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Compared study of optokinetic and caloric nystagmus in children with unilateral hyporeflexia and other vestibular disorders.

The authors compare the nystagmus evoked by the caloric test and by two slow and fast optokinetic 'look' stimulations performed in 78 subjects subdivided into two groups and recorded by ENG: group 1 composed of 22 subjects with 'significative' unilateral hyporeflexia and group 2 composed of 56 subjects with important anomalies at the vestibular caloric test. The results can be summarized as follows: 1. the presence of unilateral vestibular hyporeflexia is not exceptional in the child: 22 over 140 cases (15.7%); 2. the comparison between the caloric test and the OKN test in the 22 subjects with significant unilateral hyporeflexia shows: slow and fast TAP homolateral to the side with labyrinthine deficit prevails in ten subjects (45.4%); TAP is inconsistency with respect to the hyporeflexic side (i.e. homolateral in one test and contralateral in the other) in seven cases (31.8%); TAP is contralateral in five cases (22.7%). Within the same group, STAP varies according to cases. 3. In group II, TAP values at the OKN test overlap considerably with respect to the caloric test (18 cases with a total TAP prevailing on the right side, 32.2%; 19 cases with divergent TAP, 33.9%; 19 cases with total TAP prevailing on the left side, 33.9%). 4. The data shown in group 1 with significant vestibular hyporeflexia can be correlated to the time elapsed between the last electronystagmography and that performed soon after disease onset. Since for ENG performed some days after vertigo onset (even though clinical examination is negative) shows a concordance of OKN TAP and the hyporeflexic side (as the mechanisms of central compensation are still being developed) and then when these mechanisms improve with time, an inconsistency of OKN TAP and hyporeflexic side and finally a contralaterality. We might rely on the comparison between OKN TAP and caloric test as a finding of the time distance from the vertigo onset (when unknown) and a rough prognostic sign. The only case of vestibular neuritis by us followed in time seems to confirm our assumption.

Adolescent↗

[Evaluation of the furosemide test using the air caloric stimulator].

Both the furosemide test, and the glycerol test have been reported as being effective for detection of endolymphatic hydrops. In the furosemide test, the caloric test is performed first, and then repeated 40 minutes after i.v. injection of furosemide, 20 mg. The maximum velocities of each caloric nystagmus are compared, so the caloric stimulus conditions must be constant. In the original method, the caloric test is performed by irrigation with 50 ml of water at 30 degrees C or 44 degrees C for 20 seconds. Since it is difficult to accurately maintain the water temperature at a constant level, however, we use the air caloric stimulator NCA-105 (ICS) for the furosemide test. By using this stimulator, we can always perform the caloric test under the same conditions. The conditions of air irrigation in 28 normal subjects were set at 37 +/- 11 degrees C, 61/min, and 60 seconds. These conditions were confirmed in other normal subjects to fairly well correspond to water irrigation (30 degrees C or 44 degrees C, 50 ml, 20 seconds). Next we reassessed the furosemide test by using the air caloric stimulator in normal subjects. As a result, positive effects were observed in 7.4% of the normal subjects. This finding was similar to that reported in the literature (Futaki et al., 1971). The air caloric test is considered to be a more useful examination than the water caloric test because it is less unpleasant for the subject and easily provides the same conditions before and after furosemide administration.

Adolescent↗

Comparison of assessment of caloric nystagmus by observation of duration and by electronystagmographic measurement of slow-phase velocity.

The 'duration' of induced nystagmus was the first parameter used to quantify vestibular function during caloric testing. However, later work suggested that there was a poor correlation between this measure and the physiological events occurring during caloric testing. This, coupled with the development of electronystagmography and the value of a permanent record of the caloric responses, led to the widespread use of the 'slow-phase velocity' measurement of induced nystagmus, as the most commonly used parameter for assessment of the caloric test. Despite a wealth of literature, the 'best' parameter for measuring vestibular function using the caloric test remains undefined and the duration and slow-phase velocity parameters appear to provide different information. The strengths and shortcomings of these two parameters and their relative values are reviewed.

Adult↗

Interpretation of the combined galvanic test. Findings from cases with vestibular neuronitis.

