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PubMed1980

Caloric testing by continuous automatic alternating irrigation.

Quantitative caloric test results show a high variability. They were described as questionable by Frenzel (1955) and a review of the test was recommended by Hood (1973). Thus, we developed a new method: continuous automatic alternating irrigation. An irrigator is connected to two water-baths of 30 degrees C and 44 degrees C. A time-relays switches over from one bath to the other every 60 s. The continuous, but alternating, irrigations produce subsequently alternating exponential temperature waves in the temporal bone. The mathematical model shows a quasi-periodicity and sufficient symmetry of the alternating thermal gradient across the canal, except for the first stimulus. After 11 irrigations of 60 s, a short (20 s) "washout" irrigation terminates the sequence. By the five repetitions of each stimulus and the additional possibility of correlating the response to the paper-marked stimulus periodicity the judgement is far more reliable and therefore, in doubtful cases, despite the five-fold data, quicker. The technical device is simple enough for routine use and inexpensive. The results of the caloric test are now much more clear-cut and the correlation to a known clinical pathology is remarkably high.

Body Temperature↗
PubMed2004

[The effect of caloric test sequence on maximum slow-phase velocity].

OBJECTIVE: To determine the relation between level of nystagmic responses and caloric test sequence. METHOD: A bithermal sequential caloric air irrigator was used to obtain maximum slow component speed caloric responses. One hundred and twenty patients who reported history of dizziness were divided to two groups. The first group is stimulated by different temperature air from hot to cold. The caloric test sequence of second group is opposite. The nystagmus was measured and recorded by electronystagmography. RESULT: The differences of maximum slow-phase speed between the cold and hot stimulus are relation with caloric test sequence (P<0.01). The second group is greater than the first group. The canal paresis (CP) and the directional preponderance (DP) relative difference of the second group were greater than the first group. CONCLUSION: The caloric test sequences have effect on level of excitability of vestibular, the CP relative difference and DP relative difference.

Adolescent↗
PubMed1992

An evaluation of commercial water irrigation systems used for caloric testing.

The post-1982 Grant Caloric Test Apparatus, and the Atmos Variotherm were evaluated and compared to BS5724 Part 1 (1989). Quality of construction is satisfactory, but design features may result in failure of tests for which this type of equipment should conform; namely splash, liquid leakage and spillage. For the Variotherm the proximity of the water piping to the electrical parts could result in wetting of the electrical units in the event of a leakage. The large vents in the Grant tanks allow easy access of water to electrical parts in the event of splashing. Both sets of equipment fail BS5724 Part 1 (1989) with respect to labelling. The Grant irrigation nozzle is well designed, but the Variotherm nozzles are not so, as they can accidentally pass down the external auditory meatus causing meatal wall or tympanic membrane damage. Both sets of equipment passed on electrical safety test for Class I Type B equipment. Cut-outs are fitted to prevent heating in the absence of water or over-heating of the water. The 44 degrees C Grant tank cut out after 20 s in the absence of water and at 49 degrees C as the water temperature rose above the operating temperature. The Variotherm heater did not operate in the absence of a water supply. The Variotherm thermal cut-out was not assessed. The force of the water at recommended flow rates using the Variotherm 'standard' metal nozzle was considered to pose a potential hazard of tympanic membrane perforation, and has subsequently been withdrawn by the supplier. The plastic nozzle minimized any such risk. The Variotherm is easier to use due to the well-designed trigger handle for controlling water delivery. Both sets of equipment performed at the correct temperature to within +/- 0.5 degrees C and achieved a flow rate of 250 ml in 30 s.

Caloric Tests↗
PubMed2001

A new light on caloric test--what was disclosed by three dimensional analysis of caloric nystagmus?

For better understanding of caloric nystagmus, this phenomenon will be reviewed historically in three stages. 1) The first light on caloric nystagmus was thrown by Barany 1906. Through direct observation of eye movements, Barany established the caloric test as an important tool to determine the side of lesion for vertigo. 2) The second light is shed by electrooculogram (EOG) from the late 1950th. EOG enabled qualitative analysis of caloric nystagmus, and proved Barany's convection theory, but resulted in neglect of vertical and roll eye movements. 3) The third light is gained by 3D recording of eye movements started from the late 1980th. 3D recordings of eye movements enabled us to analyze the spatial orientation of caloric nystagmus, and disclose the close correlation of the nystagmus components in the head vertical and the space vertical planes, suggesting a contribution of the velocity storage integrator. The 3D property of caloric nystagmus will be explained in detail.

