Functional decomposition of the human ERG based on the discrete wavelet transform
Functional decomposition of the human ERG based on the discrete wavelet transform
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DOI：
10.1167/15.16.14
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发表时间：
2015-01-01
影响因子：
1.8
通讯作者：
Lachapelle, Pierre
中科院分区：
文献类型：
--
作者：
Gauvin, Mathieu;Little, John M.;Lachapelle, Pierre
视网膜电图 (ERG) 的形态可能因视网膜的正常和病理过程而改变。然而，鉴于 ERG 几乎仅根据其幅度和时间进行评估，定义 ERG 波形的形状以便系统地、可重复地检测微妙的、生理驱动的形态变化仍然是一个具有挑战性的问题。我们研究了离散小波变换 (DWT) 是否可以应对这一挑战。使用 ERG 的 DWT 描述符对引起各种亮度强度的正常人类明视 ERG（产生各种形状、幅度和时间的波形）进行分析。使用各种 DWT 描述符生成的亮度响应曲线揭示了不同的 (p < 0.05) 亮度依赖性模式，表明刺激亮度以不同方式调节 ERG 的各种时频分量及其形态。后者代表了研究 DWT 获得的 ERG 描述符的亮度依赖性的首次尝试。还介绍了从受 ON 或 OFF 视网膜通路异常影响的患者获得的 ERG 分析。我们在这里首次表明，不同的时频描述符可以与开和关锥体通路的功能具体相关。因此，在这项研究中，DWT 揭示了在各种信号幅度和形态上可重复的、具有生理意义和诊断相关的 ERG 描述符。因此，DWT 分析对电生理学家的装备来说是一个有价值的补充，它将改善正常和病理 ERG 反应的量化和解释。
The morphology of the electroretinogram (ERG) can be altered as a result of normal and pathological processes of the retina. However, given that the ERG is almost solely assessed in terms of its amplitude and timing, defining the shape of the ERG waveform so that subtle, physiologically driven, morphological changes can be systematically and reproducibly detected remains a challenging problem. We examined if the discrete wavelet transform (DWT) could meet this challenge. Normal human photopic ERGs evoked to a broad range of luminance intensities (to yield waveforms of various shapes, amplitudes, and timings) were analyzed using DWT descriptors of the ERG. Luminance-response curves that were generated using the various DWT descriptors revealed distinct (p < 0.05) luminance-dependence patterns, indicating that the stimulus luminance differently modulates the various time-frequency components of the ERG and thus its morphology. The latter represents the first attempt to study the luminance-dependence of ERG descriptors obtained with the DWT. Analyses of ERGs obtained from patients affected with ON or OFF retinal pathway anomalies were also presented. We show here for the first time that distinct time-frequency descriptors can be specifically associated to the function of the ON and OFF cone pathway. Therefore, in this study, the DWT revealed reproducible, physiologically meaningful and diagnostically relevant descriptors of the ERG over a wide range of signal amplitudes and morphologies. The DWT analysis thus represents a valuable addition to the electrophysiologist's armamentarium that will improve the quantification and interpretation of normal and pathological ERG responses.