The combined galvanic test (CGT) was developed in our department for simultaneous recording of galvanic eye movement test (GEMT) and galvanic body sway test (GBST). Twelve cases of vestibular neuronitis were studied first with the caloric test, and then with the CGT. The findings of the caloric test corresponded to those of the GEMT, but did not always correspond to those of the GBST. Thus we suggest that the GBST reflects an abnormality in a system different from that reflected by the caloric test and GEMT. It is likely that the caloric response mainly originates from the semicircular canal system. Thus the GEMT may reflect an abnormality in the semicircular canal system, while the GBST reflects an abnormality in the otolithic system. The CGT may thus be a feasible method of differentiating the disorders of the semicircular canal system from those of the otolithic system in the vestibular nervous system.

Adult↗

Motion sickness and vestibular hypersensitivity.

OBJECTIVE: Motion sickness is poorly understood, although it has been recognized for years as debilitating. Vestibular function is required for motion sickness to occur, but motion sickness can also be brought on without body motion. The aim of this study was to see if there was a correlation between caloric response and motion sickness susceptibility. DESIGN: One experiment was a prospective study carried out on 200 patients. A second prospective study was carried out on 121 patients. SETTING: Patients referred to our tertiary/quaternary care dizziness clinic. METHODS: In experiment 1, caloric scores in patients were correlated with symptoms of motion sickness as established by responses to a simple question. In experiment 2, caloric scores were correlated with symptomatic responses to caloric testing itself. MAIN OUTCOME MEASURES: Caloric responses of the best ear were measured according to standardized caloric evaluation methods. RESULTS: There was no correlation between motion sickness and caloric scores. There was a significant difference in caloric scores between patients made symptomatic by calorics and those who were not. CONCLUSIONS: The autonomic response seen in some patients is not triggered by a specific level of semicircular canal response (as measured by caloric testing). We hypothesize that (similar to space motion sickness) the trigger is a signal differential that arises between semicircular canals and otoliths and that some patients are unable to suppress this response. These patients often suffer motion sickness on a long-term basis.

Adult↗

Vestibulo-oculomotor testing during the course of a spaceflight mission.

The experimental concept and findings from a recent manned orbital spaceflight are presented. In a single-case, longitudinal study, vestibulo-oculomotor function was examined by caloric testing and active head oscillations. The results from preflight, inflight, and postflight measurements of the human vestibulo-ocular reflex, together with those of ongoing terrestrial studies, should enable separation of the canalicular and otolithic contributions to ocular torsion. This analysis enables an accurate evaluation of the adaptation of the otolithic system to the inflight microgravity and, after landing, to the 1-g force environment. Video-oculography was employed throughout for the comprehensive measurement of eye and head movements. Caloric testing involved air insufflation at 15 degrees C over 90 s, followed by an observation interval of 2 min. During inflight testing this was continued with a 30-s free-floating interval. Active head oscillations were performed at four discrete frequencies (0.12, 0.32, 0.80, 2.0 Hz) and over a frequency sweep between 0.1 and 2.0 Hz. These head oscillations were performed in yaw, pitch, and roll and for three visual conditions (head-fixed target, space-fixed target, no target). The concomitant stimulation of the semicircular canals and otolithic receptors during these oscillations should yield different oculomotor responses under 1-g and 0-g adaptations. Both the short-form caloric test and the active head movement test were performed on 4 of the 5 available mission days. The results of the caloric tests yield a caloric nystagmus intensity (slow-phase velocity) of approximately 60% of that measured before flight and indicate an adaptation in response over the 10-day period after landing.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗

A case of cerebellar infarction occurred with the 8th cranial nerve symptoms.

A rare case, 32-year-old man, of cerebellar infarction with the occurrence of the 8th cranial nerve symptoms was reported. On the neuro-otological examination, hearing test and caloric test showed a severe hearing loss and no response on the right side, respectively, and the spontaneous horizontal nystagmus fixed to the left direction was observed. Magnetic resonance (MR) imaging showed the infarctions in the areas of anterior inferior cerebellar artery (AICA) and posterior inferior cerebellar artery (PICA) on the right side. On the 14th illness day, the 8th cranial nerve symptoms disappeared, and on the 12th illness day, right hearing level and caloric response were significantly improved. We suggested that such an early recovery of the subjective symptoms and neuro-otological findings may be attributable to the recanalized circulation disturbance or the development of collateral circulation.

