TY - JOUR
T1 - VOR gain calculation methods in video head impulse recordings
AU - Zamaro, Ewa
AU - Tehrani, Ali S.Saber
AU - Kattah, Jorge C.
AU - Eibenberger, Karin
AU - Guede, Cynthia I.
AU - Armando, Lenz
AU - Caversaccio, Marco D.
AU - Newman-Toker, David E.
AU - Mantokoudis, Georgios
N1 - Funding Information:
This study was supported by the Swiss National Science Foundation PBBEP2 1365-73 and #320030 173081 (GM) and the Inselspital Bern (Insel-grant, #2602). Dr. David E. Newman-Toker’s effort was partially supported by a grant from the National Institutes of Health, National Institute of Deafness and Communication Disorders (U01DC013778). GN Otometrics and Interacoustics loaned VOG equipment for research.
Publisher Copyright:
© 2020 - IOS Press and the authors. All rights reserved.
PY - 2020
Y1 - 2020
N2 - BACKGROUND: International consensus on best practices for calculating and reporting vestibular function is lacking. Quantitative vestibulo-ocular reflex (VOR) gain using a video head impulse test (HIT) device can be calculated by various methods. OBJECTIVE: To compare different gain calculation methods and to analyze interactions between artifacts and calculation methods. METHODS: We analyzed 1300 horizontal HIT traces from 26 patients with acute vestibular syndrome and calculated the ratio between eye and head velocity at specific time points (40 ms, 60 ms) after HIT onset ('velocity gain'), ratio of velocity slopes ('regression gain'), and ratio of area under the curves after de-saccading ('position gain'). RESULTS: There was no mean difference between gain at 60 ms and position gain, both showing a significant correlation (r2 = 0.77, p < 0.001) for artifact-free recordings. All artifacts reduced high, normal-range gains modestly (range -0.06 to -0.11). The impact on abnormal, low gains was variable (depending on the artifact type) compared to artifact-free recordings. CONCLUSIONS: There is no clear superiority of a single gain calculation method for video HIT testing. Artifacts cause small but significant reductions of measured VOR gains in HITs with higher, normal-range gains, regardless of calculation method. Artifacts in abnormal HITs with low gain increased measurement noise. A larger number of HITs should be performed to confirm abnormal results, regardless of calculation method.
AB - BACKGROUND: International consensus on best practices for calculating and reporting vestibular function is lacking. Quantitative vestibulo-ocular reflex (VOR) gain using a video head impulse test (HIT) device can be calculated by various methods. OBJECTIVE: To compare different gain calculation methods and to analyze interactions between artifacts and calculation methods. METHODS: We analyzed 1300 horizontal HIT traces from 26 patients with acute vestibular syndrome and calculated the ratio between eye and head velocity at specific time points (40 ms, 60 ms) after HIT onset ('velocity gain'), ratio of velocity slopes ('regression gain'), and ratio of area under the curves after de-saccading ('position gain'). RESULTS: There was no mean difference between gain at 60 ms and position gain, both showing a significant correlation (r2 = 0.77, p < 0.001) for artifact-free recordings. All artifacts reduced high, normal-range gains modestly (range -0.06 to -0.11). The impact on abnormal, low gains was variable (depending on the artifact type) compared to artifact-free recordings. CONCLUSIONS: There is no clear superiority of a single gain calculation method for video HIT testing. Artifacts cause small but significant reductions of measured VOR gains in HITs with higher, normal-range gains, regardless of calculation method. Artifacts in abnormal HITs with low gain increased measurement noise. A larger number of HITs should be performed to confirm abnormal results, regardless of calculation method.
KW - HIT device
KW - VOR
KW - area under the curve
KW - artifacts
KW - calculation methods
KW - gain
KW - position gain
KW - regression
KW - regression gain
KW - vHIT
KW - video head impulse test
KW - video-oculography
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U2 - 10.3233/VES-200708
DO - 10.3233/VES-200708
M3 - Article
C2 - 32804110
AN - SCOPUS:85094573305
SN - 0957-4271
VL - 30
SP - 225
EP - 234
JO - Journal of Vestibular Research: Equilibrium and Orientation
JF - Journal of Vestibular Research: Equilibrium and Orientation
IS - 4
ER -