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PubMedDate not supplied

[Effect of the orientation of the head in the gravitational field on the intensity of caloric nystagmus].

The relationship between the intensity of the vertical and horizontal caloric nystagmus and the head orientation in the gravity field was studied experimentally. The positions in which the nystagmus reached the highest intensity were identified. The experimental results showed that during caloric stimulation the major contribution to the excitation of semi-circular canals was made by the convective flow of the endolymph which was dependent on the head orientation relative to the acceleration vector. The caloric tests can induce stimulation of vertical semi-circular canals which is comparable to that of horizontal canals in its strength.

Adolescent↗
PubMed1998

[The phenomenon of the fixation suppression of caloric nystagmus in the diagnosis of vestibular disorders].

Fixation nystagmus suppression in caloric tests was used in examination of 56 patients suffering from chronic remittent labyrinthopathy, acute labyrinthopathy, vestibular neuronitis, otosclerosis, adhesive otitis media, vertebrobasilar insufficiency, motor disease, chronic remittent vestibulopathy and neurinoma of the VIII nerve. The bithermal test (BT) with electronystagmography was made to calculate the fixation suppression index (FSI). Complete suppression of the caloric nystagmus in at least one BT test appeared to be the most frequent variant of the response (24 cases). This was not dependent on the severity of the vestibular analyzer lesion. In 3 cases FSI of the caloric nystagmus was rather high (> 0.50). Introduction of the period of glance fixation in performance of all the 4 BT tests may serve an additional method in differential diagnosis of the vestibular disorders. The fixation test results should be compared to findings obtained in the other vestibulometric tests.

Acute Disease↗
PubMed1988

The use of vestibular tests for the selection of anti-vertigo drugs.

Vertigo is not a disease, but a symptom. Therefore, the therapy of vertigo is primarily directed at eliminating the underlying cause. In about half of the cases the cause will not become apparent, however, and the therapy is doomed to be symptomatic. Several types of drugs have been found to have an anti-vertigo activity, e.g. antihistamines, calcium antagonists, anti-emetics. For the selection of vestibular depressants, the vestibular caloric test and the rotation test can be used. The duration of the nystagmus induced by rotation is the most useful parameter. The lag-period, the extent and duration of the vestibular effects can be determined and compared with that of other substances. A stronger action on a nystagmus does not necessarily mean a stronger anti-vertiginous action. The final proof of an anti-vertiginous activity can only be established in clinical studies in patients with vertigo.

Animals↗
PubMed2006

MRI of the vestibular nerve after selective vestibular neurectomy.

CONCLUSION: In patients with Ménière's disease and persisting vertigo attacks after vestibular neurectomy (VNx) MRI of the vestibulocochlear nerve can identify residual vestibular nerve fibres that could be responsible for the vertigo attacks. OBJECTIVE: To test if MRI of the vestibulocochlear nerve can corroborate the presence of residual vestibular nerve fibres in patients with persisting vertigo attacks and residual vestibular function after VNx. MATERIALS AND METHODS: Vestibulocochlear nerve bundles of seven post-VNx unilateral Ménière's patients were imaged using 1.5 Tesla MRI with steady state free precession (SSFP) sequences. Reformatted MR images orthogonal to the vestibulocochlear nerve axis in internal auditory canal were compared on the VNx and intact sides. Vestibular function was assessed with caloric tests, three-dimensional head impulse tests and vestibular evoked myogenic potentials. Of the seven patients only one was asymptomatic (totally free of vertigo); six had continued to experience vertigo attacks, albeit not as long or as severe as before VNx. RESULTS: On the VNx side, MRI showed intact facial and cochlear nerves in all seven patients. In the six symptomatic patients, although superior and inferior vestibular nerve bulk and signal were reduced, residual bulk suggestive of inferior vestibular nerve was evident, correlating with evidence of residual posterior canal function on impulsive testing in all six symptomatic patients. In the asymptomatic patient, superior and inferior vestibular nerves were absent on MRI and impulsive testing revealed no residual posterior canal function.

Adult↗
PubMed2002

Is the labyrinthine dysfunction a causative factor in idiopathic scoliosis?

