Caloric Test Research Articles

Unveiling the Therapeutic Impact of Virtual Reality Game-Based Exercises on Cervicocephalic Kinesthetic Sensibility in Individuals Battling Cervical Vertigo

This study was aimed to investigate the therapeutic impact of Virtual Reality game-based exercises with Epley maneuver on cervicocephalic kinesthetic sensibility in individuals experiencing cervical vertigo. 8 subjects were selected by simple random sampling method included clinically diagnosed male and female cervical vertigo patients between 40-55 years of age, who had recurring symptom of dizziness over three months, episodic dizziness lasting minutes to hours .Written consent was taken and a detailed outcome assessment was done.Intervention includes Virtual Reality abyss sharks & sea worlds for a duration of 10 minutes with a five-minute rest period and Virtual Reality thrills, for a duration of 10 minutes with a five-minute rest period along with epley maneuver 10 minutes targeting cervicocephalic kinesthetic sensibility.Total duration of the intervention includes 40min/day for 6 days for 12 weeks. Pre test included Cervical Joint Position Error Test for cervicocephalic kinesthetic sensibility and Videonystagmography measures nystagmus, rapid eye movements with a slow and fast phase, to provide objective information about vertigo. Post test done on 6th and 12th week of intervention with the same measures. On comparing pre- and post-intervention outcomes shows higher mean value (P≤0.001).In conclusion the findings of this study had the potential to contribute valuable insights into the therapeutic utility of Virtual Reality game-based exercises in managing cervical vertigo, offering a novel and engaging approach to rehabilitation. Virtual Reality-based interventions is found effective treatment for individuals battling cervicocephalic kinesthetic sensibility among patients with cervical vertigo.

Determination of Recovery by Total Restitution or Compensation Using Multifrequency Vestibular Tests and Subjective Functional Scales in a Human Model of Vestibular Neuritis

Background: Vestibular Neuritis (VN) can induce unilateral acute vestibular syndrome (AVS). This study aimed to identify predictive factors of recovery from vestibular neuritis considering total restitution and/or compensation. Methods: In this longitudinal study, 40 patients were included. The initial assessment, performed within 36 to 72 h from the onset (T0), included medical history taking (general and specific), including screening for cardiovascular risk factors (CVRFs), and a battery of diagnostic vestibular tests, comprising the bithermal caloric test (BCT), video head impulse test (VHIT), and skull vibration-induced nystagmus (SVIN) test. All patients also completed a Dizziness Handicap Inventory (DHI). All assessments were repeated 90 ± 15 days later (T3). Subjective compensation criteria were based on the DHI total score, and objective compensation criteria were based on laboratory test results. Four groups of patients (A, B, C, D) were delineated by combining patients with normal vs. abnormal vestibular tests and patients with normal vs. abnormal DHI. Results: CVRFs (but not age or body mass index (BMI)) were associated with a poorer recovery of symptoms. The BCT (lateral semicircular canal paresis %), VHIT (lateral semicircular canal gain), and SVINT (nystagmus slow phase velocity) recovered to normal values in 20%, 20%, and 27% of patients, respectively, at T3. Conclusions: Vascular risk factors (hypercholesterolemia) are correlated with patients who do not recover their symptoms via either total restitution or compensation. There was no significant difference between high- and low-frequency vestibular tests in patients recovering from their symptoms. Some patients with objective recovery may continue to have persistent subjective symptoms.

Caloric Vestibular Stimulation Alleviates Cold Water Swimming Stress Induced Changes in BDNF and Haematological Parameters

Introduction: Stress is inevitable in daily life. Stress in long term has been implicated in the development of physical and neuronal disorders. Various studies have described the levels and role of BDNF in the brain following stress. Studies representing the changes in serum BDNF and wet weight of organs in stress are limited and controversial. Aim: The aim of the present study is to find the effect of stress on serum BDNF concentration, wet weight of selected organs, haematological parameters and to evaluate the effectiveness of caloric vestibular stimulation on stress-induced changes in these parameters. Methods and material: Male Wistar rats were exposed to cold water swimming stress for 14 days for a duration of 30 minutes per day. Serum corticosterone and serum BDNF were measured using the ELISA method. Weight of liver, spleen, thymus and lymph nodes were measured and their relation to body weight was calculated. Total RBC count, total WBC count, platelet count and haemoglobin concentration were analysed. Results: A statistically significant increase in serum corticosterone and BDNF was observed following stress. Liver weight, thymus weight and lymph nodes weight did not show any significant changes but spleen weight has reduced in the normal recovery group following stress. Total RBC count, total WBC count, platelet count and haemoglobin levels were significantly higher in the stress group. Caloric vestibular stimulation was effective in managing stress-induced changes in serum corticosterone, BDNF and spleen weight. Conclusion: Caloric vestibular stimulation is effective in restoring the stress-induced changes.

