Air Caloric Test Research Articles

Multifrekvenční testování pacientů po akutním izolovaném vestibulárním deficitu

Summary Introduction: Acute unilateral vestibulopathy (AUVP) is defined as an acute peripheral vestibular syndrome without evidence of central neurological or audiological symptoms. Currently, there is no uniform instrumental testing protocol for the diagnosis and follow-up of patients with AUVP. Vestibular tests provide information in different frequency bands of the vestibuloocular reflex (VOR); therefore, the aim of our study is to evaluate the contribution of multifrequency VOR testing in the evaluation of patients with AUVP. Methods: 22 patients (9 females and 13 males) with a diagnosis of AUVP were prospectively examined. Multifrequency testing included spontaneous nystagmus with visual fixation cancellation (SPN), Head Shaking Test (HST), bithermal air caloric test, and video Head Impulse Test (vHIT). The first examination was performed within one week of AUVP; follow-up examinations were performed 3 and 6 months apart. On the third examination, the Dizziness handicap inventory (DHI) questionnaire was completed. Results: The rate of the slow component of spontaneous and induced nystagmus during HST and the values of unilateral weakness (UW) during caloric testing decreased during follow-up with a statistically significant difference (P <0.05) between both the first and second and between the second and third examinations. On vHIT, there was a statistically significant increase in the gains of individual channels during follow-up. Dissociation of vHIT and caloric test results was found in 22.73% of patients on the second and 18.18% of patients on the third examination. There was a statistically significant difference in the changes in test results of patients with different DHI. Conclusion: Multifrequency VOR testing provides a comprehensive overview of the status of vestibular function, recovery dynamics, and clinical impact of residual vestibular dysfunction after AUVP. Key words acute unilateral vestibulopathy – vestibuloocular reflex – video Head Impulse Test – caloric test – spontaneous nystagmus – Head Shaking Test

Kanıtlanmış Vestibüler ve İşitme Kaybı olan Meniere Hastalarında Supresyon Baş Savurma Paradigması (SHIMP) ve Video Baş Savurma Testinin (vHIT) Değerlendirilmesi

This study aimed to examine the results of the video head impulse test (vHIT), and suppression head impulse paradigm (SHIMP) in adult diagnosed with definite Meniere’s disease (MD). This study was conducted with 20 patients aged 18-45 years with canal paresis and sensorineural type hearing loss in symptomatic ears, who were diagnosed with unilateral definite MD. The subjects were assessed with conventional audiometry (0.125–8 kHz), the bithermal binaural air caloric test, vHIT, and SHIMP. The mean SHIMP vestibulo-ocular reflex (S-VOR) gain of the MD side was 0.69, and that of the healthy side was 0.77. The S-VOR gain values were statistically lower than the mean vHIT VOR gain (V-VOR) values on both sides (p<0.001). There was no significant difference between the MD and healthy sides in terms of the anti-compensatory saccades (ACSs) latency and amplitude and S-VOR gain (p>0.05). In the MD group, the vHIT results were abnormal in 35% (7/20 ears) of the ears, and the SHIMP results were abnormal in 50% (10/20 ears). On the healthy side, the vHIT results were abnormal in 10% (2/20 ears) of the ears, and the SHIMP results were abnormal in 35% (7/20 ears). In this study, the V-VOR and S-VOR gains, vHIT saccades, SHIMP saccade latency, and SHIMP saccade amplitude were not found to be beneficial parameters in differentiating affected and healthy ears in the patients with MD. In other words, contrary to expectations, vHIT and SHIMP tests were not sufficient to detect pathological involvement in Meniere's disease.

