Cochleovestibular Dysfunction in Patients With Diabetes Mellitus, Hypertension, and Dyslipidemia

Nightly Hypoxia Does Not Seem to Lead to Otolith Dysfunction in Patients With Obstructive Sleep Apnea

OBJECTIVES

Obstructive sleep apnea (OSA) is a common sleep disorder, which is associated with recurrent oxygen desaturation during sleep. It has already been shown that nocturnal hypoxia may lead to cochlear dysfunction in patients with OSA. Less is known whether hypoxia during sleep also impacts vestibular function in those patients. Thus, the aim of the presented study was to assess a potential vestibulotoxic effect of nightly desaturations with hypoxia in patients with OSA by investigating a possible correlation between respiratory parameters and vestibular function tests.

METHODS

A total of 56 patients were included in the study and underwent a fully attended cardiorespiratory polysomnography (PSG). Vestibular function was assessed using video head impulse test to evaluate horizontal semicircular canal function and cervical vestibular evoked myogenic potentials (cVEMPs) and ocular vestibular evoked myogenic potentials (oVEMPs) to measure otolith function. Descriptive data analysis was conducted and correlation analysis between selected PSG parameters and the results of vestibular testing was performed using Kendall τ coefficient.

RESULTS

A significant correlation between vestibular function and respiratory polysomnographic parameters could not be demonstrated in the study (P > .05) but cVEMP and oVEMP results showed a trend toward a correlation with oxygen desaturation indices and apnea-hypopnea index. Additionally, otolith hypofunction was more prevalent in patients with hypertension as well as OSA.

CONCLUSION

The results of our study show that there is no significant correlation between vestibular function and sleep apnea parameters, although otolith dysfunction might be more prevalent in patients with OSA and hypertension.

Association between diabetes and vestibular dysfunction: an integrative review

ABSTRACT Purpose: to identify, in the literature, the factors associated with the development of vestibular dysfunctions in individuals with type 2 diabetes mellitus (DM2). Methods: an integrative review of the literature, whose survey was conducted in the databases ISI, SciELO, LILACS and PubMed, using the following descriptors: “type 2 diabetes mellitus”, “vertigo”, “dizziness”, and “vestibular diseases". Articles published in the last 10 years that answered the research question (“What factors are associated with the development of vestibular disorders in individuals with DM2?”) were included in the study. Results: the search returned 426 articles, 10 of which met the eligibility criteria. Most of the participants of the selected studies who had vestibular dysfunctions were women over 40 years old and had more than one comorbidity related to DM2, the main one being the systemic arterial hypertension (SAH). According to the literature, the physiology of the inner ear allows small glucose alterations to influence its normal functioning, which makes diabetic individuals more susceptible to developing vestibular dysfunctions. Conclusion: according to this study, DM2 can trigger or contribute to the manifestation of vestibular dysfunction, whose main associated factors are advanced age, female gender, and various comorbidities, as dyslipidemia, SAH and metabolic syndrome.

Hypertension is associated with dysfunction of both peripheral and central auditory system

OBJECTIVES

Arterial hypertension negatively influences the peripheral auditory system, causing sensorineural hearing loss. Much less is known about the detrimental effects of hypertension on the central auditory functions.

METHODS

We tested 32 arterial hypertension patients and 32 age and sex-matched healthy volunteers with the expanded tonal audiometry (0.125-12.5 kHz), distortion product otoacoustic emissions (0.75-8 kHz), horizontal minimum audible angle test for eight azimuths with binaural stimulation and the random gap detection test.

RESULTS

Peripheral hearing of the hypertensive patients was impaired in comparison with the controls within all audiometric frequencies (0.125-12.5 kHz) and within specific groups of frequencies. Distortion product otoacoustic emission results were significantly lower for frequencies 4 (P = 0.04) and 6 kHz (P < 0.001). The sound localization ability in the horizontal minimum audible angle test was significantly worse in the hypertensive patients in the 0°, 45°, 90°, 135°, and 270° azimuth when the interaural pure tone average (0.5-1-2 kHz) was set less than 20 dB hearing level (P < 0.05), and in the 0°, 90°, 225°, and 270°azimuth when the binaural pure tone average (0.5-1-2 kHz) was set 20 dB or less hearing level (P < 0.05). Gap detection thresholds in the random gap detection test did not differ between the two groups.

CONCLUSION

Arterial hypertension is independently related to the damage of the peripheral part of the auditory system resulting in high-frequency hearing loss. Hypertensive disturbances of central auditory processing are more discrete and concern the spatial hearing resolution.

Impact of Diabetic Complications on Balance and Falls: Contribution of the Vestibular System

Diabetes causes many complications, including retinopathy and peripheral neuropathy, which are well understood as contributing to gait instability and falls. A less understood complication of diabetes is the effect on the vestibular system. The vestibular system contributes significantly to balance in static and dynamic conditions by providing spatially orienting information. It is noteworthy that diabetes has been reported to affect vestibular function in both animal and clinical studies. Pathophysiological changes in peripheral and central vestibular structures due to diabetes have been noted. Vestibular dysfunction is associated with impaired balance and a higher risk of falls. As the prevalence of diabetes increases, so does the potential for falls due to diabetic complications. The purpose of this perspective article is to present evidence on the pathophysiology of diabetes-related complications and their influence on balance and falls, with specific attention to emerging evidence of vestibular dysfunction due to diabetes. Understanding this relationship may be useful for screening (by physical therapists) for possible vestibular dysfunction in people with diabetes and for further developing and testing the efficacy of interventions to reduce falls in this population.