Galvanic Nystagmus in Normal Person

BACKGROUND AND OBJECTIVES: Vestibulo-ocular reflex and vestibulo-spinal reflex are induced by transmatoid galvanic stimulation of vestibular system. Nystagmus and body sway are result of each reflex. Recently, videooculograph possible to record a minute ocular movement was commonly used, vestibulo-ocular reflex induced by galvanic simualtion is easily documented. The purposes of this study are to evaluate the galvanic nystagmus in nomal persons in order to better understand the physiology of the vestibular system. MATERIALS AND METHODS: Eye movement of 20 neurootologic normal subjects by both side transmstoid galvanic stimulation (40cases) were analyzing by videonystagmography. RESULT: The direction of nystagmus in fast phase was to the negative electrode. Galvanic nystagmus was occured all normal subjects when stimulus intensity was more than 2mA. There was positive correlation between slow phase velocity(SPV) and electric current but negative correlation was noted between asymmery of SPV and electric current. CONCLUSION: It is suggested that the galvanic nystagmus test could be a new diagnostic tool for evaluation of vestibular status.

Vestibular rehabilitation in incompletely compensated acute unilateral vestibular loss / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Vestibular rehabilitation has been recommended as the treatment of choice for patients with persisting dizziness due to vestibular dysfunction, since surgery is seldom appropriate and the available pharmacological treatments are not curative and can have undesirable side-effects. This study investigated the effects f vestibular rehabilitation therapy on recovery following acute unilateral vestibular loss. MATERIALS AND METHODS: Twenty-four patients were randomly assigned to two groups of either with-treatment or without treatment. The outcome measures included equilibrium scores in dynamic posturography, motion sensitivity quotient (MSQ), and dizziness handicap inventory (DHI). RESULTS: When individual comparison measures were compared, equilibrium score results at the end of the 8-week treatment period revealed improvement of postural control in the group who received vestibular rehabilitation therapy. The DHI and MSQ results revealed less motion sensitivity and dizziness handicap, but not the acquired statistical significance compared with the non-treatment group. CONCLUSION: This results suggest that after acute unilateral vestibular loss, most patients can effectively utilize the central compensation mechanisms to recover from such an injury, but the vestibular rehabilitation therapy could provide a more rapid and complete recovery for these patients.

Clinical Significance of Saccade Abnormalities / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The saccadic eye movement means rapid eye movement in order to fixate an intended target with fovea. Frontal lobe, brain stem and paramedian pontine reticular formation operate the saccade movement in the central nervous system. Although saccadic abnormalities were usually seen in the CNS lesion(most commonly in the cerebellar lesion) some normal individuals consistently undershoot or overshoot the target(corrective saccade). Because there are several possibilities for serious error when interpreting the saccade test, clinical usefulness of saccade test may be uncertain. We study the saccade movement in out dizzy patients to find out the definite usefulness of saccadic abnormality and cause of dizziness according to the saccadic abnormalities. MATERIAL AND METHOD: For 4 years, 1994.1.-1997.12, 53 patients showed saccade abnormalities and they were classified into 5 categories-undershoot, overshoot, slow velocity of saccade, impaired saccade and fail of saccade. Spontaneous nystagmus, gaze nystagmus, pursuit test and optokinetic test were also performed. We analyzed the cause of saccade abnormality and other associated eye movement disorders. RESULTS: Almost all saccade abnormalities were seen in central disease(71%), but some could be seen in specific cases of peripheral disease(11%) and in other conditions(18%). In peripheral lesion, only saccade undershoot was seen without other abnormal eye movement. In central lesion, all kinds of saccade movement were seen with or without other abnormal eye movement disorders, but there was no correlation between the sites of lesion and types of saccade. Spontaneous nystagmus was seen in 6 patients, but there was no correlation between the causes of vertigo and the types of saccade abnormality. CONCLUSION: Saccade test must be clinically useful for differentiating between the central and peripheral lesion using the types of saccade abnormality and other abnormal eye movement. But many factors that affect saccade movement should be considered when interpreting the test results.

