Caloric Test Response Research Articles

LETTER TO THE EDITOR: "IS MENIÈRE'S DISEASE A CONTRAINDICATION TO STAPEDECTOMY?"

To the Editor: We read with interest the article that was recently published by Sioshansi et al. entitled “Is Menière's Disease a Contraindication to Stapedectomy?” (1) Issue of Otol Neurotol. The authors aimed to “Review surgical outcomes of stapedectomy for otosclerosis in patients with Menière's disease.” We congratulate the authors for their valuable work, but we would like to comment some issues. Vestibular symptoms have been reported in up to 40% of patients with otosclerosis. It is important to tease out the specifics of vestibular complaint while obtaining the history, as misdiagnosis can have significant implications on treatment outcomes. In the setting of Menière's disease (MD), saccular distention due to endolymphatic hydrops can put the saccular membrane in contact with the underside of the stapes footplate. In these patients, the stapedotomy can lead to injury of the membrane and profound sensorineural hearing loss (SNHL) (2). The American Academy of Otolaryngology—Head and Neck Surgery (AAO-HNS) has defined the diagnostic criteria that are based on the presence/absence and duration of the different symptoms allowing the classification of patients in different MD categories—probable and definite MD (3). However, the diagnosis of MD remains difficult probably due to the lack of a gold standard test. In the “MATERIAL AND METHODS” the authors affirms that “Data collected included demographics, symptomatology, vestibular testing, imaging findings, surgical findings, operative techniques, postoperative outcomes, and pre- and postoperative” (1), but we did not find what the vestibular testing was performed. It would be a valuable information to know about the vestibular symptoms of these patients before and after the surgery. It had been found that in MD patients, the reduced caloric response, rather than Video Head Impulse Test (vHIT) response, is correlated with the severity of endolymphatic hydrops. Because of the fluctuating nature of MD, the vestibular hair cell population driving the response could vary depending on the condition of the disease and the type of hair cell involved. It has been suggested the combination use of caloric test and horizontal vHIT in MD patients, as these tests allow for an integrated and comprehensive evaluation of the horizontal vestibulo-ocular reflex (VOR) function (4). Sobhy et al. (5) suggested that with the advancement in the stage of MD, the prevalence of abnormal cervical vestibular-evoked myogenic potential (cVEMP), ocular vestibular-evoked myogenic potential (oVEMP), caloric test, and vHIT responses was in agreement with the histopathological evidence of progression of the disease from the saccule up to the semicircular canals. Authors concluded “….. Menière's disease may not be an absolute contraindication to stapes surgery” (1). The audiological results presented are interesting. However, as the sample was small, the indication of stapedectomy in patients with MD may still be done with careful, once stapedotomy is an elective procedure. For the patients with otosclerosis and define MD, we recommend that a vestibular evaluation should be carried out in order to avoid severe complications. The authors disclose no conflicts of interest.

Electronystagmographic analysis of peripheral vertigo

<p class="abstract"><strong>Background:</strong> Examination of the vestibulo-ocular reflex is still the investigation of choice for evaluating the vestibular function to rule out peripheral causes. Aim and objectives were to compare the electronystagmographic changes of all peripheral forms of vertigo and to highlight its significance in the diagnosis and management of the same.</p><p class="abstract"><strong>Methods:</strong> This is a prospective study done after obtaining ethical committee approval in a total of 100 patients attending the ENT OPD at Sri Muthukumaran Medical College Hospital & Research Institute with chief complaints of vertigo. Patients diagnosed with chronic suppurative otitis media, hypertensive patients, h/o seizures, recent cardiac illness or patients on cardiac investigations, psychotic disorders, documented CNS lesions, cervical spondylitis, h/o recent eye/ ear surgery are excluded from this study. ENG analysis includes occulomotor testing, positional testing and caloric stimulation. Evaluation of gait and balance is done followed by maneuver induced vertigo testing (dix hallpike and fistula test) along with PTA. Statistical analysis was done using independent sample t test and chi square test to check the hypothesis using statistical package for social studies SPSS version 17. </p><p class="abstract"><strong>Results:</strong> The observations of ENG like spontaneous nystagmus and bi-thermal caloric test responses are represented on a claussens butterfly chart and the corresponding bar codes were obtained. The inferences for different forms of vertigo were studied.</p><p class="abstract"><strong>Conclusions:</strong> ENG is now an accepted routine and basic investigation in the management of all patients suffering from equilibrium disorders. Management consists of diagnosing the underlying pathology and treatment of the same.</p>

