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PubMed1999

[Thermographic detection of heat radiation in caloric vestibular function tests].

BACKGROUND: Since Bárány; caloric irrigations in the external ear canal have been used for unilateral stimulation of the peripheral vestibular system. However, the mechanism of heat transfer from the auditory canal to the vestibular organ is not completely known. From the physical point of view, three mechanisms may be discussed: heat conduction via the bone, convection via the middle ear gas, or radiation. Feldmann et al. (1991) singled out radiation as a very important factor in this regard. Using high-resolution thermography, we were able to "see" radiation almost directly in temporal bone experiments. METHODS: Using the system of infrared thermovision specially adapted for close-up studies, the effect of calorization can be observed and documented in colored planar thermograms. Fresh temporal bone specimens had to be prepared so as to permit simultaneous observation of the tympanic membrane and the medial tympanic wall. RESULTS: Changes in temperature were readily visible during experimental caloric tests: turning blue indicated cooling and red indicated warming. In the caloric test with 44 degrees C or 30 degrees C water, changes in color of the eardrum appeared immediately. At the very same time, however, an area of the medial tympanic wall also changed color. This velocity of transfer cannot be attained by conduction or convection: heat radiation is the only possible explanation. This could only be demonstrated at the very onset of the reaction; subsequent thermograms became more and more diffuse. In this stage the heat transfer may also be effected by conduction and/or convection. CONCLUSIONS: Thermography demonstrates that radiation is a very important factor in heat transfer; at least in the initial phase of calorization.

Body Temperature↗
PubMedDate not supplied

Relation between vestibular function and speech recognition in postlingually deafened adults with cochlear implantation.

Thirty-one postlingually deafened adults with 22-channel cochlear implants were evaluated preoperatively using vestibular function tests, the caloric test and stabilometry. The results of caloric response were classified into two diagnostic groups: normo- or hyporeflexia and areflexia. Stabilometric recordings were made using a computerized static posturographic platform. Between the two categories of caloric response, there was a significant difference in consonant recognition, but the recognition of vowels showed no significant difference. The results of the distance of body sway in stabilometry, but not of the area, correlated to the results of consonant recognition in speech perception tests. The degree of residual vestibular function seems to be one of the indicators influencing postoperative speech recognition by cochlear implant patients.

Adult↗
PubMed2003

Vertigo from herpes zoster oticus: superior or inferior vestibular nerve origin?

OBJECTIVE/HYPOTHESIS: This study aims to analyze which division of vestibular nerve in the internal auditory canal is responsible for inducing vertigo in patients with herpes zoster oticus (HZO). METHODS: Eight patients (three men and five women) suffered from auricular vesicles, otalgia, and facial palsy, and five of them also had vertigo. Each patient received a battery of tests, including neurological examination, blood examination, audiometry, caloric test, electronystagmography, and vestibular evoked myogenic potential (VEMP) test. RESULTS: All five HZO patients with vertigo had facial palsy on the lesioned side and spontaneous nystagmus beating toward the healthy side. Absent VEMPs were noted in five patients, absent caloric response was noted in four, and sensorineural HL was noted in three. Compared to another three HZO patients without vertigo, all revealed normal responses in both the caloric test and the VEMP test. On MRI scan, two out of four had abnormal gadolinium enhancement along the nerve segments within the internal auditory canal. Six months after treatment, a follow-up caloric test and VEMP test in these eight patients did not alter the results compared with before treatment. CONCLUSION: The nerve trunks within the internal auditory canal are widely affected in HZO patients with vertigo. Both superior division and inferior division of the vestibular nerve attribute to the vertiginous attack. Further, large numbers of HZO patients undergoing caloric testing and VEMP testing are required to support this tentative conclusion.

Adolescent↗
PubMed2002

Electrogastrography before and after a high-caloric, liquid test meal in healthy volunteers and patients with severe functional dyspepsia.

