title: Changes in rod and cone-driven oscillatory potentials in the aging human retina.
abstract: OBJECTIVE
  We recorded oscillatory potentials (OPs) to document how age impacts on rod- and cone-driven inner retina function.
  
  
  METHODS
  Dark- and light-adapted electroretinogram (ERG) luminance-response functions were recorded in healthy human subjects aged 20 to 39, 40 to 59, and 60 to 82 years. Raw ERG traces (0.1-300 Hz) were filtered (75-300 Hz) to measure OPs trough-to-peak in the time-amplitude domain. Morlet wavelet transform (MWT) allowed documenting OPs time-amplitude-frequency distribution from raw traces.
  
  
  RESULTS
  Under dark adaptation, both methods revealed reduced OP amplitudes and prolonged implicit times by 40 years of age. The MWT identified a high-frequency band as the main oscillator, which frequency (150-155 Hz) was unaffected by age. Under light adaptation, most OP peaks were delayed by 40 years of age. Peak-trough measures yielded inconsistent results in relation to luminance. Contrastingly, MWT distinguished two frequency bands at all luminances: high frequency (135 ± 6 Hz) time locked to the onset of early OPs and low frequency (82 ± 7 Hz), giving rise to early and late OPs. By 60 years, there was a consistent power reduction specific to the low-frequency band.
  
  
  CONCLUSIONS
  Age-related OP changes precede those seen with a- (photoreceptoral) and b-waves (postphotoreceptoral). In addition, MWT allows quantifying distinct low- and high-frequency oscillators in the human retina, which complement traditional OP analysis methods. The identification of an age-independent OP marker (light-adapted high frequency band) opens a new dimension for the screening of retinal degenerations and their impact on inner retina function.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Ioannis S
authors.initials: IS
authors.lastname: Dimopoulos
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Paul R
authors.initials: PR
authors.lastname: Freund
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Tanner
authors.initials: T
authors.lastname: Redel
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Blake
authors.initials: B
authors.lastname: Dornstauder
authors.affiliation: Department of Internal Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Gregory
authors.initials: G
authors.lastname: Gilmour
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, Alberta, Canada Department of Physiology, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Yves
authors.initials: Y
authors.lastname: Sauvé
mesh_terms: D000221:Adaptation, Ocular; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D003623:Dark Adaptation; D004596:Electroretinography / Q000379:methods*; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation; D012016:Reference Values; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology*; D017948:Retinal Rod Photoreceptor Cells / Q000502:physiology*; D055815:Young Adult
keywords: Morlet wavelet transform; aging; electroretinogram; human; oscillatory potentials; retina