Audio-vestibular and radiological analysis in Meniere’s disease

ObjectiveIntravenous gadolinium-enhanced inner ear magnetic resonance imaging (IV Gd-enhanced inner ear MRI) is a new technique for diagnosing Meniere’s disease (MD). Vestibular tests have also long been used for MD, but which tests should be included in the oto-neurological test battery remains controversial. The evaluation method to be used to confirm the clinical diagnosis in MD is not clear. This study aimed to examine the results of vestibular tests and IV Gd-enhanced inner ear MRI in individuals diagnosed with unilateral definite Meniere's disease. MethodsIV Gd-enhanced inner ear MRI (Endolymphatic Hydrops [EH] and Perilymphatic Enhancement [PE]), conventional audiometry (0.25–8 kHz), video Head Impulse Test (vHIT), cervical Vestibular Evoked Myogenic Potential (cVEMP), air caloric test, and dizziness handicap inventory were applied to 16 adult patients diagnosed with unilateral definite MD. ResultsAmong the patients with definite MD, EH (cochlear and/or vestibular) was identified in 93.7% and 68.7% of the symptomatic and the asymptomatic ears, respectively. There was a positive correlation between the hearing thresholds at 2, 4, 6 and 8 kHz and the degree of cochlear EH (p < 0.05). PE (cochlear and/or vestibular) was observed in 37.5% of the asymptomatic and symptomatic ears. The sensitivity of the vestibular test battery (vHIT, cVEMP, and caloric test) was 100% and its specificity was 50%, while the sensitivity of the IV Gd-enhanced inner ear MRI (EH and PE together) was 93.8% and the specificity was 81.3%. ConclusionMRI had higher sensitivity and specificity than the vestibular test battery. PE or vHIT alone was not considered to be reliable in the diagnosis of MD. In suspected MD, the clinical history, hearing tests, and IV Gd-enhanced inner ear MRI are sufficient for diagnosis. If MRI technique is not possible, vestibular tests (caloric test and cVEMP, not vHIT) can provide reliable results when evaluated together.

Comparison between caloric and video-head impulse tests in Ménière’s disease and vestibular neuritis

Objective To compare the diagnostic accuracies of air caloric testing with electronystagmography and the vHIT (video-head impulse test). Design Prospective, controlled study. Study sample MD (Ménière’s disease), 26; vestibular neuritis, 27; control, 56. Results In MD, CP (canal paresis) was pathological in 88.5%, the GA (gain asymmetry) on vHIT was pathological in 65.3%, and the gain was abnormal in only one patient. The GA and CP, were significantly higher in the MD group than in the control group, indicating hypofunction of the horizontal canals in MD, whereas a hyperfunction may also occur. No correlation was observed between the results of the two tests for evaluating MD, suggesting that pathological outcomes of one test do not guarantee abnormalities on the other test. For vestibular neuritis, significantly higher CP (96.3%), GA (81.5%), and gain (51.9%) values were detected. A correlation was identified between the two tests for vestibular neuritis, indicating a similar diagnostic efficiency. The higher percentage of pathological GA versus pathological gain values indicates that the asymmetry may be more informative. Conclusions The vHIT showed a higher specificity, whereas the caloric test a higher sensitivity. No correlation between the two methods was observed; therefore, the tests appear to provide complementary information.

Evaluation of the vestibular system in individuals with presbycusis using video head impulse test and videonystagmography

Background Vestibulo-ocular reflex (VOR) function is expected to be normal in patients with presbycusis during sudden head rotations. Aim This study aimed to determine whether presbycusis was accompanied by vestibular system pathologies. In addition, it was examined whether there was a difference existed between the patients with and without presbycusis in terms of normative data. Materials and Methods A total of 40 individuals were included in the study: 20 in the presbycusis group and 20 in the control group. The vestibular systems of both groups were evaluated using the video head impulse test and videonystagmography. Results The right and left lateral VOR gain values were decreased in the group with presbycusis compared to the control group. The difference between the two groups in the mean VOR gains in the right lateral canal and left lateral canal were statistically significant (p = .040 and p = .050, respectively). The air caloric tests of all individuals were found to be normal. Conclusions This result suggests that the loss of vestibular hair cells and vestibular nerve degeneration in the lateral semicircular canal may be more severe in presbycusis than in the same age group with normal hearing.

