No abstract available.
Caloric Tests*

No abstract available.
Caloric Tests* ; Humans ; Myoclonus* ; Polysomnography*

BACKGROUND AND OBJECTIVES: In caloric test, the CP (canal paresis) value was derived from Jongkees formula. The input parameters of the formula were initially nystagmus duration (seconds), which were replaced later with more stable parameters : slow component velocity (SCV, deg/sec). The nystagmus duration cannot be negative value, but SCV can be, especially in acute vestibular loss with excessive spontaneous nystagmus (SN) which is not overcome by caloric nystagmus. This study aims to investigate the occurrence of negative SCV, to check proper processing of negative SCV values in nystagmography software, and to consider the mathematical significance of CP and negative SCV values. MATERIALS AND METHOD: Tests with negative SCV values were examined in 690 alternate binaural bithermal caloric tests (open loop system). RESULTS: Nine percents (62 of 690 tests) showed negative SCV values. The reported CP was erroneously calculated from debased zero SCV values instead of negative SCV values. The underestimated CP (mean 52.1%, SD 21.8%) can be corrected (mean 80.9%, SD 21.8%) by recalculations with negative SCV values. CONCLUSION: To produce correct CP values in caloric tests, negative values should be properly processed about the SCV value of caloric nystagmus with opposite direction of physiologic response. The mathematical significance of CP was horizontal coordinate of intersection point of the warm line (LW-RW) and cold line (LC-RC) in butterfly pattern calorigram. Detailed description is presented in figures.
Butterflies ; Caloric Tests ; Nystagmus, Physiologic

We investigated normal response of bithermal caloric stimulation after repeated monothermal caloric stimulation. 12 subjects were selected for cold(30degreesC) water stimulation. 8 subjects were stimulated by warm(44degreesC) water. After the bithermal caloric test, caloric stimuli(cold or warm) was repeated 5 times on both ear with a 10 minute time interval and the next bithermal caloric test was performed. Monothermal caloric stimuli was done at the same temperature as the previous test a day later. The bithermal caloric test was repeated after 4 days. We checked the maximum slow phase eye velocity(SPEV) and calculated the canal paresis and directional preponderance. The SEPV was changed from 26.4(+/-10.9) degrees/sec to 26.7(+/-20.5) degrees/sec in repeated warm stimulation; from 25.0(+/-11.4) degrees/sec to 27.3(+/-11.1) degrees/sec in cold stimulation. Canal paresis was changed from 12.4(+/-8.7)% to 6.3(+/-5.1)% in repeated warm water stimulation; from 9.6(+/-9.9)% to 6.9(+/-3.1)% in cold stimuli. Directional preponderance was changed from 11.9(+/-6.9)% to 8.7(+/-9.9)% in warm stimuli; from 11.5(+/-7.6)% to 10.6(+/-5.5)% in cold stimuli. There was no significant change of caloric response after repeated monothermal caloric stimulation.
Caloric Tests ; Ear ; Paresis ; Water

BACKGROUND AND OBJECTIVES: Spontaneous nystagmus may have an influence on the results of sinusoidal harmonic acceleration (SHA) test, although it has not been ascertained through sufficient studies. This study evaluated the effect of spontaneous nystagmus on the gain, asymmetry and phase values of the SHA test. SUBJECTS AND METHOD: We retrospectively analyzed 19 patients with acute unilateral vestibular weakness and spontaneous nystagmus (sn). All patients underwent a battery of vestibular testing including videonystagmography, bithermal caloric test, and SHA test. Gain, asymmetry, and phase were calculated with the conventional method without correcting for sn, thus the non-corrected SHA (nSHA). Then the same three parameters were calculated again after manually correcting for spontaneous nystagmus, thus the corrected SHA (cSHA). The two methods were compared with respect to gain, asymmetry and phase values. Correlation between the SHA test and caloric test was also analyzed. RESULTS: The gain of nSHA was significantly larger than that of cSHA in all frequencies. There was no difference in the phase values between the two analysis methods. The asymmetry of nSHA was 2.8 times larger than that of cSHA. The asymmetry values of both nSHA and cSHA showed a significant correlation between the caloric test and degree of spontaneous nystagmus. CONCLUSION: It seems that the SHA test is significantly influenced by spontaneous nystagmus. Although correcting for spontaneous nystagmus may not always be necessary, we should consider the effect of spontaneous nystagmus when interpreting the SHA test results of a patient who has spontaneous nystagmus.
Acceleration ; Caloric Tests ; Humans ; Retrospective Studies ; Vertigo

