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The detection of disparity evoked potentials in ametropes.

Purpose To investigate the influence of ametropia on stereopsis and its mechanism by using the disparity evoked potential testing. Methods A new set of static random dot stereograms was utilized as a stimulation to elicit the disparity evoked potentials in 21 ametropes and 40 stereo normal subjects. Rezults The P250 wave,which was related to stereoscopic stimulation in ametropes,was recorded in both the ametropes and emetropic stereo normal persons in this series,and the characteristic changes of P250 wave with increasing visual disparity in ametropes were similar to those in normal subjects.The differences of mean amplitudes and latencies of P250 waves between myopes and hyperopes were not significant. Conclusion Ametropia in full correction dose not significanly affect the function of stereopsis. (Chin J Ocul Fundus Dis,1998,14:225-227)

体外循环心脏手术病人的视力及视诱发电位观察

体外循环(CPB)心脏手术后病人的视功能损害,国外已有报道,其主要原因是缺氧、缺血、低温等造成缺血性视神经癍，大脑枕叶病变及视网膜栓塞或梗死所致。我们观察23例患者术前术后的视力及5例患者视诱发电位（visual evoked potential,VEP）的变化。说明CPB心脏手术后可引起或加速缺血性视神经病变的发生和发展；VEP对视功能损害的检查更有价值。 （中华眼底病杂志，1993，9：158-159）

Progresses and prospects on frequency recognition methods for steady-state visual evoked potential

Steady-state visual evoked potential (SSVEP) is one of the commonly used control signals in brain-computer interface (BCI) systems. The SSVEP-based BCI has the advantages of high information transmission rate and short training time, which has become an important branch of BCI research field. In this review paper, the main progress on frequency recognition algorithm for SSVEP in past five years are summarized from three aspects, i.e., unsupervised learning algorithms, supervised learning algorithms and deep learning algorithms. Finally, some frontier topics and potential directions are explored.

Mini visual evoked optential in infants during their sensitive period of visual development

Objective　To observe the changes of amplitude and latency of mini visual evoked optential (mini VEP) examinations in infants at different age.Methods　A total of 84 healthy infants and adults (168 eyes) were randomly selected to underwent mini VEP. According to the age, all the individuals were divided into seven groups: A, 0-3 months; B, 4-6 months; C: 7-12 months; D: 1-3 years; E: 4-6 years; F: 7-12 years; G: adults (control). There were 12 individuals (24 eyes) in each group. By using the stimulater of mini VEP, the flash VEP was performed and the changes of amplitude and latency of P100 wave were recorded and analyzed.Results The average value of amplitude in group A was（7.39plusmn;1.79）mu;V which was the lowest, and the average latency was （137.45plusmn;7.64）ms which was the largest.At the same time, the average amplitude of P100 increased from group A to E (F=359.56); the average latency decreased from Group A to D（F=326.64）; the difference was significant (P＜0.01). The amplitude in group E, F, and G was high and no significant difference was found (F=2.39，P＞0.05);the latency in group D,E,F,and G was short with no significant difference (F=2.64，P＞0.05）.Conclusions　With the growth of the infants' age, the amplitude of miniVEP increases and latency decreases; moreover, the latency reaches the normal adult level in advance of the amplitude of miniVEP.

多导图像视觉诱发电位在黄斑病变中的应用

Changes of Somatosensory Evoked Potentials During Graded Spinal Cord Ischemia/reperfusion Injury in Rabbits

Objective To investigate the relationship between graded spinal cord ischemia/reperfusion injury and somatosensory evoked potentials(SEP),neurologic function score（NFS）and the histopathological changes of spinal cord. Methods Forty rabbits were randomized and equally divided into 4 groups: shamoperation group, ischemia for 30min, 45min and 60min groups. The spinal cord ischemiareperfusion injury model was created by occlusion of the abdominal aorta in rabbits. SEP was monitored before ischemia,5,10minutes after ischemia, 15, 30 minutes, 1,2, 24 and 48 hours after reperfusion. NFS was evaluated at 6,12,24 and 48 hours after reperfusion.The pathological changes of spinal cord were observed after reperfusion 48 hours. Results The pathological characters with mild,moderate and severe spinal cord ischemia/reperfusion injury could be simulated by declamping after 30， 45 and 60 minutes infrarenal aorta crossclamping. SEP amplitude returned to normal after reperfusion 15 minutes（Pgt;0.05）and SEP latency returned to normal after reperfusion 30 minutes（Pgt;0.05）during mild spinal cord ischemia/reperfusion injury.SEP amplitude returned to normal after reperfusion 30 minutes（Pgt;0.05）and SEP latency returned to normal after reperfusion 60 minutes（Pgt;0.05）during moderate spinal cord ischemia/reperfusion injury. SEP latency increased and SEP amplitude decreased during severe spinal cord ischemia/reperfusion injury,compared with other groups, there were significant differences in SEP latency and SEP amplitude by clamping the infrarenal aorta for 60min（Plt;0.01）. With graded spinal cord ischemia/reperfusion injury, compared with shamoperation group, spinal cord ischemiareperfusion groups had significant differences in NFS（Plt;0.01）. Conclusion SEP is much quicker in the recovery of amplitude than latency during spinal cord ischemia/reperfusion. SEP is a sensitive and accurate index for spinal cord function during ischemia/reperfusion injury. SEP monitoring spinal cord ischemia/reperfusion injury during operation provides experimental basis for clinical application.