Animals↗
PubMed1977

Caloric test with oculogyral illusion as response.

It has been demonstrated that the caloric test can be simplified further by making use of the oculogyral illusion. Since the test is conducted under conditions of optic fixation, this method probably also enhances the sensitivity of the caloric test. The reproducibility of the tests also appears high, at least in respect of measures of "canal paresis". When used in conjunction with other tests for detecting vestibular imbalance, e.g. examination for spontaneous and provocation nystagmus using Frenzel glasses, this OGI caloric test should provide a convenient procedure for the clinical examination of vestibular function.

Adult↗
PubMed2005

Search-coil head-thrust and caloric tests in Ménière's disease.

CONCLUSIONS: Our findings suggest that canal function is substantially preserved in subjects with active vertigo attacks as a result of Ménière's disease (MD). In these subjects, the head-thrust test (HTT) may not be as sensitive to canal dysfunction as traditional caloric testing. MD may differentially affect the low-frequency sensitivity of the canals. OBJECTIVE: Caloric tests have traditionally been used to characterize semicircular canal function in vestibular disorders, including MD. The quantitative HTT provides an objective measurement of semicircular canal function in the frequency and velocity ranges of normal head movements. The aim of this study was to compare the findings of caloric and HTTs in subjects with unilateral MD. MATERIAL AND METHODS: The study population consisted of 38 candidates for gentamicin treatment due to a high frequency of vertiginous attacks (25 males, 13 females; mean age 52.9 years; range 30-70 years). The duration of symptoms was 1-30 years (mean 5.3 years). Horizontal canal function was characterized with bithermal aqueous caloric tests and recordings of the angular vestibulo-ocular reflexes (aVORs) using the scleral search-coil technique during HTTs. The main outcomes were unilateral weakness (UW) on caloric testing and aVOR gain asymmetry (GA) during HTTs. A caloric response asymmetry of >20% was considered to be indicative of pathologic UW. A difference in GA during HTTs of >5.8% was considered significant. RESULTS: Twenty subjects (52.6%) showed abnormal results on one or both tests. Pathologic UW was present in 16 subjects (42.1%). During HTTs, 11 subjects (28.9%) showed pathologic GA. Seven subjects (18.4%) showed abnormal results on both tests. A significant correlation was found between UW and GA. However, pathologic GA during HTTs in subjects with unilateral MD was less frequent and the values smaller than those published for vestibular neuritis patients. Two subjects with unilateral MD had 100% UW, but none had >30% asymmetry on HTTs.

Adult↗
PubMedDate not supplied

Results of new air caloric testing method among normal subjects. II. Monophasic testing.

A new caloric irrigation method is described. In the new method, the temperature of a continuous aural irrigation is switched between hot and cold values at precisely specified times. The durations of hot and cold pulses have been calculated to produce specific caloric stimulation intensities based on known heat transmission characteristics of the labyrinth area. A brief "washout" irrigation is used to eliminate promptly all caloric stimulation effects at the conclusion of each test. The present study concentrated upon the question of how long the "washout" pulse should be in order to obtain optimum results. Repetitive application of a uniform stimulus intensity to 6 normal subjects indicated that short inter-test intervals can be used without causing vestibular habituation. Prompt removal of the caloric stimulus can be accomplished by proper timing the "washout" phase of the new technique.

Caloric Tests↗
PubMed1978

[Normal values of the caloric test (author's transl)].

Normal values of the caloric test are reported in 202 healthy subjects; besides the absolute values, these comprise the degree of side-difference of excitability and of directional preponderence in percent of the total reaction. In addition to mean values with standard deviations, the median values and the interquantile areas 80, 90, 94 and 100% have been reproduced in tabular form, because, according to statistical calculations, there is no normal distribution of the values in the strict sense. The problematic nature of borderline values for the separation of physiological from pathological responses is discussed in detail. In vieu of the considerable scattering, a knowledge of normal distribution areas appears to be absolutely necessary for an accurate evaluation of the caloric test in patients.

Adult↗
PubMed1989

The caloric test in electronystagmography.