Dissociation of Caloric and Video Head Impulse Tests in Patients With Delayed Endolymphatic Hydrops.

Delayed endolymphatic hydrops (DEH) represents a rare clinical entity characterized by intermittent vertigo attacks mimicking those of Ménière's disease (MD) in a patient with a prior sensorineural hearing loss. Some vestibular tests have been employed in patients with DEH. These tests provide useful diagnostic information and facilitate clinical decision-making. Here, we retrospectively studied the features of video head impulse test (vHIT) and examined its relationship with caloric test used in DEH patients. Included in this study were 17 patients with ipsilateral DEH and 2 with contralateral DEH. Among them, 73.7% (14/19) showed abnormal caloric test response (76.5% in ipsilateral DEH and 50% in contralateral DEH). Meanwhile, only 15.8% (3/19) of patients yielded abnormal horizontal vHIT results (11.8% in ipsilateral DEH and 50% in contralateral DEH). Abnormal caloric response in the presence of a preserved vHIT was common in DEH patients, especially those with ipsilateral DEH. This dissociation might be a distinctive pattern of vestibular deficit in DEH.

Evaluation of audiovestibular system in psoriasis patients without joint involvement.

Inner ear involvement may occur in systemic autoimmune diseases. Although there are studies evaluating hearing in psoriasis patients, its effect on the balance system is not clear. The aim of the present study was to evaluate the audiovestibular system in psoriasis patients without joint involvement. In this prospective study, the audiovestibular system of 32 psoriasis patients without joint involvement and 35 healthy volunteers were evaluated. The severity of the disease was determined by the psoriasis area severity index (PASI). There was no significant difference between the groups in terms of hearing test results, while the abnormal caloric test response was significantly higher in the psoriatic patients. PASI scores of psoriasis patients with abnormal caloric test results were higher than those with normal caloric test response. In psoriasis patients without joint involvement, the hearing was not affected, but the vestibular system was. The severity of the disease was associated with vestibular involvement. Particularly in patients with severe psoriasis, it must be considered that the vestibular system might be affected, and vestibular evaluations should be performed.

Vestibular evoked myogenic potential responses in Parkinson's disease.

- Our objectives were to determine the differences in the vestibular evoked myogenic potential (VEMP) responses in patients diagnosed with early staged idiopathic Parkinson's disease (PD) compared to the normal population and evaluate the vestibular system disorder causing balance-posture disorders. Second aim of this study was to investigate caloric test responses particularly in early staged PD compared to normal popu-lation. Thirty patients (14 females and 16 males; mean age, 60.6 ± 13.1 years) diagnosed with idiopathic PD and 28 healthy subjects (20 males and 8 females; mean age, 59.1 ± 6.4 years) were included. The patient and control groups were subdivided according to their age, gender and the patient group was subdivided according to onset time of the Parkinson symptoms, Hoehn-Yahr staging. The subgroups were compared for VEMP and caloric test responses. There were no significant differences between the study and control groups for right and left VEMP measurements. Patients over 60 years and under 60 years did not show significant differences in terms of right and left mean VEMP measurements. However, P1 amplitude was significantly lower in patients over 60 years old (P = .004). Gender, disease duration, BERG balance scale and Hoehn-Yahr stage had no effect on the VEMP amplitudes. There was no significant correlation with the side of Parkinsonian symptoms to the side of canal paresis (P = .566) and the side on which no VEMP response was obtained in caloric test. VEMP responses were not different between PD and healthy subjects. VEMP P1 amplitude was decreased with age in PD group. Canal paresis and symptoms side were not statistically correlated in caloric test.

