Acute vestibular neuritis visualized by 3-T magnetic resonance imaging with high-dose gadolinium

Sudden idiopathic unilateral loss of vestibular function without other signs or symptoms is called acute vestibular neuritis. It has been suggested that reactivation of human herpes simplex virus 1 could cause vestibular neuritis, Bell palsy, and sudden unilateral hearing loss. Enhancement of the facial nerve on gadolinium-enhanced magnetic resonance imaging (MRI) is a common finding in Bell palsy, but enhancement of the vestibular nerve has never been reported in acute vestibular neuritis. We present 2 consecutive cases of acute vestibular neuritis where high-field-strength MRI (3.0 T) with high-dose (0.3 mmol/kg of body weight) gadolinium-pentetic acid showed isolated enhancement of the vestibular nerve on the affected side only. These findings support the hypothesis of a viral and inflammatory cause of acute vestibular neuritis and might have implications for its treatment.     

Inferior vestibular neuritis in a fighter pilot: A case report

Pilot spatial disorientation is a leading factor contributing to many fatal flying accidents. Spatial orientation is the product of integrative inputs from the proprioceptive, vestibular, and visual systems. Vestibular neuritis (VN) can lead to sudden pilot incapacitation in flight. VN is commonly diagnosed by demonstration of unilateral vestibular failure, as unilateral loss of caloric response. As this test reflects the function of the superior part of the vestibular nerve only, cases of pure inferior nerve neuritis will be lost. This paper describes a fighter pilot with symptoms suggestive of VN but with normal caloric test results. Further test showed unilateral loss of vestibular evoked myo-genic potential. We believe that the pilot suffered from pure inferior nerve vestibular neuritis. VEMP plays a major role in the diagnosis of inferior nerve vestibular neuritis in pilots. Aeromedical concerns are also discussed.     

Retrolabyrinthine vestibular nerve section: efficacy in disorders other than Menière's disease

The retrolabyrinthine vestibular nerve section has evolved as an effective treatment for intractable vertigo of peripheral vestibular origin when hearing preservation is desired. This report studies the efficacy of retrolabyrinthine vestibular nerve section for control of vertigo due to causes other than Meniere's disease. This report details our experience with 42 patients with a wide variety of diagnoses. The reduced success rate of retrolabyrinthine vestibular nerve section in these patients is difficult to evaluate, as very few patients have been analyzed with respect to their specific diagnoses. Of patients who underwent retrolabyrinthine vestibular nerve section for control of vertigo, 23 patients had uncompensated vestibular neuritis and 19 others had a wide range of other diagnoses. For patients with uncompensated vestibular neuritis (n = 23), the physician record noted that 39% of patients were cured and 30% improved. This compares to our series of patients with Meniere's disease (n = 48), where 94% were cured and 2% improved. The true vestibular abnormality may be less reliably identified in patients with uncompensated vestibular neuritis, contributing to the less effective results. Since the development of a vestibular rehabilitation program, retrolabyrinthine vestibular nerve section for uncompensated vestibular neuritis has been all but abandoned. Retrolabyrinthine vestibular nerve section appears to achieve a high cure rate in patients with sensorineural hearing loss associated with their vestibular abnormalities. While retrolabyrinthine vestibular nerve section is helpful for control of vertigo in some diagnoses, a substantial incidence of persistent postoperative dysequilibrium was noted.     

Isolated vestibular areflexia after blunt head trauma.

The sudden unilateral loss of vestibular function is a frequent cause of vertigo. This condition is called vestibular neuronitis or vestibular neuritis. Its cause remains unknown, but many authors consider it to be a sequel of vestibular viral infection. We report the history and clinical findings of 5 patients in whom a unilateral vestibular loss occurred after head trauma. None of these patients complained of hearing loss. In all cases, the vertigo gradually subsided over days or weeks. The follow-up showed the partial recovery of vestibular function in 2 cases, while vestibular areflexia persisted in 3. The clinical course and findings were similar in every respect to those in patients with classic idiopathic vestibular neuronitis.     