Dissociation between caloric test and the video head impulse test in individuals with auditory neuropathy spectrum disorders.

Dissociation between caloric test and the video head impulse test in individuals with auditory neuropathy spectrum disorders.

Bedside Neuromodulation of Persistent Pain and Allodynia with Caloric Vestibular Stimulation.

Caloric vestibular stimulation (CVS) is a well-established neurological diagnostic technique that also induces many phenomenological modulations, including reductions in phantom limb pain (PLP), spinal cord injury pain (SCIP), and central post-stroke pain. We aimed to assess in a variety of persistent pain (PP) conditions (i) short-term pain modulation by CVS relative to a forehead ice pack cold-arousal control procedure and (ii) the duration and repeatability of CVS modulations. The tolerability of CVS was also assessed and has been reported separately. We conducted a convenience-based non-randomised single-blinded placebo-controlled study. Thirty-eight PP patients were assessed (PLP, n = 8; SCIP, n = 12; complex regional pain syndrome, CRPS, n = 14; non-specific PP, n = 4). Patients underwent 1-3 separate-day sessions of iced-water right-ear CVS. All but four also underwent the ice pack procedure. Analyses used patient-reported numerical rating scale pain intensity (NRS-PI) scores for pain and allodynia. Across all groups, NRS-PI for pain was significantly lower within 30 min post-CVS than post-ice pack (p < 0.01). Average reductions were 24.8% (CVS) and 6.4% (ice pack). CRPS appeared most responsive to CVS, while PLP and SCIP responses were less than expected from previous reports. The strongest CVS pain reductions lasted hours to over three weeks. CVS also induced substantial reductions in allodynia in three of nine allodynic CRPS patients, lasting 24 h to 1 month. As reported elsewhere, only one patient experienced emesis and CVS was widely rated by patients as a tolerable PP management intervention. Although these results require interpretative caution, CVS was found to modulate pain relative to an ice pack control. CVS also modulated allodynia in some cases. CVS should be examined for pain management efficacy using randomised controlled trials.

Correlation between the etiology of severe hearing loss and endolymphatic hydrops.

This study aimed to investigate correlation between the presence of endolymphatic hydrops(EH) and factors such as causes of hearing loss, patient age, duration of deafness, and results of vestibular function tests. We retrospectively reviewed medical charts of 128 ears of cochlear implantees who were not considered relevant to Meniere's disease. When comparing group with genetic variants of GJB2, SLC26A4, LMX1A and other genetic mutation group, the proportion of vestibular EH and cochlear EH found in group with genetic variants of GJB2, SLC26A4, LMX1A was significantly higher than group with other genetic etiology (p < 0.01) or the group with all the other causes of hearing loss (p < 0.01). The rate of vestibular and cochlear EH detection was higher in younger patients (41.5% and 35.4%) than in older patients (25.4% and 20.6%). A higher ratio of vestibular and cochlear EH was observed in patients with a longer duration of deafness (37.5% and 31.3%) than those with a shorter duration of deafness (29.7% and 25.0%). The group with vestibular EH showed a higher incidence of abnormal findings in the caloric test (42.9%) than the group without vestibular EH (28.2%). Patients with genetic variants of GJB2, SLC26A4, LMX1A, younger patients, those with longer deaf durations showed a higher prevalence of vestibular and cochlear EH, implying EH appears to be formed as a developmental disorder in association with a certain set of genetic variants, rather than a phenotypic marker as a result of severe to profound hearing loss.

Detecting endolymphatic hydrops in patients with cranial nerve VIII schwannoma using hydrops MR examination.