The cause of idiopathic scoliosis remains unknown, although research has possibly eliminated some hypothetical causes. Recent reports associating scoliosis convexity with equilibrium control central processing and motor lateralization have suggested that idiopathic scoliosis is connected causally with the motor cortex. In order to analyze these factors a study of labyrinthine function was carried out. This study included seventeen female patients 12 to 14 years old (mean age= 13.36y) with right thoracic idiopathic scoliosis and twelve normal control females 12 to 14 years old (mean age =13.1y). An electro-nystagmographic study of labyrinthine function (potential nystagmus) was performed in all the patients of the study with caloric tests. The nystagmus was recorded with the electronystagmographic technique (ENG) using Hartmann device. We evaluate these parameters: Slow phase velocity (SPV), Total amplitude (Tamp), Frequency of nystagmus (Freq). No children of the study presented spontaneous nystagmus. No correlation was found between the convexity of the curvature and the direction of nystagmus in posture tests. There were no significant differences between left- and right- beating nystagmus. The results are discussed with special reference to aetiology in idiopathic scoliosis.

Adolescent↗
PubMed2005

[Objective examination of vestibular organs to differentiate the location of damage].

The purpose of study was estimation of vestibular organ function based on results of caloric tests with computer analysis of ENG recordings, vestibular evoked myogenic potentials (VEMPs), comparison of compatibility of obtained evaluation in both ENG and VEMP and also attempt to localize vestibular organ lesion according to objective tests. Studied population consisted of 76 persons divided to three groups related to ENG results. The group I formed ills with unilateral canal paresis, group II consisted of patients with vestibular excitability abolition and group III was made up of healthy volunteers. All persons were carried out pure tone audiometry, word recognition test, extra threshold audiometry, bicaloric tests and registration of VEMPs and in chosen cases had MRI. Results of study suggested that VEMPs present valuable and supplementary method in vestibular lesion topodiagnosis.

Adolescent↗
PubMed1996

Neuro-otological findings after radiosurgery for acoustic neurinomas.

OBJECTIVE: To evaluate the neuro-otological complications in patients after radiosurgery for acoustic neurinomas. DESIGN: Inception cohort, retrospective study. SETTING: University hospital. PATIENTS: A consecutive sample of 46 patients with acoustic neurinomas who underwent unilateral gamma knife radiosurgery at the University of Tokyo, Japan, between June 1990 and June 1994 were followed up by otolaryngologists for more than 3 months. INTERVENTION: Gamma knife stereotactic radiosurgery. MAIN OUTCOME MEASURES: Neuro-otological examinations including pure tone audiometry, auditory brain stem response, and caloric test. RESULTS: Tumor growth occurred in 2 patients (4.3%). Seven (18%) of the 38 patients with preserved hearing of any extent became deaf within 1 year. In cases of gradual hearing loss, the average deterioration rate was approximately 8 dB per year. Abnormalities of auditory brain stem response preceded deafness in 2 patients. Caloric response, preserved before treatment in 13 patients, disappeared 4 to 13 months after treatment (median, 8 months) in 9 (69%) of them, whereas their hearing was preserved. Delayed facial palsy and persistent trigeminal neuropathy occurred in 10 (22%) and 7 (15%) of the 46 patients, respectively. Severe facial palsy tended to persist. CONCLUSIONS: The rates of neuro-otological complications of radiosurgery are almost comparable with those previously reported from other institutions. The deafness within 1 year after treatment might be attributed to a lesion in the cochlear nerve. Hearing loss did not parallel vestibular function loss. The persistent severe facial palsy contrasts with previously reported findings. Considering the serious facial nerve complications that occurred in some of our patients, further study to disclose the risk factors for neurological dysfunction would be needed for radiosurgery to become a true, safe alternative to microsurgery.

Adolescent↗
PubMed1984

Pitfalls in the diagnosis of acoustic neuroma.

The patient with an acoustic neuroma may present to the otologist with a variety of clinical features. Classically these include a retrocochlear pattern of sensorineural hearing loss, reduced vestibular response on caloric testing and radiological asymmetry of the internal auditory canals (IAC). The absence of any or all of these features, however, does not exclude the presence of tumour. Five cases are presented to illustrate the potential for diagnostic delay unless a routine battery of investigations is undertaken in patients with neuro-otological disorders. All patterns of subjective audiometry are encountered, auditory brain stem response testing may be unreliable where hearing loss is profound, vestibular testing is normal in half of small tumours and the intracanalicular tumour may be radiologically undetectable unless IAC meatography is employed.

