weber introduced quantitative video-based testing of the horizontal angular vestibulo-ocular reflex (aVOR) in 2009 (4). Four years later, testing of the vertical semicircular canals using vHIT was proposed by the same group (5,6).
Several vHIT systems are now commercially available. Quantitative testing of the aVOR became a cornerstone in the diagnostic workup of patients with dizziness/vertigo or balance disorders, both in the emergency department and on the ward, but also in specialized private practices and in tertiary vertigo clinics. The impact of quantitative assessments of vestibular function is significant in patients with acute vestibular syndrome, as demonstrated by Korda et al. (7) and Nham et al. (8), who reported increased diagnostic accuracy for detecting vertebrobasilar stroke by quantitative testing compared with bedside testing. Likewise, vHIT has significantly improved the diagnosis of acute peripheral vestibulopathy, especially in cases with an isolated involvement of the inferior branch of the vestibular nerve (9) or the posterior semicircular canal (10, 11). Additionally, in telemedicine approaches with acutely dizzy patients, vHIT plays an important role, as demonstrated in a recent feasibility study (12).
Thus, this Research Topic aimed to bring together new insights into the clinical utility of quantitative vestibular testing, focusing on current state-of-the-art technologies, such as vHIT and VEMPs. A highlight of this Research Topic is a series of manuscripts that discuss . After finding no evidence of a significantly reduced semicircular canal or otolith function, the authors concluded that a persistent structural affection of the vestibular system by SARS-CoV-2 seems to be unlikely. When comparing vestibular responses in patients with definite unilateral MD with migraine headaches or without headaches, a male predominance in the group without headaches and a higher rate of severe saccular dysfunction for cVEMPs in patients with MD and migraine headaches than in MD patients without headaches were reported (Inui et al.). Thus, the presence of migraine headaches may affect the pattern of vestibular function in MD. How coexisting deficits due to preceding vestibular disorders affect PPPD symptoms is not well understood. Characterizing the clinical features of PPPD with or without vestibular dysfunction using both VEMPs and vHIT and various questionnaires, including the DHI, was therefore pursued in another study (Azami et al.). Interestingly, significantly higher (i.e., worse) DHI scores were noted in those PPPD patients with combined utricular and saccular damage, emphasizing the importance of quantifying otolith function in PPPD when deciding on treatment strategies.
A systematic review and meta-analysis was performed to advance our understanding of the etiology and prevalence of vertigo disorders in children to eventually improve the diagnostic approach and management of pediatric patients presenting with dizziness or vertigo (Zhang et al.). With peripheral disorders identified in 52% of all patients and central disorders in 29%, the most frequently made diagnoses were vestibular migraine and BPPV of childhood (20% each). Reported gender specificity in vestibular migraine and psychogenic vertigo emphasizes the importance of an individualized approach. Recovery or improvement after symptomatic treatment and nonpharmacological treatment point to the most suitable management strategies in this review.
In summary, this Research Topic further emphasizes the clinical utility of state-of-the-art vestibular testing in vestibular disorders and sheds new light on the pearls and pitfalls in vHIT recording and interpretation and VEMP findings in various disorders. At the same time, it highlights current needs and future research directions in the field, such as gaining more knowledge about diagnosing and treating vertigo and dizziness in childhood and the interplay between vestibular migraine and MD.

Author contributions
AT drafted the editorial. TS, CF, DS, and TM critically reviewed and edited the editorial. All authors approved the submitted manuscript.