Vestibular evoked myogenic potential responses in obstructive sleep apnea syndrome

Exploring the relationship between sleep apnea and vestibular symptoms following traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) is a complex health problem in military veterans and service members (V/SM) that often involves comorbid vestibular impairment. Sleep apnea is another comorbidity that may exacerbate, and/or be exacerbated by, vestibular dysfunction.

OBJECTIVE

To examine the relationship between sleep apnea and vestibular symptoms in V/SM diagnosed with TBI of any severity.

DESIGN

Multicenter cohort study; cross-sectional sample.

SETTING

In-patient TBI rehabilitation units within five Veterans Affairs (VA) Polytrauma Rehabilitation Centers.

PARTICIPANTS

V/SM with a diagnosis of TBI (N = 630) enrolled in the VA TBI Model Systems study.

INTERVENTION

Not applicable.

METHODS

A multivariable regression model was used to evaluate the association between sleep apnea and vestibular symptom severity while controlling for relevant covariates, for example, posttraumatic stress disorder (PTSD).

MAIN OUTCOME MEASURES

Lifetime history of sleep apnea was determined via best source reporting. Vestibular disturbances were measured with the 3-item Vestibular subscale of the Neurobehavioral Symptom Inventory (NSI).

RESULTS

One third (30.6%) of the sample had a self-reported sleep apnea diagnosis. Initial analysis showed that participants who had sleep apnea had more severe vestibular symptoms (M = 3.84, SD = 2.86) than those without sleep apnea (M = 2.88, SD = 2.67, p < .001). However, when the data was analyzed via a multiple regression model, sleep apnea no longer reached the threshold of significance as a factor associated with vestibular symptoms. PTSD severity was shown to be significantly associated with vestibular symptoms within this sample (p < .001).

CONCLUSION

Analysis of these data revealed a relationship between sleep apnea and vestibular symptoms in V/SM with TBI. The significance of this relationship was affected when PTSD symptoms were factored into a multivariable regression model. However, given that the mechanisms and directionality of these relationships are not yet well understood, we assert that in terms of clinical relevance, providers should emphasize screening for each of the three studied comorbidities (sleep apnea, vestibular symptoms, and PTSD).

Chronic Vestibular Hypofunction Is Associated with Impaired Sleep: Results from the DizzyReg Patient Registry

Temporary or permanent vestibular hypofunction has been hypothesized to affect circadian rhythm, sleep, and thermoregulation. Chronic or long-term vestibular disorders such as unilateral vestibular hypofunction may have an even greater negative impact on sleep quality than acute vestibular problems. This study examines self-reported sleep quality, as assessed by the Pittsburgh Sleep Quality Index (PSQI), and its association with vestibular symptom duration in a group of patients with vestibular disorders. We used data from the cross-sectional DizzyReg patient registry of the German Center for Vertigo and Balance Disorders outpatient clinic. Vestibular diagnoses were ascertained based on the International Classification of Vestibular Disorders. A total of 137 patients were included (60% female, mean age 55.4 years, standard deviation, SD, 16.7). The mean PSQI total score was 6.3 (SD = 3.2), with 51% reporting overall poor sleep quality. Patients who had vertigo for two years or longer reported significantly poorer global sleep quality (63% vs. 37%, p = 0.021) and significantly more difficulties with sleep latency (79% vs. 56%, p = 0.013) and sleep efficiency (56% vs. 34%, p = 0.022). The association of poor sleep quality with a longer duration of vertigo remained significant after multivariable adjustment. Further research should investigate the interaction of vestibular disorders, sleep, and their potential mechanisms.

Evaluation of vestibular functions in patients with obstructive sleep apnea syndrome

BACKGROUND

To determine the anatomical proximity of the vestibular nuclei to the respiratory nuclei and the effect of susceptibility of the posterior labyrinth to a hypoxic state on the vestibular system.

OBJECTIVE

It was aimed to evaluate the possible effects of periodic hypoxia on vestibular reflexes and proprioceptive perception in patients with obstructive sleep apnea syndrome (OSAS).

MATERIAL AND METHODS

The study was conducted with 40 patients diagnosed with moderate and severe OSAS and 21 healthy individuals. All individuals were evaluated with Dizziness Handicap Inventory, ocular vestibular evoked myogenic potential (oVEMP), cervical vestibular evoked myogenic potential (cVEMP), video head impulse test (vHIT), videonystagmography (VNG) and sportKAT 3000.

