Unilateral Vestibular Disease Research Articles

New findings and pathophysiology in attitude control through vestibular interoception

Attitude control is associated with coordinated limb, body, head, and ocular movements through vestibular interoception. During straight walking, walking speed for velocities ranging from 1.2–1.8 m/s. Over this range of walking velocities, there is both translation and rotation of the head in the sagittal plane, reaching translational frequencies close to 2 Hz, peak vertical linear accelerations of 0.3–0.5 g, and peak pitch velocities of 15–22°/s. The magnitude and frequency of the pitch angular and vertical translational head movements are sufficient to activate both the angular and linear vestibulo-ocular (aVOR and lVOR) and vestibulo-collic (aVCR and lVCR) reflexes, which may play important roles in directing gaze and in stabilizing gait. In support of this, unilateral vestibular disease is associated with instability of gait, and astronauts, whose vestibular function has been adapted to microgravity, also experience difficulty when walking a curved path after flight. The purpose of this study was to infer a possible role for the vestibular interoception in producing head and eye movements in three dimensions as the body moves in space.

Results of subjective visual vertical tests in patients with vertigo/dizziness

ObjectiveWe previously established the head-tilt subjective visual vertical (HT-SVV) test to evaluate head-tilt perception gain (HTPG) in addition to the original head-upright SVV (HU-SVV) test (Wada-Y et al.: Laryngoscope Investig Otolaryngol, 2020). In this study, we aimed to investigate the HU-SVV and HT-SVV abnormality rates among patients with vertigo/dizziness. MethodsBetween July 2014 and December 2020, 357 patients were hospitalized for examining the HU-SVV and HT-SVV at our vertigo/dizziness center. Among these patients, 120 had Meniere's disease (MD), 99 had unilateral vestibular disease (UVD), 76 had benign paroxysmal positional vertigo (BPPV), 14 had vestibular migraine (VM), 13 had orthostatic dysfunction (OD), 12 had bilateral vestibular disease (BVD), 12 had central dizziness (CD), 7 had vestibular schwannoma (VS), and 4 had psychogenic dizziness (PD). We determined the reference values of the absolute HU-SVV (<2.5°) and HTPG (0.80–1.25) for the sitting position and used these for calculating the HU-SVV and HT-SVV abnormality rates in each type of vertigo/dizziness. ResultsAmong the 357 patients, 111 had abnormal HU-SVV results (31.1%), 132 had abnormal HT-SVV results (37.0%), and 185 had abnormal HU-SVV and/or HT-SVV results (51.8%). The modified HT-SVV test in combination with the original HU-SVV test could detect gravity perception disturbance in patients with vertigo/dizziness significantly better than the original test alone (chi-square: p=0.00019). The HU-SVV, HT-SVV, and HU-SVV and/or HT-SVV abnormality rates were significantly higher in patients with peripheral vestibular diseases, i.e., MD, UVD, BPPV, and BVD than in those with other types of vertigo/dizziness, i.e., VM, OD, CD, VS, and PD (chi-square: p=0.010, p=0.020, and p=0.0025, respectively). ConclusionThese findings suggest that the combined HT-SVV and HU-SVV test could be a powerful neuro-otologic examination for detecting pathologies in the vestibular otolithic pathway.

Virtual and augmented reality in the vestibular rehabilitation of peripheral vestibular disorders: systematic review and meta-analysis

Vestibular rehabilitation therapy is an established treatment for patients with vestibular dysfunction. Virtual reality (VR) and augmented reality (AR) can be utilised in vestibular rehabilitation. Evidence of the efficacy of VR and AR delivered rehabilitation in patients with peripheral vestibular disorders is reviewed. MEDLINE, EMBASE, CENTRAL, CINAHL, PsychInfo, PsychBITE, OTSeeker, Ei Compendex, IEE, Clinical trials.gov and WebofScience databases were searched. Reduction in vestibular dysfunction symptoms 0–3 months post-intervention was the primary outcome. Secondary outcomes included long-term symptom improvement and side effects. Risk of bias assessment and meta analyses were planned. Five studies meeting eligibility criteria were included. Dizziness Handicap Inventory (DHI) scores 0–3 months post-intervention were reported by four studies. Meta-analysis identified a 1.13 (95% CI, − 1.74, − 0.52) standardized mean difference reduction in DHI in VR and AR treated patients compared to controls. Side effects reported by two studies were reduced by week four of VR intervention. Bias assessment identified DHI scores and side effects to be at high risk or of some concern. Adjunct VR interventions reduced patient DHI significantly more than vestibular rehabilitation alone 0–3 months post-intervention in adult patients diagnosed with unilateral vestibular disease. High quality studies are needed.