This study utilized Hydrops MRI in patients with cranial nerve (CN) VIII schwannoma to assess the concomitance with endolymphatic hydrops (EH), aiming to elucidate the mechanism of hydrops formation in these patients. Twenty-six patients diagnosed as CN VIII schwannoma including vestibular schwannoma (VS) in 24 and intracochlear schwannoma (ICS) in 2 were enrolled. Fifteen patients received radiosurgery and 11 patients opted for a wait-and-scan approach. All patients underwent an inner ear test battery, followed by Hydrops MRI. Based on Hydrops MRI, 6 patients (23%) with positive EH were assigned to Group A, while the other 20 patients showing negative EH were assigned to Group B. The abnormality rates of inner ear test battery in Group A ran from the audiometry (100%), cervical vestibular-evoked myogenic potential (cVEMP) test (83%), ocular VEMP (oVEMP) test (67%) to the caloric test (33%), exhibiting a significantly declining sequence. This declining sequence is consistent with the decreasing order in the prevalence of EH from the cochlea (83%), saccule (50%) to utricle (50%). However, Group B did not show such decreasing trend, indicating that Groups A and B did not share the common mechanism. The mean tumor size prior to radiosurgery was 1.91 ± 0.89cm, which significantly reduced to 1.53 ± 0.60cm at a mean interval of 6years following radiosurgery. In contrast, tumor size remained unchanged in those opted for a wait-and-scan approach. It is recommended to utilize Hydrops MRI for patients with CN VIII schwannoma during annual follow-up, particularly those experienced episodic vertigo and/or deteriorated hearing. The Hydrops MRI can not only monitor tumor size, but also detect the presence of EH, so as to guide treatment decision.

Evaluation of e-NIHSS scale combined with HINTS for posterior circulation ischemic stroke with vestibular symptoms

Objective:To explore the predictive value of HINTS bedside examination and e-NIHSS scale for posterior circulation ischemia with vestibular symptoms. Methods:136 cases in total patients with acute vestibular syndrome（AVS） hospitalized in our hospital from April 2021 to April 2023 were selected as the study subjects, According to the classification of AVS etiology, patients with central AVS, namely posterior circulation ischemia（PCI）, were divided into case group（68 cases） and peripheral AVS patients were control group（68 cases）, Collect data and perform head impulse test-nystagmus-test of skew deviation test beside the bed, two doctors evaluated the NIHSS and e-NIHSS scales for PCI patients with vestibular symptoms respecb tively, and recorded the results after they were consistent, and improved the head MRI examination. Results:The positive rate of head pulse test in PCI patients with vestibular symptoms was 3 cases（4.41%）, and 60 cases（88.24%） with peripheral symptoms; The positive rate of nystagmus test in PCI group was 64 cases（94.12%） and peripheral 21 cases（30.88%）; The positive rate of eye deviation test in PCI group was 55 cases（80.88%） and peripheral 8 cases（11.76%）. Comparing the data with the consistency of the final diagnosis, the sensitivity was 97.0%, the specificity was 95.7%, and the accuracy was 0.963. It passed the Kappa consistency test Kappa=0.926（P<0.01）. The patients in PCI group were scored, in which the NIHSS score of brainstem group was 1.51±0.59, and the e-NIHSS score was 4.05±1.71（P<0.05）; The NIHSS score of cerebellar group was 1.42±0.62, and the e-NIHSS score was 3.86±1.59（P<0.05）; NIHSS score of thalamus group was 1.31±0.73, e-NIHSS score was 3.56±1.27 （P<0.05）; NIHSS score of non-focus group was 1.11±0.43, e-NIHSS score was 3.06±1.20 （P<0.01）. The difference between e-NIHSS score and NIHSS score in each group was statistically significant. Conclusion:HINTS examination is highly consistent with the final diagnosis of the gold standard. The e-NIHSS scoring scale has a higher detection rate than the NIHSS scoring scale for patients with posterior circulation ischemia mainly characterize〓by vestibular symptoms.

Auditory Prognosis of Patients With Sudden Sensorineural Hearing Loss in Relation to the Presence of Acute Vestibular Syndrome: A Systematic Literature Review and Meta-Analysis.