A wealth of information concerning the caloric test has accumulated since the test was introduced more than eight decades ago. Both convective and nongravity-dependent forces on endolymph are believed to underlie the response at the end-organ level. Higher-order influences are equally important and make the test findings highly dependent on specific test conditions. Slow-component eye velocity is the most widely accepted index of vestibular response, although success using nystagmus beat frequency has also been reported. Both bithermal and monothermal calorization sequences have been studied. Standardization of technique and a consensus on methods of interpretation will be necessary for the determination of the optimal clinical caloric test.

Caloric Tests↗
PubMedDate not supplied

Alternate and simultaneous binaural bithermal caloric testing: a comparison.

This study compares the results from simultaneous binaural bithermal and alternate binaural bithermal caloric testing of 652 patients with dizziness. Also compared are the abilities of these tests to distinguish between a population of healthy asymptomatic subjects and our patient population. Caloric testing used a closed-loop irrigation system. Eye movements were monitored with electro-oculography. The agreement between the results from the two tests was low. Also, while the simultaneous test was more sensitive, the alternate test was more specific. Using receiver-operator characteristic methodology, it was found that the ability of the alternate test to distinguish between a healthy population and a patient population was superior to that of the simultaneous test. There was no improvement in the ability to distinguish between a healthy population and a patient population when the results from the two tests were combined as compared to using the alternate caloric test alone.

Algorithms↗
PubMed1980

[The use of freon in caloric tests (author's transl)].

The author describes a gaseous caloric test using Freon to cool the tympanic membrane. The experiment was used to study the temperature of the tympanic membrane and its variation in relation to the temperature of the material containing the Freon. It was found that the tympanic response was stereotyped if the temperature of such material was between 22 and 30 degrees. Comparison with the aqueous caloric test showed twice as long a recovery time for the latter. Study of nystagmographic tracings in 36 patients tested successively with Freon in Bruning's positions I and IV and with water at 30 and 44 degrees showed constant relations and a great similarity in responses. Clinical study of a number of cases also showed identical responses. Statistical calculation revealed satisfactory correlation coefficients between the two methods. The single test using Freon thus represents a rapid and quantitative method for the investigation of vestibular function. It is a useful test in everyday practise.

Adult↗
PubMed1979

Impulsive and sinusoidal rotatory testing: a comparison with results of caloric testing.

The usefulness of rotatory testing (impulsive and sinusoidal) as an indicator of impaired horizontal semicircular canal function was evaluated in 63 patients with unilateral and bilateral decreased caloric responses. The rotatory stimuli were precisely controlled over a large magnitude range and EOG recorded nystagmus responses were quantified using digital analysis techniques. Rotatory testing was consistently abnormal in patients with complete unilateral caloric paralyses but was normal in over one-half of the patients with significant but less than complete unilateral caloric paralyses. The difference in maximum slow component velocity (SVMX) of induced nystagmus after the largest rotatory stimuli was the best indicator of unilateral impaired function. The patients with bilateral decreased caloric responses demonstrated three categories of rotatory response: 1. normal at all magnitudes of stimulation, 2. decreased but present after large magnitude stimuli, and 3. absent responses. It is concluded that although rotatory testing cannot replace caloric testing it can provide useful clinical information particularly in patients suspected of having bilateral vestibular disease.

Caloric Tests↗
PubMed2006

Relationship between head-only rotation and caloric test results in vestibular disorders.

Our purpose was to determine the possible existence of a relationship between abnormal findings from head-only rotation and those from caloric tests applied in patients with peripheral vestibular disorders. We retrospectively studied the head-only rotation and caloric test results of 75 patients experiencing dizziness and peripheral vestibular dysfunction. We assessed the relationship between abnormal test results using the Cramér coefficient. Abnormal findings in the head-only rotation test occurred in 87.5% of patients with vestibular hypoexcitability and in 94.3% of those with hyperexcitability or directional preponderance of post-caloric nystagmus. Statistical analysis of the association between the values found for the parameters of head-only rotation and caloric test results revealed a Cramér coefficient that was less than 0.70. We found no relationship between abnormal findings from head-only rotation and caloric tests applied to individuals with peripheral vestibular disorders.

Adolescent↗
PubMed1975

Evaluation of a screening-procedure by hot-water caloric tests.