Is the nerve origin of the vestibular schwannoma correlated with vestibular evoked myogenic potential, caloric test, and auditory brainstem response?

Conclusions. The results of the caloric test, vestibular evoked myogenic potential (VEMP), and auditory brainstem response (ABR) in patients with vestibular schwannoma (VS) did not show clear correlation with the nerve origin of the tumor but with tumor size. When we focused on patients with VS within the internal acoustic canal (IAC), neither the nerve origin of the tumor nor the tumor size showed clear correlation with the results of these tests. Objectives. This study examined the correlation of the nerve origin of VS, superior or inferior vestibular nerve, with the results of function tests. Subjects and methods. Subjects comprised 109 consecutive patients diagnosed as having unilateral VS. Each test was performed before surgery. Tumor size was measured with preoperative MRI. Results. The nerve origin of the tumor was identified in 63 of the 109 patients. The percentage of patients showing abnormal responses in each test was not different between 37 patients with superior VS and 26 patients with inferior VS. Also, no difference was observed for patients with VS within the IAC. Mean tumor size in patients showing abnormal responses was larger than that in patients showing normal responses on each test. However, this tendency was not observed for patients with VS within the IAC.

Abnormal Vestibular Evoked Myogenic Potentials in the Presence of Normal Caloric Responses

Combined use of vestibular evoked myogenic potential (VEMP) and caloric response testing has enabled us to examine the function of the inferior and superior vestibular nerves separately. Although results of VEMP testing and caloric response testing have been reported for many diseases, a clinical entity showing abnormal VEMP responses but normal caloric test responses has rarely been reported. The aim of the study was to investigate clinical features of diseases showing abnormal VEMP responses with normal caloric test responses. Retrospective. University hospital. Eight hundred eleven patients with balance problems who had undergone both caloric response and VEMP testing were included in the study. The amplitudes and latencies of the first positive-negative peak of the VEMP (p13-n23) were measured. Forty of the 811 patients (5%) were found to have abnormal VEMP responses with normal caloric test responses. Clinical diagnoses of these patients were Ménière's disease (n = 12), acoustic neuroma (n = 8), sudden deafness with vertigo (n = 6), and other diseases (n = 6). Eight patients could not be diagnosed as having a disease already recognized. Clinical manifestations of these eight patients were rotatory vertigo in six patients and non-rotatory dizziness in two. None of these patients showed abnormalities other than VEMP responses on neurologic or neurotologic examinations. Apart from Ménière's disease, acoustic neuroma, and sudden deafness with vertigo, which are already known as diseases with abnormal VEMP responses but normal caloric test responses, some patients might be diagnosed as having a disease that involves only the inferior vestibular nerve region.

Vestibular evoked myogenic potentials in basilar artery migraine.