正确使用视觉电生理技术提高其临床应用价值

以眼部病变为首发症状的脑肿瘤二例

Analysis and Management of Blood Pressure on Intraoperative Cortex Somatosensory Evoked Potential in the Surgery of Severe Scoliosis

ObjectiveTo investigate the influence and management of blood pressure on intraoperative cortex somatosensory evoked potential (CSEP) in the surgery of severe scoliosis. MethodsFrom June 2009 to March 2012, CSEP monitoring during surgery of severe scoliosis were performed on 43 patients, in whom 4 had abnormal CSEP while blood pressure decline. There were 2 males and 21 females. The average age was 16.1 years. The average preoperative Cobb angle was 96.1° (88.7-107.5°). Latency and amplitude of cortical potentials were observed with the value of the latency extension more than 10% and peak amplitude reduction more than 50% defined as abnormality. The arterial blood pressure (ABP) was used to evaluate the intraoperative blood pressure. ResultThe incidence rate of bilateral CSEP wave abnormalities after blood pressure decline was 9.3% in the surgery of severe scoliosis. One case of CSEP abnormality occurred during the installing of pedicle screws; two cases during the Smith-Petersen osteotomy, and one case during the bone graft after correction. With the ABP dropping to about 92/57 mm Hg (1 mm Hg=0.133 kPa), the amplitude decreased 80% in 24-33 minutes. After the ABP increased to 113/75 mm Hg by treatment, the index was backed up normally in 5-10 minutes. There was no neurological complication after surgery. ConclusionA high incidence rate and significantly decreased amplitude of CSEP abnormality after blood pressure decline in the surgery of severe scoliosis are found. Intraoperative stable blood pressure should be maintained for patients with severe scoliosis. When the amplitude of CSEP decreases followed with blood pressure decline, blood pressure should be actively corrected by treatment, so that the CSEP may get back to normal as soon as possible.

球后视神经炎与前部缺血性视神经病变的图形视觉诱发电位分析

目的 研究球后视神经炎与前部缺血性视神经病变患者在图形视觉诱发电位（pattern visual evoked potential，P-VEP）上的改变。 方法 对临床上确诊为球后视神经炎的患者 34 例共 41 只眼、前部缺血性视神经病变的患者 30 例共 38 只眼以及无任何眼部疾病的正常者 25 例共 50 只眼进行 P-VEP 检查，比较分析球后视神经炎与前部缺血性视神经病变患者、正常者相比 P-VEP 的 P100 波潜伏时及振幅的改变。 结果 球后视神经炎组患者 P-VEP 的 P100 波潜伏时为（111.93±9.16）ms，振幅为（10.69±7.29）μV；前部缺血性视神经病变组患者 P100 波潜伏时为（115.11±11.91）ms，振幅为（8.29±4.96）μV；正常组 P100 波潜伏时为（100.61±4.14）ms，振幅为（13.74±4.78）μV。球后视神经炎组患者与正常组相比 P-VEP 的 P100 波潜伏时差异有统计学意义（P<0.001），振幅之间的差异无统计学意义（P=0.071）；前部缺血性视神经病变组患者与正常组相比 P-VEP 的 P100 波潜伏时与振幅差异均有统计学意义（P<0.001）；前部缺血性视神经病变组患者与球后视神经炎组患者相比 P-VEP 的 P100 波潜伏时与振幅差异均无统计学意义（P=0.059）。 结论 球后视神经炎与前部缺血性视神经病变患者的 P-VEP 均有所改变，球后视神经炎患者主要表现为潜伏时的改变，而前部缺血性视神经病变患者在潜伏时与振幅上均有所改变，但两组患者间 P-VEP 的差别不明显。因此，P-VEP 可以作为诊断球后视神经炎与前部缺血性视神经病变的重要依据，但是 P-VEP 的改变不能作为鉴别诊断视神经炎与前部缺血性视神经病变的指标，若要鉴别这两种疾病还需要联合其他检查手段才能完成。