Ebdali Samira, Hashemi Bijan, Hashemi Hassan, Jafarzadehpur Ebrahim, Asgari Soheila
Medical Physics Department, Faculty of Medical Sciences, Tarbiat Modares University, Jalal Ale Ahmad Highway, P.O. Box: 14115-111, Tehran, Iran.
Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran.
Int Ophthalmol. 2018 Dec;38(6):2435-2444. doi: 10.1007/s10792-017-0748-3. Epub 2017 Nov 30.
To evaluate the effects of retinitis pigmentosa (RP) on time, frequency, and time-frequency components of Xenon flash ERG signals using Fourier and wavelet transforms.
Xenon flash ERG was done in 18 eyes of nine RP patients and 20 normal eyes. After examining latency and amplitude, Fourier and wavelet transforms were performed using MATLAB software. Then, we extracted the mode frequency from the Fourier transform and main frequencies and their occurrence time from the wavelet transform. Finally, mean differences were analyzed using statistical tests.
The results indicated increased latency and reduced ERG wave amplitude, no significant inter-group difference in the average mode frequency, and significant reduction in main signal frequencies and their increased occurrence times. Also one or two of the three main frequencies had disappeared in more advanced cases.
Retinitis pigmentosa can induce changes in ERG time and time-frequency components. Impacted areas can be identified more accurately by wavelet transform and converting scales to frequencies.
使用傅里叶变换和小波变换评估视网膜色素变性（RP）对氙闪光视网膜电图（ERG）信号的时间、频率和时频成分的影响。
对9例RP患者的18只眼和20只正常眼进行氙闪光ERG检查。在检查潜伏期和振幅后，使用MATLAB软件进行傅里叶变换和小波变换。然后，我们从傅里叶变换中提取模式频率，从小波变换中提取主要频率及其出现时间。最后，使用统计检验分析平均差异。
结果表明潜伏期延长和ERG波振幅降低，平均模式频率组间无显著差异，主要信号频率显著降低且其出现时间增加。在更晚期的病例中，三个主要频率中的一个或两个也消失了。
视网膜色素变性可引起ERG时间和时频成分的变化。通过小波变换并将尺度转换为频率，可以更准确地识别受影响的区域。
