Importance of High-Frequency Vestibular Function in the Prognosis of Bilateral Vestibulopathy

Prognosis of vestibular dysfunction in idiopathic sudden sensorineural hearing loss with vertigo: a prospective cohort study

BACKGROUND

Approximately 28%-57% of patients with idiopathic sudden sensorineural hearing loss (ISSNHL) have an acute vertigo attack and probable vestibular dysfunction; however, the prognosis of vestibular function in these patients remains unclear.

METHODS

A prospective cohort study of patients with ISSNHL and vertigo was conducted to evaluate the prognosis of vestibular function, especially the roles of peripheral vestibular restoration and central compensation, in patients with ISSNHL and vertigo. Clinical data were recorded at baseline and at 60 days from onset in participants with unilateral ISSNHL with vertigo. Enrolment occurred from May 1, 2019 to May 1, 2022 in the outpatient clinics and inpatient departments of the Eye and ENT Hospital of Fudan University in Shanghai. The primary outcome measure was the recovery rate of vestibular function 60 days after onset as assessed by vestibular function tests, including caloric tests, cervical and ocular vestibular-evoked myogenic potential tests (cVEMP, oVEMP), video head impulse tests (vHIT), and sensory organization tests (SOT). The secondary outcome measure was the recovery of subjective evaluations in vestibular dysfunction (the dizziness handicap inventory [DHI], and the visual analogue scale for vertigo [VAS-V]) and hearing assessments (pure-tone audiometry [PTA]).

RESULTS

Overall, 86 patients were recruited, with an average duration of disease of 11.7 days and follow-up time of 60.7 days. Vestibular function was significantly improved (p < 0.05) after 60 days. The recovery rates were 100% for anterior semicircular canal (ASC), 56% for posterior semicircular canal (PSC), 41% for horizontal semicircular canal (HSC), 28% for saccule, and 23% for utricle. The recovery of vestibular function was not significantly related to changes in DHI (p = 0.245), VAS-V score (p = 0.509), or hearing outcome (p = 0.390).

CONCLUSIONS

Restoration of peripheral vestibular sensory input and central vestibular compensation can occur during the course of ISSNHL with vertigo. The otolith organs are at a higher risk of being affected and have worse recovery than the semicircular canals. Incomplete and in-process restoration of vestibular dysfunction may perturb and delay the establishment of central compensation for balance. Neither hearing outcomes nor subjective vestibular symptoms are related to recovery from vestibular dysfunction.

TRIAL REGISTRATION

ClinicalTrials.gov (identifier NCT03951584).

Combining vestibular rehabilitation with noisy galvanic vestibular stimulation for treatment of bilateral vestibulopathy

OBJECTIVE

Noisy galvanic vestibular stimulation (nGVS) has been shown to partly restore vestibular function and to stabilize stance and gait in patients with incomplete bilateral vestibulopathy (BVP). Here, we examined potential synergistic effects of nGVS when combined with standardized vestibular rehabilitation training (VRT).

METHODS

23 patients with confirmed BVP received a 30-min vestibular rehabilitation training (VRT) program three times a week for 2 weeks. The intervention group (n = 12) was stimulated with nGVS (at individually determined optimal amplitudes) during training, whereas the control group (n = 11) received zero-amplitude nGVS (sham stimulation) during training. Outcome measurements assessed at baseline, after 2 weeks of training, and at 2-week follow-up included quantitative posturography, instrumented gait analysis, Timed Up and Go Test (TUG), Functional Gait Assessment (FGA), and clinical scores related to quality of life and balance confidence.

RESULTS

After 2 weeks of VRT, all patients showed moderate improvement in balance. Irrespective of nGVS treatment, performance improved in the TUG (p < 0.013), and in the FGA (p < 0.040). Furthermore, base of support when walking with closed eyes was reduced after 2-week training (p < 0.003). Postural sway did not change. There was no difference between groups and thereby no evidence for an additional influence of nGVS on the VRT treatment effects.

CONCLUSION

nGVS does not induce synergistic treatment effects in combination with VRT in patients with BVP when applied during treatment sessions. Hence, rather than being applied in parallel, nGVS and VRT might be complementary therapeutic options with nGVS being used during postural activities in daily life, e.g., walking.

Efficacy of nGVS to improve postural stability in people with bilateral vestibulopathy: A systematic review and meta-analysis

Objective

Noisy galvanic vestibular stimulation (nGVS) has been used to boost vestibular afferent information to the central nervous system. This has the potential to improve postural control for people for whom vestibular signals are weak, such as in bilateral vestibulopathy (BVP). The aim of this systematic review and meta-analysis is to investigate the evidence for nGVS as a modality to improve postural control in people with BVP.

Methods

A comprehensive systematic search was conducted of five databases up to July 2022 to find studies applying nGVS to people with BVP, with the aim of improving postural control. Two independent reviewers screened and identified eligible studies, completed a risk of bias evaluation (Cochrane) and extracted relevant data. The standardized mean difference (SMD) based on Hedges' g was calculated as a measure of effect size for the primary outcome measure that best identified postural control, and a forest plot generated.

Results

Seven studies met the eligibility criteria, with five being suitable for meta-analysis. Meta-analysis revealed a moderate effect in favor of nGVS improving postural control during standing and walking [pooled SMD = 0.47 95% CI (0.25, 0.7)]. nGVS-mediated improvements in postural control were most evident in observations of reduced sway velocity when standing on a firm surface with eyes closed, and in the reduced variability of gait parameters, particularly those measuring lateral stability.

Conclusions

Coincident nGVS in people with BVP improves postural control during standing and walking. This improvement appears to be context specific, in that vestibular augmentation is most effective in situations where visual inputs are limited, and where reliable context specific proprioceptive cues are available. Further research is warranted investigating additional circumstances in which nGVS improves postural control, including investigating the residual, and sustained effects of nGVS.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=342147, identifier: 342147.

Bilateral vestibulopathy: the causes, diagnosis, and treatments

PURPOSE OF REVIEW

The current review covers recent advances in bilateral vestibulopathy (BVP) in terms of its etiology, diagnosis, and treatments.

RECENT FINDINGS

The etiology of BVP depends on its clinical course and associated findings, and genetic abnormalities are increasingly recognized in isolated as well as complicated form of BVP. Recent developments in evaluation of the vestibular function have greatly enhanced the detection of BVP, and introduction of the consensus diagnostic criteria by Barany Society has facilitated research on BVP. Vestibular prosthesis may improve vestibular function, posture, gait and quality of life in patients with BVP and would expand the therapeutic options for BVP in near future.

SUMMARY

Genetics is expanding its role in identifying the causes of BVP of hitherto unknown etiology. The detection and investigation of BVP have been greatly enhanced by introduction of consensus diagnostic criteria and recent developments in methodology evaluating the vestibular function. Vestibular prothesis appears promising in managing BVP.

VIDEO ABSTRACT

http://links.lww.com/CONR/A59.