Perioperative vestibular assessment and testing

Vestibular disorders can be difficult to accurately diagnose and manage. A careful history and focused physical examination are typically adequate to establish a diagnosis and initiate medical treatment. Vestibular testing is an important component of the work-up, but it is particularly essential for patients being considered for surgical intervention for a vestibular disorder, where the testing can be used to more definitively confirm a suspected diagnosis and to determine baseline vestibular organ function. In this article, we will first briefly review key components of the history and physical examination of patients with vestibular complaints. We will then discuss the most commonly used vestibular tests and their role in the preoperative assessment of patients undergoing vestibular surgery, including nystagmography, caloric testing, rotary chair testing, video head impulse testing, and vestibular evoked myogenic potential testing.

Clinical comparative study of caloric test with water or air in healthyindividuals and diagnosing study on air caloric test

Objective:To explore the equivalence of the test results of the water or air caloric tests and the compliance of the test in the healthy individuals. To provide scientific basis for clinical standardization of caloric test.Method: Randomized crossover clinical trial, 60 healthy individuals were divided into group A and group B. Water caloric test was carried out first in group A, and air caloric test was carried out after elution effect(one day interval). The treatment of group B was opposite to group A. SPV(Slow Phase Velocity), CP(canal paralysis) and SPV and CP' s 95%CI were used as evaluation indexes to analyze the equivalence of water and air caloric test in healthy people and the clinical normal reference value and stability and compliance of the water and air caloric test. Result: ①60 cases of caloric test CP value of chi square test suggested that there was no statistical difference between two kinds of media in the examination of the vestibular function of healthy individuals, and the CP value of the two was 85%(51/60). ②the SPV value of the was obviously higher than that of the air caloric test. The SPV value at each temperature of the water caloric test stimulation is quite different from the air caloric test stimulation. ③The range of water caloric test stimulation CP 95%CI was 8%-12%, and the average value was 10%. The interval of air caloric test stimulation CP 95%CI was 10%-15% and the average value was 12%. ④This study provided the corresponding SPV 95%CI as the medical reference values. ⑤The subjects of 98.33%(59/60) of the questionnaire survey selecting air caloric test and the results of the observation indicated that the duration of the air caloric test was shorter and more comfortable. Conclusion: ①Air caloric test can satisfied the needs of clinical assessment of horizontal semicircular canal function, and can make patients feel more comfortable. However, due to the weak intensity of nystagmus, water caloric test has to be used when the SPV value is too low. ②In this study, the upper limit of the CP value of the air caloric test in healthy individuals was 0.21, which is quite different from the upper limit of the standard value was 0.25 of the water caloric test. Therefore, the laboratory should establish their own reference value of the laboratory caloric test, and should not blindly apply the standard value of the water caloric test as the standard of the hemiplegia of the unilateral semicircular canal. The results of this study suggest that air caloric test can be used instead of water caloric test in clinic. And if the patient has no contraindications, air caloric test can be used as a priority.

Distinct activation of the sympathetic adreno-medullar system and hypothalamus pituitary adrenal axis following the caloric vestibular test in healthy subjects.

IntroductionThe vestibular acute stress induces reversible alert-like reactions that involve the sympathetic adrenal-medullar system and hypothalamic-pituitary-adrenal axis responses. The present study aimed to evaluate salivary α-amylase and salivary cortisol production in relation with cardiovascular reactivity induced by acute stress in healthy subjects.Material and methodsForty-eight young healthy male volunteers were examined under basal conditions and at various times after reaching the maximal nystagmic reaction following air caloric vestibular test. Heart rate, systolic blood pressure, diastolic blood pressure and mean arterial pressure were recorded at the same time as measurement of the salivary α-amylase and salivary cortisol. At the end of the caloric vestibular test session, perceived stress scale questionnaires were administered to measure the self-perceived stress impact induced by the task, and individual scores were compared with those measured on the enrollment day.ResultsFollowing caloric vestibular test-evoked vertigo, salivary α-amylase and cortisol showed distinct trends in their production after acute stress: Student’s t-test was used to compare the α-amylase vs cortisol slopes of the respective interpolated regression lines, and the difference was significant (t = -3.283; p<0.001); an increase in salivary cortisol production corresponded with a decrease in the salivary α-amylase concentration. In addition, salivary biomarker modifications were associated with consistent changes in the heart rate, systolic blood pressure and mean arterial pressure.ConclusionsUsing the air caloric vestibular test task as a stressor, the present study demonstrated a connection between the acute hormonal stress response to vestibular stimulation and cardiovascular output. However, further research is needed before we can define the potential importance of the consistent cardiovascular activity changes evoked by vestibular stimulation and the possible functional consequences for cardiovascular regulation and orthostatic tolerance in humans.