RESULTS

In the vHIT, a statistically significant difference was found between the groups in terms of anterior and posterior semicircular canal vestibulo-ocular reflex gains (p < .05). A negative correlation was found between the lateral gain asymmetry and RALP gain asymmetry and the awake blood oxygen level in the OSAS groups. There was a statistically significant difference between the groups in terms of wave response rates cVEMP 100 dB nHL and oVEMP 100-110 dB nHL (p < .05).

CONCLUSION AND SIGNIFICANCE

It was concluded that vestibular reflexes and proprioceptive perception were affected due to periodic/chronic hypoxia in patients with moderate and severe OSAS.

The use of vestibular evoked myogenic potentials (VEMP) in the diagnosis of otolithic dysfunction of patients with obstructive sleep apnea: a survey of awareness and recognition of otorhinolaryngology medical staffs

PURPOSE

To assess awareness and recognition of vestibular function tests in otorhinolaryngology medical staffs, especially the vestibular evoked myogenic potentials (VEMP) testing in patients with obstructive sleep apnea (OSA).

METHODS

A survey was delivered via either email or a social media app. The medical staffs of the Chinese Medical Association of Otolaryngology Head and Neck Surgery from various branches were enrolled. Study data were collected and managed with an online data collection tool.

RESULTS

A total of 1781 emails and 623 social media messages were sent to 2404 otorhinolaryngology medical staffs. One hundred and fifty-seven of them participated in the survey, including 24 via emails and 133 via the social media app. Regarding the knowledge of VEMP, only 59 (37.6%) of them agreed that OSA could be related to vertigo/dizziness/imbalance and 28 (17.8%) believed that OSA could result in VEMP abnormalities and would factor this in diagnosing the impairment of the vestibular function of OSA patients. A total of 7.6% of the respondents had never heard of the VEMP tests. Responses regarding the minimum age at which VEMP are possible ranged from younger than 6 months to greater than 18 years of age. Beliefs regarding the utility and reliability of VEMP varied, with 'unsure' being the most frequent response. In addition, only 17.8% of otolaryngologists indicated some access to the VEMP test.

CONCLUSIONS

Knowledge and beliefs about the role of VEMP in diagnosing otolithic organ dysfunction caused by OSA in otorhinolaryngology vary widely. It is important for otorhinolaryngology medical staffs to learn the latest literatures and updated knowledge through continuing education.

The correlation between the body shape and otolithic function in patients with obstructive sleep apnea

OBJECTIVE

To identify the typical pattern of changes of vestibular-evoked myogenic potentials (VEMPs) and explore the relationship between VEMPs and the anthropometry factors in patients with obstructive sleep apnea (OSA).

METHODS

Patients diagnosed as OSA after overnight polysomnography (PSG) tests were enrolled as the study group. Healthy volunteers were recruited as the control group. Anthropometry data of the body shape and VEMPs results were collected completely. The correlation analysis was conducted among those parameters.

RESULTS

Forty-nine patients with OSA who were diagnosed in the Therapy Center of Sleep-disordered Breathing in our hospital and sex- and age-matched healthy controls as well. Significant changes in ocular and cervical VEMPs (oVEMP and cVEMP) in the study group were observed, which were reduced response rates, elevated thresholds, decreased amplitudes, and prolonged first wave latencies. In oVEMP, the first wave (n1) latency was significantly correlated with weight, body mass index (BMI), neck circumference, waist circumference, hip circumference, and apnea hypopnea index (AHI). In a tentative application, combined use of BMI and oVEMP n1 latency increased the detection rate during OSA screening prior to PSG.

CONCLUSION

OSA can negatively affect function of otolithic organs and their pathways. The first wave latency of the VEMPs waveform may be another important parameter to define peripheral nervous system lesions caused by systemic diseases as OSA.