Horizontal vestibulo-ocular reflex dynamics in acute vestibular neuritis and viral labyrinthitis: evidence of otolith-canal interaction

OBJECTIVE: To evaluate the dynamic properties of the horizontal vestibulo-ocular reflex (h-VOR) in the acute stage of two common labyrinthine diseases that provoke severe attacks of vertigo with spontaneous nystagmus: vestibular neuritis (vestibular loss alone) and viral labyrinthitis (cochleovestibular loss). MATERIAL AND METHODS: Sixty-three patients were investigated: 42 were diagnosed with vestibular neuritis and 21 with viral labyrinthitis. The h-VOR function was evaluated by conventional caloric and impulsive testing. A simplified model of vestibular function was used to analyze the vestibulo-ocular response to rotational stimulation. RESULTS: The results showed a significant difference in h-VOR characteristics between the two pathologies. Patients with vestibular neuritis exhibited a strong horizontal semicircular canal deficit, but no h-VOR asymmetry between the two rotational directions. In contrast, patients with viral labyrinthitis demonstrated moderate canal paresis and a marked h-VOR deficit in rotation toward the affected ear. CONCLUSION: These findings support the hypothesis that the h-VOR dynamic asymmetry that occurs after an acute unilateral inner ear lesion is not due to canal dysfunction alone, but involves complex adaptive changes in the central VOR that may implicate the otolith system. Based on histopathologic and clinical differences in the two pathologies reported in the literature, we postulate that this otolith-canal interaction is mainly linked to the loss of saccular function.     

Vestibular-evoked myogenic potential in patients with unilateral vestibular neuritis: abnormal VEMP and its recovery

The incidence of inferior vestibular nerve disorders in patients suffering from unilateral vestibular neuritis and the recovery of these disorders were evaluated by monitoring the vestibular-evoked myogenic potential (VEMP). Eight patients ranged from 21 to 73 years that suffered from unilateral vestibular neuritis underwent VEMP and caloric testing. Abnormal VEMP was observed in two of the eight patients with unilateral vestibular neuritis. Two patients were diagnosed as having an inferior vestibular nerve disorder. One of these patients showed recovery of the inferior vestibular nerve function as assessed by the VEMP. Disorders of the inferior vestibular nerve function and their recovery was confirmed by our current results. The time course of recoveries of the superior and inferior vestibular nerve systems were similar in the two patients.     

Horizontal vestibulo-ocular reflex dynamics in acute vestibular neuritis and viral labyrinthitis: evidence of otolith-canal interaction

Objective To evaluate the dynamic properties of the horizontal vestibulo-ocular reflex (h-VOR) in the acute stage of two common labyrinthine diseases that provoke severe attacks of vertigo with spontaneous nystagmus: vestibular neuritis (vestibular loss alone) and viral labyrinthitis (cochleovestibular loss).

Material and Methods Sixty-three patients were investigated: 42 were diagnosed with vestibular neuritis and 21 with viral labyrinthitis. The h-VOR function was evaluated by conventional caloric and impulsive testing. A simplified model of vestibular function was used to analyze the vestibulo-ocular response to rotational stimulation.

Results The results showed a significant difference in h-VOR characteristics between the two pathologies. Patients with vestibular neuritis exhibited a strong horizontal semicircular canal deficit, but no h-VOR asymmetry between the two rotational directions. In contrast, patients with viral labyrinthitis demonstrated moderate canal paresis and a marked h-VOR deficit in rotation toward the affected ear.

Conclusions These findings support the hypothesis that the h-VOR dynamic asymmetry that occurs after an acute unilateral inner ear lesion is not due to canal dysfunction alone, but involves complex adaptive changes in the central VOR that may implicate the otolith system. Based on histopathologic and clinical differences in the two pathologies reported in the literature, we postulate that this otolith-canal interaction is mainly linked to the loss of saccular function.     