Effects of cavity reconstruction on morbidity and quality of life after canal wall down tympanomastoidectomy.

IntroductionCanal wall down tympanomastoidectomy is commonly used to treat advanced chronic otitis media or cholesteatoma. The advantages of canal wall down mastoidectomy are excellent exposure for disease eradication and postoperative control of residual disease; its disadvantages include the accumulation of debris requiring life-long otological maintenance and cleaning, continuous ear drainage, fungal cavity infections, and the occurrence of dizziness and vertigo by changing temperature or pressure.ObjectiveTo evaluate whether cavity-induced problems can be eliminated and patient comfort can be increased with mastoid cavity reconstruction.MethodsIn total, 11 patients who underwent mastoid cavity reconstruction between March 2013 and June 2013 comprised the study group, and 11 patients who had dry, epithelialized CWD cavities were recruited as the control group. The study examined three parameters: epithelial migration, air caloric testing, and the Glasgow Benefit Inventory. Epithelial migration, air caloric testing, and the Glasgow Benefit Inventory were evaluated in the study and control groups.ResultsThe epithelial migration rate was significantly faster in study group (1.63 ± 0.5 mm/week) than control group (0.94 ± 0.37 mm/week) (p = 0.003, p < 0.05). The mean slow component velocity of nystagmus of the study group (13.33 ± 5.36°/s) was significantly lower when compared to control group (32.11 ± 9.12°/s) (p = 0.018). The overall the Glasgow Benefit Inventory score was −7.21, and the general subscale, physical and social health scores were −9.71, −21.09, and +20.35, respectively in the control group. These were +33.93, +35.59, +33.31, and +29.61, respectively in the study group. All but the social health score improved significantly (0.007, 0.008, 0.018, and 0.181, respectively).ConclusionsCavity reconstruction improves epithelial migration, normalizes caloric responses and increases the quality of life. Thus, cavity rehabilitation eliminates open-cavity-induced problems by restoring the functional anatomy of the ear.

Compensated Vestibular Dysfunction Post Cochlear Implantation in Children with Sensorineural Hearing Loss: A Prospective Study

Children with sensorineural hearing loss have risk of surgically induced vestibular dysfunction post cochlear implantation due to instrumentation. It is clinically important to estimate the risk of vestibular loss post cochlear implant so the patient can be made fully aware of these risks when considering cochlear implantation. The aim of the study was to identify compensated vestibular dysfunction post cochlear implantation. Vestibular function was evaluated both pre and post CI using monothermal warm air caloric testing. Recordings were made using head band camera on SYNAPSYS Ulmer VNG software. 'Monothermal caloric asymmetry' (MCA) was depicted as 'unilateral weakness' based on the slow phase velocity of nystagmus. MCA of >15% was taken as evidence of canal paresis. The incidence of compensated vestibular dysfunction post CI surgery was found to be 16.66%. The results were statistically significant (p value 0.02) and indicated worsening of canal paresis indicative of vestibular dysfunction. Children for cochlear implantation should undergo evaluation of their vestibular system pre and post surgery. Caution should be exercised before planning bilateral cochlear implantation in the same sitting.

Vestibular dysfunction in children with sensorineural hearing loss: A cross-sectional study

Introduction: The cochlea and vestibule are anatomically and functionally related to each other and any dysfunction in each or both of them may result in vestibular functional derangement and subsequent deficit in the function of balance. This is especially true in children where the two systems are still evolving. Vestibular dysfunction has been reported in approximately 20-70 % of children with hearing loss of different causes. This study was aimed to detect and evaluate the prevalence of vestibular dysfunction in children with SNHL. Methods and Materials: Vestibular function assessment was done with monothermal warm air caloric test on 50 children less than 12 years of age with bilateral severe to profound SNHL. Recordings were made using a head band camera on SYNAPSYS Ulmer VNG software. “Monothermal Caloric Asymmetry” (MCA) was depicted in the recording software as unilateral weakness. MCA of >15 % was taken as evidence of canal paresis. Results: The mean age of the children was 5.48 years. Of the 48 children who successfully completed the test, 09 children had vestibular dysfunction indicative of canal paresis. Prevalence was 18.75 % with 95% CI (7.3, 30.2). Correlation between compensated vestibular function results with age and severity of SNHL was not significant. Conclusions: Children with SNHL should be evaluated for occult compensated vestibular dysfunction. It may also be relevant in the context of any further vestibular pathology the child may develop and should be kept in mind when surgical procedures like cochlear implantation are being contemplated.