Because the sacculocollic reflex is a descending pathway passing through the territory of basilar artery, the aim of the study was to investigate whether hypoperfusion affects this pathway by applying vestibular evoked myogenic potential (VEMP) testing in patients with basilar artery migraine. A prospective study from May 2000 to April 2002. Twenty patients were diagnosed as having basilar artery migraine according to the criteria of the International Headache Society and literature. Eight were male and 12 were female patients, and their ages ranged from 9 to 48 years (mean age, 40 y). Each patient underwent a battery of audio-vestibular tests. Electronystagmography disclosed abnormal eye tracking test in six patients (30%), and there were abnormal optokinetic nystagmus test results in nine patients (45%). Caloric test revealed canal paresis in seven patients, directional preponderance in four patients, and normal responses in nine patients (45%). Vestibular evoked myogenic potential testing disclosed absent vestibular evoked myogenic potentials in seven patients and delayed vestibular evoked myogenic potentials in two patients, with one patient showing absent vestibular evoked myogenic potentials on one side and delayed vestibular evoked myogenic potentials on the other side. The remaining 10 patients (50%) had bilateral normal vestibular evoked myogenic potentials. Five patients had preserved both caloric and VEMP test responses, six patients displayed absent caloric and VEMP test responses, and the remaining nine patients had either abnormal caloric test responses or abnormal vestibular evoked myogenic potentials, exhibiting a nonsignificant relationship between caloric test responses and vestibular evoked myogenic potentials. Relief of headache and vertigo was achieved after 3 months of medication. Ten asymptomatic patients with either absent or delayed vestibular evoked myogenic potentials before treatment underwent follow-up VEMP test, and nine patients (90%) displayed normal vestibular evoked myogenic potentials bilaterally. Vestibular evoked myogenic potential testing evaluates the sacculocollic reflex, which descends through the lower brainstem. Some patients with basilar artery migraine have absent or delayed vestibular evoked myogenic potentials, presumably because the descending pathway from the saccule through the brainstem to cranial nerve XI is interrupted, which is attributed to hypoperfusion in the territory of the basilar artery. After 3 months of medication, recovery of normal vestibular evoked myogenic potentials in an asymptomatic patient indicates reversible ischemia in the territory of the basilar artery.

Vestibular evoked myogenic potentials in brainstem stroke.

Despite its widespread application in the posterior fossa tumor, the study of vestibular evoked myogenic potential (VEMP) in cases of posterior fossa stroke remains scarce. The purpose of the study was to establish the role of VEMP in patients with brainstem stroke. Retrospective study. Patients with acute vertigo were admitted and underwent a battery of auditory vestibular tests including caloric and VEMP tests; then they were surveyed by magnetic resonance imaging scan. Seven patients (two men and five women) were demonstrated as having brainstem stroke, including infarction in five patients and hemorrhage in two. Clinical manifestations consisted of dizziness/vertigo in all patients, spontaneous nystagmus in five (71%), and ataxia in three. No patients had experienced conscious change or conventional neurological deficits (eg, long tract signs). Electronystagmography revealed abnormal findings on eye tracking test in 100% of patients, on optokinetic nystagmus test in 71% of the patients, and on caloric testing in 10 ears (71%), including absent ice-water caloric test response in 7 ears and canal paresis in 3 ears. Vestibular evoked myogenic potential testing displayed normal response in 3 ears and abnormal response in 11 ears (79%), including absent vestibular evoked myogenic potentials in 8 ears and delayed vestibular evoked myogenic potentials in 3 ears. When results of both caloric testing and VEMP test were combined, the abnormal rate increased to 93% (13 of 14 patients). Caloric testing assesses the vestibulo-ocular reflex, which passes upward through the upper brainstem, whereas VEMP testing evaluates the sacculocollic reflex, which travels downward through the lower brainstem. Hence, in evaluating the extension of brainstem stroke, both caloric and VEMP testing should be performed.

Intentional ablation of vestibular function using commercially available topical gentamicin-betamethasone eardrops in patients with Meniere's disease: further evidence for topical eardrop ototoxicity.

To determine whether the controversial findings of suspected ototoxicity from commercially available gentamicin sulfate and betamethasone sodium phosphate eardrops can be used in a therapeutic fashion to ablate (or attenuate) vestibular function in patients with unilateral Meniere's disease. Prospective case review. At a tertiary care dizziness unit at the University Health Network, Toronto General Hospital, University of Toronto (Toronto, Ontario, Canada), adults with unilateral Meniere's disease undergoing intratympanic ablation therapy were studied. After insertion of a tympanostomy tube with the patient under local anesthesia, patients instilled gentamicin containing eardrops three times daily until they became vertiginous for longer than 24 hours and then for an additional 2 days longer or for 1 month, whichever came first. Electronystagmographic caloric test responses were measured before treatment using bithermal water caloric and after treatment using air caloric tests. Main outcome measures included clinical titration of drops to the onset of prolonged vertigo. As well, post-treatment findings on electronystagmography and audiometry were compared with pretreatment testing. Twenty patients were available for review. Fifteen patients had a significant reduction in caloric test responses compared with pretreatment values; among them, 10 patients had absent air caloric test responses on the treated side. In 10 patients hearing worsened according to the 1995 American Academy of Otolaryngology-Head and Neck Surgery Committee on Hearing and Equilibrium Guidelines for reporting in Meniere's disease. Topical gentamicin-betamethasone eardrops can pass through a tube into the middle ear, where they may prove primarily vestibulo-ototoxic patients with Meniere's disease. The study further confirms clinical observations that gentamicin-containing eardrops might prove ototoxic, especially in noninflamed ears with a tympanic membrane defect.