BACKGROUND AND OBJECTIVES: The aim of this study was to evaluate the results of high-frequency and high-acceleration rotary chair test in patients with acute unilateral vestibular neuritis. MATERIALS AND METHODS: Twenty-four patients who were diagnosed as acute vestibular neuritis and underwent rotational chair and caloric tests during March 2012 to March 2013 were included. Slow harmonic acceleration (SHA) test was performed at 0.01, 0.04, 0.16, 0.64, 1.28, and 2.00 Hz. Step velocity tests at the peak velocity of 100degrees/sec (low-acceleration) and 240degrees/sec (high-acceleration) were performed. Gains and phases in SHA test and gains and time constants (Tc) in step velocity test were analyzed. RESULTS: In SHA test, decreased gain and phase lead was observed mostly in low frequencies. Gains (phases) at 0.01, 0.04, 0.16, 0.64, 1.28, and 2.00 Hz were 0.2+/-0.1 (62.2+/-15.4), 0.3+/-0.2 (24.5+/-13.0), 0.4+/-0.2 (7.2+/-18.8), 0.5+/-0.1 (7.2+/-11.3), 0.7+/-0.2 (11.0+/-7.5), and 0.8+/-0.3 (4.4+/-14.4), respectively. In step velocity (SV) test, gains stimulating the lesion side were significantly lower than those stimulating the intact side in both low- and high-acceleration SV test (p<0.05) and per-rotatory gain stimulating the lesion side in high-acceleration SV test was significantly lower than that in low-acceleration SV test. Tc stimulating the lesion side were significantly shorter than those stimulating the intact side in low- acceleration SV test (p<0.05) but not in high-acceleration SV test. Per- and post-rotatory Tc in high-acceleration SV test stimulating the intact side was significantly lower than those in low-acceleration SV test (p<0.05). CONCLUSION: At high-frequency SHA test, gain was pretty normal and phase lead was observed in some patients. High-acceleration SV test showed shortened Tc regardless of the sides, suggesting that high-acceleration SV test can reveal the impaired velocity storage system in patients with vestibular neuritis more frequently than low-acceleration SV test.
Acceleration ; Caloric Tests ; Humans ; Vestibular Neuronitis

OBJECTIVE: Spontaneous nystagmus is typical sign in vestibular neuronitis. However, the clinical significance of spontaneous nystagmus frequency remains unclear. The aim of this study is to analyze the spontaneous nystagmus frequency in patients with vestibular neuronitis. METHODS: Twenty-five patients with vestibular neuronitis were included. Patients were divided good (≥20%) and poor (<20%) group according to change of spontanous nystagmus frequency. Frequency and velocity of spontaneous nystagmus were analyzed by using video-nystagmography. Caloric test and slow harmonic acceleration test were also performed. RESULTS: There was a positive linear correlation between frequency and velocity in initial and follow test (R2=0.51, 0.43, p<0.01, p<0.01). Also, there was a strong positive linear correlation betweeng change of frequency and change of velocity (R2=0.64, p<0.01). The phase lead of slow harmonic acceleration test of good group was smaller compared with poor group, and this was statistically significant in 0.04 Hz. CONCLUSION: We suggested that frequency of spontaneous nystagmus may be a useful clinical factor in vestibular neuronitis.
Acceleration ; Caloric Tests ; Humans ; Vestibular Neuronitis

