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PubMedDate not supplied

Sources of error in interpretation of caloric tests.

Caloric testing plays a prominent role in evaluating the vestibular system. A unilateral reduced vestibular response (RVR) is a common abnormality and is consistent with peripheral vestibular pathology. An erroneous interpretation of RVR may be made due to the following circumstances: laboratory technique, the influence of directional preponderance (DP) on monothermal tests (MT), unilateral hyperactivity, or pseudocaloric (PC) nystagmus. These errors in interpretation may be avoided by (1) repeating any single irrigation that is significantly different from the other three, to rule out laboratory technical error; (2) performing bithermal (BT) testing exists, to eliminate the effects of directional preponderance; (3) observing that a right/left (R/L) difference is not due to unilateral hyperactivity, by noting absolute slow phase (SP) velocity; and (4) by demonstrating bidirectional sensitivity of the cupula before concluding that residual caloric function exists instead of no function.

Caloric Tests↗
PubMed2004

[Vibratory test and head shaking test and caloric test: a series of 87 patients].

OBJECTIVES: The purpose of this work was to study the complementary contribution of the vibratory test (VT), the head shaking test (HST) and the caloric test (CT) in patients with total or partial vestibular lesions. We investigated the usefulness of these three tests, particularly the high frequency VT, for multiple-frequency vestibular study. MATERIALS AND METHODS: The study cohort included 40 patients with total vestibular lesions (TVL) and 47 patients with partial vestibular lesions (PVL), the latter group including 21 patients with recent Menière disease, 15 with sudden-onset loss of vestibular function (SLVF), 5 with tumors of the cerebropontine angle, and six with diverse conditions. The HST protocol was 2 Hz stimulation (head speed greater than 180 degrees /s). The VT used an ABC 100 Hz vibrator operating at 0.8 mm and an S stimulator delivering frequencies between 30 and 115 Hz during 10 s stimulations. An LIVN-2 videoscope (biodigital France) and a 2D and 3D videonystagmograph (synapsis France) were used for the recordings. Mastoid stimulation was used for the VT. RESULTS: For the 40 patients with TVL, the three tests (VT, CT, HST) were in agreement for all frequencies. The nystagmus produced by the VT demonstrated a horizontal component in 96% of the patients, a vertical component in 47%, and a rotational component in 30%. For the 47 patients with PVL, 9 of the 21 with Menière disease had a normal CT. Conversely, nystagmus was triggered by the HST in 10 and by the VT in 6. Nystagmus triggered by the VT and the HST was non-coherent with opposing direction in two-thirds of the patients. In certain cases, the VT demonstrated a variation in the direction of the nystagmus depending on the stimulation frequency, 30 or 100 Hz. Among the 15 patients with SLVF, the HST triggered nystagmus in only 5 and the VT in 14 (5 patients had nystagmus non-coherent with the side of the lesion). For the 5 patients with tumors of the cerebropontine angle (small neuroma or meningioma), the CT was negative in all 5, the HST was negative in 3, and the VT demonstrated lesional nystagmus in 4. Looking at the overall results, in the 47 patients with PVL (including 21 cases of Menière disease outside an acute phase) the CT demonstrated significant hypovalence in 70%, while the nystagmus demonstrated asymmetrical response in 44% when triggered by the HST and in 85% when triggered by the VT. CONCLUSION: The VT is less invasive than the HST, particularly for elderly patients with osteoarthritis. It would be interesting in patients with bilateral tympanic perforation since the CT cannot be performed. It can reveal vestibular asymmetry. For unilateral partial vestibular lesions, the VT triggers nystagmus more often than the HST. It is particularly sensitive between acute episodes in patients with Menière disease. A discordance between the direction of the nystagmus triggered by the HST and the VT is particularly frequent in patients with labyrinthine hydropsis who exibit a normal CT. In certain cases of apparent bilateral areflexia to the CT for low frequencies, the VT can disclose vestibular asymmetry for high frequencies. The nystagmus triggered by the VT begins and ends with stimulation with little or no tiring. The nystagmus triggered by the HST occurs after the stimulation and depends on the frequency of the head shaking. Thus, the HST (2 Hz and its harmonics), the VT (100 Hz) and the CT (<0.01 Hz) all make significant contributions to multiple-frequency analysis of vestibular function, particularly useful in patients with partial vestibular lesions. These tests probably solicit cells with different topographies or different frequency sensitivities.