Whole-brain monosynaptic outputs and presynaptic inputs of GABAergic neurons in the vestibular nuclei complex of mice

GABAergic neurons in the vestibular nuclei (VN) participate in multiple vital vestibular sensory processing allowing for the maintenance and rehabilitation of vestibular functions. However, although the important role of GABA in the central vestibular system has been widely reported, the underlying neural circuits between VN GABAergic neurons and other brain functional regions remain elusive, which limits the further study of the underlying mechanism. Hence, it is necessary to elucidate neural connectivity based on outputs and inputs of GABAergic neurons in the VN. This study employed a modified rabies virus retrograde tracing vector and cre-dependent adeno-associated viruses (AAVs) anterograde tracing vector, combined with a transgenic VGAT-IRES-Cre mice, to map the inputs and outputs of VN GABAergic neurons in the whole brain. We found that 51 discrete brain regions received projections from VN GABAergic neurons in the whole brain, and there were 77 upstream nuclei innervating GABAergic neurons in the VN. These nuclei were mainly located in four brain regions, including the medulla, pons, midbrain, and cerebellum. Among them, VN GABAergic neurons established neural circuits with some functional nuclei in the whole brain, especially regulating balance maintenance, emotion control, pain processing, sleep and circadian rhythm regulation, and fluid homeostasis. Therefore, this study deepens a comprehensive understanding of the whole-brain neural connectivity of VN, providing the neuroanatomical information for further research on the neural mechanism of the co-morbidities with vestibular dysfunction.

Uneven Effects of Sleep Apnea on Semicircular Canals and Otolithic Organs

OBJECTIVE

This study aimed to explore how obstructive sleep apnea (OSA) affects the function of each vestibular organ and to identify the correlations among them.

METHODS

A prospective study was conducted involving 32 healthy controls and 64 patients with OSA. The objective detection methods of the utricle and saccule are vestibular-evoked myogenic potentials (VEMPs). A combination of the caloric test and video head impulse test (vHIT) was used to comprehensively evaluate the objective function of semicircular canals.

RESULTS

Elevated thresholds (p < 0.001), decreased waveform amplitudes (p < 0.001), prolonged first wave latencies (p < 0.001), and shortened first interpeak latencies (p < 0.001) were observed in both ocular VEMP (oVEMP) and cervical VEMP (cVEMP). A significant difference was found in the caloric test comparison (χ² = 4.030, p = 0.045) but not in the vHIT. The intergroup comparison of normal rates among the VEMPs, caloric test, and vHIT groups showed a significant difference (p < 0.001).

CONCLUSION

The impairment of vestibular function in patients with OSA was uneven and biased. More attention should be given to vestibular dysfunction in the diagnosis and treatment of OSA.

Evaluation of Vestibular Function in Patients Affected by Obstructive Sleep Apnea Performing Functional Head Impulse Test (fHIT)

PURPOSE

Obstructive sleep apnoea (OSA) is a common disease with significantly related complications. Since a connection between the vestibular nucleus and sleep regulator pathways has been demonstrated, vestibular evaluation in OSA patients was partially studied and none used functional head impulse test (fHIT) for this purpose. This paper aimed at evaluating the vestibular function in patients affected by OSA using fHIT, selecting patients who did not present any other related to cardiovascular, neurological, or metabolic diseases.

PATIENTS AND METHODS

Patients enrolled had a diagnosis of OSA by polysomnography type III and were cataloged according to American Association of Sleep Medicine criteria. Each patient underwent fHIT. Statistical significance was set at 0.05.

RESULTS

A total of 85 patients were enrolled in the study of which 50 had a diagnosis of OSA and were included in the case group, while 35 belonged to the control group. In 88.6% of subjects of the case group was evidenced a vestibular impairment with a substantial difference between the two study groups (p<0.05).

CONCLUSION

The results show that the incidence of vestibular lesions in patients with obstructive sleep apnoea is underestimated and that fHIT can identify these lesions early.

Characteristic manifestation of ocular and cervical vestibular evoked myogenic potentials findings in severe obstructive sleep apnea patients

BACKGROUND

Studies of saccular and utricular function in patients with obstructive sleep apnea (OSA) are rare. We noticed that some OSA patients also had positive results in vestibular function tests, and this inspired our interest in exploring the vestibular function patterns of OSA patients.

OBJECTIVES

To investigate otolithic organ function in severe OSA patients who lack vestibular symptoms and systemic disease.

MATERIAL AND METHODS

32 patients (64 ears) with severe OSA and 22 healthy controls (44 ears) were enrolled. The ocular and cervical vestibular-evoked myogenic potentials (oVEMP and cVEMP) and the caloric test were recorded and analyzed.

RESULTS

The response rates of oVEMP (73.4%) and cVEMP (82.8%) in patients with severe OSA were significantly lower than those in controls. In oVEMP, elevated thresholds (p = .002), decreased n1-p1 amplitudes (p < .001), prolonged n1 latencies (p < .001) were observed. In cVEMP, the elevation of thresholds (p < .001), decrease in p1-n1 amplitudes (p < .001), and n1-p2 amplitudes (p < .001), prolongation of p1 latencies (p = .003) were observed. No significant difference in the caloric test was found between the two groups.