Hearing recovery following idiopathic sudden sensorineural hearing loss (ISSNHL) is influenced by various prognostic factors, and the presence of acute vestibular syndrome (AVS) may adversely impact auditory outcomes. Evaluating vestibular function in SSNHL patients could offer insights into predicting hearing recovery. This systematic review aims to assess whether the presence of AVS exacerbates the audiological prognosis of ISSNHL. A comprehensive systematic review was conducted using databases such as PubMed, Cochrane Library, EMBASE, and Scopus, encompassing articles published in the last decade. Included were retrospective and prospective case-control and cohort studies, as well as randomized clinical trials. Meta-analysis was performed based on the findings from these studies. Among 386 articles identified, six addressed the systematic review's question, all being retrospective studies. These articles collectively involved 393 patients for the meta-analysis. Vestibular function assessment methods varied widely, posing challenges for direct comparisons. The likelihood of unfavorable hearing outcomes was 2.29 times higher in patients with associated AVS. Hearing recovery was 3.22 times more likely to be worse in patients with altered cervical vestibular evoked myogenic potentials-air-conducted sound. Abnormal caloric test results showed no significant association with worse hearing prognosis, although patients with unaltered caloric tests demonstrated a significantly greater improvement in pure-tone audiometry. Hearing recovery from ISSNHL appears to be diminished in patients with associated AVS and abnormal vestibular test results.

Differentiating Definite and Probable Ménière Disease: A Comprehensive Evaluation of Audio-Vestibular Function Testing Combined with Inner Ear MRI.

To evaluate the differences between audio-vestibular function testing and inner ear gadolinium magnetic resonance imaging (MRI) in distinguishing definite Ménière disease (DMD) and probable Ménière disease (PMD), and to provide a reference for early clinical diagnosis and intervention. A total of 116 patients diagnosed with DMD (n = 80) and PMD (n = 36) were enrolled. The differences in the results of pure tone audiometry, caloric test, and tympanic injection of gadolinium for contrast-enhanced MRI between the two groups were compared and analyzed. Parameters that could differentiate between the two conditions were identified, and the sensitivity and specificity and the area under the curve (AUC) of individual and combined indices in the differential diagnosis of DMD and PMD were evaluated. The hearing threshold and hearing asymmetry rate of the DMD group were significantly higher than those of the PMD group (p < 0.001), 98.8% and 30.6%, respectively. The abnormal rates of canal paresis (CP) and severity of endolymphatic hydrops in the DMD group were higher than those in the PMD group (p < 0.05). When combined with high-frequency hearing thresholds, hearing asymmetry, hearing curve type, endolymphatic hydrops, and abnormal CP, the diagnostic accuracy of DMD was improved compared to using high-frequency alone (p < 0.05). This study showed that PMD and DMD may represent two different stages in the development of MD disease. The comprehensive assessment of audio-vestibular function testing and inner ear MRI proves beneficial for early diagnosis, potentially contributing to the preservation of inner ear function.

Peripheral neuropathy, an independent risk factor for falls in the elderly, impairs stepping as a postural control mechanism: A case-cohort study.

Peripheral neuropathies perturbate the sensorimotor system, causing difficulties in walking-related motor tasks and, eventually, falls. Falls result in functional dependency and reliance on healthcare, especially in older persons. We investigated if peripheral neuropathy is a genuine risk factor for falls in the elderly and if quantification of postural control via posturography is helpful in identifying subjects at risk of falls. Seventeen older persons with a clinical polyneuropathic syndrome of the lower limbs and converging electrophysiology were compared with 14 older persons without polyneuropathy. All participants were characterized via quantitative motor and sensory testing, neuropsychological assessment, and self-questionnaires. Video-nystagmography and caloric test excluded vestibulocochlear dysfunction. For further analysis, all subjects were stratified into fallers and non-fallers. Overall, 28 patients underwent computerized dynamic posturography for individual fall risk assessment. Regression analyses were performed to identify risk factors and predictive posturography parameters. Neuropathy is an independent risk factor for falls in the elderly, while no differences were observed for age, gender, weight, frailty, DemTect test, timed "Up & Go" test, and dizziness-related handicap score. In computerized dynamic posturography, fallers stepped more often to regain postural control in challenging conditions, while the Rhythmic Weight Shift test showed a lack of anterior-posterior bidirectional voluntary control. Our study confirms peripheral neuropathy as a risk factor for older persons' falls. Fallers frequently used stepping to regain postural control. The voluntary control of this coping movement was impaired. Further investigations into these parameters' value in predicting the risk of falls in the elderly are warranted.

Bilateral Horizontal Canal Dysplasia Presenting as Hearing Loss With Recurrent Vertigo Mimicking Meniere's Disease.

