Division of Balance Disorders, Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Centre, Maastricht, The Netherlands.
Department of ENT/Audiology, School for Mental Health and Neuroscience (MHENS), Maastricht University Medical Centre, Maastricht, The Netherlands.
J Neurol. 2020 Dec;267(Suppl 1):256-264. doi: 10.1007/s00415-020-10060-w. Epub 2020 Jul 27.
A horizontal vestibulo-ocular reflex gain (VOR gain) of < 0.6, measured by the video head impulse test (VHIT), is one of the diagnostic criteria for bilateral vestibulopathy (BV) according to the Báràny Society. Several VHIT systems are commercially available, each with different techniques of tracking head and eye movements and different methods of gain calculation. This study compared three different VHIT systems in patients diagnosed with BV.
This study comprised 46 BV patients (diagnosed according to the Báràny criteria), tested with three commercial VHIT systems (Interacoustics, Otometrics and Synapsys) in random order. Main outcome parameter was VOR gain as calculated by the system, and the agreement on BV diagnosis (VOR gain < 0.6) between the VHIT systems. Peak head velocities, the order effect and covert saccades were analysed separately, to determine whether these parameters could have influenced differences in outcome between VHIT systems.
VOR gain in the Synapsys system differed significantly from VOR gain in the other two systems [F(1.256, 33.916) = 35.681, p < 0.000]. The VHIT systems agreed in 83% of the patients on the BV diagnosis. Peak head velocities, the order effect and covert saccades were not likely to have influenced the above mentioned results.
To conclude, using different VHIT systems in the same BV patient can lead to clinically significant differences in VOR gain, when using a cut-off value of 0.6. This might hinder proper diagnosis of BV patients. It would, therefore, be preferred that VHIT systems are standardised regarding eye and head tracking methods, and VOR gain calculation algorithms. Until then, it is advised to not only take the VOR gain in consideration when assessing a VHIT trial, but also look at the raw traces and the compensatory saccades.
根据 Bárány 学会的标准，水平半规管-眼动反射增益（VOR 增益）<0.6 通过视频头脉冲测试（VHIT）测量，是双侧前庭病（BV）的诊断标准之一。目前有几种 VHIT 系统可用于商业用途，每个系统都有不同的头部和眼部运动跟踪技术以及不同的增益计算方法。本研究比较了三种不同的 VHIT 系统在诊断为 BV 的患者中的应用。
本研究纳入了 46 例 BV 患者（根据 Bárány 标准诊断），他们以随机顺序使用三种商业 VHIT 系统（Interacoustics、Otometrics 和 Synapsys）进行测试。主要观察参数是系统计算得出的 VOR 增益，以及 VHIT 系统在 BV 诊断（VOR 增益<0.6）上的一致性。分别分析了峰值头部速度、顺序效应和隐匿性扫视，以确定这些参数是否会影响 VHIT 系统之间的结果差异。
Synapsys 系统的 VOR 增益与其他两种系统的 VOR 增益有显著差异 [F(1.256, 33.916) = 35.681, p < 0.000]。VHIT 系统在 83%的患者中对 BV 诊断的结果一致。峰值头部速度、顺序效应和隐匿性扫视不太可能影响上述结果。
综上所述，在同一 BV 患者中使用不同的 VHIT 系统可能会导致 VOR 增益出现临床上显著的差异，当使用 0.6 的截断值时。这可能会阻碍对 BV 患者的正确诊断。因此，最好是使 VHIT 系统在眼部和头部跟踪方法以及 VOR 增益计算算法方面标准化。在那之前，建议在评估 VHIT 试验时不仅要考虑 VOR 增益，还要观察原始轨迹和代偿性扫视。
