ABSTRACT
AIMS: We report the case of a 58-year-old female patient who consulted our Department complaining of positional vertigo and showing spontaneous upbeat nystagmus (UBN) in darkness. METHOD: We analyzed her UBN three-dimensionally. The MRI scan revealed the astrocytoma in the left cerebellum involving the cerebellar vermis. RESULT: Three-dimensional analysis showed a spontaneous UBN rotating around the intra-aural axis in the pitch plane. CONCLUSION: Since the cerebellar vermis is known to plays an inhibitory role on the central vertical vestibule-ocular reflex (VOR), the present results suggest that the spontaneous UBN in darkness observed in this patient was induced by an imbalance of central vertical VOR tone.
Subject(s)
Astrocytoma/physiopathology , Cerebellar Neoplasms/physiopathology , Imaging, Three-Dimensional , Nystagmus, Pathologic/physiopathology , Videotape Recording , Electronystagmography , Female , Humans , Magnetic Resonance Imaging , Middle Aged , Reflex, Vestibulo-Ocular/physiology , Vestibular Function TestsABSTRACT
CONCLUSIONS: Results of audiometry, caloric testing and vestibular evoked myogenic potential (VEMP) testing were hardly influenced by plugging surgery. OBJECTIVE: To evaluate the influence of surgical plugging of the posterior semicircular canal on inner ear function in patients with benign paroxysmal positional vertigo (BPPV). SUBJECTS AND METHODS: The subjects were five consecutive patients with intractable BPPV who underwent plugging surgery. The following functions of the inner ear were examined before and 6 months after surgery. Cochlea function was evaluated by the average hearing level of three frequencies (500, 1000 and 2000 Hz), that of the semicircular canal by canal paresis percent (CP%) in caloric testing and that of the otolith by the left-right difference ratio on VEMP testing. RESULTS: Positional vertigo was resolved in all patients. One subject was completely deaf before and after surgery. The average hearing level did not change more than 10 dB after surgery in the other four cases. CP% did not worsen more than 10% in any case. The VEMP results after surgery did not change more than 10% from before surgery in any case.
Subject(s)
Audiometry , Hearing Loss, Sensorineural/diagnosis , Postoperative Complications/diagnosis , Semicircular Canals/surgery , Surgical Instruments , Vertigo/surgery , Vestibular Diseases/diagnosis , Vestibular Function Tests , Adult , Aged , Caloric Tests , Evoked Potentials, Motor/physiology , Female , Follow-Up Studies , Hearing Loss, Sensorineural/physiopathology , Humans , Male , Middle Aged , Neck Muscles/innervation , Postoperative Complications/physiopathology , Postural Balance/physiology , Semicircular Canals/physiopathology , Vertigo/physiopathology , Vestibular Diseases/physiopathologyABSTRACT
CONCLUSIONS: Bone-conducted vestibular evoked myogenic potentials (B-VEMPs) showed high specificity for the presence of vertigo in patients with unilateral chronic otitis media (COM). These results suggest that vestibular function can be evaluated with B-VEMPs, even in patients with conductive hearing loss. OBJECTIVE: The purpose of this study was to investigate the VEMPs induced by bone-conducted stimuli (B-VEMPs) in patients with conductive hearing loss due to perforated COM. SUBJECTS AND METHODS: The subjects were 48 patients with unilateral perforated COM and conductive hearing loss. The disequilibrium group consisted of 25 patients, and the non-disequilibrium group consisted of 23 patients. The control group comprised 35 healthy volunteers. B-VEMPs were stimulated with tone burst sound of 60 dB nHL and 250 Hz delivered from a bone vibrator and were recorded for each subject. The results of B-VEMP were compared between disequilibrium and non-disequilibrium groups. RESULTS: The mean interaural ratio was 16.5+/-12.1% in the control group, thus the normal range was <40.7%. Abnormal results were not found in any subject in the non-disequilibrium group but were found in 13 patients (54.0%) in the disequilibrium group (p<0.001). The ear with COM showed lower responses than the intact ear in all subjects with abnormal results.