From nystagmus to the air and water caloric tests

The caloric test is an important tool for the assessment of labyrinthine function.Objective: To compare the nystagmus response in the caloric tests with air at 50°C and 24°C and with water at 44°C and 30°C. Study Design: Randomized crossover clinical trial.Materials and Methods: 40 healthy individuals were submitted to a neurotological evaluation, including caloric tests with air at 50°C and 24°C and water at 44°C and 30°C.Results: Comparing the air and water caloric tests, there were no significant differences among the post-caloric nystagmus slow-phase velocity in relation to the stimulation order, between ears and between the values of unilateral weakness and directional preponderance. The slow-phase velocity values were higher with water (p = 0.008, p < 0.001), and cold stimulation produced stronger responses (p < 0.001).Conclusion: Comparing 50°C and 24°C air caloric test and 44°C and 30°C water caloric test, we observed similar slow-phase velocity values for both ears, higher responses in the cold temperature and in the test with water, and similar results of unilateral weakness or directional preponderance for post-caloric nystagmus in both tests.

The air caloric test and its normal values.

The air caloric test and its normal values.

A study of the relationship between the video head impulse test and air calorics.

The video head impulse test (vHIT) has been proposed as an objective approach to detect peripheral vestibular disorder in a clinical setting. Data from several studies indicate that the vHIT is a useful addition to the vestibular test battery and can give complementary information to caloric testing. This study explores the relationship between lateral canal vestibular occular reflex gain measured using the vHIT system and canal paresis indicated using air calorics in a sample of patients attending a clinic for balance disorder. Sensitivity and specificity of the vHIT test relative to calorics was studied for a clinical sample of 51 patients (20 male, 31 female) who attended a private clinic for balance disorders. vHIT gains were compared to the manufacturer's normative range and to data from a normative study using 30 young volunteers. Of 14 patients in the clinical sample that had significant canal paresis indicated by air calorics, only 4 showed a significant abnormality in either canal using a measurement of vHIT gain. vHIT gain does not correlate with canal paresis as indicated by air caloric testing. vHIT gain appears relatively insensitive to peripheral vestibular disorder as indicated by air caloric testing, although patients that had no caloric response on one side showed abnormal vHIT gain. vHIT testing may be a useful addition to the existing vestibular test battery, but it does not appear to be an alternative to it.

末梢前庭機能評価の観点からみた振子様手動回転による前庭眼反射検査の有用性

This study included 209 patients with vertigo of various causes who underwent both manually rotated vestibulo-ocular reflex (VOR) testing and bithermal air caloric testing at our hospital from January 2009 to July 2012. The VOR directional predominance (VOR-DP%) values in the 79 patients with greater than 30% caloric canal paresis (CP) were significantly higher than those in the 43 normal subjects. On the other hand, the VOR-DP% values in 81% of patients with CP were within normal limits, as those in the 43 normal subjects varied widely (the normal range is considered to be wide). In all of the vertiginous cases, the VOR-DP% values showed only a slight correlation with the CP% values. However, the VOR-DP% was well-correlated with the CP% in patients with vestibular neuritis, Hunt syndrome and sudden deafness with vertigo, especially in the acute stage within 2 weeks of the onset. The VOR-DP% values in these latter patients with vestibular neuritis, Hunt syndrome and sudden deafness with vertigo decreased with time, regardless of the presence or absence of recovery from CP. Manually rotated VOR testing is thought to be one of the useful tools in daily clinical practice, that allows estimation of both peripheral vestibular function and the degree of recovery from imbalance in patients with acute unilateral peripheral vestibular deficit.