CONCLUSIONS AND SIGNIFICANCE

Disappearance or impairment of VEMPs could be observed in patients with severe OSA, and reflects different degrees of impairment in the utricle and saccule.

Sleep Performance and Chronotype Behavior in Unilateral Vestibular Hypofunction

OBJECTIVE

To evaluate sleep behavior and its relation to otoneurological parameters in a group of patients with chronic unilateral vestibular hypofunction (UVH) without self-reported sleep disturbances when compared with healthy subjects serving as a control group (CG).

METHODS

Fifty-one patients affected by UVH underwent a retrospective clinical and instrumental otoneurological examination, a 1-week actigraphy sleep analysis, and a series of self-report and performance measures (SRM/PM). A CG of 60 gender- and age-matched healthy subjects was also enrolled. A between-group analysis of variance was performed for each variable, while correlation analysis was performed in UVH patients between otoneurological, SRM/PM, and actigraphy measure scores.

RESULTS

When compared with CG subjects, UVH patients were found to be spending less time sleeping and taking more time to go from being fully awake to asleep, based on actigraphy-based sleep analysis. Also, SRM/PM depicted UVH patients to have poor sleep quality and to be more prone to an evening-type behavior. Correlations were found between vestibular-related functionality indexes and subjective sleep quality, as well as between longer disease duration and reduced sleep time.

CONCLUSION

For the first time, a multiparametric sleep analysis was performed on a large population-based sample of chronic UVH patients. While a different pattern in sleep behavior was found, the cause is still unclear. Further research is needed to expand the extent of knowledge about sleep disruption in vestibular disorders.

LEVEL OF EVIDENCE

Level 3 Laryngoscope, 2021.

Whole-brain monosynaptic inputs and outputs of glutamatergic neurons of the vestibular nuclei complex in mice

Vestibular nuclei complex (VN) glutamatergic neurons play a critical role in the multisensory and multimodal processing. The dysfunction of VN leads to a series of vestibular concurrent symptoms, such as disequilibrium, spatial disorientation, autonomic disorders and even emotion disorders. However, the reciprocal neural connectivity in the whole brain of VN glutamatergic neurons was incompletely understood. Here, we employed a cell-type-specific, cre-dependent, modified virus vector to retrogradely and anterogradely trace VN glutamatergic neurons in the VGLUT2-IRES-Cre mouse line. We identified and analyzed statistically the afferents and efferents of VN glutamatergic neurons in the whole brain, and also reconstructed monosynaptic inputs distribution of VN glutamatergic neurons at the three-dimensional level with the combination of a fluorescence micro-optical sectioning tomography system (fMOST). We found that VN glutamatergic neurons primarily received afferents from 57 nuclei and send efferents to 59 nuclei in the whole brain, intensively located in the brainstem and cerebellum. Projections from nuclei in the cerebellum targeting VN glutamatergic neurons mainly performed the balance control - the principal function of the vestibular system. In addition, VN glutamatergic neurons sent projections to oculomotor nucleus, trochlear nucleus and abducens nucleus dominating the eye movement. Except for the maintenance of balance, VN glutamatergic neurons were also directly connected with other functional regions, such as sleep-wake state (locus coeruleus, dorsal raphe nucleus, and laterodorsal tegmental nucleus, gigantocellular reticular nucleus, lateral paragigantocellular nucleus, periaqueductal gray, subcoeruleus nucleus, parvicellular reticular nucleus, paramedian raphe nucleus), and emotional regulation (locus coeruleus and dorsal raphe nucleus). Hence, this study revealed a comprehensive whole-brain neural connectivity of VN glutamatergic neurons and provided with a neuroanatomic foundation to further study on central vestibular circuits.

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.

Vestibular-evoked myogenic potentials in patients with severe obstructive sleep apnea

Objective

Previous studies have shown that patients with obstructive sleep apnea syndrome (OSAS) may have various vestibular abnormalities, and these mainly present as subclinical lesions. In this study, we attempted to combine ocular vestibular-evoked myogenic potentials (VEMPs) and cervical (VEMPs) to investigate vestibular dysfunction in patients with OSAS.