Correlation and difference analysis in parameters between video head impulse test and caloric test in vestibular disease

Objective:To investigate interrelationships in parameters between caloric test and video head impulse test（vHIT） in the common peripheral vertigo diseases and healthy people, and to conduct correlation and difference analysis between the results in two tests, so as to evaluate the clinical diagnosis value of peripheral vertigo. Methods:The caloric test and vHIT were fulfilled in 68 patients with vertigo and 17 healthy volunteers. The diagnosis was done according to history inquiring, otology and audiology examination and vestibular tests. The vestibulo-ocular reflex（VOR） gain and gain asymmetry（GA） of a vHIT as well as unilateral weakness（UW） and the sum of the slow-phase velocities（SPVs） of warm and cold irrigation of the same side were compared. A cutoff value of VOR gain of a vHIT was also calculated using a receiver-operating characteristic curve. Results:In all ears（n=170）, there was significant correlation in ipsilateral SPVs and VOR gain（r=0.568, P<0.0001）; In all ears（n=34） of 17 healthy volunteers, there was no correlation in ipsilateral SPVs and VOR gain（r=-0.05, P=0.778）; In all affected ears（n=76）, there was statistically positive correlation in ipsilateral SPVs and VOR gain（r=0.571, P<0.0001）; In all the unaffected ears（n=94）, there was positive correlation in ipsilateral SPVs and VOR gain（r=0.286, P=0.005）. In 60 patients with unilateral vestibular disease（n=60）, there was statistically significant negative correlation between the VOR gain of affected ears and UW（r=-0.513, P<0.0001）; there was statistically significant positive correlation between GA of a vHIT and UW（r=0.713, P<0.0001）. There was a statistically significant negative correlation between the VOR gain of affected ears and UW in the fluctuating vertigo group（r=-0.516, P=0.002） as well as a positive correlation between GA and UW（r=0.529, P=0.001）; In the non-fluctuating vertigo group, there was a statistically significant negative correlation between the VOR gain of affected ears and UW（r=-0.428, P=0.029）; there was a positive correlation between GA of a vHIT and UW（r=0.743, P<0.0001）. In the vestibular neuropathy group, there was a negative correlation between the VOR gain of affected ears and UW（r=-0.462, P=0.030）; there was a statistically significant positive correlation between GA of a vHIT and UW（r=0.757, P<0.0001）. There was a negative correlation between the VOR gain of affected ears and UW in the vestibular peripheral disease group（r=-0.516, P=0.002） as well as a statistically significant positive correlation between GA and UW（r=0.529, P=0.001）. The mean value of UW（65.5%） was higher in the overt saccade group than that in the normal VOR group, there was statistically significant difference（P=0.006）. According to the UW damage degree grading, there was statistically significant difference in abnormal educe rates（χ²=17.76, P<0.05）. Based on the gold standard of caloric response, a cutoff value of 0.865 was determined; the parameters of the two tests were dissociated in 28.3%. Conclusion:There was a statistically significant correlation in parameters between vHIT and caloric test. The patients of overt saccade always accompany with the high UW, which could indicate that the vestibular function severely damaged. vHIT and caloric test can be complementary tools for the comprehensive evaluation of patients' vestibule function, on account of dissociation between the results of vHIT and caloric test and general result of consistent check.

Hearing as an Independent Predictor of Postural Balance in 1075 Patients Evaluated for Dizziness

To evaluate the association between hearing and postural balance. Retrospective cross-sectional study. Tertiary care otolaryngology clinic. Patients examined for suspected vestibular disorder were included in this study. The outcome variable was postural sway measured by static posturography during quiet standing with eyes closed. The predictor variable was pure-tone average hearing threshold on the best hearing ear at 0.5, 1, 2, and 3 kHz. Covariates were age, sex, and vestibular disease or vestibular asymmetry assessed by bithermal caloric irrigation. In total, 1075 patients were included. Increased hearing threshold was a strong predictor of increased postural sway (path length) after correcting for age and sex. A 10-dB increase in hearing loss on the best hearing ear predicted a mean 6.0% increase in path length (confidence interval, 2.9%-9.3%, P < .001). Of the covariates, increasing age (P < .001) and male sex (P = .009) were significant predictors of increased postural sway. The effect of increased hearing threshold was also significant after adjusting for vestibular disease. Increased hearing threshold was an independent predictor of increased postural instability, and this effect was strongest for the best hearing ear. Unilateral vestibular disease did not seem to explain this association between hearing and postural balance. Reduced hearing is associated with impaired balance, and interventions to prevent falls should be considered for patients at risk.