Effectiveness of Cupulolith Repositioning Maneuver in the Treatment of Lateral Semicircular Canal Cupulolithiasis / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: There is still a controversy surrounding lesion side differentiation and treatment of the lateral canal cupulolithiasis. The purpose of this study is to understand side differentiation, and study the treatment of this disease through analyses of clinical features, electronystagmographic (ENG) results, treatment maneuvers and its effectiveness. MATERIALS AND METHODS: Twenty three patients who showed ageotropic direction-changing horizontal positional nystagmus were included in this study. A supine head turning test was performed to induce positional nystagmus. Clinical findings and typical features of the nystagmus were recorded. Neurologic examinations, ENG tests, and MRI (6 cases) were checked to exclude the possibility of any central lesions. Cupulolith Repositioning Maneuver (CuRM) was applied on the patients and these patients were instructed to keep the healthy side at the lateral decubitus position while sleeping. RESULTS: The nystagmus had a short latency, no fatigability, and persistency in character. In one patient, nystagmus was resolved spontaneously, so we could not decide the lesion side. However, seventeen out of 22 patients showed significant differences between the intensity of each side nystagmus, and all of them showed stronger nystagmus when the head was rotated to the unaffected side. In five patients who showed no significant difference between the intensity of each side nystagmus, two cases showed same results and three cases showed opposite results. Typical nystagmus and spinning sensation in the supine head-turning test had completely subsided after physical therapy. CONCLUSION: In the cupulolithiasis of lateral semicircular canal, ageotropic nystagmus was stronger when the pathological ear was at the uppermost position, and this excitatory nystagmus beat to the lesion side. But, if there was no significant difference between the intensity of each side nystagmus, associated canal paresis, other types of BPPV, past history of acute vestibuloneuritis, and Meniere's disease, etc. might be helpful to localize the lesion side. CuRM and post- treatment lateral decubitus position kept during the night (while sleeping on the day of treatment) were effective in treating the cupulolithiasis of lateral semicircular canal.

Two Cases of Acute Cerebellitis

Acute cerebellitis occurrs in the absence of cerebral hemispheric involvement and is exceptionally rare. It is charac-terized by an acute onset of cerebellar dysfunction following a respiratory, gastrointesitnal infection or skin rash. However, almost all patients show good prognosis. We experienced two cases of acute cerebellitis in young adults. One patient was admitted due to gait ataxia and dysarthria. The immunological laboratory findings revealed an acute Ebstein Barr virus infection and an electronystagmogram showed a periodic alternating nystagmus. The other patient was admitted due to severe gait ataxia, with no identification of any organism. CSF examinations revealed elevated protein and brain magnetic resonance images showed cerebellar foliae enhancement bilaterally. Both patients recovered without any disabilities.

Clinical Aspect of Acute Vestibular Neuritis / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The etiology and pathophysiology of acute vestibular neuritis are largely unknown and its diagnostic criteria and clinical course also have not been established definitely. This study was performed to provide a basis for creating the classification system and diagnostic criteria of vestibular neuritis. MATERIALS AND METHODS:We studied sixty-seven patients who showed no subjective auditory symptoms, and who showed spontaneous nystagmus for more than 24 hours under ENG (Electronystagmography) after the onset of vertigo. We evaluated the frequency of nystagmus and the site of lesion, and looked for the presence of any combined infectious diseases. Eye tracking test with ENG and auditory test were performed. Bithermal caloric test was performed after disappearance of sponteneous nystagmus and canal paresis was calculated. RESULTS: We found 52 cases (78%) of unilateral single attack, 10 cases (15%) of unilateral recurrent attack, 4 cases (6%) of opposite recurrent attack and one case (1%) of bilateral simultaneous attack. For the presence of combined infectious diseases, we found 24 casees (36%) with URI, one case (2%) with mumps and three cases (5%) with Ramsay-Hunt syndrome. Ipsilateral sensorineural hearing loss at 8000 Hz was found in 10 cases (24%). Neurologic abnormality was found in 14 cases (21%), but not found in 53 cases (79%). The canal paresis on bithermal caloric response was more than 50% for 30 cases (68%), 26%-50% for 4 cases (9%), and in the normal range for 10 cases (23%). CONCLUSION: There are some cases of the acute vestibular neuritis that showed atypical clinical features (recurrent attack, bilateral attack), which is inconsistent with the Coates criteria. Appropriate classification system and diagnostic criteria for acute vestibular neuritis, including recurrent attack and bilateral attack, are required.