Adult↗

Extent of lesions in idiopathic sudden hearing loss with vertigo: study using click and galvanic vestibular evoked myogenic potentials.

OBJECTIVE: To clarify the extent of the vestibular lesions in idiopathic sudden hearing loss with vertigo using vestibular evoked myogenic potentials (VEMPs) in response to click (click-VEMP) and galvanic (galvanic-VEMP) stimulation, as well as caloric tests. DESIGN: Retrospective study. SETTING: University hospital. PATIENTS: We enrolled 22 patients with idiopathic sudden hearing loss with vertigo in this study. All patients underwent audiometry and click-VEMP and caloric tests. Eight patients underwent a galvanic-VEMP test. RESULTS: Among the 22 patients, 17 (77%) showed an absence of click-VEMPs on the affected side. In response to caloric testing, 10 patients (45%) showed a decreased response on the affected side. All 8 patients who underwent galvanic-VEMP testing showed normal responses. Most patients with decreased caloric responses (9 [90%] of 10 patients) showed an absence of click-VEMPs, whereas 9 (53%) of the 17 patients who showed abnormal click-VEMPs showed decreased caloric responses. Initial hearing level and hearing outcome significantly correlated with abnormalities on the vestibular test results. CONCLUSIONS: The lesion site of vestibular disorders in idiopathic sudden hearing loss with vertigo appeared to be within the labyrinth on the basis of galvanic-VEMP findings. Results of the click-VEMP and caloric tests suggested that the saccule could be involved more frequently than the semicircular canals. The combined use of click-VEMP and caloric tests is useful for evaluating vestibular functions in idiopathic sudden hearing loss with vertigo because the extent of vestibular abnormalities correlated well with hearing outcome.

Adult↗

Recovery of vestibular evoked myogenic potentials after a vertigo attack due to vestibular neuritis.

CONCLUSIONS: Inferior vestibular nerve functions could recover in patients with vestibular neuritis (VN). OBJECTIVES: Although the recovery of superior vestibular nerve functions has been reported, there is little information about the recovery of inferior vestibular nerve functions in patients with VN. This study was done to clarify if inferior vestibular nerve functions recover after an attack of VN. METHODS: Neuro-otological tests including vestibular evoked myogenic potential (VEMP) testing and caloric testing were sequentially performed in 13 patients with VN, who showed absence of VEMP on the affected side at the initial examination (7 men and 6 women, 28-82 years of age). VEMPs to click stimulation (95 dBnHL) were recorded with surface electrodes over each sternocleidomastoid muscle. RESULTS: Among the 13 patients, 5 patients (4 men and 1 woman) showed recovery of VEMP responses. Four of the five patients (three men and one woman) showed recovery of VEMP to the normal range. It takes 6 months to 2 years to recover within the normal range. On the other hand, caloric responses recovered to the normal range only in one patient.

Adult↗

[Audio-vestibular function in patients with benign paroxysmal positional vertigo].

OBJECTIVE: To investigate the audio-vestibular function and the possible mechanism of benign paroxysmal positional vertigo (BPPV) and to raise the therapeutic strategy. METHODS: Patients with BPPV were tested with pure tone audiometry, high frequency ABR audiometry, bithermal caloric test and vestibular evoked myogenic potential test (VEMP). The positive rate of these otologic function test were analyzed. RESULTS: Primary BPPV comprised 82 percent (70/86) of patients with BPPV. Among all of the patients, the results of pure tone audiometry were abnormal in 52 percent (45/86) of the cases. High frequency auditory brainstem response (ABR) was abnormal in 60 percent (30/50) of cases. Vestibular evoked myogenic potential (VEMP) was abnormal in 34 percent (11/32) of cases who had this examination. And bithermal caloric test were abnormal in 28 percent (20/72) of cases. In the abnormal cases, 67 percent (12/18) of cases were ipsilateral with BPPV. The majority of the BPPV with abnormal results of bithermal caloric test (89%, 16/18) belong to posterior semicircular canal BPPV. CONCLUSIONS: The incidence of primary BPPV was higher than that of secondary BPPV. The abnormality in superior labyrinth was much more correlated with the occurrence of BPPV. The inner ear ischemia might be a factor in the morbidity of BPPV, especially for the primary BPPV.