We report an extremely rare case with bilateral horizontal semicircular canal (HSC) dysplasia presenting as hearing loss with recurrent vertigo mimicking Meniere's disease in a previously healthy 49-year-old male patient. HSC malformation is one of the common isolated developmental anomalies of the bony labyrinth usually associated with varying degree of hearing loss. He suffered from recurrent episodes of vertigo lasting more than 20 minutes accompanied by left hearing loss and tinnitus for 3 years. Pure-tone audiometry revealed a mild to moderate hearing loss at low frequencies in the left ear. Bithermal caloric testing revealed significant left-sided canal paralysis, but other vestibular testing was normal. Computerized tomography (CT) of the temporal bone showed the left HSC hypoplasia lacking a central bony island fused together with an enlarged vestibule, and right dysplasia, finally diagnosed with bilateral HSC dysplasia. Meniere's disease-like recurrent vertigo attack and hearing loss were suspected to be caused by subsequent endolymphatic hydrops which could be due to HSC dysplasia.

A Proposal for Comprehensive Audio-Vestibular Test Battery Protocol for Diagnosis and Follow-Up Monitoring in Patients with Vestibular Schwannoma Undergoing Surgical Tumor Removal.

Background: A vestibular schwannoma (VS) is a benign tumor, causing audiological and vestibular symptoms. This study aimed to propose a comprehensive audio-vestibular test battery protocol for diagnosis and follow-up monitoring in patients with unilateral VSs undergoing surgical removal. Methods: The detailed interpretation of audiological and vestibular findings was presented in two example cases. The surgery was performed through the middle cranial fossa (#1) and translabyrinthine approach (#2). The participants were evaluated with tonal, speech, and impedance audiometry, ABR, caloric test, vHIT, cVEMP, oVEMP, SOT, and DHI. Patient and tumor characteristics were retrieved from the patient's history. Results: In the postoperative period, the reduction in gain of the lateral semicircular canal was observed in the vHITs of both patients. The DHI in case #1 increased after surgery, while it decreased in case #2. The improvement in postural performances compared to the preoperative SOT (CON 5, CON 6, composite score) and immediately after the procedure was observed. Conclusions: A specific diagnostic protocol is necessary to compare the results of different surgical techniques and approaches. Diagnostic tests performed before the surgery should be repeated within a specific time frame during postoperative follow-up to enable the comparison of results. The proposed protocol can help us better understand the processes ongoing during tumor growth and postoperative vestibular compensation.

Video head impulse test (vHIT) versus videonystagmography (VNG) in migraine with dizziness

BackgroundMigraine disease is a chronic headache disorder characterized by recurrent attacks. Migraine and vestibular disorders are common associations. The exact pathophysiology is still unknown. ObjectivesTo study the results of vHIT and VNG in dizzy migraineurs.MethodsThis is a case-control study that included 140 subjects 70 of them were migraine patients with vestibular symptoms, while the other 70 were a control group of healthy subjects matched in age. A full history with pure tone audiometry and tympanogram for hearing evaluation was done for both groups then videonystagmography and the video head impulse tests were done.ResultsThe vHIT results showed that there were no significant differences among control and study groups regarding the VOR gain and gain asymmetry with no corrective saccades recorded in patients or control groups that denote the VOR is intact. The VNG test revealed in OPK and saccade tests that there was a significant difference between the control and the study groups. A positive weak correlation between vHIT and caloric test results in the left lateral and posterior canal gain in the study group.ConclusionThe migraine disease with vestibular symptoms does not affect the VOR gain in vHIT and affects the oculomotor tests in VNG.

The dissociation between pathological caloric testing and a normal video head impulse test helps differentiate between Menière's disease, vestibular migraine, and other vestibular disorders: a confirmatory study in a large cohort of 2,101 patients.

Vestibular migraine (VM) and Menière's disease (MD) are characterized by episodes of vertigo of similar duration. It is well known that differentiation between both diseases is not always possible based only on the patient history, physical examination, and audiological testing. In addition, the quantification of the vestibular function can also be helpful since, among patients with MD, there is often a dissociation between a normal/pseudo-normal video head impulse test (vHIT) and reduced caloric testing. The goal of this confirmatory study was to determine the sensitivity, specificity, and positive and negative predictive values (PPV and NPV) of this dissociation to differentiate between MD and VM as well as between MD and other vestibular diseases. We performed a retrospective analysis of 2,101 patients. The examination group consisted of 1,100 patients; of these, 627 (57%) had MD according to the diagnostic criteria of the Bárány Society and 473 (43%) had VM. The comparison group consisted of 1,001 patients with other peripheral, central, or functional vestibular disorders. Statistical analysis revealed the following findings for the dissociation: MD vs. VM: specificity: 83.5%, sensitivity: 58.9%, PPV: 82.6%, and NPV: 60.5%, and MD vs. all other vestibular disorders (VM plus others): specificity: 83.5%, sensitivity: 58.9%, PPV: 60.3%, and NPV: 82.7%. The dissociation between a normal vHIT and a reduced caloric response is due to the high specificity and PPV suited for the differentiation between MD and VM. This part of the study confirms previous findings in a large cohort of patients. When it comes to differentiating between MD and all observed vestibular disorders, if there is no dissociation, the diagnosis of MD is unlikely.