The Changes of Vestibulo-Ocular Reflex after Acute Peripheral Unilateral Vestibular Loss / 대한이비인후과학회지

BACKGROUND AND OBJECTIVE: It is well known that compensation begins after acute unilateral peripheral vestibular function loss. The change of vestibulo-ocular reflex (VOR) is variable and affected by many factors. But there is no studies reported on the changes of individuals with the lapse of time. Using the rotation chair test and caloric test, we wanted to know the individual compensatory process of VOR as time progresses following an acute unilateral peripheral vestibular loss. MATERIALS AND METHODS: Subjects were patients of acute peripheral vestibular neuritis (n=19) whose nystagmus showed more than 24 hours. The follow up period was 10 weeks until the head shake nystagmus (HSN) disappeared. We measured the duration of each spontaneous nystagmus (SN) and HSN. Sinusoidal harmonic acceleration (SHA) was tested at 0.04 and at 0.08 Hz level, with the step velocity of 100 degrees per second. We also performed caloric test after HSN disappeared. RESULTS: SN and HSN each lasted 25 days and 50 days. VOR changes had an irregular pattern among individuals with gain increasing after decrement and phase lead decreasing after increment. Furthermore, the gain asymmetry was more irregular and lasted longer as well at the step velocity. Even though compensation has been reached, the caloric test revealed continuous abnormal values, which is quite different from the recovery of VOR in the rotatory test. CONCLUSION: During the early compensation period, we could recognize that the individual VOR changes recovered with a irregular pattern. On the other hand, the caloric test was not altered even after compensation.

Direction Changing Positional Nystagmus from Canalolithiasis and Cupulolithiasis of Lateral Semicircular Canal / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Clinical features of positional nystagmus may be different according to the etiology. Thus, efforts have been made to find out etiologies of various positional nystagmus. Until recently, positional vertigo was thought to arise from lesions of central nervous system. However, more recent investigations suggest that the peripheral lesion may be the main cause. Moreover, there have been some reports suggesting that directional changing positional nystagmus occurs due to canalolithiasis and cupulolithiasis of the lateral semicircular canal. The objectives of the study were to investigate the etiologies and clinical aspects of DCPN (direction changing positional nystagmus) from canalolithiasis and cupulolithiasis of the lateral semicircular canal, and to assess the effectiveness of the treatment. MATERIALS AND METHODS: Among 15 patients with DCPN, 9 patients showed nystagmus compatible with canalolithiasis of lateral semicircular canal and 6 patients with cupulolithiasis of lateral semicircular canal. Patients with cupulolithiasis and canalithiasis of the lateral semicircular canal did not respond to physical therapy for posterior semicircular canal. However, they were completely recovered by reposition maneuver for the lateral semicircular canal with or without using vibrator although 3 of them had recurred symptom. Four patients had BPPV of the posterior semicircular canal prior to the development of DCPN and 3 patients underwent the treatment of previous Meniere's disease. CONCLUSION: The patients with DCPN were due to canalithiasis and cupulolithiasis of the lateral semicircular canal, and physical therapy for lateral semicircular canal was rewarding.