Successful treatment of hyperventilation-induced nystagmus in vestibular schwannoma with oxcarbacepine

JO N 2842 tion was performed and the lesion was monitored clinically and radiologically. To treat paroxysmal symptoms, oxcarbacepine (2 x 150 mg) was prescribed and well-tolerated. The nystagmus could no longer be provoked by hyperventilation. After a pause in medication, the hyperventilation-induced nystagmus reoccurred. Nystagmus is very infrequently induced by hyperventilation. However, patients with demyelinating lesions of the vestibular nerve (due to compression by a tumor or a small blood vessel) or in central structures (multiple sclerosis) may show hyperventilation-induced nystagmus (HIN) [4]. In acoustic neuroma, the presumed mechanism of HIN is improved axonal conduction in the partially demyelinated vestibular nerve by hyperventilation. Carbon dioxide levels have been shown to decrease after a 30-second period of hyperventilation. CSF pH rises in association with this reduction in PCO2, which leads to a reduction in extracellular ionized Ca2+. Hyperventilation hence results in a transient increase in activity from partially demyelinated axons as a result of the lowering of extracellular Ca2+ [5]. Hyperventilation can cause nystagmus beating towards the side of a vestibular nerve lesion (i.e., excitatory nystagmus) and is the only test that unmasks unilateral vestibular disease without testing the dynamic properties of the vestibulo-ocular Guido Ahle Wenke Visser Annika Juergens Uwe Schlegel

Head impulse test in unilateral vestibular loss

Quantitative head impulse test (HIT) measures the gain of the angular vestibulo-ocular reflex (VOR) during head rotation as the ratio of eye to head acceleration. Bedside HIT identifies subsequent catch-up saccades after the head rotation as indirect signs of VOR deficit. To determine the VOR deficit and catch-up saccade characteristics in unilateral vestibular disease in response to HIT of varying accelerations. Eye and head rotations were measured with search coils during manually applied horizontal HITs of varying accelerations in patients after vestibular neuritis (VN, n = 13) and unilateral vestibular deafferentation (UVD, n = 15) compared to normal subjects (n = 12). Normal VOR gain was close to unity and symmetric over the entire head-acceleration range. Patients with VN and UVD showed VOR gain asymmetry, with larger ipsilesional than contralesional deficits. As accelerations increased from 750 to 6,000 degrees /sec(2), ipsilesional gains decreased from 0.59 to 0.29 in VN and from 0.47 to 0.13 in UVD producing increasing asymmetry. Initial catch-up saccades can occur during or after head rotation. Covert saccades during head rotation are most likely imperceptible, while overt saccades after head rotation are detectable by clinicians. With increasing acceleration, the amplitude of overt saccades in patients became larger; however, initial covert saccades also became increasingly common, occurring in up to about 70% of trials. Head impulse test (HIT) with high acceleration reveals vestibulo-ocular reflex deficits better and elicits larger overt catch-up saccades in unilateral vestibular patients. Covert saccades during head rotation, however, occur more frequently with higher acceleration and may be missed by clinicians. To avoid false-negative results, bedside HIT should be repeated to improve chances of detection.

Utilidad del nistagmo de agitación cefálica en la exploración vestibular clínica básica

ObjectivesTo determine the sensitivity and specificity of the head-shaking nystagmus test (HSN), the nystagmus elicited in response to a vigorous rotation of the head in the horizontal plane, in the study of patients with peripheral unilateral vestibular disease. Patients and methodsRetrospectively, we analyze the relationships between the HSN and the rest of the videonystagmographic tests on eighty-three patients with peripheral unilateral vestibular disease. ResultsTwenty-three patients showed a positive head-shaking nystagmus; twenty-one of them had unilateral caloric hypofunction and only two had a symmetric caloric test, but both of them showed some type of vestibular dysfunction on other videonystagmographic test. In our series, the HSN sensitivity for the existence of peripheral vestibular disease was 48.8%, while the specificity was 95% in relation to the caloric test, reaching 100% when the gold standard was the presence of any abnormal videonystagmographic test. ConclusionHSN is a simple test that can be useful to identify patients having unilateral vestibular hypofunction.