Subject(s)
Bone Conduction , Evoked Potentials, Auditory , Hearing Loss, Conductive/physiopathology , Neck Muscles/physiopathology , Vestibule, Labyrinth/physiopathology , Adult , Aged , Chronic Disease , Female , Hearing Loss, Conductive/complications , Humans , Male , Middle Aged , Otitis Media/complications , Postural Balance , Sensation Disorders/complicationsABSTRACT
OBJECTIVE: To study the relationship between vestibular-evoked myogenic potential evoked by air-conducted stimuli (A-VEMP) and those evoked by bone-conducted stimuli (B-VEMP). STUDY DESIGN: Prospective study. SETTING: University Hospital. PATIENTS: To determine the optimum stimulus conditions for B-VEMP, 40 ears of 20 healthy volunteers were used. To compare results of A-VEMP and B-VEMP, 60 ears of 30 healthy volunteers and 70 ears of 35 patients with unilateral vestibular disorder without conductive hearing loss were used. MAIN OUTCOME MEASURE: A-VEMP and B-VEMP were measured. Both examinations involved evaluation of the interaural ratio (IAR) of the p13-n23 peak-to-peak amplitude. To compare the relationship between A-VEMP and B-VEMP in healthy subjects and patients with unilateral vestibular disorder. RESULTS: The optimum stimulus for B-VEMP seemed to be a tone-burst sound with 8-ms duration at 250 Hz. In all healthy subjects, both A-VEMP and B-VEMP could be recorded. The mean IAR of B-VEMP (0.5 +/- 21.0%) was not significantly different from that of A-VEMP (0.2 +/- 19.4%). In patients with unilateral vestibular disorder, B-VEMP could not be detected in 10 ears in which A-VEMP also could not be detected. The IAR of A-VEMP was strongly correlated with that of B-VEMP (correlation coefficient, 0.98). CONCLUSION: The results of B-VEMP were almost the same as those for A-VEMP, at least, for patients without conductive hearing loss.
Subject(s)
Bone Conduction/physiology , Evoked Potentials, Auditory/physiology , Vestibular Diseases/physiopathology , Acoustic Stimulation , Adult , Aged , Case-Control Studies , Female , Humans , Male , Middle Aged , Prospective Studies , Reaction Time , VertigoABSTRACT
OBJECTIVE: To measure the frequency dynamics of the vestibular evoked myogenic potential in patients with endolymphatic hydrops. STUDY DESIGN: A prospective study. SETTING: A university hospital. SUBJECTS: The endolymphatic hydrops group consisted of 28 affected ears of patients with definite unilateral Ménière's disease and a control group of 36 ears of 20 healthy volunteers. INTERVENTIONS: Vestibular evoked myogenic potentials generated by tone bursts at 250, 500, 700, 1,000, 1,500, 2,000, and 4,000 Hz were measured in both groups. Vestibular evoked myogenic potentials were also measured after furosemide administration in six patients in the endolymphatic hydrops group. MAIN OUTCOME MEASURE: The frequency sensitivity of vestibular evoked myogenic potential, as evaluated by p13-n23 normalized amplitude. RESULTS: Peak amplitudes were noted at 500 Hz in the control group and at 1,000 Hz in the endolymphatic hydrops group. After furosemide loading, peak amplitude shifted to a lower frequency in four of six ears. CONCLUSION: The peak amplitude of vestibular evoked myogenic potentials in the endolymphatic hydrops group was at a higher frequency than in the control group. The frequency of the saccule (nu) should be proportional to radical(tau/sigma), where tau is the tension of membrane and sigma is its density. We advocate the hypothesis that the shift in frequency dynamics of vestibular evoked myogenic potential in patients with endolymphatic hydrops originates from the morphologic features of the saccule, analogous to an expanded balloon.
