Electrical Vestibular Stimulation in Humans: A Narrative Review.

BACKGROUND: In patients with bilateral vestibulopathy, the regular treatment options, such as medication, surgery, and/or vestibular rehabilitation, do not always suffice. Therefore, the focus in this field of vestibular research shifted to electrical vestibular stimulation (EVS) and the development of a system capable of artificially restoring the vestibular function. Key Message: Currently, three approaches are being investigated: vestibular co-stimulation with a cochlear implant (CI), EVS with a vestibular implant (VI), and galvanic vestibular stimulation (GVS). All three applications show promising results but due to conceptual differences and the experimental state, a consensus on which application is the most ideal for which type of patient is still missing. SUMMARY: Vestibular co-stimulation with a CI is based on "spread of excitation," which is a phenomenon that occurs when the currents from the CI spread to the surrounding structures and stimulate them. It has been shown that CI activation can indeed result in stimulation of the vestibular structures. Therefore, the question was raised whether vestibular co-stimulation can be functionally used in patients with bilateral vestibulopathy. A more direct vestibular stimulation method can be accomplished by implantation and activation of a VI. The concept of the VI is based on the technology and principles of the CI. Different VI prototypes are currently being evaluated regarding feasibility and functionality. So far, all of them were capable of activating different types of vestibular reflexes. A third stimulation method is GVS, which requires the use of surface electrodes instead of an implanted electrode array. However, as the currents are sent through the skull from one mastoid to the other, GVS is rather unspecific. It should be mentioned though, that the reported spread of excitation in both CI and VI use also seems to induce a more unspecific stimulation. Although all three applications of EVS were shown to be effective, it has yet to be defined which option is more desirable based on applicability and efficiency. It is possible and even likely that there is a place for all three approaches, given the diversity of the patient population who serves to gain from such technologies.

Delayed Effect of Active Pressure Treatment on Endolymphatic Hydrops.

OBJECTIVE: To identify eventual correlations between the effect of low-pressure treatment and endolymphatic hydrops in Ménière patients. MATERIAL AND METHODS: The study group consisted of subjects affected by definite Ménière disease (2015) and a severe degree of disability, who received a ventilation tube with or without a low-pressure treatment before undergoing a surgical procedure (vestibular neurectomy). After the placement of the ventilation tube, the subjects were either left alone with the tube or received 1 month of self-administered low-pressure therapy with a portable device. In all subjects, an electrocochleography (ECochG) was performed and specific questionnaires - Dizziness Handicap Inventory (DHI) and Functional Scale Level (FSL) - were completed before starting either arm of treatment, at the end of treatment, and then 3 and 6 months later. RESULTS: All selected subjects presented with an ECochG pattern that was indicative of endolymphatic hydrops before starting either treatment. At the end of pressure treatment, 80% showed symptomatic improvement while maintaining the hydropic ECochG pattern. At the 3-month control stage, the hydropic pattern resulted normalized (<0.5) in all the improved subjects. CONCLUSIONS: Although 1 month of low-pressure treatment provided a positive symptomatological outcome, normalization of the hydropic ECochG parameters occurred only at a later time. Therefore, it is possible to assume that endolymphatic hydrops could be concurrent with a non-symptomatic stage of Ménière disease, and that the anti-hydropic effect of the low-pressure treatment, if any, would present with a certain delay after its completion.

Silent reflux: ex juvantibus criteria for diagnosis and treatment of laryngeal disorders.

CONCLUSIONS: Some primary laryngeal pathologies with specific clinical presentation may be related to silent laryngeal reflux. An ex adjuvantibus proton pump inhibitor (PPI) treatment may be helpful for showing evidence of such a hidden laryngeal disorder. OBJECTIVE: To assess the validity of PPI as an ex adjuvantibus criterion for diagnosis and treatment of suspected reflux-associated laryngitis. PATIENTS AND METHODS: Sixty patients with clinical suspicion of laryngo-pharyngeal reflux (LPR) were identified on the grounds of laryngeal symptoms (dysphonia, cough, globus sensation, increased throat clearing, bad taste, and laryngeal spasm), laryngeal features (arytenoid edema/erythema, partial or total vocal fold erythema, and posterior glottic edema) with or without gastro-esophageal reflux disorder (GERD). They were consequently subdivided in three groups: type I, with LPR symptoms and features without GERD; type II with LPR symptoms and features with GERD; and type III with LPR features only. Types I and III were randomly treated with omeprazole (group A) or with immunostimulating vaccine (group B) for 3 months. Pre- and post-treatment laryngeal features and symptoms in all groups were evaluated by laryngo-stroboscopy and analyzed for statistical correlation. RESULTS: All omeprazole-treated patients showed improvement of laryngeal features and symptoms. With PPI treatment, a more significant improvement was noticed with respect to nonspecific immunostimulant therapy. Also, patients without LPR symptoms showed improvement of laryngeal features.