The Value Of Vestibular Graviceptive Pathway Evaluation And Combined With 45°SVV In The Diagnosis Of Unilateral Peripheral Vestibular Dysfunction

Background For a considerable period,the localization and diagnosis of unilateral peripheral vestibular dysfunction(UPVD)by clinicians has mainly relied on semicircular canal evaluation.In recent years,there has been an increasing focus among researchers on the evaluation of the vestibular graviceptive pathway(VGP)in UPVD patients,along with its diagnosis through the combined use of 45°SVV.Objective Exploring the clinical diagnostic value of VGP related indicators and their combined use with 45°SVV in patients with UPVD.Methods Ninety-five patients with UPVD who admitted to the Neurology Outpatient Department and Inpatient Ward of Aerospace Center Hospital in Beijing from April 2021 to August 2022 were included in this study.Baseline clinical data were collected,including age,gender,duration of vertigo and previous vertigorelated history.Meanwhile,VGP related evaluation are improved,including subjective visual vertical(SVV)in head-upright position,subjective visual horizontal(SVH)in head-upright position,head tilt(HT),ocular torsion(OT)and skew deviation(SD).The clinical characteristics of the above indicators in patients with UPVD attack and remission stages and their correlation with cochleovestibular function test results were analyzed.Additionally,the clinical characteristics and possible etiology of 14 patients with contralesional VGP(cVGP)were further analyzed.To further investigate the application value of VGP combined with 45°SVV in the diagnosis of UPVD patients,40 healthy controls were included to improve the evaluation of 45°SVV in the UPVD group and the healthy control group.The clinical characteristics of the three groups’ 45°SVV were compared and analyzed,and VGP evaluation was combined to explore the application value in the diagnosis of UPVD.Results1.The value of VGP evaluation in the diagnosis of UPVD(1)Positive rates of SVV,SVH,OT,SD were significantly higher in the attack phase group than in the remission group(SVV: 65.2% vs.24.5%,χ2=15.956,P<0.001;SVH: 67.4% vs.32.4%,χ2=11.454,P=0.001;OT: 47.8% vs.18.4%,χ2=9.366,P=0.00;SD: 17.4% vs.2.0%,P=0.012).The degrees of SVV,SVH,and OT were significantly greater in the attack phase group than in the remission phase group(SVV: 4.15±3.24 vs.1.64±1.71,Z=-4.277,P<0.001;SVH: 3.95±2.92 vs.2.02±1.45,Z=-3.878,P < 0.001;OT: 7.55±6.30 vs.3.89±3.88,Z=-3.028,P=0.002).(2)Significant correlation was found between the sides with abnormal VGP evaluation results and the sides with hearing loss(χ2=11.783,P=0.001),abnormal caloric test(χ2=21.456,P<0.001)and abnormal video head impulse test(v HIT)(χ2=20.151,P<0.001).(3)14(14.7%)patients with UPVD showed c-VGP,including 4 patients with contralateral benign paroxysmal positional vertigo(BPPV),8 with bilateral hearing loss,1 with bilateral v HIT gain reduction,6 with autoimmune diseases,6 with vascular risk factors,3 with lacunar infarction,and 3 with endolymphatic hydrops.2.The value of VGP evaluation combined with 45°SVV in the diagnosis of UPVD(1)The incidence of A-effect on the ipsilesional side and E-effect on the contralesional side in the UPVD attack group was significantly higher than that in the healthy control group(30.4% vs.12.5%,χ2=7.09,P=0.008);The absolute value of E-effect on the ipsilesional side in the UPVD attack group was significantly higher than that on the contralesional side(17.33±10.09 vs.13.83±6.42,Z=-2.16,P=0.031),showing asymmetrical enlargement of E-effect.However,there was no statistical difference in the absolute value of bilateral Eeffect in the UPVD remission group(15.03±12.54 vs.12.54±8.95,Z=-1.59,P=0.113),showing pathological symmetrical enlargement of E-effect.(2)Compared with the evaluation using VGP alone,the combined evaluation of VGP and 45°SVV effectively increased the diagnosis rate of UPVD remission patients(71.4% vs.55.1%,χ2=3.60,P=0.046).Conclusions1、Alterations in SVV,SVH,OT,and SD were noted in patients with UPVD in different phases,which are presumed to be related to dynamic vestibular compensation.There were significant correlations between VGP evaluation results and semicircular canal function test,audiological test results,indicating that VGP evaluation may be helpful for lateralization diagnosis of side involvement in patients with UPVD.2、The presence of c-VGP may be related to bilateral labyrinth lesions or endolymphatic hydrops on the affected side,the involvement of autoimmune mechanisms also deserves attention.3、VGP combined with 45°SVV effectively improves the diagnostic value of patients with UPVD,especially those in the remission stage.The pathological symmetrical and asymmetrical changes in bilateral E-effects of 45°SVV in different stages of UPVD may be related to dynamic compensation of the vestibular system.