Analysis of auditory and vestibular function in patients with unilateral Meniere's disease

Conclusion: The percentage of the unilateral weakness of the caloric response also reflects the clinical progress of Meniere's disease (MD), including clinical hearing loss. Objective: To evaluate the relationship between hearing status and vestibular function in patients with MD. Methods: Seventy-nine patients with unilateral definite MD underwent bithermal air caloric testing, vestibular evoked myogenic potential (VEMP) testing, and pure tone audiometry (PTA). The stages of the disease, clinical hearing level of the diseased ears, and dPTA (the difference in hearing level between ears in each patient) were compared with the percentage of the unilateral weakness of the caloric response and the interaural amplitude difference (IAD) ratio of the VEMP response. Results: Twenty ears (25.3%) revealed normal caloric responses and 59 ears (74.7%) showed reduced caloric responses. Testing revealed that the VEMPs were normal in 49 ears (62%), while 30 ears (38%) had abnormal VEMPs. The percentage of the unilateral weakness of the caloric response was positively correlated with the clinical hearing level of the diseased ears (p = 0.006) and the dPTA (p = 0.013).

Effect of transtympanic low-pressure therapy in patients with unilateral Menière's disease unresponsive to betahistine: a randomised, placebo-controlled, double-blinded, clinical trial

To determine the effect of the Meniett low-pressure generator on the subjective symptoms and audiovestibular disease markers of patients with unilateral Menière's disease unresponsive to betahistine treatment. Randomised, placebo-controlled, double-blinded, clinical trial at a tertiary referral centre. After ventilation tube placement, patients were randomised to the active treatment or placebo group. Monitoring comprised audiometry and air caloric testing and a vertigo diary (enabling calculation of vertigo and activity scores, and the number of vertigo days, vertigo-free days and sick days). Sixty-eight patients completed the study. For the active treatment versus placebo group, the following pre- and post-treatment values, and significances for treatment effect comparisons, were respectively seen: cumulative vertigo scores, 22.47 and 15.97 vs 20.42 and 19.23 (p = 0.048); vertigo days, 6.5 and 4.08 vs 5.94 and 5.52 (p = 0.102); sick days, 3.08 and 0.78 vs 2.87 and 3.45 (p = 0.041); vertigo-free days, 14.47 and 17.61 vs 15.48 and 17.58 (p = 0.362); activity score, 23.61 and 13.42 vs 24.68 and 20.23 (p = 0.078); low-tone hearing threshold, 49.15 and 53.18 dB nHL vs 41.66 and 46.10 dB nHL (p > 0.05); and slow phase velocity in response to caloric stimulation, 18.86 and 18.72 °/second vs 14.97 and 15.95 °/second, (p > 0.05). Use of the Meniett low-pressure generator improved patients' vertigo but not their hearing or vestibular function. This safe, minimally invasive treatment is recommended as second-line treatment for unilateral Menière's disease.

Reversible cochlear disorders with normal vestibular functions in three cases with Wegener's granulomatosis

Patients with Wegener's granulomatosis (WG) often suffer from hearing loss, but its precise mechanisms have not been well understood. We experienced 3 WG cases whose initial symptoms were bilateral progressive mixed (both conductive and sensorineural) hearing loss, followed by systemic symptoms one year later. They were diagnosed as WG based on positive serology of anti-neutrophil cytoplasmic antibodies (ANCAs) and pathologic findings of affected lesions in addition to systemic symptoms. Although they were different in the type of ANCAs and systemic lesions, all showed considerably reversible cochlear disorders with normal vestibular functions. Moreover, their initial otologic manifestations shared same characteristic features, (1) thick ear drums with pulsatile serous intratympanic effusion, (2) poor speech discrimination ability, and (3) steroid-dependent changes of hearing levels (HLs). They exhibited no significant vestibular abnormalities in chair vestibule-ocular reflex (VOR) testing and cold air caloric tests even when they had severe hearing loss. On the basis of these results, we hypothesized that vasculitis of stria vascularis which generates endocochlear potential might cause these reversible cochlear-specific dysfunctions.

