扫描图形视觉诱发电位在视觉发育期儿童中的应用

Sweep pattern visual evoked potential acuity in visual developing children

背景扫描图形视觉诱发电位（SPVEP）作为一种客观视功能检测技术，可被用于婴幼儿及合作度较差的成年人的客观视力测定。已有研究显示，振幅一视角对数（A—LogVA）回归方法可提高SPVEP推算视力的准确性。目的研究SPVEP在视觉发育期儿童中的应用，并比较两种不同的视力推断方法，即振幅一空间频率（A—SP）回归方法和A—LogVA回归方法在儿童，尤其是弱视儿童客观视力评估中的有效性和准确性。方法选取3～12岁各种原因所致弱视儿童26例26眼为弱视组，同时选取与弱视组儿童年龄相匹配的正常儿童31人为正常组。检测其最佳矫正LogMAR视力，并使用视觉电生理仪检测SPVEP，选用0．99～12．89cpd的10个不同空间频率正弦调制水平光栅连续刺激视网膜，结果经离散傅里叶分析后采用A—sP回归方法和A—LogVA回归方法计算SPVEP视力，对检测结果行相关性分析。结果在正常组，由A—sP回归方法和A—LogVA回归方法计算所得的SPVEP视力与LogMAR视力的相关系数分别为0．600（P〈0．01）和0．733（P〈0．01），均数差异有统计学意义（F=113．173，P〈0．01）。由A—sP回归方法所测得的SPVEP视力（A—sP视力）与LogMAR视力均数差值的绝对值为0．40±0．02，由A—LogVA回归方法所测得的SPVEP视力（A—LogVA视力）与LogMAR视力均数差值的绝对值为0．26±0．02，A—SP视力与A—LogVA视力均数差值的绝对值为0．14±O．02。在弱视组，由A—sP回归方法和A—LogVA回归方法计算所得的SPVEP视力与LogMAR视力的相关系数分别为0．134（P=0．515）和0．456（P〈0．05），均数差异有统计学意义（F=5．433，P〈0．05）。A—SP视力与LogMAR视力均数差值的绝对值为0．07±0．05，A—LogVA视力与LogMAR视力均数差值的绝对值为0．12±0．05，A。SP视力与A—LogVA视力均数差值的绝对值为0．05±0．01。在不同视力段，SPVEP视力存在高估或低估现象。结论SPVEP可对正常视力及弱视儿童的客观视力进行评估，且A—LogVA回归方法推断所得客观视力更为准确。

Background Sweep pattern visual evoked potential（SPVEP） acuity, as an objective detective technique of visual function,can be used to measure visual acuity in children and uncooperative adults. Recent studies have shown that the amplitude-logarithm of the visual angle （A-LogVA）function regression method was more accurate than the amplitude-spatial frequency （A-SP）function regression method in evaluating SPVEP acuity. Objective This study was to explore the clinical use of SPVEP acuity in visual developing children and compare the evaluating the SPVEP acuity of children between A-SP function regression method and A-LogVA function regression method. Methods Twenty-six eyes of 26 asthenopic children with age range of 3-12 years and 31 age-matched normal children were enrolled in this study. SPVEP acuity was recorded with GT-2000 NV （ GUOTE MEDICAL APPARATUS LTD,China） using sinusoidally modulated horizontal gratings of 10 different spatial frequencies from 0.99 to 12.89 epd as stimulus. The responses were averaged and displayed through discrete Fourier transformations （DFT） on the monitor display. SPVEP acuity was estimated by using both the SPVEP A-SP function regression method and the SPVEP A-LogVA function regression method. The LogMAR chart was used to acquire LogMAR visual acuity. Results In the normal group,the correlation eoeffieient between LogMAR visual acuity and acuity calculated by theA-SP function regression method was 0. 600 （ P〈0.01 ）. The correlation coefficient between LogMAR visual acuity and acuity calculated by the A-LogVA function regression method was 0. 733 （ P〈0.01 ）. The ANOVA of the LogMAR acuity and the SPVEP acuity calculated from the A-SP function regression method and A-LogVA function regression method were 113. 173 （P〈0.01） ,which indicated that there were significant difference among all of subjects. The differences of the mean values of LogMAR visual acuity and the SPVEP acuity calculated from the A-SP function regression method and A-LogVA function regression method were respectively 0. 40 ±0.02,0.26 ±0.02 and 0. 14 ±0.02. In the amblyopia group,the correlation coefficient between LogMAR visual acuity and acuity calculated by the A-SP function regression method was 0. 134 （P = 0. 515 ）. The correlation coefficient between LogMAR visual acuity and acuity calculated by the A-LogVA function regression method was 0. 456 （P〈0. 05）. The ANOVA of the LogMAR acuity and the SPVEP acuity calculated from the A-SP function regression method and A-LogVA function regression method were 3. 433 （ P〈0.05 ） , indicating that there were significant difference among all of subjects. The differences of the mean values of LogMAR visual acuity and the SPVEP acuity calculated from the A-SP function regression method and A-LogVA function regression method were 0.07 ±0.05,0. 12 ±0.05 and 0.05± 0.01 respectively. Conclusions SPVEP can evaluate the visual acuity in children, although SPVEP acuity may overestimate or underestimate acuity in comparison with different LogMAR visual acuities. The amplitude-LogVA function regression method is more accurate in extrapolating SPVEP acuity.