The Effects of Dimenhydrinate on Eye Tracking Tests and VOR / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Dimenhydrinate is known to act on the vestibular system, causing vestiular suppression. But the effects related with therapeutic dosage on eye tracking tests and vestibulo-ocular reflex (VOR) are not clear yet. We performed this study to evaluate the effects of dimenhyrinate on eye tracking tests and VOR. MATERIALS AND METHODS: Twenty five healthy subjects, comprising of 12 men and 13 women between the ages of 15 and 69 (mean age=39) participated in this study. The assessment included saccade test, smooth pursuit test, optokinetic nystagmus test for eye tracking test and sinusoidal harmonic acceleration test for VOR test. Each test was performed before, and 2 hours and 4 hours after the oral intake of dimenhydrinate (therapeutic dosage: 50 mg). The subjects were kept alert by performing a calculation task and communicating with the investigator during tests. RESULTS: Analysis of results showed that latency was prolonged after 2 hours but was returned to initiae value after 4 hours. Gain was not changed in the saccade test as well as in the smooth pursuit test. Mean slow phase eye velocity (SPEV) decreased after 4 hours in optokinetic nystagmus test. Gain and phase lead decreased only at 0.01 Hz in sinusoidal harmonic acceleration test. CONCLUSION: Dimenhydrinate had minimal effects on eye tracking tests and VOR when the patient's alertness was kept during test.

Streptomycin Perfusion through the Round Window in Meniere's Disease / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Many local application methods have been developed for preventing vertigo attacks while preserving hearing loss. Among them, ototoxicity of aminoglycosides has been used for the treatment of Meniere's disease. The etiology and pathophysiology of Meniere's disease remain unknown, however, intratympanic aminoglycoside infiltration has proved to be a very effective treatment method for Meniere's disease. Therefore, currently, variable modalities of intratympanic aminoglycoside inflitration have been attempted in patients with Meniere's disease. We attempted to evaluate streptomycin perfusion for the control of vertigo with the preservation of hearing in patients with Meniere's disease. MATERIALS AND METHODS: Streptomycin powder was administered by filling up the round window niches in 15 patients with menere's disease from 1993 to 1996. Transmeatal approach was used for this technique and streptomycin infiltration was conducted for three consecutive days until patients developed spontaneous nystagmus or dizziness. RESULTS: 13 (83%) patients had no episodes of vertigo, and 2 patients had decreased vertigo attack. The preservation or improvement of hearing was reported in 87% of the patients. We observed that tinnitus disappeared in 33.3% of patients, and ear fullness in 40% of patient. After the operation, all of the patients reported to have no problems in daily activity. CONCLUSION: The streptomycin perfusion is a safe and simple procedure that is effective in controlling the vertigo, tinnitus and earfullness; however, futher further studies must be done on the preservation of hearing.

Two Cases of Bilateral Reversed Optokinetic Nystagmus / 대한이비인후과학회지

Normally, the fast phase of optokinetic nystagmus (OKN) beats on the opposite direction to the movement of an optokinetic stimulus. The fast component of OKN beating in the same direction are called "reversed OKN". Eventhough the mechanism of reversed OKN is still disputed, it is well known that reversed OKN occurs exclusively in patients with congenital nystagmus, or in some cases, with acquired neurologic disease. It is easy to diagnose the congenital nystagmus when the spontaneous nystagmus can be seen at birth. But when the congenital nystagmus can be seen only on eccentric gaze or when the patient has a wide neutral region around the primary position, the abnormal eye movement can not be detected until a medical examination is performed. It is thought that causes of reversed OKN may be the abnormal neural decussation of the visual system or spontaneous nystagmus. Recently, we experienced two cases of bidirectional reversed OKN as a congenital nystagmus. One patient had bilateral reversed optokinetic nystagmus and gaze evoked nystagmus, whereas the other patient had periodic alternative nystagmus and bilateral reversed OKN. Bilateral reversed OKN may be one of the pathognomic signs of congenital nystagmus.