Methods

Thirty-eight patients with severe OSAS and 42 healthy controls were enrolled and divided into two groups according to results of polysomnography. All parameters of VEMP graphs were analyzed.

Results

The response rate of ocular VEMPs was significantly lower in patients with severe OSAS (85.5%) than in controls (96.4%). The mean n1 latency of patients with severe OSAS (10.6 ± 1.0 months) was significantly longer than that of controls (10.2 ± 1.1 months). With regard to cervical VEMP, p1-n1 amplitudes were significantly different between the groups. Other VEMP parameters were not significantly different between the groups.

Conclusions

VEMPs can potentially be used to evaluate vestibular system lesions at the early stage of OSAS, including not only the vestibular nerve, but also the otolith organs involved.

The relationship between the findings of vestibular evoked myogenic potentials and severity of obstructive sleep apnea syndrome

PURPOSE

Our study aimed to evaluate the effects of chronic hypoxic state in Obstructive Sleep Apnea Syndrome (OSAS) on brainstem pathways using Vestibular Evoked Myogenic Potential (VEMP) test and to investigate the presence of new markers likely to be correlated with the severity of the disease.

METHODS

The study was planned as prospective and double blind. A total of 60 patients (120 ears) diagnosed with mild, moderate and severe OSAS were included in the study and the patients are grouped as 20 patients in each group. Twenty volunteer healthy individuals (40 ears) shown to be without OSAS were included in the study. VEMP measurements were made in 60 study group patients (120 ears) and in 20 healthy controls (40 ears). The groups were compared in terms of variables such as the acquisition rate of oVEMP and cVEMP waves, interval between the waves, latency and amplitude of the waves. p < 0.05 values were considered as significant.

RESULTS

The results of cVEMP test showed that the rate of wave acquisition in the moderate and severe OSAS groups was significantly lower than the control group and mild OSAS groups (p = 0.008). There was no difference between the control group and the mild OSAS group in terms of the rate of obtaining the wave (p > 0.05). In the moderate and severe OSAS groups, P1N1 amplitude and N1P2 amplitude values were found to be significantly lower than the mild OSAS group (p = 0.007 and p = 0.017, respectively). In the oVEMP test, there was no significant difference between the mild OSAS group and the control group in terms of the wave yield (p > 0.05); however, it was found that the rate of wave acquisition in the moderate and severe OSAS groups was significantly lower than the mild OSAS group (p = 0.041). There was inverse correlation between the N1P2 interval and P1N1 amplitude value and AHI in simple regression analysis and multiple regression analysis (p = 0.012 and p = 0.021; p = 0.009 and p = 0.040, respectively).

CONCLUSION

The negative effects of chronic intermittent hypoxia related with OSAS on the brainstem and vestibular system can be demonstrated by VEMP tests. Especially, the inability to obtain the wave is the most important finding showing this situation. Also, we think that N1P2 interval and P1N1 amplitude markers can be used to detect the subclinical negative effect of chronic hypoxia on vestibular nuclei in the brainstem.

Postural and vestibular changes related to CPAP treatment in moderate-to-severe OSA patients: a 12-month longitudinal study

PURPOSE

To assess whether vestibulo-ocular reflex (VOR) gain, posturography parameters and related clinical outcomes can improve in OSA patients after 12 months of CPAP treatment, taking into consideration that a certain degree of vestibular dysfunction has been identified in these subjects.

METHODS

Vestibular, postural, clinical, and polygraphic parameters were assessed in 32 OSA patients before and after beneficial CPAP treatment by means of video head impulse test (vHIT), static posturography (SP), Dizziness Handicap Inventory (DHI), Epworth Sleepiness Scale (ESS), and Apnea-Hypopnea Index (AHI), respectively, and were compared by means of a "within-subject" ANOVA model and Spearman's rank correlation.

RESULTS

After the 12-month period of treatment, OSA patients demonstrated a significant reduction in AHI values, in both opened and closed eyes conditions of surface and length as well as in power spectra recorded in low, middle, and high frequency interval. Although a significant improvement was also recorded among DHI and ESS scores, VOR gain increase did not survive to post-hoc corrections. Finally, positive correlations between the differences between pre- and post-treatment AHI, ESS, and PS values were found.

CONCLUSIONS

The present work highlighted that postural instability and dizziness-related conditions due to OSA may improve after 12 months of CPAP treatment. Although VOR gain did not demonstrate significant improvement, this study might open future perspectives directed to assessing VOR gain changes after longer periods of CPAP treatment.