Strain G M, Claxton M S, Olcott B M, Turnquist S E
Department of Veterinary Physiology, Pharmacology, and Toxicology, School of Veterinary Medicine, Louisiana State University, Baton Rouge 70803-8420.
Am J Vet Res. 1990 Oct;51(10):1513-7.
Electrodiagnostic visual testing (electroretinogram [ERG] and visual-evoked potential [VEP]) was performed on 5 ruminants (3 lambs, 1 kid, and 1 steer) with thiamine-responsive polioencephalomalacia (PEM) and on 2 sheep with listeriosis. The lambs and kid had typical clinical signs of PEM, especially blindness. In these animals, the ERG was normal but the VEP was abnormal. Follow-up recordings in the kid and 1 lamb indicated an improvement in VEP recordings accompanying a gradual return of vision after thiamine treatment. Possible subtle changes in VEP peak latencies could not be assessed because of lack of normative VEP data for sheep and goats. All animals had complete return of vision (owner-assessed). The steer did not have signs of blindness, and the ERG and VEP were normal. Changes in VEP accompanying permanent PEM blindness are not known. One sheep with suspected listeriosis had lack of menace response and palpebral and corneal reflexes, but had intact vision. The ERG and VEP were normal. The second sheep with suspected listeriosis had intact menace response and vision, but became acutely blind and died; the ERG was normal, but VEP amplitudes were depressed.
对5只患有硫胺素反应性脑灰质软化症（PEM）的反刍动物（3只羔羊、1只小山羊和1头公牛）以及2只患有李氏杆菌病的绵羊进行了电诊断视觉测试（视网膜电图[ERG]和视觉诱发电位[VEP]）。羔羊和小山羊有PEM的典型临床症状，尤其是失明。在这些动物中，ERG正常但VEP异常。对小山羊和1只羔羊的后续记录表明，硫胺素治疗后，随着视力逐渐恢复，VEP记录有所改善。由于缺乏绵羊和山羊的VEP标准数据，无法评估VEP峰值潜伏期可能存在的细微变化。所有动物的视力均完全恢复（主人评估）。公牛没有失明迹象，ERG和VEP均正常。永久性PEM失明伴随的VEP变化尚不清楚。一只疑似患有李氏杆菌病的绵羊没有威胁反应、眼睑和角膜反射，但视力完好。ERG和VEP均正常。第二只疑似患有李氏杆菌病的绵羊有完整的威胁反应和视力，但突然失明并死亡；ERG正常，但VEP振幅降低。
