1/16. Variance of vestibular-evoked myogenic potentials. OBJECTIVES/HYPOTHESIS: Vestibular-evoked myogenic potential (VEMP) has been thought to originate from sacculus. The variance of this potential and the effectiveness of the adjustments of pInII amplitudes using average muscle tonus of ipsilateral sternocleidomastoid muscle were evaluated. In addition, clinical application of VEMP was examined in patients with acoustic tumors (ATs) and vestibular neurolabyrinthitis (VNL). STUDY DESIGN: Prospective evaluation of the VEMP in 18 normal volunteers and 6 patients. methods: Variance and left-right difference of each parameter, including pI latency, nII latency, pInII amplitude, and threshold, was analyzed. Input-output function of pInII amplitude was evaluated. Average muscle tonus was calculated in 20 ears and applied for adjustment of pInII amplitude. Sensitivity of each parameter of VEMP was examined in 3 patients with ATs and 3 patients with VNL. RESULTS: VEMP was present in all 36 ears of 18 control subjects. Thresholds of VEMP for normal subjects were 80 to 95 dB normal hearing level (nHL). The muscle tonus affected pInII amplitude significantly; however, no statistically significant improvement was observed in test-retest investigation after adjustment using muscle tonus. The threshold of the affected side was elevated compared with the non-affected side in all patients with ATs, whereas 2 of 3 patients showed normal pInII-ratio. One patient with VNL presented normal VEMP, whereas 2 patients presented no VEMP to the highest stimulus intensity. CONCLUSIONS: Interaural difference of thresholds might be the most useful parameters. Adjustment using average muscle tonus is not necessary when the subject is able to get sufficient muscle tonus. ( info) |
2/16. 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. ( info) |
| Idiopathic bilateral vestibulopathy (IBV) is an acquired bilateral peripheral vestibular disorder of unknown cause. Three patients diagnosed as IBV by neuro-otological examination were reported. They underwent vestibular evoked myogenic potential (VEMP) testing which reflects the functionality of the sacculo-collic pathway. As a result, 2 of the 3 patients showed bilateral absence of VEMPs and one showed unilateral absence. The VEMPs of the 3 patients revealed that IBV affects not only the superior but also the inferior vestibular nerve systems. As previously reported in the cases of vestibular neuritis, VEMP could be useful for classifying IBV according to the function of the inferior vestibular nerve. ( info) |
4/16. Vestibular symptoms as a complication of sildenafil: a case report. Potential vasodilator side effects of sildenafil such as headache, flushing, dyspepsia, heartburn, nasal congestion, dizziness and visual changes have been frequently observed. We report a 79-year-old man who developed severe vestibular neuritis-like symptoms (horizontal nystagmus with rotatory components and vomiting) two hours after taking 50 mg sildenafil. Additionally, the patient complained of tinnitus in both ears. Internal and neurological examination revealed no pathological findings and the patient had no history of cardiovascular disease. The symptoms lasted for 24 hours and then resolved completely. All of the patient's complaints indicated a drug-related phenomenon. This drug related adverse reaction should be included in the long list of potential side effects of sildenafil. ( info) |
5/16. 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. ( info) |
6/16. Neurotologic issues. Progress has been made in the diagnosis and treatment of inner ear disorders. Autoimmune inner ear disorders and Meniere's disease (MD), the prototype inner ear disease, are highlighted in this review of current knowledge and contemporary dietary, medical, surgical, and vestibular rehabilitation therapy. A number of other peripheral vestibular disorders are presented and contrasted with MD. ( info) |
| 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. ( info) |
8/16. Audiovestibular evolution in a patient with multiple sclerosis. multiple sclerosis is characterized by the presence of multiple plaques within the central nervous system, manifesting as remission and exacerbation of neurologic dysfunction over variable time courses. We present the case of a 20-year-old woman. Before treatment, her auditory brain stem response (ABR) test revealed bilateral prolongation. A caloric test showed canal paresis of the right ear and a normal response on the left. A vestibular evoked myogenic potential (VEMP) test displayed an absent response in the right ear and a delayed response in the left. A magnetic resonance imaging (MRI) scan demonstrated multiple diffuse high signal lesions in the hemispheres, brain stem, and cerebellum. Six months after treatment, the demyelinating plaques were shown to have resolved spontaneously on MRI. Recovery of caloric responses was anticipated. Bilateral prolongation of ABRs remained, but the VEMP test disclosed a normal response in the right ear and a delayed response in the left. Accordingly, in addition to MRI, caloric tests and ABR and VEMP tests are useful in monitoring the evolution of audiovestibular function in patients with multiple sclerosis. ( info) |
9/16. Vestibular neuritis in a child with otitis media with effusion; clinical application of vestibular evoked myogenic potential by bone-conducted sound. Vestibular evoked myogenic potential (VEMP) has been applied for patients with vestibulo-cochlear disorders. The impairment of the sound transmission due to middle ear pathology affects VEMP results. In children, otitis media with effusion (OME) is well documented and it is difficult to apply conventional VEMP in such cases. To overcome the attenuation of stimulation due to middle ear pathology, VEMP by bone-conducted sound has been developed. We report a 3-year-old girl with vestibular neuritis and OME as a representative case of clinical application of VEMP by bone-conducted sound. VEMP by bone-conducted sound can be an alternative method to elicit vestibular-dependent potential. ( info) |
10/16. Lesion site in idiopathic bilateral vestibulopathy: a galvanic vestibular-evoked myogenic potential study. CONCLUSION: The result suggests that patients with idiopathic bilateral vestibulopathy may have nerve lesions when the inferior nerve system is affected, while the inferior vestibular nerve system may be spared. OBJECTIVE: To clarify the lesion site in idiopathic bilateral vestibulopathy, an acquired bilateral vestibulopathy of unknown cause. MATERIAL AND methods: Two 75-year-old males diagnosed with idiopathic bilateral vestibulopathy were enrolled. Both showed absent or highly decreased responses on the caloric test on both sides. They underwent vestibular-evoked myogenic potential (VEMP) testing by means of acoustical and electrical stimulation. As acoustic stimulation, 95 dB nHL clicks and short tone bursts (500 Hz) were presented, while 3 mA (1 ms) short-duration galvanic stimuli were presented as electrical stimulation. Responses were recorded on the sternocleidomastoid muscles. RESULTS: Both patients showed unilateral absence of VEMPs with both acoustic and short-duration galvanic stimuli. ( info) |