The Clinical Efficacy of Vestibular Function Tests in Patients with Acute Unilateral Vestibulopathy / 대한평형의학회지

OBJECTIVES: Aim of this study is to investigate the clinical efficacy of the vestibular function tests (VFTs) and the predictability of lesion side of vestibular asymmetry parameters in acute unilateral peripheral vestibulopathy. METHODS: Medical records and results of VFTs (caloric, rotatory chair, and head impulse tests) of 57 patients with acute unilateral vestibulopathy were reviewed retrospectively. The VFTs were examined within 7 days after the clinical onset. RESULTS: For the caloric test, 74% showed significant canal paresis and the predictability of lesion side was 88%. For the sinusoidal harmonic acceleration test, 91% had low gain in at least 1 Hz, phase lead showed 70%, 89% showed phase asymmetry and the predictability of lesion side was 90%. For velocity step test, 67% had abnormal Tc asymmetry and the predictability of lesion side was 95%. In bedside head impulse test (HIT), abnormal catch up saccades were observed in 89% and the predictability of lesion side was 100%. For the video HIT, cover or overt catch-up saccades were observed in 95% and the predictability of lesion side was 100%. One hundred percent (100%) had low gain on the video HIT, but the lesion sides were uncertain because of bilateral involvements or artifacts. CONCLUSIONS: The most important things in the diagnosis of acute unilateral vestibulopathy are typical clinical symptoms and spontaneous nystagmus. A combination of rotatory, caloric, and HITs will result in a more complete examination of the vestibular system. Among them, HIT is recommended as the best tool in acute unilateral vestibulopathy.

Vestibular Function Test of Vestibular Neuritis in Acute and Compensated Stage

BACKGROUND: Vestibular neuritis (VN) is a common peripheral vestibulopathy. VN is most likely a partial rather than a complete vestibular paralysis, It has a natural history of gradual recovery within 1-6weeks. The investigation of vestibulo-ocular reflex (VOR) change in acute and compensated VN are relatively few in Korea. We performed the vestibular function test including electronystagmography (ENG) and rotary chair test (RCT) in the patients with acute and compensated VN, and evaluated the efficacy of ENG and RCT to know the degree of compensation. METHODS: Tweenty-four patients with acute VN, 14 patients who had cllinically compensated VN during follow-up period and 30 normal controls were studied. Mean intervals from symptom onset to test were 3.6 days (acute) and 102.5 days (com-pensated). RESULTS: Eight patients had asymmetrically impaired pursuit, and ten patients had asymmetrcally impaired OKN during acute stage. The degree of side differences in pursuit and OKN gain was correlated with intensity of spon-taneous nystagmus. In the acute stage, the gain of the VOR was reduced at low frequency (0.01-0.16Hz), but it was normal at high frequency (0.32Hz). Prolonged phase lead and gain asymmetries were present at all range of frequency. In the compensated stage, the gain, phase and symmetry of the VOR at all range of frequency were not different from those of controls, except for prolonged phase lead and asymmetry at 0.01 Hz. The rate of the patients with unilateral canal paresis was 100% at acute stage and 50% at compensated stage in mono-thermal cold caloric stimulation. CONCLUSIONS: These results suggested that pursuit and OKN abnormalities may be found in acute peripheral vestibu-lopathy, in which coarse spontaneous nystagmus may contribute to the development of these abnormality. Absence of caloric response does not indicate an complete absence of vestibular function and RCT is a useful method in evaluation of VOR status in patients with acute and compensated VN.

A Study of Rotation Test in Patients with Unilateral Peripheral Vestibular Loss / 대한이비인후과학회지

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.