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At least 415 records · Page 23Linked to original sources
PubMed1979

Vestibular adaptation to long-term stimuli.

Experimental procedures are described which respectively enlarge stimulus duration in vestibular peracceleratory tests, and allow to rule out direct thermal effects on the vestibular nerve during long term calorisations. First experimental results indicate that time course of nystagmus during prolonged stimulations differs markedly in rotational and caloric tests. Whereas there is a distinct decline of response during rotation (in accordance to the predictions of current mathematical models), in caloric tests nystagmus reaches a steady state level, maintained for at least 15 min.

Adaptation, Physiological↗
PubMed2003

Preservation of the saccular nerve and of the vestibular evoked myogenic potential during vestibular schwannoma surgery.

OBJECTIVE: The aim of the study was to present a case report demonstrating that vestibular evoked myogenic potentials originate from the saccular nerve. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. INTERVENTION: Vestibular evoked myogenic potentials are shown before and after operation in a patient with a surgically confirmed superior vestibular schwannoma (1.3 cm). MAIN OUTCOME MEASURES: Preoperative and postoperative audiometry, auditory brainstem response, caloric test, vestibular evoked myogenic potentials, and magnetic resonance imaging outcomes. RESULTS On preoperative audiometry, slight sensorineural hearing loss with normal auditory brainstem response could be detected. Caloric tests showed a reduced response of the right labyrinth. Vestibular evoked myogenic potentials were normal. The tumor was removed via a combined retrosigmoid and partial labyrinthectomy approach with the removal of the posterior semicircular canal. The facial, auditory, and inferior semicircular nerves were anatomically preserved. Postoperative audiometry revealed preservation of hearing and vestibular evoked myogenic potentials; caloric responses were now absent. CONCLUSION: The combined retrosigmoid and partial labyrinthectomy approach represents an ideal condition to study the influence of the saccular nerve on the origin of the vestibular evoked myogenic potentials. The maintenance of the vestibular evoked myogenic potential responses in our patient supports the concept that the vestibular evoked myogenic potential originates in the saccule and is transmitted in the saccular nerve.

Audiometry, Pure-Tone↗
PubMed2003

[Selection of vestibular system function in Chinese astronauts].

OBJECTIVE: To examine and evaluate the vestibular function of Chinese astronaut candidates in order to select the astronauts with good vestibular function. METHOD: Fifty-nine male candidates, the fighter plane pilots, participated in the Caloric tests, and 38 pilots among all the candidates experienced the parallel swing and Coriolis acceleration stimuli in tests. The parameters, such as vestibule-autonomic nervous reflex symptoms, electrogastrography (EGG), electronystagmography (ENG), ECG, blood pressure, postural equilibrium ability were employed to evaluate the vestibular function. RESULT: Caloric tests indicated that there were function symmetry on both sides of semicircular canals, as well as normality of visual-vestibular and vestibulo-ocular reflexes in all the candidates. The parallel swing and Coriolis acceleration stimulus demonstrated that there were differences of vestibular functions in 38 pilots. Incidence of I category (stability type) of vestibular function exceeded 52.6%, and II category (relatively stable type) approached 42.1% as well III category (relatively susceptible type) was reported to be 5.3%. CONCLUSION: Vestibular function of astronaut candidates could be evaluated comprehensively and objectively in the present tests. The Chinese astronauts can be chosen from the candidates with stable type or relatively stable type up to standard vestibular function.

Astronauts↗
PubMedDate not supplied

The effect of variations in temporal bone structure upon the caloric response.