Is galvanic VEMP a prediction of the nerve origin and damage in patients of vestibular schwannoma

Background Recent studies proved that certain proportions of vestibular schwannoma (VS) originated other than vestibular nerve of the eighth cranial nerve. Aims/objectives Unlike air-conducted sounds (ACS) and bone-conducted vibration (BCV), galvanic vestibular stimulation (GVS) evokes vestibular evoked myogenic potentials (VEMPs) from the vestibular nerve. Materials and methods Case-control study was conducted in unilateral VS patients pre-operatively. Healthy ears were controls. Patients examined ACS, BCV and GVS ocular VEMP (oVEMP) and cervical VEMP (cVEMP), caloric test, video head impulse test (vHIT), suppression head impulse paradigm (SHIMP) and pure tone audiometry (PTA). Results Seven (26.9%) tumors affected left ear and 19 (73.1%) on the right(p < .05). Response rates in VS group were statistically lower than control except for ACS-cVEMP (p < .05). Response rates of VEMPs in VS patients decreased with the tumor size grows. But not all BCV and GVS VEMPs disappeared in the largest tumor group. Abnormal rates of caloric test, vHIT gains and SHIMP were found. Conclusions and significance Response rates of GVS VEMPs decreased with the residual functional nerve fibers. GVS VEMPs help to differentiating labyrinthine and retro-labyrinthine lesions. GVS combined with BCV VEMPs probably reflex the tumor origin from the eighth cranial nerve and/or the remaining vestibular function.

Concurrent abnormalities in galvanic cervical and ocular vestibular-evoked myogenic potentials as a predictive marker for prolonged dizziness in vestibular neuritis

Background Despite the growing use of cervical (cVEMP) and ocular (oVEMP) VEMP tests, their effectiveness in predicting chronic dizziness in vestibular neuritis (VN) patients remains unclear. Our research examines the link between long-lasting dizziness and inner ear assessments, encompassing VEMPs induced by air-conducted sound (ACS), bone-conducted vibration (BCV), and galvanic vestibular stimulation (GVS). Objectives This study explores prognostic markers by examining the relationship between the persistence of dizziness symptoms and various inner ear test findings in VN patients. Material and methods A retrospective cohort of 60 unilateral VN patients underwent comprehensive audiovestibular tests, including pure tone audiometry, cVEMP and oVEMP induced by ACS, BCV, GVS, and caloric tests. Patient subgroups were established based on dizziness duration: short-term (<3 months) and long-term (≥3 months). Results No substantial correlation existed between the dizziness duration and the outcomes of any particular single inner ear test. However, patients exhibiting concurrent abnormal GVS-cVEMP and GVS-oVEMP were more likely to experience prolonged dizziness, indicating more extensive vestibular system involvement. Conclusions Concurrent abnormalities in GVS-cVEMP and GVS-oVEMP may indicate a higher chance of long-term dizziness in VN. Significance This study identifies concurrent abnormalities in GVS-cVEMP and GVS-VEMP as a potential prognostic marker for prolonged dizziness in VN.

Qualitative analysis of the presence of gaze-evoked nystagmus in astronauts after long term space flights. Results of “field test” experiment