Vestibular and cochlear nerve enhancement on MRI and its correlation with vestibulocochlear functional deficits in patients with Ramsay Hunt syndrome

ObjectiveThe correlation between enhancement of the vestibulocochlear nerves on gadolinium-enhanced magnetic resonance imaging (MRI) and vestibulocochlear functional deficits was examined in patients with Ramsay Hunt syndrome (RHS).MethodsNineteen patients with RHS who showed herpes zoster oticus, peripheral facial palsy, and vertigo were enrolled. Canal paresis (CP) in the caloric test, abnormal response to ocular and cervical vestibular myogenic potentials (oVEMP and cVEMP), and refractory sensorineural hearing loss were evaluated. MRI images perpendicular to the internal auditory canal were reconstructed to identify the superior (SVN) and inferior vestibular nerves (IVN) and the cochlear nerve (CV). The signal intensity increase (SIinc) of the four-nerve enhancement was calculated as an index.ResultsAmong RHS patients, 79%, 53%, 17% and 26% showed CP in the caloric test, abnormal responses to oVEMP and cVEMP, and refractory sensorineural hearing loss, respectively. SIinc rates of the SVN were significantly increased in RHS patients with CP in the caloric test, and with abnormal responses to oVEMP and cVEMP. SIinc rates of the SVN tended to increase in RHS patients with refractory sensorineural hearing loss (p = 0.052). SIinc rates of the IVN were significantly increased in RHS patients with abnormal responses to oVEMP and cVEMP, and refractory sensorineural hearing loss, but not in those with CP in the caloric test. SIinc rates of the CN were significantly increased in RHS patients with CP in the caloric test, abnormal response to oVEMP and refractory sensorineural hearing loss, but not in those with abnormal response to cVEMP.ConclusionIn patients with RHS, the origin of vertigo may be superior vestibular neuritis, which is affected by reactive varicella-zoster virus from the geniculate ganglion of the facial nerve through the faciovestibular anastomosis. The results also suggested that in some RHS patients, inferior vestibular neuritis contributes to the development of vertigo and that the origin of refractory sensorineural hearing loss is cochlear neuritis.     

Peripheral vestibular neuropathy and a central vestibular equivalent

The results of the initial and follow-up examinations of 217 patients with vestibular neuritis and 63 patients with a so called "vestibular neuritis syndrome" were statistically evaluated and quantified using the vestibular index. The results for patients with vestibular neuritis were compared at the different stages to those of patients after neurectomy of the vestibular nerve. The site of the lesion in patients with vestibular neuritis may therefore be in the region of Scarpa's ganglion (retrolabyrinthine). Alternatively the total peripheral end-organ may be affected. This conclusion agrees with histopathological findings. The "vestibular neuritis syndrome" included patients with the same history as patients with true vestibular neuritis but with signs of a central-vestibular disturbance or a combination of a central and peripheral lesion of the vestibular system. In these cases the lesion may be situated closer to the vestibular nuclei or its central pathways. Both disorders were similar with respect to history, etiology and the prognosis.     

Acute bilateral sequential vestibular neuritis

Two cases of bilateral sequential vestibular neuritis demonstrate the significant persistent disequilibrium that follows involvement of the second ear. The etiology for the loss of vestibular function is postulated to be a viral neuritis. Vestibular suppressant drugs are helpful in relieving nausea and vomiting in the acute phase of the disease; however, they are of no therapeutic value for the protracted disequilibrium following involvement of the second ear. An awareness of this disorder as a disease entity will minimize diagnostic and therapeutic frustration on the part of the physician and provide a realistic prognosis for the patient. Unfortunately, the prognosis is for permanent but somewhat lessening disequilibrium with the passage of time and depends in great part on the subject's age.     