In order to introduce a screening-procedure for vestibular caloric testing, we tried to evaluate the hot and cold caloric tests separately. We made a review of a series of cases having been tested by the classical 4 tests (cold and hot bilateral). In supposing that we should have stopped the investigation when the hot calorics showed a side-difference of 20% or more for the slow-phase velocity at the culminationpoint, we verified how many cases would have been missed, presenting by global examination a significant difference either for the reflexivity or for the DP. This study showed us that an important number of cases would have been missed equally well by the hot calorics as by the cold ones. The comparison shows no difference between them. By narrowing the criteria we would allow a screening-technique either by the cold or by the hotwater test, but in this way more than 3/4 of the cases were indicated for complete examination.

Caloric Tests↗
PubMed2004

The origin of order effects in the results of the bi-thermal caloric test.

An order effect, characterized by a progressive decline in response magnitude, has been observed in the caloric test, and it has been suggested that the effect may be countered by applying a correction. This study was undertaken to determine whether the effect has its origin in physiological adaptation or in calibration drift of the recording system. Thirty-two normal subjects underwent the caloric test, in which their nystagmus was monitored simultaneously by both electronystagmography (ENG) and videonystagmography (VNG). The experimental design also allowed other aspects of the caloric test sequence to be investigated. No evidence of physiological adaptation of the response was seen. However, there was a significant change in corneoretinal potential, and hence ENG calibration, during the tests. This was more marked if subjects' eyes were maintained in darkness. It is recommended that no correction be made for order effects but that the calibration of ENG-based systems is adjusted immediately prior to each caloric irrigation.

Action Potentials↗
PubMed1991

Monothermal differential caloric testing in patients with Menière's disease.

The monothermal differential caloric test allows determination of vestibular recruitment and decruitment, variables which may help discriminate peripheral from central vestibular lesions. Previous reports indicated a strong association between vestibular recruitment and Menière's disease. This study examined patients having unilateral Menière's disease. Nystagmus beat frequency (NBF) and slow-component velocity (SCV) responses were recorded by electronystagmography (ENG). Electronystagmographic findings showing unilateral dysfunction were present in 54% of patients by slow-component velocity and in 31% by nystagmus beat frequency. Unilateral hypofunction was the most frequent lateralizing ENG finding. Absolute vestibular recruitment occurred in less than 10% of patients but relative recruitment was found in nearly 20% of patients. Slow-component velocity had higher sensitivity than nystagmus beat frequency, with excellent clinical concordance. Monothermal caloric testing as described in this study best detects peripheral vestibular disease in Meniere's patients using slow-component velocity to determine unilateral hypofunction and relative vestibular recruitment.

Adolescent↗
PubMed2006

[Analysis of air caloric testing results for patients suffering from tympanic membrane perforation with vertigo].

OBJECTIVE: To analyze characteristic of air caloric testing for patients with tympanic membrane perforation and to assess the availability of this testing for the patients. METHOD: Forty-three cases of chronic otitis media with tympanic membrane perforation and vertigo were investigated, in which there were 37 cases with single ear perforation and 6 cases with bilateral perforation. The patients were performed by air caloric testing, to observe the characteristic of nystagmus,slow phase velocity (SPV) and unilateral weakness (UW). RESULT: Four types of nystagmus, including enhancing, "normal", weakening and inversion, were observed with bilateral caloric air stimulation in ears with tympanic membrane perforation. Nystagmus of perforated ear presented SPV increased exceeding normal range or non-perforated ear and UW > 15% (15 cases, 17 ears), which was called enhancing type; normal nystagmus SPV in bilateral ear and UW < 15% (7 cases) was called "normal" type; weakened nystagmus SPV in perforated ear to non-perforated ear and UW > 15% (9 cases) was called weakening type; normal nystagmus in non-perforated ear and inverted caloric nystagmus in perforated ear (12 cases, 14 ears) was called inversion type. In patients with chronic otitis media recurring lately, inverted nystagmus was observed in perforated ears with effusion and humidity in the tympanic cavity, the other types were observed in patients in stillness stage of otitis media. CONCLUSION: Bilateral caloric air became strong stimulation for the perforated ear, nystagmus of perforated ear with normal function of semicircular canal was stronger than that of the non-perforated ear. While the perforated ear with undermined function of semicircular canal, nystagmus could present normal or weakened. In the patients with otitis media in active stage, hot air stimulation could be turned to cool stimulation response so as to cause inverted nystagmus. Air caloric testing can be used to assess vestibular function of the patients with tympanic membrane perforation and vertigo.

Adult↗