Ritter Michelle Sari, Bertolini Giovanni, Straumann Dominik, Bögli Stefan Yu
Department of Neurology, University Hospital Zurich, Zurich, Switzerland.
University of Zurich, Zurich, Switzerland.
Front Neurol. 2020 Oct 22;11:547015. doi: 10.3389/fneur.2020.547015. eCollection 2020.
Cerebellar diseases frequently affect the ocular motor neural velocity-to-position integrator by increasing its leakiness and thereby causing gaze-evoked nystagmus (GEN) and rebound nystagmus (RN). Minor leakiness is physiological and occasionally causes GEN in healthy humans. We aimed to evaluate the characteristics of GEN/RN in healthy subjects for better differentiation between physiological and pathological GEN/RN. Using video-oculography, eye position was measured in 14 healthy humans at straight ahead eye position before and after, and during 30 s of ocular fixation at 4 horizontal eccentric targets between 30° and 45°. We determined the eye drift velocity and the prevalence of nystagmus before/during/after eccentric fixation. Eye drift velocities during (range: 0.62 ± 0.53°/s to 1.78 ± 0.69°/s) and after eccentric gaze (range: 0.28 ± 0.52°/s to 1.48 ± 1.02°/s) increased with the amount of gaze eccentricity (30°-45°). During continuous eccentric gaze, eye drift velocities decreased by 0.41 ± 0.18°/s at 30°, and 0.84 ± 0.38°/s at 45° gaze eccentricity. GEN was elicited in 71% of subjects at 30° gaze eccentricity. Twenty-one percent showed RN thereafter. This prevalence increased to 100% (GEN)/72% (RN) at 45° gaze eccentricity. RN found after 30° gaze eccentricity was of low velocity (0.82 ± 0.21°/s) and occurred after minor drift velocity decrease during prior eccentric gaze (0.43 ± 0.15°/s). GEN and RN should be tested using horizontal gaze eccentricities of <30°, since most healthy subjects physiologically show GEN and RN at higher eccentricities. In case of an uncertain result, both the reduction of eye drift velocity during eccentric gaze and the velocity of RN can be analyzed to distinguish physiological from pathological nystagmus.
小脑疾病常常通过增加其泄漏性来影响眼球运动神经速度-位置积分器，从而导致视动性眼震（GEN）和反弹眼震（RN）。轻微泄漏是生理性的，偶尔会在健康人中引起GEN。我们旨在评估健康受试者中GEN/RN的特征，以便更好地区分生理性和病理性GEN/RN。使用视频眼震图，在14名健康人向前平视时、向前平视前后以及在30°至45°之间的4个水平偏心目标上进行30秒的眼球注视期间，测量其眼位。我们确定了偏心注视前/期间/后的眼漂移速度和眼震发生率。偏心注视期间（范围：0.62±0.53°/秒至1.78±0.69°/秒）和偏心注视后（范围：0.28±0.52°/秒至1.48±1.02°/秒）的眼漂移速度随着注视偏心度（30°-45°）的增加而增加。在持续偏心注视期间，在30°注视偏心度时眼漂移速度降低0.41±0.18°/秒，在45°注视偏心度时降低0.84±0.38°/秒。在30°注视偏心度时，71%的受试者诱发了GEN。此后，21%的受试者出现了RN。在45°注视偏心度时，这一发生率增加到100%（GEN）/72%（RN）。在30°注视偏心度后发现的RN速度较低（0.82±0.21°/秒），并且发生在先前偏心注视期间眼漂移速度轻微降低（0.43±0.15°/秒）之后。应使用<30°的水平注视偏心度来测试GEN和RN，因为大多数健康受试者在较高偏心度时生理性地表现出GEN和RN。如果结果不确定，可以分析偏心注视期间眼漂移速度的降低以及RN的速度，以区分生理性和病理性眼震。