A high degree of inter-subject variability reduces the clinical usefulness of the caloric test. Both anatomical and physiological factors are responsible for this problem, but the proportion of variability caused by either factor has not been determined. This study sets a quantitative estimate on the amount of caloric test variability which can be ascribed to anatomical variations in the study population. Polytome radiographs of 48 "normal' subjects were studied do determine how individual variations in the intensity of caloric-induced nystagmus might be related to anatomical features of the temporal bone. A statistical analysis showed that pneumatization in the petrous and "buttress' areas, and the dimensions of the internal auditory canal were significantly correlated with caloric response intensity. Furthermore, about 23% of caloric response variability in this population could be accounted for by a combination of anatomical characteristics. However, neither the extent of mastoid pneumatization nor the dimensions of the external auditory canal were found to be significantly related to caloric responsiveness.

Adolescent↗
PubMed2004

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.

Adult↗
PubMed2004

Subclassification of vestibular disorders by means of statistical analysis in caloric labyrinth testing.

OBJECTIVE: In the past, various attempts were made to perform a quantitative analysis of nystagmographic findings but their diagnostic value was limited. Therefore, the authors present a multivariate analysis of nystagmus findings with the aim of increasing the precision of diagnostic differentiation in cases of vestibular dysfunction. MATERIAL AND METHODS: A group of 387 patients and 40 healthy volunteers were examined over a 14-month period using electronystagmography after stimulation by bithermal, bilateral irrigation of the labyrinth. Amplitude, slow-phase velocity, frequency and directional preponderance were evaluated. RESULTS: No defined normal values for caloric nystagmus parameters could be obtained. However, by using the Mann Whitney U-test and logistic regression analysis a differentiation between pathological and healthy findings as well as between central and peripheral vestibular disorders and even between distinct vestibular disease entities is possible. Using these methods, the nystagmus amplitude was found to be the strongest discriminating parameter. Therefore, sole assessment of nystagmographic findings by selective calculation of the nystagmus slow-phase velocity falls short of the potential offered by electronystagmographic registration. CONCLUSION: For daily clinical routine, counting nystagmus beats leads to the same diagnostic precision as the analysis of slow-phase velocities. In contrast, multivariate analysis of several nystagmus parameters can distinguish between distinct diseases with fairly high precision. This stepwise analysis of nystagmographic data could create the basis for an expert-system tool in the near future.

Caloric Tests↗
PubMedDate not supplied

[New symptom in early diagnosis of bilateral acoustic neuroma].

Eleven patients were admitted to the hospital with the diagnosis of unilateral tumor of the vestibulocochlear nerve at the stage of clinical manifestations or at a well advanced stage. Their otoneurological examinations revealed a microtumor at the side opposite to the major tumor node. Of great diagnostic importance were vestibulometric data which showed lack of vestibular excitation on both sides: in some cases it was not recorded during caloric tests while in other cases it was not recorded during caloric or rotation tests. In view of the lack of the vestibular response on the "healthy" side, it was supposed that there was a microtumor there. In all cases this diagnosis was confirmed either by computer tomography or by CT and surgery. This symptom can be very helpful for an early detection of a microtumor or the vestibulocochlear nerve on the side opposite to the major tumor node. It is emphasized that special attention should be given to arm displacement, during caloric tests.

Caloric Tests↗
PubMed1999

Variations in calibration for computerized electronystagmography.

The accuracy of the analyses of vestibular test results obtained from a computerized electronystagmography (ENG) system depends on the accuracy with which the system has been calibrated to record the patient's eye movements. The variability of the calibration sensitivity was investigated by analysing the records of 50 consecutive patients who attended for vestibular testing and a study was carried out using 16 volunteer subjects to examine the contributions that time, changes in lighting and subject movement made to this variability. The effect of calibration frequency on the results obtained from caloric testing was also examined by analysing 16 patient records. The mean percentage change in sensitivity between the first two calibrations carried out on patients was found to be -17%, with a standard deviation of 18%. However, there seems to be little baseline drift over time under constant lighting conditions. Changes in lighting have a marked effect, and the adjustment to lighting changes is slow. Gentle movement has little effect. Repeated calibration does not seem to be an effective method to control the calibration-related errors in caloric test results. Careful control of room illumination and the use of adequate adaptation periods to allow patients to adjust to the lighting should help to improve accuracy but, even in the absence of satisfactory calibration, the use of a computerized ENG system can provide valuable diagnostic information.

