Zhou Peng, Zhao Ming-Wei, Li Xiao-Xin, Hu Xiao-Feng, Wu Xi, Niu Lan-Jun, Yu Wen-Zhen, Xu Xiu-Lan
Department of Ophthalmology, Peking University People's Hospital, Beijing, 100044, People's Republic of China.
Doc Ophthalmol. 2008 Sep;117(2):85-91. doi: 10.1007/s10633-007-9095-4. Epub 2007 Oct 31.
In order to compare the amplitude-spatial frequency (A-SP) regression method with amplitude-logVA (A-logVA) regression methods in extrapolating the sweep pattern visual evoked potential (SPVEP) acuity.
We measured SPVEPs in 21 children and three adults using sinusoidally-modulated horizontal gratings as stimuli. The responses were averaged and displayed through discrete Fourier transformations. SPVER acuity was then estimated by using both the SPVEP amplitude- spatial frequency function (A-SP function regression method) and the SPVEP amplitude-log visual-angle function (A-logVA function regression method). Furthermore, the Bailey Lovie logMAR chart was employed to define visual acuity. Curve estimates were calculated to derive a correlation index (R) for each method.
There are significant differences (t = 2.71, P < 0.05) between the correlation indices of curves obtained using the A-logVA function (logarithmic model, 0.95 +/- 0.01) and that obtained by the A-SP function (inverse model, 0.92 +/- 0.02). The overall correlation coefficient (r) between logMAR acuity and acuity calculated by the A-logVA regression method was 0.32 (P < 0.05). The overall correlation coefficient (r) between logMAR acuity and acuity calculated by the A-SP regression method was 0.41 (P < 0.05). Paired t-tests show that SPVEP acuity from the A-logVA function was not significantly different from acuities of the logMAR function (t = 1.77, P = 0.09). The difference in their mean values is 0.14 +/- 0.08. However, SPVEP acuity calculated using the A-SP function regression method is significantly different from the acuity calculated from the logMAR function (t = 10.09, P < 0.01). The difference in their mean values is 0.41 +/- 0.04.
The amplitude-logVA function regression method is more accurate in estimating SPVEP acuity in normal subjects with good visual acuity.
为了比较振幅-空间频率（A-SP）回归方法与振幅-对数视力（A-logVA）回归方法在外推扫描模式视觉诱发电位（SPVEP）视力方面的差异。
我们使用正弦调制的水平光栅作为刺激，测量了21名儿童和3名成人的SPVEP。通过离散傅里叶变换对反应进行平均并显示。然后使用SPVEP振幅-空间频率函数（A-SP函数回归方法）和SPVEP振幅-对数视角函数（A-logVA函数回归方法）来估计SPVER视力。此外，采用贝利-洛维对数最小分辨角视力表来定义视力。计算曲线估计值以得出每种方法的相关指数（R）。
使用A-logVA函数（对数模型，0.95±0.01）获得的曲线相关指数与使用A-SP函数（反比模型，0.92±0.02）获得的曲线相关指数之间存在显著差异（t = 2.71，P < 0.05）。对数最小分辨角视力与通过A-logVA回归方法计算的视力之间的总体相关系数（r）为0.32（P < 0.05）。对数最小分辨角视力与通过A-SP回归方法计算的视力之间的总体相关系数（r）为0.41（P < 0.05）。配对t检验表明，A-logVA函数得出的SPVEP视力与对数最小分辨角函数的视力无显著差异（t = 1.77，P = 0.09）。它们的平均值差异为0.14±0.08。然而，使用A-SP函数回归方法计算的SPVEP视力与根据对数最小分辨角函数计算的视力有显著差异（t = 10.09，P < 0.01）。它们的平均值差异为0.41±0.04。
对于视力良好的正常受试者，振幅-对数VA函数回归方法在估计SPVEP视力方面更准确。
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