Adult↗
PubMed2001

Walk-rotate-walk test identifies patients responding to Lempert's maneuver, with benign paroxysmal positional vertigo of the horizontal canal.

Two hundred and fifteen patients were diagnosed and treated for benign paroxysmal positional vertigo of the horizontal canal (BPPV-HC). All patients were tested with conventional positional nystagmus tests lying supine and rotating head for geotropic nystagmus, registered with Frenzels glasses, and in 109 cases with ENG. The walk-rotate-walk (WRW) test, developed by one of us (T.R.) and described in the text, was applied to all patients. The immediate good treatment results with Lempert's maneuver verify the correct diagnosis of BPPV-HC. The WRW test is a more sensitive test for BPPV-HC than earlier positional tests. The unhabituated acute phase of vestibular neuritis shows positive test results and must be eliminated with caloric tests. The WRW test identifies as a dynamic test patients with symptoms of even lesser magnitude, where the compensatory capacity of the equilibrium system suppresses the diagnostic findings with earlier positional horizontal canal tests.

Adolescent↗
PubMed1996

Mild impairment of neuro-otological function in early treated congenital hypothyroidism.

Pure tone audiometry, tympanometry, acoustic stapedial reflex thresholds (ASRTs), and auditory evoked brain stem responses (AEBRs) were carried out in 38 children with early treated congenital hypothyroidism aged 10-12 years, together with tests of vestibular function (electronystagraphy, rotational, and caloric tests). Sensorineural hearing loss with thresholds of greater than 15 dB was detected in 18 children (10 at 8 kHz only); only two children had more than 40 dB hearing loss, each in one ear. Raised ASRTs were found in eight children and two children had abnormal AEBRs. Of the 29 children tested, 12 had an abnormality of vestibular function. Although not significant at the 5% level, there was a tendency for the abnormalities to be more prevalent and severe in the children with more severe hypothyroidism, as judged by pretreatment plasma thyroxine. It is concluded that (i) mild abnormality of hearing is still common in children with congenital hypothyroidism despite early treatment but this is much less severe than that found before neonatal screening and (ii) mild abnormalities of vestibular function may be common in early treated congenital hypothyroidism.

Acoustic Impedance Tests↗
PubMed1995

Computer assisted data collection in vestibular disorders.

We have developed an interactive database for vertigo than can be used to assist in the diagnostic procedure and to store the data in a form of a database. The database offers the possibility to split and reunite the collected information in a desired way. The database contains detailed information about patient history, symptoms and findings in neurotological, audiological and imaging tests. The symptoms are classified into three sets of questions: vertigo (including postural instability), hearing loss and tinnitus, and provoking factors. Confounding disorders are screened. The neurotological tests involve saccades, smooth pursuit, posturography and caloric test. In addition, findings in specified antibody testing, clinical neurotological tests. MRI, brain stem audiometry and electrocochleography are included. The input information can be applied in an expert system ONE for vertigo work-up. The database is user-friendly. Besides diagnostic purposes the database is excellent for research purposes, and combined with the expert system it works as a tutorial guide for medical students.

Artificial Intelligence↗
PubMedDate not supplied

[Reading test as a qualitative method for evaluating the vestibulo-ocular reflex].

In the reading test the patient reads a text while his or her head is passively moved from one side to another with a frequency over 2 Hz. The vestibulo-ocular reflex (VOR) should stabilize the patient's gaze if it is performing adequately, allowing him or her to read well. Reading becomes impossible if the VOR is defective. We tested this method by assessing VOR in a 30-patient series by means of VAT and a previous reading-test score, and we compared the results of both groups. Next, the test was clinically validated with the bithermal caloric test. There were significant differences in ocular asymmetry between normal and strongly positive groups. The sensitivity, specificity, and positive and negative predictive values validated the reading testing as clinically useful.

Adult↗
PubMed1975

[Early diagnosis and selection of operative approach for acoustic neuroma (author's transl)].