The Simultaneous Binaural Bithermal Caloric Test / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The simultaneous binaural bithermal caloric test is performed by stimulating both ear canals with the water of same temperature at the same time. There are some reports that the simultaneous binaural bithermal caloric test appears to be more sensitive than the alternative bithermal caloric test in detecting caloric vestibular abnormalities. However, it is not well known yet what effect simultaneous binaural bithermal caloric test has on the vestibulo-ocular reflex. We attempted to verify the clinical usefulness of the simultaneous binaural bithermal caloric test. MATERIALS AND METHODS: Otoneurologically normal subjects (n=20) and patients who have complaints of dizziness (n=141) were tested. The regular bithermal caloric test was performed, using Life-Tech water irrigator and the water of temperatures 30degreesC and 44degreesC. The simultaneous binaural bithermal test was performed using Brooker-Grams closed loop irrigator with 27degreesC and 44degreesC water. The irrigation time was 40 seconds and nystagmus was detected for more than 120 seconds by electronystagmography. We divided the test response into six types with the reference value of canal paresis (CP) of the regular bithermal caloric test. RESULTS: The distribution of nystagmus type did not show regular pattern in the normal controls. The distribution of type I and II was 77.4% when CP was more than 25% in patients, 50.6% when CP was less than 25% in patients, and 42.5% in the normal group. The maximal velocity of slow component increased in the unilateral canal paresis patients (CP>25%), compared with the normal controls and no unilateral canal paresis patients (Cp<0.05). CONCLUSION: We observed that the simultaneous binaural bithermal caloric test has advantages of being less time-consuming and more comfortable. When the maximal velocity of slow component is more than 22.6 deg/sec with type I or II response, we could predict canal paresis; however, further studies should be made for abnormal response of simultaneous caloric response on the central nervous ststem.

A Case of Acute Labyrinthine Infarction by Vertebrobasilar Insufficiency / 대한이비인후과학회지

Acute labyrinthine infarction due to vertebrobasilar insufficiency results in acute vestibular and cochlear functional loss. It is very difficult to differentiate acute labyrinthine infarction from acute viral labyrinthitis, vestibulocochlear neuritis and sudden sensorineural hearing loss. Because its definite diagnosis criteria has not been yet established and confirmative diagnosis tool is limited, the diagnosis and appropriate treatment is more difficult. It is often misdiagnosed as a peripheral vestibular disorder because its clinical symptom is usually a form of dizzy attack with hearing impairment. We experienced a case of acute labyrinthine infarction due to vertebrobasilar insufficiency. We differentiated it from acute labyrinthitis and vestibulocochlear neuritis using ENG and diagnosed it by means of periodic ENG follow-up. Confirmative diagnosis was made by means of MR angiography. MR angiography shows non-opacification of right vertebral artery and focal stenosis of right basilar artery. We treated this patient with 500,000 unit of urokinase per day for 5 days and observed recovery of impaired vestibular and cochlear function.

Myogenic potential evoked by auditory stimulation in vestibulocollic reflex

BACKGROUND AND OBJECTIVES: Click sound can evoke myogenic potentials in active sternocleidomastoid(SCM) muscle. These potentials are due to the activity of the vestibular rather than cochlear afferents, which produce very short latency inhibition of ipsilateral motor unit activity and is best detected by averaging the unrectified surface electromyogram(EMG) from the muscle. We investigated the click evoked vestibulocollic reflexes in neck muscles to find out the significance and relationship of latency and amplitude of myogenic potentials between two different methods of muscle activation. METHODS: EMGs were recorded from surface electrode evoked by sound stimuli (95dB, 5/sec repetitive rate, 512 times) over SCM muscles on each side. Myogenic potential have two biphasic responses, which are termed P1, N1, P2 and N2 based on the polarity of their components. The subjects were 24 normal volunteers. Surface EMG activities from 12 subjects(Group I) were recorded by neck flexion to activate bilateral SCM muscles through the averaging runs(bilateral SCM muscle activation method). EMGs from another 12 subjects(Group II) were recorded by rotating head to the opposite side to activate SCM muscle throughout the procedure(unilateral SCM muscle activation method). The latencies and amplitudes of myogenic potential in the SCM muscle after stimulation were analysed and compared between each method. RESULTS: The latencies(msec) of P1 and N1 were 11.2+2.4, 21.7+1.1 in Group 1, respectively and 13.3+2.4, 23.0+/-1.1 in Group 11, respectively. The amplitudes(microvolt) of P1-N1 were 38.7+8.1 in Group 1 and 33.2+8.1 in Group II. There was no significant difference in latencies and amplitudes of P1 and N1 between each group(p> 0.05) and was no asymmetry of latency and amplitude in P1-N1 between each side. CONCLUSIONS: The myogenic potential was constantly evoked by click stimulation and we think it could be a simple method of examining vestibulocollic reflex.