Results of Air Caloric and Other Vestibular Tests in Patients with Chronic Otitis Media

ObjectivesAir caloric results are supposed to be influenced by anatomic changes of the middle ear. The aims of our study were to evaluate the incidence and characteristics of abnormal air caloric results in patients with unilateral chronic otitis media and without any history of vertigo, and to compare caloric results with there of other vestibular function tests (VFTs).MethodsTwenty five patients with unilateral chronic otitis media (COM) who were scheduled for surgery underwent VFTs preoperatively. Hearing was assessed using pure-tone audiometry and vestibular function was assessed using a set of VFTs: air caloric, head-shaking nystagmus (HSN), vibration-induced nystagmus (VIN), and subjective visual vertical (SVV) tests.ResultsSix patients (24%) showed pathologic canal paresis (CP) on COM-sided ears. Two patients showed pathologic CP on the contralateral side. However, both of the two showed inverted nystagmus to warm air stimulation on the COM-side and hyperactive nystagmus to cold air stimulation on the COM-side, which means that the COM-sided ear was stimulated too much. There was pathologic HSN in 12 patients (48%), pathologic VIN in 7 (28%), and pathologic SVV in 5 (20%). Overall, 20 (80%) patients showed abnormal findings through a set of VFTs. Patients with an interaural difference of bone-conduction hearing thresholds ≥10 dB tended to show more abnormal VFT results than those for whom the interaural difference of bone-conduction hearing thresholds was <10 dB.ConclusionOur data show that one-fourth of patients with unilateral COM show abnormal caloric results on the COM side. However, subclinical latent vestibular imbalances were found to be common, which might be related to the gradual vestibular involvement in inflammatory processes, regardless of the caloric results. Results of a set of VFTs should be referred to when determining vestibular imbalance in patients with COM.

A Comparison of Water and Air Caloric Responses and Their Ability to Distinguish Between Patients with Normal and Impaired Ears

The caloric test is a mainstay of modern vestibular assessment. Yet caloric test methods have not been well standardized, and normal response values have not been universally agreed upon. The air caloric test has been particularly problematic. In this article, we present our efforts to establish a population-based description of the caloric response evoked by water and air stimuli at both cool and warm temperatures. Data were collected from a retrospective record review of patients who underwent caloric testing at Mayo Clinic Jacksonville between 2002 and 2006. Two subgroups were identified. One group was found to have no vestibulopathy after comprehensive medical investigation. The second group was found to have severe bilateral vestibular weakness; this diagnosis was based on medical evaluation and objective test results. Caloric response distributions and associated probability estimates were developed from each group. A total of 2587 medical records were found to contain caloric response data. Of these, 693 patients met the criteria to be classified as having no identifiable vestibulopathy (otologically normal patients with normal caloric responses). Sixty-eight patients met the criteria for bilateral vestibular weakness (reduced or absent rotatory chair responses). Our analysis yielded the following results: (1) there were differences between nystagmus distributions across stimuli. On average, the magnitude of cool water (30 degrees C) maximum slow-phase velocities was smaller than those from warm water (44 degrees C). Maximum slow-phase velocity distributions from cool (21 degrees C) and warm (51 degrees C) air stimuli were more similar to each other than were responses to water stimuli and fell between the water distributions. (2) Combined metrics (combined eye speed and total eye speed) were comparable for water and air stimuli. (3) Response distributions from otologically normal patients were different from those of patients with bilateral vestibular weakness. (4) Derived probability estimates allowed for quantification of caloric response normal limits, sensitivity, specificity, and error rates. Current bithermal test methods assume an equivalence of caloric response strength from warm and cool stimuli. Our results show standard cool and warm water stimuli provoke substantially different response magnitudes, with warm stimuli provoking stronger responses. When calibrated as described herein, air stimuli perform comparably with water stimuli for bithermal caloric test purposes, with more uniform and less variable response distributions. Both air- and water-based tests were able to distinguish between normal and abnormally weak ears with sensitivity and specificity values between 0.82 and 0.84. We advocate for the calibration of all caloric stimuli based on the test's statistical performance and not arbitrary assumptions about stimulus equivalence.