BACKGROUND AND OBJECTIVES: There are caloric test, SCEP, DP in Step velocity and VOR asymmetry in SHA test as parameters for evaluation in unilateral peripheral vestibulopathy in parameter of vestibular function test. The aim of this study is to assess the correlation between these parameters and intensity of spontaneous nystagmus in vestibular neuritis. MATERIALS AND METHOD: We evaluated 75 patients who were diagnosed as vestibular neuritis with 3 degree spontaneous nystagmus at vestibular function test lab from January 2000 to July 2005 in Dankook university hospital. The correlations between direction and intensity of spontaneous nystagmus and monothermal caloric test, SCEP and DP in step velocity, VOR asymmetry (0.01, 0.04, 0.16 Hz) in SHA test were analysed. And correlations according to sex, age were also analysed. RESULTS: The correlation coefficient between intensity of spontaneous nystagmus and monothermal caloric test was 0.60. The correlation coefficient between intensity of spontaneous nystagmus and SCEP was 0.35. The correlation coefficient between intensity of spontaneous nystagmus and Tc DP was 0.36 and it showed no significant correlation. The correlation coefficient between intensity of spontaneous nystagmus and VOR asymmetry (0.01, 0.04, 0.16) was 0.57, 0.46, 0.51, respectively and there was higher correlation in man, age under 60. CONCLUSION: Intensity of spontaneous nystagmus showed close relations to monothermal caloric test, VOR asymmetry of SHA, Tc DP, SCEP DP in sequence. In addition, young male patients tends to be closely related to intensity of spontaneous nystagmus.
Caloric Tests ; Humans ; Male ; Vestibular Function Tests* ; Vestibular Neuronitis*

BACKGROUND AND OBJECTIVES: here have been some studies on the influence of age on the results of vestibular function tests with conflicting results. In influence of age on the results of caloric test, we investigated the sensation of dizziness during caloric test by drawing a correlation between the direction of rotatory sensation and the direction of nystagmus. MATERIALS AND METHODS: We performed monothermal caloric test on 44 healthy adults and divided them into six age groups ranging from 16 and 67. RESULTS: During the test with eyes-closed, 80.23% of patients reported a sensation of self-rotation. Of those, 55.81% expressed the direction of rotation to be the same as that of the fast component of nystagmus, whereas 24.42% expressed the direction to be the same as that of the slow component of nystagmus. During caloric test with eyes-open in light, 59.30% reported a sensation that their surroundings rotated around them. Of those, 43.02% expressed the direction of rotatory sensation to be the same as that of the fast component of nystagmus, whereas 16.28% expressed the direction to be the same as that of the slow component of nystagmus. During caloric test with eyes-closed, most of the subjects felt themselves rotating, whereas most of the subjects felt the outside world were rotating in tests with eyes-open in the light. CONCLUSION: Nystagmus parameters (latency, duration, SPEV at eyes-open and at eyes-closed, visual suppression) did not result in significant differences among different age groups: therefore, we conclude that age doesn't influence the results of caloric tests.
Adult ; Caloric Tests* ; Dizziness* ; Humans ; Sensation* ; Vestibular Function Tests

BACKGROUND: In general, it is well known that dizzy patients show a remarkable ability to compensate for the loss of peripheral vestubular function. When the patient had decreased response to caloric stimulation and showed no symptoms of vestibular dysfunction, we thought that was a compensated state of unilateral peripheral vestibular loss. OBJECTIVES: The purpose of this study is to provide the basic data for analysis of findings of further rotatory chair test through analyzing the results of rotation test of unilateral peripheral vestibular loss patients. MATERIALS AND METHODS: We analysed the findings of rotatory chair test and clinical manifestations of 24 cases of unilateral vestublar loss which didn't show any symptoms of vestibular dysfunction and they were confirmed by bithermal caloric test and Kobrak's ice water test. RESULTS: We could find that phase lead, low gain and asymmetry could persist despite of chronic compensated state and these findings were relatively common in patients with nonspecific vestibular symptoms. CONCLUSION: Abnornal phase lead and decreased gain were observed in the compensated unilateral vestibular loss patients who showed nonspecific symptoms including oscillopsia, vague unsteadiness. We thought that their compensation was not completely perfect and SHA test was a good tool which detect the minor degree of vestibular dysfunction. We have to consider the past history and nonspecific symptoms of patients through precise history taking. Frequency of SHA test is slower than that of normal human movement and this status is not a real physiologic condition, so it would be advisable to consider the results of other vestibular function tests for precise evaluation the degree of compensation, and the serial check is also recommended.
Caloric Tests ; Compensation and Redress ; Humans ; Ice ; Vestibular Function Tests ; Water