めまいの感覚について （第３報） 温度眼振反応のめまい感と視運動性眼振反応の年齢による違い

During vertigo attacks, some patients complain of a strong self-rotating sensation, while others feel only a vague unsteadiness. Interested in this difference, we studied the mechanism of vertiginous sensations. In the present study, we investigated age-related changes in vertiginous sensation during the caloric test and optokinetic response. The subjects consisted of 44 volunteers (10 males and 34 females), ranging from 17 to 78 (mean 43.9) years of age. None of subjects had a history of spontaneous nystagmus, vestibular dysfunction or central nervous disorders. After obtaining informed consent, a total of 176 caloric stimuli were administered by the alternate bithermal method (30 and 44°C) to the bilateral ears of 44 subjects under ENG monitoring. Induced vertiginous sensations were recorded. OKP test was also performed in all the subjects. We obtained the following results; 1) Older subjects tended to complain of a stronger sensation of vertigo on caloric test. 2) There were no remarkable age-related changes in caloric response. 3) Older subjects showed a smaller maximal slow phase velocity on OKP test. This might be attributable to their stronger sensation of vertigo during the test.

Follow-up of caloric test response after acute peripheral vestibular dysfunction

This study examined retrospectively the spontaneous recovery of patients with an acute peripheral vestibular deficit in order to determine whether the caloric test response and with it vestibular function improves over time. The caloric bithermal was tested three times on 79 patients who were hospitalised with an acute deficit. The first test was recorded on emergency admission by observing nystagmus beats under the Frenzel glasses. Two to five days later a complete electronystagmus (ENG) examination was performed. A second ENG was performed, on average, 4 months later. 46% of the patients recovered a normal caloric canal paresis value (less than 32%). By comparing the canal paresis values in the first and second ENG an improvement exceeding 30% was demonstrated in 50% of the patients and there was no correlation between the extent of the canal paresis deficit and the amount of recovery. A simultaneous cochlear deficit had no influence on the recovery of vestibular function.

Vestibular disorders in patients with migraine.

Vestibular symptoms frequently occur in patients with migraine headache. The common migraine is defined in neurology as a unilateral, pulsating headache, which may be associated with nausea and vomiting, and lasts one or several days. In the classic form patients have visual prodromal symptoms. Focal neurological signs in the migraine complique include, for example, oculomotor palsy and vestibular abnormalities. This so-called vestibular migraine is different from basilar migraine, which involves the irritation of the cervical sympathetic system, and can cause symptoms that resemble transient brainstem ischemia. In order to evaluate vestibular dysfunction electronystagmography (ENG) was used. Patients frequently had abnormal caloric test responses, especially with a directional preponderance, and most had a spontaneous nystagmus. In the migraine attack the patients are presumed to have hypersensitivity of the labyrinth with nausea and vomiting, while in the headache-free period the ENG was almost normal. At present, we have had a high success rate in treating patients with pyracetam. Diazepam was used to treat basilar migraine and flunarizine to prevent vestibular migraine.

Caloric irrigators: air, open-loop water and closed-loop water.