In the first days after a spaceflight (SF), re-entry motion sickness and motor coordination problems reflect the need to readapt back to the natural gravitational state. Gravity is a natural stimulus for the receptors of vestibular apparatus, which plays an important role in multisensory interactions. Changes indicating an increase in excitability of the vestibular apparatus during SF (Kornilova et al., 2017) suggest a high probability of the occurrence of gaze-evoked nystagmus after prolonged SF. Russian-American experiment “Field Test” included a nystagmus test. 22 ISS crewmembers (14 Russian cosmonauts and 8 astronauts; flight duration 159.8 ± 19.5 days) participated in the experiment. The study was conducted twice before flight and several times after flight, starting within 3 h after landing. In a seated position, astronauts tracked with their eyes only (without moving their head) horizontal and vertical movements of the researcher's finger from the central position to the gaze end points (right, left, upper). Eye movements were recorded with a video camera. The videos were analyzed qualitatively for presence of nystagmus. Preflight, gaze-evoked nystagmus was detected in 5 people, the greatest changes were observed on landing day. 10 crewmembers exhibited nystagmus in the extreme left gaze position and 13 crewmembers – in the extreme right gaze position (partial recovery was observed 1–4 days after SF). A noticeable decrease in the frequency of manifestation of the nystagmus was observed only 10–13 days after landing (n = 16). Gaze-evoked nystagmus is usually considered a clinical sign of cerebellar alterations. However, it is often described in healthy people with a prevalence of up to 21 %. In a similar study involving 18 astronauts, participants of long-term SF, the frequency of occurrence of gaze-evoked nystagmus also increased in the first hours after SF (Reschke, Good and Clement, 2017). However, in this study, a detailed analysis of the presence of nystagmus in various directions was conducted for the first time. Of particular interest is the frequent detection of a gaze-evoked nystagmus in the right position after SF - this phenomenon may be a sign of presence of a central vestibular imbalance (Robinson et al., 1984), which also occurs in patients with cerebellar disorders (Bayer and Dietrich, 2011). The results allow us to expand our understanding of the severity and frequency of vestibular disorders and the dynamics of their recovery after prolonged SF.

Impact of audiovestibular factors on prognosis in patients with sudden sensorineural hearing loss without vertigo.

This study aimed to investigate the hearing outcomes in patients with sudden sensorineural hearing loss without vertigo (SSNHLwoV). Patients with SSNHLwoV managed from December 2016 to March 2020 were prospectively enrolled in an academic tertiary referral center. Fifty-one patients with SSNHLwoV who completed high-dose steroid treatment. The hearing prognosis was analyzed using a multivariate Cox regression model. The rates of complete, partial, and no hearing recovery were 52.9%, 17.6%, and 29.4% in patients with SSNHLwoV, respectively. The video head impulse test (vHIT) of the posterior semicircular canal (PSC), high-tone hearing loss (4-8kHz) ≥ 30 dB, and average hearing threshold (0.5-1-2-4kHz) were significantly associated with incomplete recovery of hearing after treatment. In multivariate analysis, the vHIT of the PSC (hazard ratio [HR], 14.502; 95% confidence interval [CI], 1.371-153.355) and high-tone hearing loss ≥ 30 dB (HR, 9.170; 95% CI, 2.283-36.830) remained robust. Abnormal vestibular function tests were performed in 80.4% of the patients with SSNHLwoV. Abnormal vHIT of the PSC and high-tone hearing loss ≥ 30 dB were independent factors resulting in incomplete recovery of hearing in patients with SSNHLwoV. In the SSNHLwoV cohort, the caloric test was not significantly associated with hearing prognosis, and vHIT was a feasible predictor of treatment outcome.

Association Between Noise-Induced Hearing Loss and Vestibular Dysfunction in Workers Chronically Exposed to Occupational Noise

Background: Despite the understanding of the association between noise exposure and noise-induced hearing loss (NIHL), the effects of noise on vestibular function are less well understood and neglected. Aim: The aim of this study was to investigate the function of the vestibular system in workers with NIHL. Materials and Methods: Thirty male textile workers with symmetrical NIHL (49.3 ± 4.5 dB at 4 kHz) and thirty healthy male textile office staff with normal hearing were included in this study. Pure tone audiometry using air conduction and bone conduction was used to determine hearing thresholds. The videonystagmography battery test, including the oculomotor test, caloric test, and video head impulse test (vHIT), was used for the evaluation of vestibular system function. Results: There was no difference in saccadic tracking, smooth pursuit tracking, and optokinetic nystagmus between the two groups. It was found that the abnormal vHIT was significantly higher in workers with NIHL (40%) than in the control group (3.3%). In addition, the abnormal caloric test was significantly higher in workers with NIHL (33.3%) than in the control group (0%). The association between the hearing thresholds of 3, 4, 6, and 8 kHz and vestibular dysfunction was significant. Conclusion: This study provides evidence of the simultaneous occurrence of NIHL and vestibular dysfunction. In other words, the results support the role of noise as a risk factor for the development of vestibular dysfunction in textile workers.