Adolescent↗
PubMed2005

Vestibular evoked myogenic potentials in neurofibromatosis 2.

Neurofibromatosis 2 (NF2) is characterized by bilateral vestibular neurofibromas. Although the facial nerve, the cochlear nerve, and the superior division of the vestibular nerve can be evaluated before surgery, whether the inferior division of the vestibular nerve is affected remains undetermined without an operation. A total of 7 patients with NF2 (2 men and 5 women) underwent pure tone audiometry, caloric testing, vestibular evoked myogenic potential (VEMP) testing, and magnetic resonance imaging. Audiometry revealed mean hearing levels of less than 26 dB for 1 ear, 26 to 70 dB for 8 ears, 71 to 90 dB for 3 ears, and more than 90 dB for 2 ears. Caloric testing revealed an absent response in 71% of the 14 ears. Seven ears underwent VEMP testing, and only 1 ear (14%) displayed absent VEMPs. Magnetic resonance imaging depicted space-occupying lesions in all 14 auditory canals: small tumors in 3 ears, medium tumors in 7 ears, and large tumors in 4 ears. The tumor size of NF2 is related to the caloric response, but is unrelated to the mean hearing level or VEMPs. In conclusion, NF2 originates from the superior vestibular nerve more often than the inferior vestibular nerve. It more often infiltrates the cochlear nerve than the inferior vestibular nerve.

Adolescent↗
PubMed2002

The diagnostic significance of the 3D-reconstructed MRI in vestibular schwannoma surgery: prediction of tumor origin.

In hearing preservation surgery for the treatment of vestibular schwannoma (VS), one of the important factors is the determination of the origin of VS. In this study, we investigated the diagnostic significance of using an MRI obtained by the three-dimensional Fourier transform fast spin-echo technique (3D-reconstructed MRI) in order to determine the origin of VS. The subjects consisted of 20 patients with mainly intra-canalicular sized VS who underwent tumor removal at our hospital. The origin of VS was determined from the 3D-reconstructed MRI findings and the results of the caloric test. These findings were then compared with the surgical findings. In 15 out of 20 patients, the MRI findings closely corresponded to the surgical ones, while the origin of VS hardly could be detected when a tumor filled up to the fundus acoustics on the MRI findings of the axial sections. On the other hand, 6 out of 15 patients (40%) whose tumor originated from the inferior vestibular nerve showed canal paresis. In conclusion, 3D-reconstructed MRI is considered to be helpful in obtaining more precise information regarding the origin of VS compared to the caloric test.

Caloric Tests↗
PubMed1995

[Vestibulo-spinal and vestibulo-ocular reflexes in athletes].

There have been done tests of vestibulo-spinal et vestibulo- ocular reflexes at record-seeking sportsmen. At 141 sportsmen the vestibulo-spinal reflexes were tested by Unterberger-Fukuda stepping test in modification of Zilstorff-Pedersen and Peitersen. The angle of rotation (a), the distance of translocating to front or back (b) and the distance of sideward translocation (c) were estimated. The test was also done at 194 persons not playing sport. Comparing the average results of both groups the conclusion was drawn that sportsmen are characterized by lesser translocation of body within the range of all parameters of test, and differences of average are statistically substantial at the level of trust p = 0, 001. The vestibulo- ocular reflexes were tested at 62 sportsmen by caloric test by method of Fitzgerald-Hallpike with electronystagmographic registering of nystagmus. The control group consisted of 30 persons not playing sport. The following features of nystagmus were estimated: duration time, maximum frequency, maximum amplitude and maximum angular velocity of the slow phase. The sportsmen were characterized by average lesser calorie excitability of labyrinth, although the differences between the tested groups were statistically substantial only within the range of some features of nystagmus.