Adolescent↗

Discrimination of peripheral and central vestibular disorders by means of a quantitative statistical method.

This paper presents an approach to the prediction of peripheral and central vestibular disorders from a mathematical statistical point of view. An analysis was performed by the quantification method for multi-dimensional qualitative data. The data analysed were from 713 patients with a complaint of dizziness or vertigo who were subjected mainly to neurootological tests on 14 items. The categorical discriminant analysis of peripheral and central vestibular disorders revealed a discriminant success rate of 82%. We used the following five tests in discrimination: optokinetic test (OKN), caloric test, eye-tracking test (ETT), hearing test, and standing test. A system for the screening of patients with vertigo was assessed by use of a microcomputer and is in daily use in our department.

Central Nervous System Diseases↗

Sound-evoked myogenic potentials and responses with 3-ms latency in auditory brainstem response.

OBJECTIVES: The vestibular-evoked myogenic potential (VEMP) has shed new light on vestibular testing. A large negative deflection with a 3-ms latency within the auditory brainstem response (ABR) has been reported in some patients with deafness. This negative deflection has been termed the N3 potential and it is assumed to be a vestibular-evoked potential. This study investigated the relationship between the VEMP and the N3 potential. STUDY DESIGN: Prospective evaluation of the VEMP and the N3 potential in 21 patients. METHODS: The oto-neurological tests, including caloric test, hearing sensitivity test, VEMP, and ABR, were performed and data were analyzed. RESULTS: The average hearing threshold ranged from 65 to above 110 dB, which includes 9 (37.5%) totally deaf ears. The N3 potentials were recorded in 10 (41.7%) ears. A normal VEMP was detected in 16 (66.7%) ears. Canal paresis was observed in 11 (45.8%) ears. CONCLUSIONS: Both the VEMP and the N3 potential appear to originate from the sacculus, but because the characteristics of these two responses are not identical, additional factors might be involved in the generation of the N3 potential.

Acoustic Stimulation↗

[Vestibular changes due to barotrauma].

Morphological vestibular changes caused by barotrauma were studied in guinea pigs. Animals were exposed to rapid decompression from 2 absolute atmospheric pressures (ATA) to 1 ATA, which causes inner ear barotrauma in the guinea pig. During decompression, spontaneous nystagmus was recorded, which consisted of irritative symptoms initially, followed by paralytic nystagmus. After pressure loading and observation to confirm the absence of Preyer's reflex with vertigo, the animals were tested for caloric nystagmus using ice water and then sacrificed at varying intervals. Then, morphological changes in vestibular organs and the organ of Corti were studied. Half of the experimental animals showed canal paresis on caloric testing. Damage to the organ of Corti was severe while that to vestibular organs was very slight. Damage to the sensory cells of the vestibular organs was not clear on light microscopy, despite a partial collapse of labyrinthine membranes. Under scanning electron microscopy, local damage was observed in a portion of the crista ampullaris of the semicircular canals. In this area, incomplete or complete disappearance of kinocilia and stereocilia, similar to that seen after rotatostimulation, was observed. However, no damage to sensory hairs was seen in the utricles and saccules. The observed vestibular organ damage, resulting from inner ear barotrauma, suggested effects on endolymphatic flow.

Animals↗

[Electronystagmography study in patients with the insufficiency of vertebrobasilar artery after betahistine treatment].

The aim of the study was objective assessment of the results of betahistyne treatment in patients with chronic insufficiency of the vertebrobasilar artery system by means of elektronystagmography (ENG). The patients had mostly vertigo and/or dizziness, headache, ear buzzing and disequilibrium sensations. In 46 patients clinical, audiological and ENG examinations were carried out. All symptoms decreased in frequency after the treatment. Vertigo and/or dizziness improvement was noted in 58.5% patients of cases, headache decreased in 56.5% of cases, ear buzzing decreased in 42.8% and hearing improved in 22.2%. Before treatment 76% of patients had pathologic changes in ENG, after treatment improvement of ENG was noted in all tests, particularly in 17 cases (48.6%). This was most frequent in spontaneous nystagmus (83%), positional test (85%), caloric test (83%), and optokinetic test (71%). Comparison of complaints and ENG findings before and after treatment showed improvement both in symptoms and signs. Betaserc was effective in the treatment of patients with vertebrobasilar system insufficiency both in subjective opinions of patients and in objective assessment by ENG.

