Department of Neurology, Korea University Medical Center, 73 Goryeodae-ro, Seongbuk-gu, Seoul, 02841, South Korea.
Neurotology and Neuro-Ophthalmology Laboratory, Korea University Anam Hospital, Seoul, South Korea.
J Neurol. 2024 Feb;271(2):819-825. doi: 10.1007/s00415-023-12026-0. Epub 2023 Oct 8.
The results of video head impulse tests (video-HITs) may be confounded by data artifacts of various origins, including pupil size and eyelid obstruction of the pupil. This study aimed to determine the effect of these factors on the results of video-HITs. We simulated ptosis by adopting pharmacological dilatation of the pupil in 21 healthy participants (11 women; age 24-58 years). Each participant underwent video-HITs before and after pupillary dilatation using 0.5% tropicamide. We assessed the changes in the vestibulo-ocular reflex (VOR) gain, corrective saccade amplitude, and frequency of eyelid flicks. After pupillary dilatation, the VOR gain decreased for both right (RAC; 1.12 [Formula: see text] 0.12 vs. 1.01 [Formula: see text] 0.16, p = 0.011) and left anterior canals (LACs; 1.15 [Formula: see text] 0.13 vs. 0.96 [Formula: see text] 0.14, p < 0.001), and right posterior canal (RPC, 1.10 [Formula: see text] 0.13 vs. 0.98 [Formula: see text] 0.09, p = 0.001). The corrective saccade amplitudes also decreased significantly for all four vertical canals. The frequency of eyelid flicks, however, did not change. The changes of VOR gain were positively correlated with the lid excursion in RPC (r = 0.629, p = 0.002) and LPC (r = 0.549, p = 0.010). Our study indicates that eyelid position and pupil size should be considered when interpreting the results of video-HITs, especially for the vertical canals. Pupils should be shrunk in a very well-lit room, and artifacts should be prevented by taping or lifting the eyelids as required during video-HITs.
视频头脉冲试验（video-HIT）的结果可能会受到各种来源的数据伪影的影响，包括瞳孔大小和眼睑对瞳孔的遮挡。本研究旨在确定这些因素对视频-HIT 结果的影响。我们通过在 21 名健康参与者（11 名女性；年龄 24-58 岁）中采用瞳孔药理学扩张来模拟上睑下垂。每个参与者在使用 0.5%托吡卡胺散瞳前后接受视频-HIT。我们评估了前庭眼反射（VOR）增益、矫正扫视幅度和眨眼频率的变化。瞳孔扩大后，右侧（RAC；1.12 ± 0.12 比 1.01 ± 0.16，p = 0.011）和左侧前管（LACs；1.15 ± 0.13 比 0.96 ± 0.14，p < 0.001）以及右侧后管（RPC，1.10 ± 0.13 比 0.98 ± 0.09，p = 0.001）的 VOR 增益均降低。所有四个垂直管的矫正扫视幅度也显著降低。然而，眨眼频率没有变化。VOR 增益的变化与 RPC（r = 0.629，p = 0.002）和 LPC（r = 0.549，p = 0.010）的眼睑偏移呈正相关。我们的研究表明，在解释视频-HIT 的结果时，应考虑眼睑位置和瞳孔大小，特别是对于垂直管。瞳孔应在光线充足的房间中缩小，并且应通过必要时粘贴或提起眼睑来防止伪影。