突发性聋与前庭神经炎的前庭损伤差异性研究

目的　通过比较研究伴有前庭损伤的突发性聋和前庭神经炎,探讨两类疾病前庭损伤的差异。方法  2016-02-25～2016-07-20解放军总医院耳鼻咽喉头颈外科眩晕诊疗中心,突发性聋组55例,其中39例伴眩晕患者;前庭神经炎组46例。前庭双温冷热试验、头脉冲试验、颈性前庭诱发肌源性电位、眼性前庭诱发肌源性电位评价及比较突发性聋及前庭神经炎两组疾病前庭损伤差异性。结果　前庭双温冷热试验突发性聋组异常率25.45%,前庭神经炎组异常率97.82%,两组比较差异有统计学意义（χ2=54.01,P＜0.001）。头脉冲试验：突发性聋组异常率9.09%,前庭神经炎组异常率32.61%,两组比较差异有统计学意义（χ2=8.72,P =0.003）。颈性前庭诱发肌源性电位突 发性聋组异常率69.10%,前庭神经炎组异常率43.47%,两组比较差异有统计学意义（χ2=6.72,P =0.010）;眼性前庭诱发肌源性电位突发性聋组异常率54.55%,前庭神经炎组异常率63.04%,两组比较差异无统计学意义（χ2=0.745,P =0.388）。结论　突发性聋与前庭神经炎两组患者前庭损伤比较,突发性聋合并眩晕者更有可能为球囊/前庭下神经受累,损伤部位更多靠近神经终末端,损伤是低频段的;前庭神经炎的前庭损伤范围大,损伤是全频段的,高位可能性更大。     

Anatomic differences in the lateral vestibular nerve channels and their implications in vestibular neuritis.

HYPOTHESIS: Anatomic differences may render the superior division of the vestibular nerve more susceptible to injury during vestibular neuritis. BACKGROUND: Neural degeneration has been identified in temporal bone studies of vestibular neuritis. Previous anatomic and physiologic studies of vestibular neuritis have demonstrated that the superior division of the vestibular nerve is preferentially affected, with sparing of the inferior division. A preliminary temporal bone study has implicated neural entrapment as a possible cause for this preferential injury. METHODS: Two independent unbiased observers performed histologic analysis of 184 temporal bones from our temporal bone library. Measurements of the medial, midpoint, and lateral portions of the superior vestibular, inferior vestibular, and the singular nerves and their bony channels lateral to the internal auditory canal were made. These measurements included the length and width of each bony channel and an estimated percent of each channel occupied by bony spicules at each location. RESULTS: The lengths of the bony channels of the singular nerve (0.598 mm) and the inferior vestibular nerve (0.277 mm) were significantly shorter than the average length of the superior vestibular channel (1.944 mm; p < 0.0001). The total percent of the channel occupied by bone at the midpoint was significantly greater for the superior vestibular (28%) compared with either the singular (0%) or the inferior vestibular channel (18%) (p < 0.0001). CONCLUSION: The lateral bony channel of the superior vestibular nerve is seven times longer than the inferior vestibular and more than three times longer than the singular channel. There are a larger percentage of bony spicules occupying the superior vestibular compared with the inferior vestibular or singular channels. In addition, the superior nerve passes through a longer area of severe narrowing compared with the inferior or singular nerves. This anatomic arrangement of a longer bony channel with more interspersed bony spicules could make the superior vestibular nerve more susceptible to entrapment and ischemia.     

HSV-1 not only in human vestibular ganglia but also in the vestibular labyrinth.

Reactivation of herpes simplex virus type 1 (HSV-1) in the vestibular ganglion (VG) is the suspected cause of vestibular neuritis (VN). Recent studies reported the presence of HSV-1 DNA not only in human VGs but also in vestibular nuclei, a finding that indicates the possibility of viral migration to the human vestibular labyrinth. Distribution of HSV-1 DNA was determined in geniculate ganglia, VGs, semicircular canals, and macula organs of 21 randomly obtained human temporal bones by nested PCR. Viral DNA was detected in 48% of the labyrinths, 62% of the VGs, and 57% of the geniculate ganglia. The potential significance of this finding is twofold: (1) Inflammation in VN could also involve the labyrinth and thereby cause acute unilateral vestibular deafferentation. (2) As benign paroxysmal positional vertigo often occurs in patients who have had VN, it could also be a sequel of viral labyrinthitis.     