Adolescent↗
PubMedDate not supplied

[Delayed endolymphatic hydrops: an analysis of 12 cases].

Delayed Endolymphatic Hydrops (DEH) is a clinical entity which is characterized by an early phase with a profound sensorineural hearing loss in one ear. After a prolonged period of time (from 1 to 68 years) a late phase of the disease appears with different otologic symptoms. The ipsilateral type of endolymphatic hydrops appears in the deaf ear with consequent episodic vertigo. The contralateral type develops symptoms of endolymphatic hydrop in the previously normal ear, with the onset of fluctuating hearing loss and/or episodic vertigo. This paper is a review of 12 cases of DEH (7 ipsilateral and 5 contralateral, age ranging from 19 to 79 years). Diagnosis was established on the basis of clinical history and the results of audio-vestibular investigations, specifically designed to detect signs of endolymphatic hydrops (including the glycerol-test and neuroradiological imaging of the cerebello-pontine angle). In 8 patients the levels and frequency of anti-collagen I-II-IV-V, anti-laminin autoantibodies, complement, Ig and immuno-complexes were measured. Viral infections (measles, mumps, influenza) were thought to have caused the early phase in 6 cases. In the entire group of 12 patients the delay between the onset of the ear loss and vertigo averaged 12 years. In the group of the ipsilateral DEH, caloric tests showed in 5 cases a reduced or absent response of the deaf ear. About contralateral DEH, caloric tests showed bilateral reduced response in 2 cases, and, in 3 cases, a decreased response only in the previously normal ear. Regarding immunological study, an abnormal level of Ig and Complement was detected in 3 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

[Asymptomatic acoustic neurinoma associated with hypophyseal macroadenoma].

UNLABELLED: The widespread use of gadolinium-enhanced MRI (Gd-MRI) in our hospitals has supposed an increase in detection of asymptomatic acoustic neuromas (AN) as incidental finding. Concurrent primary intracranial tumors of different cell types are extremely uncommon. CLINICAL CASE: A 23 year-old woman complained of irregular menstrual cycles and galactorrhea for two years. A Gd-MRI scan showed a pituitary macroadenoma and an AN of 1.4 cm. with intracanalicular and cisternal extension. The patient did not have any otologic or neuro-otologic symptoms or signs. Audiograms revealed bilateral normal hearing. The results of acoustic reflex test and electronystagmographic caloric tests were normal. The AN underwent radiosurgery treatment. DISCUSSION: The literature about atypical AN is reviewed, giving a particular concern on asymptomatic cases. We only have found one case of association between AN and pituitary adenoma. The real prevalence of AN in general population is discussed.

Adenoma↗
PubMed2004

P0 antigen detection in sudden hearing loss and Ménière's disease: a new diagnostic marker?

OBJECTIVE: To evaluate the presence of IgG autoantibodies against the P0 antigen in patients affected by sudden hearing loss and Meniere's disease (MD). MATERIAL AND METHODS: All patients underwent a tonal audiometric evaluation, tympanometry, evaluation of the stapedial reflex threshold with decay time, determination of auditory brainstem responses and a complete vestibular assessment involving evaluation of spontaneous and positional nystagmus (Frenzel glasses), a head thrust test and a caloric test (Fitzgerald-Hallpike technique). Blood samples were drawn from all patients for the immunologic assessment of IgG antibodies against the P0 antigen (30-kDa protein) of guinea pig inner ear extracts using a Western blot assay. RESULTS: Ten patients affected by sudden hearing loss showed specific IgG antibodies against the P0 protein. Specifically, the P0 positive band was detectable in 5/45 patients with unilateral auditory impairment and in 5/5 of those with bilateral forms of auditory impairment. Among MD patients, the P0 positive band was detectable only in those with bilateral audiovestibular impairment (n = 10). Interestingly, in none of the 35 patients affected by monolateral MD were specific IgG antibodies against the P0 protein detectable. CONCLUSION: The positive reactions to P0 in all bilateral MD and bilateral sudden hearing loss patients found in this study strongly indicate that these pathologies are the result of an ongoing autoimmune process directed against specific antigens of the inner ear.