The recent advances of various diagnostic procedures made possible to detect intracanalicular neuroma in early stage. The operative results have been also greatly improved by transtemporal approach using surgical microscope and dental burr. In addition, the revised suboccipital approach contributed to obtain better operative results. Reviewing our clinical experiences with 15 cases operated from May 1969 to December 1971, appropriate combination of applicable diagnostic procedures and selection of operative method are discussed. Multiple audiologic examinations consisting of pure tone audiometry, speech discrimination, Békésy audiometry, alternate binaural loudness balance test, tone decay and uncomfortable lebel were performed in 11 cases. 9 of these cases manifested retrocochlear type of hearing loss. Spontaneous nystagmus and induced nystagmus, together with balance test, were evaluated for vestibular function. Bithermal caloric test disclosed unilateral canal paresis in all cases. In 13 cases, spontaneous nystagmus was observed. Analysis of optokinetic nystagmus using electronystagmography suggested tumor invasion to the brain stem and cerebellum. Tomography of the internal auditory canal showed abnormal findings in all cases. Cisternography with 2 ml of myodil was performed in 7 cases, all of which were diagnosed definitely by filling defect. Angiography showed abnormal vascular displacement with the tumor of size exceeding 3 cm in diameter. Translabyrinthine approach was performed in 5 cases. Suboccipital approach was applied in 6 cases. Combined approach of these two routes was used in 4 cases. 11 patients returned to their original work postoperatively. To obtain the correct diagnosis of acoustic neuroma in early stage, multiple audiologic examination are indispensable together with detailed vestibular function tests when the unilateral sensory neural hearing loss is suspected. Tomography of the internal auditory canal is also advisable as routine roentonologic study. If the clinical sign is confined to the 8th nerve only, myodil cisternography is useful, however, angiography is reliable in more advanced cases. When the tumor size is below 2 cm and signs of the spread to the brain stem, cerebellum or lower cranial nerves are lacking, translabyrinthine approach is indicated. Suboccipital approach is advisable for more advanced cases or undefinitive cases. Planning of combined approach of both routes is seemed to be not necessary in any case from our experience.

Adult↗
PubMed1994

[Electronystagmographic changes in patients with posterior cranial fossa tumors].

Findings of electronystagmography in 30 patients with posterior cranial fossa tumor were analysed. Of the 23 cases of CPA tumor, size varied between 0.7-5.0 cm, the ENG showed: (1) The nystagmus occurred in 83% of patients. (2) In ODT, overshoots was showed in 22% of patients. (3) ETT showed type III or IV curves in 55.6% of patients. (4) OKP test decreased in 59% of patients. (5) Caloric test showed canal paresis in 85% of the patients. (6) Abnormal visual suppression test occurred in 60% of patients. (7) Abnormal ABR was found in 89% of patients. We also found that tumor larger than 2.5 cm presented a central type nystagmus (Bruns nystagmus) and involvement of the eye movement system. The electronystagmographic changes of the tumors of cerebellum (3 cases) and brain stem (4 cases) was discussed.

Adolescent↗
PubMed2000

[Semiologic value and optimum stimuli trial during the vibratory test: results of a 3D analysis of nystagmus].

Nystagmus signaling vestibular dysfunction was observed after vibratory stimulation with a 100 Hz ABC stimulator in a population of 36 patients with unilateral labyrinthine pathology (ULP) (pre and postoperative neuromas, vestibular neurectomies) and 10 patients with vestibular neuritis. The stimulus was applied on 3 bony points of the skull (vertex and 2 mastoids) and 2 muscular points of the neck (right and left posterior cervical region). These results were compared with those in 95 normal subjects and 19 cases of central disease and were correlated on the same day with results of the caloric test and head shaking test (HST). A consistent nystagmus was found in only 6 % of the normal subjects (specificity 94 %) and in 10 % of the central lesions, but in 94 % of the 36 peripheral ULP. The sensitivity of the test was equivalent to the HST. The signal was optimized in 30 patients: stimulus frequency, amplitude, stimulator mass, form of the contact, patient tolerance. The best results were obtained for a frequency of 100 Hz and an amplitude of 0.5 mm (there was no response under 0.1 mm vibration amplitude). Under videoscopy and 3D videonystagmography, the direction or side of the nystagmus was constant, but its axis (horizontal, oblique or rotational) changed according to the location of the stimulator: on the mastoid (elective location of stimulation with responses in 94 % of cases) the axis was most often horizontal or horizontal rotational. On the vertex location (where nystagmus was observed in 60 % of cases) the axis of nystagmus was most often rotational or oblique and sometimes horizontal-rotational. The nystagmus showed short latency (less than 200 ms). It started and stopped as stimulation was initiated and interrupted. Nystagmus persisted for the duration of patient tolerance. This nystagmus generally signifies unilateral vestibular weakness rather than vestibular predominance. It is a good indicator of unilateral vestibular dysfunction and could serve as a useful test in clinical practice. We discuss the origin of the nystagmus which may originate in muscle proprioception (by propagation of the vibration to neck muscles) or in the labyrinth (simultaneous excitation of 3 canals on each side).