Clinical Significance of the Optokinetic Nystagmus Abnormality / 대한이비인후과학회지

Optokinetic nystagmus(OKN) is commonly employed in the assessment of central vestibular lesion. Asymmetry in the OKN has been found in lesions ipsilateral to the direction of the slow phase in parietal lobe, in brain stem, and in the cerebellum. Asymmetry of the OKN may also occur in peripheral vestibular lesions due to spontaneous nystagmus, and this may explain why even enhanced velocities of OKN are sometimes met in these patients. The ocular abnormality as congenital strabismus, extraocular paresis, and congenital nystagmus can cause abnormalities of optokinetic nystagmus. We investigated the clinical significance of OKN test and spontaneous nystagmus for differentiation of peripheral and central vestibular disorder. In this study, we recorded the optokinetic nystagmus by the electronystagmography. We divided the optokinetic response from normal to type III according to direction of the nystagmus and difference of(Rt-Lt) Vmean. At the result, all of the vestibuloneuronitis who had the optokinetic abnormality showed type I OKN abnormality with spontaneous nystagmus. Type II and type III OKN abnormality always appeared in central vertigo patients. Type I OKN abnormality could be seen in peripheral and central vertigo patient. But half of the central vertigo patients who had type I OKN abnormality did not have spontaneous nystagmus. We could not correlated OKN abnormality with specific location of central nervous system.

The Changes of Na+-K+ ATPase Activity and Ultrastructure of Endolymphatic Secretory Epithelium by Local and Systemic Streptomycin Treatment / 대한이비인후과학회지

The endolymphatic secretory epithelium are stria vascularis in cochlear and dark cell in vestibule which are regulated by Na+-K+ ATPase. It is important that we study intracytoplasmic Na+-K+ ATPase for the physiologic research of inner ear. Recently cerium-based method for stain of Na+-K+ ATPase was developed. This study was underkaken to investigate the morphologic changes and Na+-K+ ATPase activity in stria vascularis and vestibular dark cell of mongolian gerbil after systemic intramuscular injection(200mg/kg or 300mg/kg) for 7days or local infiltration of streptomycin through round window. The results are as follows. 1) The strong Na+-K+ ATPase activity was seen at basolateral infoldings of marginal cell in stria vascularis but weak Na+-K+ ATPase activity in dark cell near transitional area. 2) There was no change of Na+-K+ ATPase activity in the stria vascularis and dark cell by systemic injection of streptomycin. The decrease of Na+-K+ ATPase activity in stria vascularis was seen at destruction site of infoldings by local infiltration of streptomycin but no changes in dark cell. 3) The ultrastructural changes of marginal cell by local infiltration of streptomycin were intracytoplasmic vacuole, partial loss of cytoplasmic infoldings, edema, and increase of melanin particle. but, there was no change of ultrastructure in dark cell except increase of melanin particle. The changes of ultrastructure of stria vascularis was variable by systemic streptomycin injection and there was no dark cell change except increased melanin particle. From the above results, the changes of ultrastructure and Na+-K+ ATPase were more severe by local infiltration of streptomycin through round window than systemic injection of streptomycin. The local infiltration of streptomycin through round window may be suitable method for the induction of inner ear damage.