Neuritis des N.?vestibularis inferior

Vestibular evoked myogenic potentials (VEMP) are a new method to establish the functional status of the otolith organs. The sacculocollic reflex of the cervical VEMP to air conduction (AC) reflects predominantly saccular function due to saccular afferents to the inferior vestibular nerve. We describe a case of inferior vestibular neuritis as a rare differential diagnosis of vestibular neuritis. Clinical signs were a normal caloric response, unilaterally absent AC cVEMPs and bilaterally preserved ocular VEMPs (AC oVEMPs).     

Vestibular evoked myogenic potentials

Vestibular Evoked Myogenic Potentials (VEMP) are commonly recorded in patients experiencing vertigo or chronic instability. This test evaluates the patient's otolith function and is often combined with both Videonystagmography and Video Head Impulse Test. VEMP is a simple, reproducible test, in the absence of any pre-existing conductive hearing loss. Cervical VEMP explore both saccular function and the inferior vestibular nerve, whereas ocular VEMP assess utricular function and the superior vestibular nerve. In combination with previously described tests, VEMP allows characterization of vertigo and provides support for the diagnosis of superior semicircular canal dehiscence syndrome, Menière's disease, vestibular neuritis, vestibular schwannoma or idiopathic bilateral vestibulopathy. A good knowledge of these electrophysiological tests is essential in order to precisely assess the presence or absence of vestibular function impairment. We describe the test recording technique and the most common pitfalls in interpretation of the results. We then outline the results observed in various diseases impacting vestibular function.     

New clinical finding in vestibular neuritis: high-frequency audiometry hearing loss in the affected ear

Twenty-one patients with established vestibular neuronitis were examined otoneurologically and audiologically. High-frequency audiometry up to 20,000 Hz was performed on all the patients. In 17 cases a high-frequency hearing loss was greater in the ear with vestibular neuritis. The mean hearing loss difference varied from 14 dB to 24 depending on the frequency. Our results reveal that in most cases of vestibular neuritis there are no isolated vestibular lesions, but most cases also involve an auditory end-organ lesion. This finding is in unison with the anatomic conditions of the cochlea and the vestibular end-organ.     

Differential diagnosis of virus-like particles in the human inner ear.

The entire endolymphatic duct and sac as well as the vestibular epithelia were obtained from four patients with Meniere's disease during translabyrinthine (TL) eighth nerve section and from 12 patients undergoing TL resection of acoustic schwannomas. After these specimens were processed for routine transmission electron microscopy (TEM), they were studied for morphologic evidence of viral infection. Although no virus particles were identified, numerous regularly occurring cell components and artifacts were found to morphologically mimic viruses. An atlas of these structures is presented.     

The role of acute and latent virus infections in the pathogenesis of inner ear disturbances

The possible role of herpesviral infections of the inner ear in suddenly appearing inner ear disturbances was investigated. Experimental pseudorabies virus (PRV, Herpes sui 1) infection of mice and swine was used as a model system. Infected mice represented the productive cycle of PRV infection (acute phase), whereas the latent phase of infection could be tested in swine. From the acutely infected mice the virus could be reisolated from perilymphatic fluid and various parts of the brain. Massive histopathologic alterations and signs of total cell damage to the organ of Corti and the vestibular organ were found. Accordingly, in all of the cells of the inner ear multiple copies of the PRV genome could be demonstrated. We therefore suggest that the disturbances of the inner ear were induced by the acute virus infection. In two latently infected swine (sixty weeks after infection), PRV could not be recovered either from the perilymphatic fluid or from a variety of different neural and extraneural tissues. However, histopathologic changes similar to those found in the acutely infected mice were observed. The presence of viral DNA could be demonstrated by in situ cytohybridization in both sensory and supportive cells of the inner ear and vestibular organ, but not in the corresponding nerve fibers, which is in contrast to the acutely infected mice. The distribution of the viral genome was further analyzed in adjacent areas of the central nervous system. An involvement of acute and latent herpes virus infection in inner ear dysfunction including sudden deafness and vestibular neuronitis in man, might be suggested from the results described. The presented animal model system, PRV-infected swine, should permit further studies on a possible role of herpetic recurrences, particularly with regard to inner ear disturbances.