Effects of obesity on time-frequency components of electroretinogram signal using continuous wavelet transform

•There different responses of ERG signals for each levels of disease are analyzed to show physiological effect of obesity.•Effects of obesity levels are also researched with two majority components (“a” and “b” waves) of ERG.•The effects of obesity on ERG signals show with statistical analysis on time domain.•The effects of obesity on ERG signals show with STFT, CWT and DWT analysis on time-frequency domains.•The present paper is the first attempt to address the effects of obesity on ERG signals. We investigate impacts of the obesity on three different responses (cone, rod and maximal combined) of electroretinogram signals. To analyze and extract features of the responses, two major components of electroretinogram signal (namely “a” and “b” waves) have been used. The amplitudes and respective peak times of the waves have been firstly calculated by using statistical methods in time domain. These time domain analysis could be integrated by time-frequency domain analysis to reflect electroretinogram components considerably. To achieve this aim, we have analyzed the “a” and “b” waves by applying short time Fourier transform, continuous wavelet transform and discrete wavelet transform methods on electroretinogram signals. Our findings prove that the continuous wavelet transform gives better results than other methods with respect to time-frequency results extracted from scalogram analyses. In this context, it is also showed that the usage of Mexican hat is the most proper wavelet to analyze obesity effect on electroretinogram. Moreover, we show that the “a” wave does not change considerably by obesity for electroretinogram responses. On the contrary, the “b” wave is significantly affected from obesity for maximal combined response as compared with other responses. The novelty of this work lies in the fact that the present paper is the first attempt to address the effects of obesity on electroretinogram signals. Furthermore, it is clearly denoted that the electroretinogram signals are affected adversely with levels of the obesity.