title: Assessing the Contribution of the Oscillatory Potentials to the Genesis of the Photopic ERG with the Discrete Wavelet Transform.
abstract: The electroretinogram (ERG) is composed of slow (i.e., a-, b-waves) and fast (i.e., oscillatory potentials: OPs) components. OPs have been shown to be preferably affected in some diseases (such as diabetic retinopathy), while the a- and b-waves remain relatively intact. The purpose of this study was to determine the contribution of OPs to the building of the ERG and to examine whether a signal mostly composed of OPs could also exist. DWT analyses were performed on photopic ERGs (flash intensities: -2.23 to 2.64 log cd·s·m-2in 21 steps) obtained from normal subjects (n= 40) and patients (n= 21) affected with a retinopathy. In controls, the %OP value (i.e., OPs energy/ERG energy) is stimulus- and amplitude-independent (range: 56.6-61.6%; CV = 6.3%). In contrast, the %OPs measured from the ERGs of our patients varied significantly more (range: 35.4%-89.2%;p< 0.05) depending on the pathology, some presenting with ERGs that are almost solely composed of OPs. In conclusion, patients may present with a wide range of %OP values. Findings herein also support the hypothesis that, in certain conditions, the photopic ERG can be mostly composed of high-frequency components.
authors.affiliation: Department of Ophthalmology, Research Institute of the McGill University Health Centre/Montreal Children's Hospital, Montréal, QC, Canada; Department of Neurology-Neurosurgery, Research Institute of the McGill University Health Centre/Montreal Children's Hospital, Montréal, QC, Canada.
authors.forename: Mathieu
authors.identifier: 0000-0002-8600-5982
authors.initials: M
authors.lastname: Gauvin
authors.affiliation: Department of Ophthalmology, Research Institute of the McGill University Health Centre/Montreal Children's Hospital, Montréal, QC, Canada.
authors.forename: Allison L
authors.initials: AL
authors.lastname: Dorfman
authors.affiliation: Department of Ophthalmology, Research Institute of the McGill University Health Centre/Montreal Children's Hospital, Montréal, QC, Canada.
authors.forename: Nataly
authors.initials: N
authors.lastname: Trang
authors.affiliation: Department of Ophthalmology, Research Institute of the McGill University Health Centre/Montreal Children's Hospital, Montréal, QC, Canada.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Gauthier
authors.affiliation: Department of Ophthalmology, Research Institute of the McGill University Health Centre/Montreal Children's Hospital, Montréal, QC, Canada.
authors.forename: John M
authors.initials: JM
authors.lastname: Little
authors.affiliation: Département de Génie Électrique, École de Technologie Supérieure, Montréal, QC, Canada; Centre de Recherches Mathématiques, Montréal, QC, Canada.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Lina
authors.affiliation: Department of Ophthalmology, Research Institute of the McGill University Health Centre/Montreal Children's Hospital, Montréal, QC, Canada; Department of Neurology-Neurosurgery, Research Institute of the McGill University Health Centre/Montreal Children's Hospital, Montréal, QC, Canada.
authors.forename: Pierre
authors.identifier: 0000-0002-7792-1102
authors.initials: P
authors.lastname: Lachapelle
mesh_terms: D004596:Electroretinography / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008962:Models, Theoretical