Selective stimulation of the semicircular canal system of one ear by establishing a temperature gradient is still widely used in the clinic in the caloric test. The results obtained are noted for their imprecision and variability. This is, in part, due to a lack of uniformly applied standardized test protocols, as well as difficulties in applying a precise stimulus. The relative merit of the three types of irrigation are reviewed. Whilst some authors argue that both the closed-loop and air irrigators produce even more variability of response than open water systems, the present author believes that intratest replication studies indicate that the closed-loop irrigation stimulus is the least variable and best tolerated by the patient. In perhaps one-fifth of patients, response to the first irrigation is much stronger than subsequent stimulus applications. It is suggested that there may therefore be a case for routinely performing five irrigations in the bithermal caloric test, including a replication of the first irrigation. It is assumed that psychological factors, especially anxiety, may explain the phenomenon of enhanced initial response, and some of the variability of caloric test responses in general. Use of the closed-loop irrigator is advocated for ease of use, reduced routine maintenance and to minimize patient distress, thereby reducing anxiety and result variability.

めまい，難聴を初発とした髄膜癌腫例

We reported a case of diffuse metastatic leptomeningeal carcinomatosis (DMLC) with vertigo and hearing loss as early symptoms. From the examinations of a hearing test, internal auditory meatus tomography, caloric test, and auditory brain stem response, acoustic neurinoma was suspected firstly, and was ruled out finally by differential diagnosis. No remarkable findings were revealed in either CT or MRI and the cytological examination of cerebrospinal fluid showed many atypical cells, and the final diagnosis was DMLC. We made some discussions on this case and other cases reported in the literature.

Screening for retrocochlear pathology.

In 1982, 135 patients were screened for possible retrocochlear pathology, by means of an investigation protocol consisting of caloric test, impedance audiometry and brainstem response audiometry (BRA). A combination of the first two of these procedures had an unacceptably low prognostic accuracy. BRA indicated retrocochlear pathology in 8 and was inconclusive in 4 cases. Enhanced computer tomography revealed an intracranial tumour in 4 of the former, while no space-occupying lesion could be demonstrated in the remainder nor in the 4 patients with inconclusive BRA. BRA is the best single test for screening of this patient category.

The caloric response in the contralateral ear in acoustic neuroma.

The caloric test response from the unaffected ear in a case of acoustic neuroma may be normal, hypoactive or hyperactive; each has a different pathophysiological connotation: a normal response is the anticipated finding; a hyperactive contralateral response is due to the presence of a large neuroma with brainstem compression; and a hypoactive response may result from several factors, such as lack of mental alertness during the test, drugs like barbiturates, raised intracranial tension, or the presence of bilateral neuromas.

Labyrinthine Defects as Shown by Ataxia and Caloric Tests

Most of the individuals with labyrinthine defects severe enough to produce ataxia test performance scores within the lowest 5% of the normal distributions also showed threshold caloric test responses which fell within the same range. Similarly, almost as many individuals with decreased threshold caloric test responses also showed poor ataxia test performance scores. While vestibular influences governing threshold caloric test responses are far more specific than those affecting results on the ataxia tests, the high agreement shown between results of each in groups of individuals with various loss or disturbance of labyrinthine function implies a common vestibular effect to a considerable degree.

Nystagmus rate as an index of caloric test response.

Using a sample of 20 otologically normal adults, the number of nystagmus beats in the period 60 to 90 seconds after the onset of irrigation was found to be a valid measure of caloric test response. This value shows a Gaussian distribution, as does the two-ear difference in this value after a logarithmic transformation. Utilising a 10% probability level, less than 33 beats in this period would be abnormal, as would a difference of more than 20 beats between the two ears.

Validity of Measures of Caloric Test Response

The duration and the maximum velocity of the slow phase of the nystagmus induced by the hot and cold stimuli in the caloric test were correlated with the auditory thresholds for the one hundred ears of a consecutive series of fifty cases of Meniere's disease. The highest correlations were observed to occur with respect to the maximum velocity of the slow phase of the nystagmus induced by the hot thermal stimulus. A principal component analysis showed the other measures (nystagmus duration and responses to the cold stimulus) of the caloric response to have high loadings on principal components other than Component I.