Aged↗
PubMed2006

[Comparative study of vestibular autorotation test and caloric test for patients with peripheral vestibular disorders].

OBJECTIVE: To analyse the value of vestibular autorotation test (VAT) for assessing vestibular function. METHOD: VAT (WSR. USA) and caloric test (CT) were performed on 48 patients with peripheral vestibular disorders. Videonystagmograph (Synapsis. France) was used for caloric nystagmus recordings. The results of VAT were compared with that of CT. Parameters analysed in this study included gain, phase and asymmetry of VAT; the canal paresis (CP) and the directional preponderance (DP) of CT. That any of five parameters of VAT was abnormal or one of CP and DP appeared could be defined as abnormal VAT or abnormal CT. RESULT: VAT was found to be abnormal in 36 (75.0%) patients, including 32 (66.7%) patients (21 cases with decreased gain, 24 cases with lagged phase and 6 cases with asymmetry) in horizontal testing and 15 (31.2%) patients (7 cases with decreased or increased gain, 14 cases with lagged phase) in vertical testing. Four patients had abnormal vertical testing alone. Abnormal phase can be observed more frequently than abnormal gain. The abnormal parameters of phase and gain were consistent in the 2.0-6.0 Hz range. Asymmetry appeared in all cases in the 6.0-11.0 Hz range, consistent with the side of vestibular weakness tested by CT. Thirty-three patients (68.8%) showed CP or DP of CT (bilateral or unilateral CP 28 cases and DP 16 cases). VAT and CT showed abnormal results in 25 patients simultaneously, solo abnormal results were found in 11 patients and 8 patients respectively. There were 4 patients with normal results of both VAT and CT. Abnormal results of VAT combined with CT were assessed in 44 (91.7%) patients. When vestibular lesion was complete, results of VAT and CT were all abnormal and the abnormal parameters of VAT were observed at all frequencies of band tested. CONCLUSION: VAT is a vestibular test of high-frequencies and wide-bands and can indicate information of not only vestibular function in higher frequency band, but also vertical semicircular canal function. As the supplement of CT, error diagnosis can be partly avoided by VAT.

Adolescent↗
PubMed1991

Compensatory process of vestibular neuronitis. From findings of combined galvanic test and caloric test.

The compensatory process of vestibular neuronitis in 7 patients was followed up and evaluated using the Combined Galvanic Test (CGT) and other neuro-otological data. CGT is the simultaneous recording of both galvanic eye movement (GEM) and galvanic body sway (GBS), and has proved to be reliable in the diagnosis of retrolabyrinthine disorders. The results were as follows: The subjective symptoms remained in 3 cases from 1 month to 1 year. The recovery of the GBS response was seen earlier than that of both GEM and caloric responses. The recovery of GEM and caloric responses was observed at almost the same time. We observed the favorable recovery process of caloric response and GEM response in some cases which had recovery of GBS response within 4 weeks and suggest that the system of GBS response is different from that of GEM and caloric response. However, the systems of the latter two may be the same. We assume that the recovery of GBS response is earlier than that of GEM and caloric responses because the otolithic system recovers more easily than the semicircular canal system. The CGT and caloric test were reliable in examining the compensatory process of vestibular neuronitis.

Adult↗
PubMed2005

The minimal ice water caloric test compared with established vestibular caloric test procedures.