Functional significance of peripheral head-shaking nystagmus.

The objective was to determine the characteristics of horizontal head-shaking nystagmus of peripheral origin and its relationship to vestibular dysfunction. Retrospective case series. Eighty-three patients met the inclusion criteria of having peripheral and unilateral vestibular disease. Patients were tested with video nystagmography. Head-shaking nystagmus was performed in the horizontal plane during 30 cycles at a frequency of approximately 3 Hz. Head-shaking nystagmus was classified as monophasic or biphasic and, based on the pathological ear, as ipsilateral or contralateral related to nystagmus fast phases. The two-tailed t test, ANOVA, Mann-Whitney and chi2 tests, and lineal and polynomial regression tests were used for statistical analysis. Twenty-three patients showed a positive head-shaking nystagmus. All cases of head-shaking nystagmus observed were horizontal. There were four biphasic and 19 monophasic cases of head-shaking nystagmus. First phases of biphasic head-shaking nystagmus beat toward the normal ear. Eleven of the monophasic cases of head-shaking nystagmus were ipsilateral, and nine were contralateral. There was a statistically significant correlation between caloric weakness and head-shaking nystagmus. Ipsilateral head-shaking nystagmus corresponded to lower caloric asymmetries, and contralateral and biphasic head-shaking nystagmus corresponded to greater caloric weakness (P <.001). As the caloric asymmetry increased, the maximal slow-phase eye velocity of head-shaking nystagmus was greater (P =.01) and its duration shortened (P =.008). Ipsilateral responses could be distinguished from contralateral responses based on their latency (P =.03), maximal slow-phase eye velocity (P <.05), and duration (P =.02). The frequency of head-shaking nystagmus was significantly higher among older patients. There was no correlation between head-shaking nystagmus and clinical patterns. Head-shaking nystagmus of peripheral vestibular origin is a response both qualitatively and quantitatively associated with the degree of the vestibular loss.

Evaluation of the patient for surgical intervention of vertigo

Proper patient selection is critical for success in surgically treating patients with vertigo. The highest cure rates are seen in the treatment of Menière's disease. Patients must be aware that destructive surgeries will substitute some degree of ataxia for the intractable vertigo they are experiencing. The highest success occurs when there is unilateral vestibular disease, no contraindications to surgery (such as central dysfunction), and realistic expectation for surgical outcomes. In some circumstances, bilateral Menière's disease is amenable to nondestructive intervention. The preoperative work for surgical intervention consists of audiometry, electronystagmography (ENG), and may include supplementary tests, such as rotational or posture platform testing. The audiogram, ENG, and history are the most helpful tests, with supplementary tests added to evaluate cases of bilateral disease or further define central disease.

The pitfalls of limiting ENG testing to patients with vertigo.

A high incidence of patients who do not experience vertigo with unilateral vestibular disease has been observed. Recognizing that many clinicians perform electronystagmographic vestibular testing on only patients who describe vertigo, a retrospective study of 229 patients was designed to study the potential pitfalls of this practice. The results confirm a preliminary study and show that 66% of the patients described no vertigo. Included were 13 intracranial lesions of which only one had the classic symptom. Differences in cortical perception and adaptation are postulated as factors responsible for these and other observations relative to caloric stimulation, torsion swing testing, and the presence of spontaneous nystagmus.

Jumbling Phenomenon in a Case of Unilateral Peripheral Vestibular Disease

One kind of oscillopsia of vestibular origin consists of disorders in visual perception when a patient with loss of vestibular function moves rapidly. It is called “jumbling” and may be induced by insufficiency of compensatory vestibular eye movement.Usually “jumbling phenomenon” appears in cases of loss of bilateral vestibular function, since an intact unilateral labyrinth may completely cover the absence of unilateral vestibular function. However, it appeared in our three patients with unilateral vestibular disease: vestibular neuritis or unilateral labyrinthine disease due to meningitis. All three complained of difficulty in walking in dim light and sensed apparent move ments of a still target when they moved their head towards the side of the diseased ear either actively or passively.They had normal clear vision during movement of the head to the side of the intact ear. This may be called “unilateral jumbling” as opposed to “bilateral jumbling”, which is oscillopsia caused by moving the head to either. Unilateral jumbling, which seems to be provoked by strong DP (directional preponderance of nystagmus) due to acute vestibular asymmetry, may disappear as soon as vestibular symmetry disappears. However, unilateral jumbling in older patients or in those with unilateral vestibular disease combined with some central nervous system disorder may persist for a long time.