BACKGROUND: The cutaneous recording of gastric electric rhythm, so-called electrogastrography (EGG), has been purported as a non-invasive method for studying patients with functional dyspepsia and unexplained nausea and vomiting. The aims of this study were to determine normal values for EGG characteristics before and after a liquid, high-caloric test meal and to investigate whether EGG could discriminate between patients with functional dyspepsia and normal controls. METHODS: In studying 20 healthy volunteers and 10 patients with functional dyspepsia, we recorded gastric electrical activity during the 30 min before and after a liquid 1.0-1.5 kcal/ml test meal. Satiety before and after the meal was estimated on a 10-point scale. EGG was analysed regarding dominant frequency, instability of the dominant frequency, power ratio and percentage activity in the normal frequency range. RESULTS: The mean (+/-s) caloric intake in patients with functional dyspepsia (286 +/- 160 kcal) was significantly lower (P < 0.001) than in healthy volunteers (610 +/- 211 kcal). The patients reported a more pronounced feeling of satiety before the test meal (5.6 +/- 3.2) compared to healthy volunteers (3.6 +/- 1.2, P < 0.05), but at the end of the test meal there was no difference in satiety (7.9 +/- 2.5 versus 7.7 +/- 1.0). However, none of the EGG parameters showed any difference between patients and healthy volunteers. CONCLUSIONS: EGG before and after a high-caloric test meal showed large variation in healthy subjects and seemed to be of little value for differentiating between healthy individuals and patients with functional dyspepsia.

Adolescent↗
PubMed1989

Effect of temperature on fixation suppression ability in normal subjects: the need for temperature- and age-dependent normal values.

The purpose of the present investigation was to determine whether temperature has an effect on the magnitude of fixation suppression (FS) in normal subjects. The subject population consisted of 23 patients ranging in age from 35 to 74 years (mean age of 58.13 years). Each subject received a conventional vestibulometric test battery that included bithermal caloric testing and the FS test. The warm caloric media elicited larger nystagmus slow-phase eye velocities than the cool caloric media. Following warm caloric irrigations, FS was significantly smaller than that following cool caloric irrigations. It also worsened as a function of subject age. The results suggest that separate normal upper limits for FS need to be determined for cool and warm caloric testing. They also suggest that FS ability may decrease with age.

Adult↗
PubMedDate not supplied

Caloric vestibular test in the weightless phase of parabolic flight.

Twenty-four caloric vestibular tests were conducted in 20 test subjects during parabolic flight, in which weightless periods of about 10 seconds were elicited. The caloric nystagmus disappeared completely in all experiments in weightlessness, whereas in the higher G-periods the speed of the nystagmus increased. With regard to the modes of response during the periods with increased G-values prior to and following the weightlessness, four different types could be distinguished. In mode I the speed of the slow nystagmus phase increased in the higher G-periods, the nystagmus showed a prolonged duration, while in weightlessness it faded out completely. A reversed nystagmus appeared when the primary caloric nystagmus had disappeared. In modes II, III and IV the direction of the nystagmus reversed during weightlessness. In modes II and III this reversed nystagmus appeared even when the primary caloric nystagmus had disappeared. In mode III the nystagmus resembled the type of mode II, with the difference that it faded away much earlier than could be expected. In mode IV the primary nystagmus lasted rather briefly, while the reversed nystagmus during weightlessness was also much shorter. The experiments produced two remarkable facts: the appearance of a nystagmus reversal, a 'secondary nystagmus', in all experiments in weightlessness, and furthermore great differences in findings between the individuals as well as between experiments in the same person. The only explanation for the inconsistency in the findings is the assumption that effects on other canals, otoliths and vestibular nuclei are continuously changing and therefore interfere with the only endproduct measured, the horizontal nystagmus.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2002

Dysrhythmia of caloric nystagmus.

OBJECTIVES: Objectives of the study were 1) to determine the prevalence and characteristics of dysrhythmia, 2) to identify associations between dysrhythmia and other patient variables, and 3) to determine whether dysrhythmia is more a characteristic of individuals than simply a correlate of alertness or response intensity. STUDY DESIGN: Cross-sectional. METHODS: Review of records from 150 patients undergoing the caloric test. RESULTS: Dysrhythmia severe enough to interfere with accurate analysis of the caloric test was present in 40% of the cases. Individuals were entered into an "orderly" group (n = 67) or a "dysrhythmic" group (n = 83) and were 5.8 times more likely to remain in the same group on a second visit than to change groups. Stronger response scores were associated with less dysrhythmia. Higher caloric-induced vertigo scores were associated with both stronger response scores and lower dysrhythmia scores. Cases in the dysrhythmic group were 3.8 times more likely to have abnormal caloric test results than individuals in the orderly group. CONCLUSIONS: Dysrhythmia frequently interferes with valid and accurate interpretation of the caloric test. Current methods of "mental alerting" frequently fail to eliminate dysrhythmia. The presence of dysrhythmia appears to be a strong predictor of an abnormal caloric test result, and there is a moderate correlation between dysrhythmia and response intensity. Nevertheless, our results suggest that dysrhythmia is specific to individuals, rather than simply a manifestation of peripheral vestibular disease or a correlate of alertness or response intensity.