Caloric testing of the vestibular labyrinth is usually performed by classical caloric test procedures (CCTP) using water warmed to 30 degrees C and 44 degrees C. Ice water irrigation (4 degrees C) is usually not performed, although it might be useful as a bedside test. To verify the validity of the Minimal Ice Water Caloric Test (MIWCT), comparative video-oculographic investigations were performed in 22 healthy subjects using ice water (0.5 ml, 1.0 ml, 2 ml), CCTP, and cold air (27 degrees C). Frequency, amplitude, slow phase velocity (SPV), the onset, and the duration of nystagmus were documented. After addition of three ice cubes, the temperature of conventional tap water (16 degrees C) fell within 13 min to 4 degrees C. In pessimum position the subjects demonstrated no nystagmus response. Compared to CCTP, MIWCT was associated with a significantly later onset of nystagmus and a significant prolongation of the nystagmus reaction. In contrast to air stimulation (27 degrees C), a significant Spearman's correlation was noted between MIWCT (1 and 2 ml) and established CCTP in respect of essential nystagmus parameters (frequency, amplitude and SPV). Furthermore, MIWCT (0.5 and 1 ml) showed a higher sensitivity and specificity with regard to the detection of canal paresis based on Jongkees' formula compared to stimulation with air 27 degrees C. Thus, MIWCT appears to be a suitable procedure for bedside investigation of vestibular function outside the vestibular laboratory, e.g. in a hospital ward, where bedridden patients with vertigo occasionally require vestibular testing.

Adult↗
PubMed1979

[Air caloric test: as useful as the water caloric test (author's transl)].

Twenty normal probands were examined by us with air (60 sec, 121/min, 45 degrees/29 degrees C) and 25 with water (30 sec, 30 cm3, 44 degrees/30 degrees C) caloric test. Additionally we evaluated the influence of flow rate and tip position on the temperature near the tympanic membrane during the irrigation, using a polyacryl copy of the external auditory canal. A high flow rate and a reproducible tip position very near to the tympanic membrane during the irrigation appeared to be essential to achieve reliable results in air caloric test. Measurements of the actual temperatur should be done therefore at the irrigation tip delivery in every caloric test with air. Lower heat capacity of air, air jamming near the tympanic membrane and heat losses through the meatus wall are the main reasons of more distinct temperature drops and a higher variability in air caloric test, than in the common caloric test with water. Therefore, the air caloric test as a reliable instrument should be reserved for those cases, were water is contradicted.

Air↗
PubMed1984

Caloric tests.

The caloric test is still the most useful vestibular test by far. Rotatory tests may allow more accurate control of the stimulus and the response parameters may vary less in normal individuals, but only the caloric test allows individual testing of each ear. By various means described in this article, it is possible to minimize potential sources of error and thus maximize the reliability of the test. Although the test allows a good measure of horizontal semicircular canal function and, by inference, an estimate of labyrinthine disease, the fact that the reflex arc traverses the vestibular nerve and brain stem renders this pathway liable to damage by central vestibular disease. Thus the electronystagmographic recording of the caloric nystagmus response may show a variety of changes, depending on the site and nature of the central vestibular lesion. Some of these changes are discussed.

Caloric Tests↗
PubMed1997

[Rotatory impulse test does not replace caloric tests].

We sought to determine whether the rotatory impulsional test was capable of exploring the canalar function with sufficient precision to replace the caloric test, as it has been recently affirmed. We first compared the observed preponderance from this test with that measured during a sinusoidal (20 and 4 s) test. We observed that, in the case of a significant preponderance for a given test, there was complete redondance with the preponderance observed with any other test. The rotatory impulsional test does not present any specific advantage compared to other kinetic test as far as the observation of the preponderance phenomenon. We then compared the preponderance with the results of the caloric tests and came to the following conclusions i) the absence of preponderance does not allow us to predict the absence of vestibular deficit, due to the fact that 37% of the deficits were compensated for including acoustic neuroma; ii) the presence of a preponderance does not allow a priori to say whether it is of vestibular, cervical, or central origin and systematic caloric tests shows that almost one fourth of preponderance observed is not associated with unilateral weakness iii) supposing that a clinical argument allow us to conclude as to the probable vestibular origin of a vestibular preponderance, the direction of this preponderance does not allow us to determine which side is involved. In fact, if the undercompensated deficits are 3 times more frequent than overcompensated deficits, the proportion of preponderance not linked to a significant deficit indicates that the probability of encountering a preponderance related to a specific undercompensated deficit is approximately 50%. We thus did not find in the rotatory impulsional test any specific advantage allowing us to predict the laterality of a vestibular lesion.