Aged↗

Fixed combination of cinnarizine and dimenhydrinate versus betahistine dimesylate in the treatment of Ménière's disease: a randomized, double-blind, parallel group clinical study.

In a randomized, double-blind clinical study, we evaluated the efficacy and tolerability of the fixed combination of cinnarizine, 20 mg, and dimenhydrinate, 40 mg (Arlevert [ARL]) in comparison to betahistine dimesylate (12 mg) in 82 patients suffering from Ménière's disease for at least 3 months and showing the characteristic triad of symptoms (paroxysmal vertigo attacks, cochlear hearing loss, and tinnitus). The treatment (one tablet three times daily) extended to 12 weeks, with control visits at 1, 3, 6, and 12 weeks after drug intake. The study demonstrated for both the fixed-combination ARL and for betahistine a highly efficient reduction of vertigo symptoms in the course of the 12 weeks of treatment; however, no statistically significant difference between the two treatment groups could be established. Similar results were found for tinnitus (approximately 60% reduction) and for the associated vegetative symptoms (almost complete disappearance). Vestibulospinal reactions, recorded by means of craniocorpography, also improved distinctly, with a statistically significant superiority of ARL versus betahistine (p < .042) for the parameter of lateral sway (Unterberger's test). The caloric tests (electronystagmography) showed only minor changes for both treatment groups in the course of the study. A statistically significant improvement of hearing function of the affected ear (p = .042) was found for the combination preparation after 12 weeks of treatment. The tolerability was judged by the vast majority of patients (97.5%) in both groups to be very good. Only one patient (betahistine group) reported a nonserious adverse event, and two betahistine patients did not complete the study. In conclusion, the combination preparation proved to be a highly efficient and safe treatment option for Ménière's disease and may be used both in the management of acute episodes and in long-term treatment. Efficacy and safety were found to be similar to the widely used standard therapy with betahistine.

Adult↗

A clinical evaluation of head impulse testing.

The head impulse test is a simple clinical test comprising high acceleration head rotation. In the presence of a severe unilateral vestibular weakness the normal vestibulo-ocular reflex is replaced by a misalignment of the eye followed by a series of corrective saccades which are evident to the examiner. Previous reports have shown the high sensitivity of the head impulse test in detecting complete unilateral weakness, but indicate poor sensitivity for mild weaknesses. This prospective, blinded study examined the head impulse test in a general clinical population of balance disorder patients to examine the sensitivity and specificity of the test, and to determine the degree of vestibular weakness that is required before the test becomes positive. One hundred and fifty patients were examined and the head impulse test results were compared to results from bithermal caloric testing. Results show that the overall sensitivity of the head impulse test is 34% with a specificity of 100%. The test does not detect mild or moderate vestibular weaknesses but is very sensitive to the presence of a severe paresis (87.5%). Head impulse testing will not replace caloric testing but is a very useful adjunct to it.

Acceleration↗

Corneoretinal potential variations: significance in electronystagmography.

Spontaneous variations in the corneoretinal potential (CRP) may introduce large errors when using electronystagmography (ENG) to measure responses during clinical caloric testing. Whether or not conventional calibration techniques are adequate to control such measurement errors has not been established. We studied CRP variations in normal subjects and patients by measuring calibration before and after a series of caloric tests. Among patients the CRP either rose or fell in a random manner; we were unable to discover independent measures that might serve to predict the magnitude or polarity of the CRP changes. Among normal subjects the CRP consistently dropped during each caloric test, probably due to longer periods of eye closure imposed in this group. Recalibration before each caloric test, using an averaging technique, would greatly reduce (but not eliminate) ENG measurement errors.

Action Potentials↗

Lateralising value of the computerized dynamic posturography (CDP) test.

The side of labyrinthine pathology, as indicated by caloric tests, Quix test, audiometry or otoscopy is investigated by Computerised Dynamic Posturography. The correlation level fluctuates from high with audiometry to low with caloric tests. The quantification possibility of the dynamic posture is stressed.

Adult↗