Adolescent↗
PubMed1989

Visual suppression tests in acoustic neuroma patients.

Fifty-five patients with a unilateral acoustic neuroma were investigated preoperatively with visual suppression tests during rotatory oscillation and caloric irrigation. During a sinusoidal oscillation, 29% of the patients showed a reduced suppression compared to 9% during pseudo-random oscillation and 11% in the caloric test. In the sinusoidal and caloric tests the majority of the patients with deficient suppression had large or medium-sized tumors. In a few patients with small tumors, pathology was observed in both sinusoidal and randomized tests, presumably as a sign of unconcentration. The study shows that the sinusoidal visual suppression test and to a lesser degree suppression during caloric irrigation are of value for identification of brainstem-cerebellum compression of acoustic neuromas.

Adult↗
PubMed2000

A case of Meniere's disease with vertical nystagmus after administration of glycerol.

A 62-year-old woman who complained of repetitive vertigo with a left fluctuating hearing loss was admitted to our hospital three times. A glycerol test was done on the third admission. Two hours after the administration of glycerol, the patient complained of rotatory vertigo with a downbeat vertical nystagmus. This nystagmus then changed its direction upward. Her left hearing loss was improved during the glycerol test. On the day after the glycerol test, a caloric test was done. The caloric response of the right ear was remarkably improved. Although she had not felt a hearing loss in the right ear, an overwritten audiogram showed a fluctuation of hearing in the right ear. The bilateral caloric responses fluctuated. From these findings, it appears that the function of the inner ear on both sides fluctuating. We speculate that the administration of glycerol elicited an asymmetry in the function of the inner ear on both sides and ocuured vertigo with vertical nystagmus because of the irritation of both ears.

Audiometry↗
PubMed2002

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

OBJECTIVE: 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. STUDY DESIGN: Prospective case review. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Administration, Topical↗
PubMed2001

Assessment of migraine-related cochleovestibular symptoms.

The objective was to assess the cochleovestibular symptoms in migraine. Therefore, a questionnaire form was prepared to record the data obtained from 20 migraineurs. All patients were assessed with audiometry, bithermal caloric testing and auditory brainstem response testing (ABR) between the migraine attacks, and 8 of them were also assessed during the attacks. Dizziness (30%) was the most common symptom that was followed by vertigo (25%) and tinnitus (20%). All patients had hearing within normal limits. Positional test (Hallpike maneuver) was positive in 2 (10%). Bithermal caloric testing revealed canal paresis in 3 (15%) patients. ABR results were normal in 13 patients. Seven patients (35%) had abnormal ABR results. Four of them (20%) had elongation in the absolute wave latencies (wave I, III and V) and normal IPLs of wave I-III, III-V and I-V. Three (15%) patients had elongation in the absolute wave latencies as well as in the IPLs of wave I-III, III-V and I-V. In conclusion, cochleovestibular symptoms can be seen in migraineurs. The test results between and during attacks are similar. The subjective cochleovestibular symptoms did not correlate with the objective tests performed (audiometry, ABR and caloric testing).

Adolescent↗
PubMed1998

Vestibular decruitment, hyperactivity, and rebound caloric nystagmus.

OBJECTIVE: This study examined the collective sensitivities of decruitment, hyperactivity, and rebound caloric nystagmus (RCN) for lesions of the brain stem/cerebellum against the current gold standard of imaging, the contrast enhanced magnetic resonance imaging (MRI). STUDY DESIGN: This is a retrospective study of patients who underwent a vestibular evaluation and a contrast-enhanced MRI scan. SETTING: The study was performed at a tertiary referral center. PATIENTS: The patients included in this study were evaluated for investigation of a variety of reported problems, including vertigo/dysequilibrium, headache, hearing loss, and tinnitus. Their age range was 13 to 79 years. INTERVENTION: Every patient underwent a vestibular evaluation, which included the Torok monothermal caloric test and an MRI scan. MAIN OUTCOME MEASURES: The results of this caloric test include vestibular decruitment, hyperactivity, and rebound caloric nystagmus. The sensitivity and specificity of these results for MRI confirmed brain stem/cerebellar lesions were determined. RESULTS: The overall sensitivity of the measures of this caloric test was 90%. The overall specificity was 25%. CONCLUSIONS: As a screening test for brain stem cerebellar lesions, the Torok monothermal caloric test performs well in terms of its sensitivity. The specificity is low, and this probably because MRI looks at morphology rather than function.

