title: Advance in ERG analysis: from peak time and amplitude to frequency, power, and energy.
abstract: OBJECTIVE
  To compare time domain (TD: peak time and amplitude) analysis of the human photopic electroretinogram (ERG) with measures obtained in the frequency domain (Fourier analysis: FA) and in the time-frequency domain (continuous (CWT) and discrete (DWT) wavelet transforms).
  
  
  METHODS
  Normal ERGs (n = 40) were analyzed using traditional peak time and amplitude measurements of the a- and b-waves in the TD and descriptors extracted from FA, CWT, and DWT. Selected descriptors were also compared in their ability to monitor the long-term consequences of disease process.
  
  
  RESULTS
  Each method extracted relevant information but had distinct limitations (i.e., temporal and frequency resolutions). The DWT offered the best compromise by allowing us to extract more relevant descriptors of the ERG signal at the cost of lesser temporal and frequency resolutions. Follow-ups of disease progression were more prolonged with the DWT (max 29 years compared to 13 with TD).
  
  
  CONCLUSIONS
  Standardized time domain analysis of retinal function should be complemented with advanced DWT descriptors of the ERG. This method should allow more sensitive/specific quantifications of ERG responses, facilitate follow-up of disease progression, and identify diagnostically significant changes of ERG waveforms that are not resolved when the analysis is only limited to time domain measurements.
authors: Department of Ophthalmology & Neurology-Neurosurgery, Montreal Children's Hospital Research Institute, McGill University, 2300 Tupper Street, Montreal, QC, Canada H3H 1P3.
authors: Mathieu
authors: 0000-0002-8600-5982
authors: M
authors: Gauvin
authors: Département de Génie Électrique, École de Technologie Supérieure, Montréal, QC, Canada ; Centre de Recherches Mathématiques, Montréal, QC, Canada.
authors: Jean-Marc
authors: JM
authors: Lina
authors: Department of Ophthalmology & Neurology-Neurosurgery, Montreal Children's Hospital Research Institute, McGill University, 2300 Tupper Street, Montreal, QC, Canada H3H 1P3.
authors: Pierre
authors: P
authors: Lachapelle
mesh_terms: D000328:Adult; D004596:Electroretinography / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008962:Models, Theoretical; D012160:Retina / Q000503:physiopathology*; D012164:Retinal Diseases / Q000175:diagnosis* / Q000503:physiopathology*