Caloric Tests↗
PubMed1999

An adequate parameter evaluating the galvanic body sway test: comparison with the caloric test in patients with vestibular schwannomas.

It has been reported that the galvanic body sway test does not correlate with the caloric test. We evaluated the galvanic body sway test in patients with vestibular schwannomas using three parameters: the angle of deviation response onset, the maximum value of the deviation response, and the area of deviation. These parameters reflect velocity, position, and locus of the centre of pressure, respectively. Among these parameters, only the angle of deviation response onset showed unilateral weakness of the response correlating with the canal paresis value, which indicates that velocity is responsible for conduction in the vestibular nerve. However, the galvanic body sway test is apt to be preferred to the caloric test. This might be attributed to the decreased sensitivity of this test.

Adolescent↗
PubMed2005

Fluid-structural dynamics of ground-based and microgravity caloric tests.

Microgravity caloric tests aboard the 1983 SpaceLab1 mission produced nystagmus results with an intensity comparable to those elicited during post- and pre- flight tests, thus contradicting the basic premise of Barany's convection hypothesis for caloric stimulation. In this work, we present a dynamic fluid structural analysis of the caloric stimulation of the lateral semicircular canal based on two simultaneous driving forces for the endolymphatic flow: natural convection driven by the temperature-dependent density variation in the bulk fluid and expansive convection caused by direct volumetric displacement of the endolymph during the thermal irrigation. Direct numerical simulations indicate that on earth, the natural convection mechanism is dominant. But in the microgravity environment of orbiting spacecraft, where buoyancy effects are mitigated, expansive convection becomes the sole mechanism for producing cupular displacement. A series of transient 1 g and microgravity case studies are presented to delineate the differences between the dynamics of the 1 g and microgravity endolymphatic flows. The impact of these different flow dynamics on the endolymph-cupula fluid-structural interactions is also analyzed based on the time evolutions of cupular displacement and velocity and the transcupular pressure differences.

Algorithms↗
PubMed1979

A protocol for the air caloric test and a comparison with a standard water caloric test.

This communication describes the development of a protocol for the air caloric stimulus for vestibular testing. The protocol is based on matching the peak responses of air and water caloric stimuli and minimizing subject discomfort. Air stimulus temperatures of 30 and 44 degrees C are used, and these appear to minimize subject complaints of pain with the test. Composite data are presented from 16 normal subjects who were tested with the protocol. A comparison is made with their responses to a standard water protocol. Test-retest data for both air and water protocols are also presented, and these data indicate similar day-to-day variation in the two methods. On the basis of the work presented, it is concluded that the air protocol produces responses equivalent to that of standard water calorics in a group of normal subjects. Neither test was found, in the present experiments, to be particularly sensitive.

Air↗
PubMed1991

Positional envelope as a response parameter in caloric testing.

Bithermal caloric testing was carried out in 57 normal subjects and 374 patients presenting with subjective complaints of vertigo over a 4-year period from December 1984 to December 1988. Responses were quantitatively assessed using a DEC PDP 11/73 laboratory minicomputer. Patients were classified as normal and abnormal according to caloric responses based on standard methods of calculating unilateral hypoexcitability and directional preponderance using the maximum slow component velocity. Results obtained from the slow component velocity for unilateral hypoexcitability and directional preponderance were compared to the same values obtained from the overall positional envelope calculated by an integration of the slow component velocity vs. time curve. Although duration of nystagmus varies extensively in normal subjects and has not proven clinically useful in identifying abnormalities, the integral of response amplitude over time gives a more complete description of the vestibular response. However, when compared to the maximum slow component velocity in abnormal patients, the positional envelope identified only 94 of the total 119 abnormalities (79%). Therefore, maximum slow component velocity is the more sensitive response parameter in identifying vestibular pathology.

