计算机辅助动态视敏度与vHIT的一致性评估

Evaluation of Consistency in Computerized Dynamic Visual Acuity and Video Head Impulse Test

目的 动态视敏度(Dynamic Visual Acuity, DVA)与视频头脉冲试验(video head impulse test, vHIT)均可提供半规管功能的损伤评估和康复反馈。本文主要比较计算机辅助测量的DVA(computerized DVA,cDVA)与vHIT评估眩晕患者的表现,探讨cDVA评估前庭损伤的适用性与有效性。方法 本文选择35名眩晕患者以及4名健康受试者进行cDVA与vHIT试验。用验光C字环在头静止和头动时分别记录静态视敏度(static visual acuity, SVA)与DVA,计算DVA-SVA差值标为DVA值。vHIT原始数据以XML格式导出,用HitCal软件记录扫视波参数。使用IBM SPSS 20.0软件行统计分析,P<0.05时认为有统计学差异,使用python进行数据可视化。结果 35名患者平均年龄为46±17岁,无扫视波侧别的DVA值为0.33,明显小于有扫视波侧(DVA值为0.42,无扫视波侧N=30,有扫视波侧N=40,P=0.045)。健康受试者的DVA值均≤0.3(除外一例有扫视波侧>0.3)。双侧DVA值>0.3的患者中,分别有10/21(左侧)和10/18(右侧)扫视波幅度较高(≥75°/s),4/21(左侧)和2/18(右侧)有中等幅度扫视(40~74°/s),双侧均有6名无扫视波的患者,但均有4名对侧存在较高幅度扫视;DVA值>0.3的侧别中,扫视波出现时间>200ms分别有11/21(左侧)和7/18(右侧),扫视波出现时间介于140~200ms之间的分别有2/21(左侧)和5/21(右侧)。结论 vHIT中扫视波幅度大于75°/s、扫视波出现时间>200ms的侧别较易产生0.3以上的异常DVA值。在有扫视波但无DVA值异常部分侧别中,对侧DVA值也较易有异常高的值。

Objective Both dynamic visual acuity(DVA) and video head impulse test(vHIT) can be used in assessment for vestibular dysfunction and rehabilitation. This study aims to evaluate the consistency of computerized DVA(cDVA) to vHIT in vertigo patients for its applicability and effectiveness. Method In this study, 35 patients with vertigo and 4 healthy controls received cDVA and vHIT tests. Static visual acuity(SVA) and DVA were recorded with the head resting still and during head movement. The difference between DVA and SVA was assigned as DVA value. Raw saccades in vHIT were marked using the HitCal software and analyzed using the SPSS 20.0 software. Result The mean age of the 35 patients was 46±17 years. The DVA value on the non-saccades side(0.33, N = 30) was significantly lower than that on the saccades side(0.42, N = 40)(P=0.045). In one healthy subject with saccades, DVA value was 0.4 on one side and ≤ 0.3 on the other side. When DVA value was > 0.3, most patients showed high saccades amplitudes(≥75°/s)(10/21 on left and 10/18 on right) while some showed moderate level saccade amplitudes(40-74 °/s)(4/21 on left and2/18 on right). Six patients showed no saccades on left side and 6 showed no saccades on right side. However, 4 of these patients showed high amplitude saccades on the opposite side. Saccade latency was longer than 200 ms in 11/21(left)and 7/18(right) patients, and between 140 and 200 ms in 2/21(left) and 5/21(right) patients. Conclusion When the saccades amplitude is greater than 75°/s or saccade latency is longer than 200 ms,vertigo patients are more likely to exhibit an abnormal DVA value ≥0.3. If one side shows no saccade and a normal DVA value, DVA value is likely to be abnormally high on the other.