Welgampola Miriam S, Migliaccio Americo A, Myrie Oluwaseun A, Minor Lloyd B, Carey John P
Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Missenden Road, Camperdown, Sydney, NSW 2050, Australia.
Clin Neurophysiol. 2009 Jan;120(1):158-66. doi: 10.1016/j.clinph.2008.06.020. Epub 2008 Dec 12.
Sound and vibration evoke a short-latency eye movement or "sound-evoked vestibulo-ocular reflex" (VOR) and an infraorbital surface potential: the "ocular vestibular-evoked myogenic potential" (OVEMP). We examined their relationship by measuring the modulation of both responses by gaze and stimulus parameters.
In seven subjects with superior semicircular-canal dehiscence (SCD) and six controls, the sound-evoked VOR was measured in 3D using scleral search coils. OVEMPs were recorded simultaneously, using surface electromyography.
Eye movement onset (11.6+/-0.8ms) coincided with the OVEMP peak (12.1+/-0.35ms). OVEMP and VOR magnitudes were 5-15 times larger in SCD compared with controls. OVEMP amplitudes were maximal on upgaze and abolished on downgaze; VOR magnitudes were unaffected. When stimulus type was changed from sound to vibration, OVEMP and VOR changed concordantly: increasing in controls and decreasing in SCD. OVEMP and VOR tuned to identical stimulus frequencies. OVEMP and VOR magnitudes on upgaze were significantly correlated (R=0.83-0.97).
Selective decrease of the OVEMP upon downgaze is consistent with relaxation or retraction of the inferior oblique muscles. The temporal relationship of OVEMP and VOR and their identical modulation by external factors confirms a common origin.
Sound-evoked OVEMP and VOR represent the electrical and mechanical correlates of the same vestibulo-ocular response.
声音和振动可诱发一种短潜伏期眼动或“声音诱发前庭眼反射”（VOR）以及眶下表面电位：“眼前庭诱发肌源性电位”（OVEMP）。我们通过测量注视和刺激参数对这两种反应的调节来研究它们之间的关系。
在7名患有上半规管裂（SCD）的受试者和6名对照者中，使用巩膜搜索线圈以三维方式测量声音诱发的VOR。同时使用表面肌电图记录OVEMP。
眼动起始（11.6±0.8毫秒）与OVEMP峰值（12.1±0.35毫秒）同时出现。与对照者相比，SCD患者的OVEMP和VOR幅度大5至15倍。OVEMP幅度在向上注视时最大，在向下注视时消失；VOR幅度不受影响。当刺激类型从声音变为振动时，OVEMP和VOR变化一致：在对照者中增加，在SCD患者中减少。OVEMP和VOR调谐到相同的刺激频率。向上注视时的OVEMP和VOR幅度显著相关（R = 0.83 - 0.97）。
向下注视时OVEMP的选择性降低与下斜肌的松弛或回缩一致。OVEMP和VOR的时间关系以及它们受外部因素的相同调节证实了共同起源。
声音诱发的OVEMP和VOR代表了同一种前庭眼反应的电和机械相关指标。