Algorithms↗
PubMed1980

Air versus water caloric test.

The air caloric test is favoured because of the advantage of higher convenience for patient and operator and its applicability in situations where water is contradicted. We examined 20 normal subjects with air (60 s, 12 min, 45 degrees/29 degrees C) and 25 with water (30 s, 30 cm3, 44 degrees/30 degrees C) caloric test. Additionally, we evaluated the influence of flow rate and irrigating tip position on the temperature near the tympanic membrane during the irrigation, using a polyacryl copy of the external auditory canal. A high flow rate and a reproducible tip position--close to the tympanic membrane appeared to be essential to achieve reliable results in air caloric test. Furthermore, measurements of the actual temperature should be done at the irrigation tip delivery in every air caloric test. The lower heat capacity of air, turbulences near the tympanic membrane and air aspired from the environment are the main reasons of more distinct temperature drops in the air caloric test. We observed a significant (P less than 0.05) difference between maximum slow phase velocity in air (11.5 degrees C/s) and water (19.5 degrees C/s) irrigation. The relative standard deviation was markedly higher for air irrigations. Therefore, in spite of the advantages of the air caloric test, the disadvantage of a higher variability, even when using a sophisticated technique, has to be considered.

Adult↗
PubMed1996

The test-retest variability of the caloric test: a comparison of a modified air irrigation with the conventional water technique.

The bithermal caloric test has traditionally been carried out using water but air may also be used. One of the reported disadvantages of air is the high test-retest variability (Coats et al., 1976). A recent study by Moon and Munro (1996) demonstrated that the variability could be reduced by modifying the air irrigator probe to allow greater control of probe placement and direction of air flow within the ear canal. The aim of the present study was to compare the test-retest variability of the modified air technique and the conventional water technique. Twelve normal subjects underwent four full caloric tests: twice with water and twice with air. The results show that it is possible to obtain a similar test-retest variability with the two techniques. The range for canal paresis and directional preponderance are also similar. While further research is required, the modified air technique appears to provide a reliable alternative to the traditional water technique.

Adolescent↗
PubMed1999

Comparison between air and water caloric tests in children.

The caloric test represents an essential part of each procedure evaluating vestibular function. The use of water has many contraindications: tympanic perforation, external otitis and mastoid diseases. Sometimes, nausea can make test execution very difficult. Several authors contributed to the study and diffusion of the caloric test for the evaluation of labyrinthine function using different types of otoalcorimeters. We compared two methods in the child--generally intolerant to the water test--and the results obtained were adapted to a mathematical model of air and water caloric nystagmus. Twenty-seven normal children, aged between 5 and 14 years, subdivided into three age groups (5-7, 8-10 and 11-14 years), underwent the water caloric test (250 cm3 at 31 and 43 degrees C for 40 s) and then the air test, together with another nine subjects undergoing only the air test (flow-rate 8 l/min at 25 and 49 degrees C) on different days. The comparison between the two stimulation methods showed a statistically significant difference (P < 0.002) between maximum slow speed component (max SSC) in degrees per second (degrees/s) of water (4.74 degrees/s) and air (2.98 degrees/s). The results of two caloric tests and the interindividual and intraindividual analysis of our electronystagmographic results are in agreement with the data obtained by other authors in studies on adults. Therefore, notwithstanding the differences between the two stimulation methods, the air caloric test can be applied in a larger number of cases, it is better tolerated and can thus be used even in children for the study of labyrinthine function.

Adolescent↗
PubMed1993

Clinical evaluation of the monothermal caloric test.

