The Study Of Vestibular Autorotation Test In Sudden Deafness With Vertigo

ObjectiveSudden deafness is a common ontological disease in the department of otolaryngology head ad neck surgery, with an unknown cause sudden drop in hearing in a short time. At present, it’s mostly because of the inner ear microcirculatory disorders, viral infections, rupture fenestrated membrane, allergic reaction, stria vascularis dysfunction and dysbolismus. Patients with sudden deafness is often accompanied by vertigo, increasingly rich in the vestibular function of patients with sudden deafness, The existing studies of sudden deafness patients’vestibular tests confirm that sudden deafness with vertigo may involve the vestibular function, also showed than vestibular function is normal or not to have a certain impact on the prognosis of sudden deafness. Vestibular autorotation test(VAT) is one of the newly test which through the vestibule-ocular reflex(VOR) to assess the vestibular function, the test frequency was (2.0～6.0Hz), include the high frequency out of the frequency of tradition vestibular tests, it’s close to the normal movement frequency of people’s daily life, VAT widely used in the assessment of vestibular disease inspection and vestibular function. In our study, we want to summary and analyze the nomal VAT results and sudden deafness patients with vertigo to explore its property and reason, to provide reliable and valid basis for the vestibular functional assessment and rehabilitation of the patients with sudden deafness in clinical.Methods78normal persons (male41, female37) who accepted examinations at the same period were enrolled in this study as control group. They have no cases history of otology, vertigo, intracalvarium and nervous disease, the ophthalmology results were also normal.229sudden deafness patients (male97, female132) who visited the balance center from March2009to May2011were enrolled in this study as test group. Diagnosised sudden deafness based on the Society of Ophthalmology of China, The neurological examination no signs of central lesions, imaging studies to exclude acoustic neuroma, brain ischemia or hemorrhagic lesions. Both groups were subjected to the Vestibular Autorotation Test (VAT). Electro-oculographic electrodes were placed for measurement of eye movement, both in the horizontal and vertical planes, connected to a head band that contained an electronystagmograph(ENG) amplifer and an angular velocity senser. There were five indicators include horizontal and vertical eye movement gain, phase and asymmetry of VAT. Gain is measured at each frequency as the quotient of eye velocity respective to head velocity, normal gain close to1, abnormal results of two kinds were high and low gain. Phase is measured in degrees based on eye position relative to head position, high and low phase were the abnormal results means phase delay. Asymmetry measures provided a useful estimator of the weaker side in patients with unilateral lesions. we assessment the test positive when one or more parameters abnormal above the five indicators, the gain and phase positive when one or more gain and phase abnormal above the horizontal and vertical indicators. Statistical analysis by SPSS16.0, measurement data are presented as mean±standard deviation or median, count data expressed as a percentage of the t test, used the t-test and chi-square test, P<0.05was considered statistically significant.Results1. The VAT results in healthy control group frequency band of gain and phase were2,3,4,5,6Hz, and2,3,4,5,6,7,8,9,10Hz for asymmetry, compare with the normal reference values were no statistically significant difference, P>0.05.2. The VAT results in test group:VAT positive rate93.4%, gain68.1%, phase79.5%, asymmetry62.4%;2.1The positive cases of gain include horizontal abnormal44.9%, vertical abnormal8.3%, and both horizontal and vertical abnormal14.8%; there were92cases high-gain and98cases low-gain, there was no statistically significant difference between them, P>0.05; the horizontal high-gain and horizontal low-gain were64and73, the vertical high-gain and vertical low-gain were28and25cases, there also show the no statistically significant difference between them, P>0.05.2.2The positive cases of phase include horizontal abnormal20.5%, vertical abnormal28.4%, and both horizontal and vertical abnormal30.6%; there were198cases high-phase and54cases low-phase, they had the statistically significant differences, P<0.05; the horizontal high-phase and horizontal low-phase were65and52, there was no statistically significant difference between them, P>0.05; the vertical high-phase and vertical low-phase were133and2, they had the statistically significant differences, P<0.05.3. The compare between control group and test group3.1Compare the positive rate in control and test group:the control group VAT positive rate8.1%, gain4.7%, phase5.8%and asymmetry3.5%; in the test group: VAT93.4%, gain68.1%, phase79.5%,, asymmetry62.4%; compared each values in two groups with chi-square test,.P=0.000, the differences were statistically significant.3.2Compare the five indicators’mean of VAT between two groups:3.2.1The horizontal gain mean value of two groups had the statistically significant differences at the2,3,5,6Hz frequency band, P<0.05.3.2.2The horizontal phase mean value of two groups had the statistically significant differences at the3,4,5,6Hz frequency band, P<0.05.3.2.3The vertical gain mean value of two groups had the statistically significant differences at the2,6Hz frequency band, P<0.05.3.2.4The vertical phase mean value of two groups had the statistically significant differences at the2,3,4,5,6Hz frequency band, P<0.05.3.2.5The asymmetry mean value of two groups had the statistically significant differences at the2,3,4,5,6,7,8,9,10Hz frequency band, P<0.05.ConclusionOur laboratory VAT indicators conformity with the systemic reference values, the results are reliable; The VAT gain indicators in sudden deafness with vertigo patients include high-gain and low-gain, it related to the etiology and ambit of vestibular trauma in the patients; the vertical phase showed low-phase of the whole band in sudden deafness patients. Suggesting that the vestibular ocular reflex delay; the asymmetry was anomalism in sudden deafness, can prompt the lesion side; the VAT gain indicators is beneficial for the qualitative assessment, and analyze etiology of vestibular system damage in patients with sudden deafness.