Adolescent↗
PubMed2000

[The relationship between ECochG and glycerol test in vertigo patients (report of 112 cases)].

OBJECTIVE: For further investigating the diagnostic value of the ECochG in Meniere's disease. METHOD: 112 vertigo patients including Meniere's disease, sudden deafness, cervical vertigo and other vertigo disease, had been done ECochG, glycerol test, audiometry and caloric test. The results were compared with those of normal group. RESULT: In Meniere's disease, the positive rate of abnormal-SP/AP in ECochG was 54.69% and the positive rate of glycerol test was 53.12%. There are no statistics difference (P > 0.05) between this two tests with X analysis. CONCLUSION: We think that the glycerol test and other relative examination are necessary for the diagnosis of Meniere's disease while the-SP/AP > 0.4 ms in the examination of ECochG.

Adolescent↗
PubMed1991

[Inverted caloric nystagmus of perforated ears upon air caloric stimulation].

It is well known that inverted caloric nystagmus is seen during air caloric testing in cases of chronic otitis media. The mechanism of inversion and its clinical significance are discussed here. Temperature changes in the tympanic cavity and external ear canal were measured with a microthermister and a digital tester in seventeen ears with tympanic membrane perforation, during bithermal air caloric testing. The tympanic cavity mucosa was cooled by hot stimulation because of the evaporation of heat. When the perforation was closed or humidified air was used, the tympanic cavity mucosa was not cooled by hot stimulation and the inverted caloric nystagmus changed to a normal response. Inverted caloric nystagmus occurred in 30.4% of 335 ears affected by chronic otitis media with perforation. Inverted caloric nystagmus occurred in 90 ears with hot stimulation and in 12 ears with cold stimulation. Inverted caloric nystagmus turned to normal response after myringoplasty in all of 10 ears. The cooling effect caused by evaporation of water from the moist middle ear mucosa during dry air blowing and direct thermal conduction to the vestibulum through a perforation of the ear drum and inversion of the endolymphatic convection seemed to cause the inversion.

Adolescent↗
PubMed1981

Meniere's disease and the summating potential. II. Vestibular test results.

Results of electronystagmographic (ENG) position and bithermal caloric tests from patients with abnormally enlarged summating potentials (SPs) were compared with results from a unilateral weakness (UW)-matched ENG-comparison group and with a group of patients with unilateral cochlear deficits and dizziness but without enlarged SPs. The patients with enlarged SPs had significantly higher incidence of caloric UW on the involved side than did the patients with cochlear deficits but without enlarged SPs. Also, the patients with SP enlargement had a significantly higher incidence of directional preponderance toward the involved side than did either of the comparison groups. Across-group differences in position test results were predictable from the caloric test results, but these differences were not statistically significant.

Adult↗
PubMed1979

Vestibular suppression in peripheral and central vestibular disorders.

Caloric tests have been carried out both in the presence of optic fixation and in total darkness upon normal subjects, patients with peripheral vestibular disorders and patients with central vestibular lesions. Nystagmic responses were recorded electronystagmographically and measurements made of latency and duration of response, maximum slow component velocity and beat frequency. The relative enhancement of the response in darkness is expressed as a fixation index: maximum slow component velocity in darkness maximum slow component velocity with fixation. Compared to the normal group the peripheral group were found to have abnormally high fixation indices, the central group abnormally low. A hypothesis has been developed of the nervous mechanisms underlying the suppressive effects of optic fixation in both peripheral and central lesions which accords well with the available clinical, anatomical and physiological data. The clinical implications of the findings are discussed both in respect of their localizing value and relevance to current innovations in the design of caloric tests.

Brain Neoplasms↗