The Torok Monothermal Caloric Test has been described as offering a strong advantage over bithermal caloric testing because it can distinguish labyrinthine from retrolabyrinthine lesions. Weak and strong irrigations of room-temperature water are administered to each ear and the ratios of strong to weak nystagmus responses compared to those of normal individuals. Ratios that fall below normal are said to represent decruitment and to denote retrolabyrinthine disease. Ratios that exceed normal are said to represent recruitment and to denote labyrinthine lesions. We attempted to verify the clinical value of the Monothermal Caloric Test by examining patients with known labyrinthine (N = 9) and retrolabyrinthine (N = 25) lesions. Ten patients with dysequilibrium and nonlocalizing testing were also examined. The test was performed exactly as described by the originator. Decruitment was found either unilaterally or bilaterally in 56% of patients with retrolabyrinthine lesions. However, it occurred on the side of the lesion in only 42%. Decruitment was also found in 47% of patients without retrolabyrinthine lesions, including 63% of those with unilateral Meniere's disease. Recruitment was never found on the side of a labyrinthine lesion. A description of the test and a summary of our results are presented. We conclude that the Monothermal Caloric Test is moderately sensitive to the presence of retrolabyrinthine lesions, but lateralizes poorly and is not highly selective. The test was found to be insensitive to the presence of labyrinthine disease.

Caloric Tests↗
PubMed2001

Does high-frequency pseudo-random rotational chair testing increase the diagnostic yield of the eng caloric test in detecting bilateral vestibular loss in the dizzy patient?

OBJECTIVES: To assess the incremental diagnostic yield of testing vestibulo-ocular (VOR) gain with high-frequency pseudo-random rotational chair (PsRRC) over testing with bithermal electronystagmography caloric tests in the dizzy patient, particularly in detecting bilateral vestibular loss. PATIENTS AND METHODS: One hundred ninety-eight patients presenting with dizziness underwent PsRRC and caloric testing. The VOR gain on PsRRC was measured at 0.32 to 5.0 Hz, with gain categorized as normal or decreased. PsRRC results were compared with caloric responses, also categorized as normal, or into graded categories of unilateral or bilateral vestibular loss. RESULTS: Reduced PsRRC gain was found in 29 (15%) patients, and reduced caloric tests responses in 70 (35%), with 25 (13%) having bilateral loss. Of patients with reduced chair gain, 25 of 29 (86%) demonstrated bilateral caloric loss. PsRRC gain was normal in most patients with unilateral caloric weakness, but was decreased in all patients with bilateral caloric weakness. The probability of a patient with completely normal caloric responses having an abnormal rotation chair in this study group was under 1% (1 of 128). CONCLUSIONS: PsRRC testing does not offer much additional diagnostic benefit when caloric responses are normal. It is useful in specific conditions, such as unilateral caloric loss for which the patient is not compensating, borderline caloric loss when traditional water caloric tests cannot be used, or for monitoring progressive bilateral vestibular loss.

Adult↗
PubMedDate not supplied

Influence of age on results of vestibular function tests. Review of literature and presentation of caloric test results.

Following a bibliographic review of currently known, age-dependent morphological and functional changes of the vestibular and auditory system, results are presented of our investigations concerning the influence of age on the outcome of the caloric test on 102 healthy subjects from six age groups ranging between the ages of 11 and 70 years. They prove, without any doubt, that the absolute values of nystagmic parameters in the caloric test are dependent upon age; but not in such a way that the intensity of reaction decreases with advancing age. On the contrary, they indicate that in awake, healthy subjects of middle and late middle-age, the most intensive reactions occur (maximum slow phase velocity, maximum amplitude, maximum frequency, total number of beats). In addition, based on the statistical analysis, it seems probable that the extent of the side difference of excitability depends upon age. Individuals in their middle years show side differences to a considerably lesser degree than children and elderly subjects. These represent findings which, to our knowledge, are reported here for the first time. Provided our results gain further substantiation, standard values for a true quantitative evaluation of the caloric test could only be determined as in the audiometric functional tests on the basis of larger test series of healthy subjects belonging to different age groups.

Adolescent↗