Adolescent↗
PubMed1981

[Pseudocaloric nystagmus (author's transl)].

The effect of bithermal caloric tests on the velocity of spontaneous nystagmus was retrospectively studied in 107 patients with unilateral vestibular areflexia. In 35 out of 107 patients, the velocity or pre-test nystagmus was not lower than 15 jerks in 30 seconds. In our series, spontaneous nystagmus before the caloric test was mostly seen in patients with neuritis or sudden deafness, and as a rule, the tests had little effect on the velocity of the nystagmus. In 7 out of 10 cases of areflexic Mènière's disease spontaneous nystagmus was revealed by caloric tests. Spontaneous pre-test nystagmus was present in 6 out of 29 cases of neurinoma; its velocity was always reduced during the caloric tests. In 14 out of 25 cases of head injury, areflexia was usually compensated. Vestibular compensation can now be defined as the absence of vertigo, of spontaneous nystagmus before and after caloric tests and directional predominance.

Adult↗
PubMed2005

Symptomatic high frequency/acceleration vestibular loss: consideration of a new clinical syndrome of vestibular dysfunction.

CONCLUSION: Symptomatic high frequency/acceleration vestibular loss is a distinct clinical entity that can be missed on conventional ENG with caloric testing. Under certain circumstances, symptomatic patients with a high frequency/acceleration vestibular loss should undergo an MSSC study for confirmation, if required. OBJECTIVE: To document that normal electronystagmography (ENG) with conventional bithermal caloric testing is inadequate for diagnosing clinically significant high frequency/acceleration vestibular loss. MATERIAL AND METHODS: Patients with clinical symptoms and signs of persistent peripheral vestibular dysfunction despite normal conventional bithermal caloric testing on ENG underwent high frequency/acceleration horizontal magnetic scleral search coil (MSSC) eye movement studies. The clinical findings and results from audiometric tests, conventional ENG with bithermal caloric tests and MSSC tests were reviewed. RESULTS: Eleven patients were identified as having an abnormal MSSC study, indicating a high frequency/acceleration vestibular loss consistent with their clinical history despite normal or equivocal bithermal caloric responses on conventional ENG. Although valuable, ENG caloric testing evaluates lateral semicircular canal function and should be considered a non-physiological test primarily of low frequency vestibular function. High frequency/acceleration head thrust testing clinically detected a "high frequency/acceleration vestibular loss" in 8/11(72.7%) cases.

Adolescent↗
PubMed2006

[Significance of some otologic function tests in diagnosis of Meniere's disease].

OBJECTIVE: To investigate the significance of vestibular function battery and electrocochleogram on diagnosis of Meniere's disease. METHOD: Patients with Meniere's disease were given pure tone hearing threshold test, auditory brainstem responses (ABR), electrocochleogram (ECoG), vestibular bithermal caloric test and vestibular evoked myogenic potentials (VEMP) test. RESULT: (1) As for the bithermal caloric test, the percentage of the abnormal canal paresis (CP) at three durations, i.e. , 0 to approximately 5 years, 6 to approximately 10 years and over 11 years were 56.9%, 75.9% and 61.6% respectively. The total positive rate was 50.0%. CP and duration of Meniere's disease had low correlation (P < 0.05). (2) The percentage of the abnormal VEMP at three durations, i.e., 0-5 years,6-10 years and over 11 years were 57.4%, 60% and 57.1% respectively. The total positive rate was 58.0%. The duration of Meniere 's disease with normal and abnormal VEMP had no significant difference( P >0.05). (3) The percentage of the abnormal ECoG at three durations, i.e., 0-5 years, 6-10 years and over 11 years were 72.1%, 73.3% and 81.3% (49/68,22/30 and 13/16) respectively. The total positive rate was 76.9%. The duration of Meniere's disease with normal and abnormal ECoG had no significant difference (P >0.05). CONCLUSION: Diagnosis of Meniere's disease is mainly based on the medical history. If it could combine with ECoG, bithermal caloric test and VEMP, the diagnosis would be earlier and more accurate.

Adolescent↗