Adult↗
PubMed1978

Air as the caloric stimulus.

The use of air as the caloric medium was investigated and compared to that of water. The ability of air and water to generate surface temperatures close to the fluid outlet temperature was studied by irrigation onto a thermocouple. Results of caloric tests performed with air and water are compared by calculating the average nystagmus response for the hot and cold stimuli for two groups of sixty patients. Also, the number of canal paresis, directional preponderance, mixed, bi-lateral canal paresis and normal responses are compared for each group. Finally, the effect of performing a bi-thermal air caloric on a patient having a unilateral drum perforation is discussed.

Air↗
PubMed1982

Brainstem auditory evoked potentials in postconcussion syndrome.

Brainstem auditory evoked potentials (BAEPs) were recorded from 55 patients with postconcussion syndrome (PCS) to elicit evidence of an organic and subclinical brainstem disorder. Fifteen patients (27.3%) showed abnormal responses unilaterally or bilaterally, especially for one or more interpeak latencies prolonged beyond the upper 99% confidence limits. Other 9 patients had borderline responses. The BAEP alterations were not correlated either with dizziness at the time of recording, or with vestibular troubles in the routine caloric test. Though BAEP abnormalities may be present a long time after injury, we found an improvement of responses in the majority of 14 re-tested patients. These data show that BAEP can give an objective demonstration of a reversible brainstem disorder in patients with PCS.

Adolescent↗
PubMed2002

Neurotoxic mechanism of cinnabar and mercuric sulfide on the vestibulo-ocular reflex system of guinea pigs.

Cinnabar, a naturally occurring mercuric sulfide (HgS), has been combined with Chinese herbal medicine as a sedative for more than 2000 years. To date, its neurotoxic effect on the vestibulo-ocular reflex (VOR) system has not been reported. By means of a caloric test coupled with electronystagmographic recordings, the effect of commercial HgS and cinnabar on the VOR system of guinea pigs was studied. HgS or cinnabar was administered orally (1.0 g/kg) to Hartley-strain guinea pigs once daily for 7 consecutive days. A battery of electrophysiological, biochemical, and histopathological examinations were performed. The results showed that HgS induced a 60% caloric response abnormality (40% caloric hyperfunction and 20% hypofunction), whereas the abnormal responses appeared to be more severe (six out of six) in the cinnabar group. The Hg contents of whole blood and cerebellum were increased and correlated to their neurotoxic effects on the VOR system, indicating that both insoluble HgS and cinnabar could be absorbed from the gastrointestinal tract and distributed to the cerebellum. Although the vestibular labyrinth revealed no remarkable change under light microscopy, loss of Purkinje cells in the cerebellum was detected, and the enzymatic Na(+)/K(+)-ATPase activity of cerebellum (a higher inhibitory center of the VOR system) was significantly inhibited by HgS and cinnabar. Moreover, cerebellar nitric oxide (NO) production was increased significantly. Hence, we tentatively conclude that the increased Hg contents in the cerebellum following oral administration of HgS and cinnabar were responsible, at least in part, for the detrimental neurotoxic effect on the VOR system. Potentially, decreasing Na(+)/K(+)-ATPase activity and increasing NO production within the cerebellar regulatory center are postulated to mediate this VOR dysfunction caused by the mercurial compounds and cinnabar.

Administration, Oral↗