Vestibulo-Ocular Reflex according to the Change of Angular Acceleration in Sinusoidal Harmonic Acceleration Test / 대한이비인후과학회지

We investigated the vestibulo-ocular reflex which is followed by the change of angular acceleration in sinusoidal harmonic acceleration test. 20 normal volunteers with no evidence of previous otoneurologic disease were tested. The maximal slow phase eye velocity, gain and asymmetry were obtained in five different amplitudes of rotation, 30degrees, 60degrees, 90degrees, 120degrees and 150degrees with properly fixed conditions such as darkness and the frequency of rotation fixed at 0.05Hz. During each test, we asked the examinees to be alert and keep the eyes open. At least 5 minute interval was given between the tests and recalibrations were done before each test. The results of this test were as follows. 1) The maximal slow phase eye velocities were gradually increased according to the increment of the amplitudes of rotation with the statistical significances(p0.05). Therefore, from the above results, sinusoidal harmonic acceleration test with the frequency fixed at 0.05Hz, gain is higher when the amplitude of rotation is smaller and the pattern of the nystagmus is more evident when the amplitude of rotation is bigger. But The authors conclude that in order to get the results which are statistically significant, the amplitude of rotation should be lower than 90degrees.

Plasticity of Vestibulo-ocular Reflex in Slow Harmonic Acceleration Test / 대한이비인후과학회지

The results of rotation chair test were known to variable by many parameters such as eye opening and alertness, etc. The situational change in rotation chair test must be considered to interpretation of its result. But in Korea, there were no reports or articles about parameters which influence the result of rotation chair test. So, we assumed that eye opening and alertness were main parameters and took rotation chair test in neurotologically normal subjects. For evaluation of the effect of eye-open or eye-closure and alertness on the rotational vestibular stimulation, we have taken sinusoidal harmonic acceleration test in 30 otoneurologically normal subjects. The maximal slow phase eye velocity, gain and asymmetry were obtained and compared with each other in four different conditions with properly fixed conditions such as in darkness and 0.05Hz frequency. At least five minutes interval was given between the tests and recalibrations were done before each tests. The results of this test were as follows. 1) Vestibular-ocular reflex(VOR) changes according to eye open or closure. In cases of examinees which were given alerting tasks, larger gain was obtained with eyes opened than with eyes closed, and that was statistically significant(p0.05). 2) VOR changes according to alertness. In cases of examinees which opened their eyes, larger gain was obtained with alerting tasks than without alerting tasks, and that was statistically significant(p<0.05). In cases of examinees which closed their eyes, larger gain was obtained with alerting tasks than without alerting tasks, and that was statistically significant(p<0.05). 3) There was no significant changes of asymmetry according to the conditions. Therefore, from above results, we recommend the condition in which examinees open their eyes and be given alerting tasks as one of the optimal condition in sinusoidal harmonic acceleration test.

Symptomatic Improvement in Patients with Perennial Allergic Rhinitis Following Laser Turbinate Surgery / 대한이비인후과학회지

Laser surgery of allergic rhinitis has been reported to be successful by several authors, but there has been little study on factors that may help the physician select patients who are likely to respond to surgery. The aim of this study was to assess the factors that influence the surgical outcome of laser surgery for allergic rhinitis patients. We analyzed the data from questionnaire in 211 patients who were diagnosed as perennial allergic rhinitis and underwent CO2 laser surgery in our department from October 1993 to October 1995. All nasal symptoms including nasal obstruction, watery rhinorrhea and sneezing were significantly improved. Improvement rates do not differ according to the number of surgery, follow-up period, number of positive allergens and residency type. The results of this study suggest that laser surgery might improve nasal symptoms in patients with perennial allergic rhinitis. There was no significant difference in improvement rate in terms of both number of surgery and follow-up period.

Effect of Repeated Monothermal Caloric Stimulation on the Bithermal Caloric Response / 대한이비인후과학회지

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.