Origin of deficits in the flicker electroretinogram of the cone system in X-linked retinoschisis as derived from response nonlinearities.
The aim of this study was to identify the origin of a high-frequency attenuation in the flicker electroretinogram (ERG) of patients with X-linked retinoschisis (XLRS) through an analysis of nonlinearities in the ERG response. The ERGs of six patients with XLRS and six age-similar control subjects were recorded in response to stimuli that consisted of pairs of sinusoids that had varying temporal frequencies and that differed by either 8 or 16 Hz. Compared with the control subjects, the patients with XLRS showed a significant reduction in the amplitude of the difference frequency to high-frequency stimuli that paralleled the high-frequency attenuation of their ERG response fundamental. This result indicates that a response attenuation at an initial linear filter, most likely photoreceptoral, was a major determinant of the reduced ERG amplitude of the XLRS patients at high temporal frequencies. Additional analyses of nonlinearities in the ERG responses provided evidence of a postreceptoral component to the flicker ERG deficits of the XLRS patients, as well.
Alexander
K R
KR
Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, 60612, USA. kennalex@uic.edu
Barnes
C S
CS
Fishman
G A
GA
D000328:Adult; D004596:Electroretinography / Q000592:standards*; D005260:Female; D008040:Genetic Linkage; D006801:Humans; D008268:Macular Degeneration / Q000175:diagnosis* / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation / Q000379:methods; D012016:Reference Values; D017949:Retinal Cone Photoreceptor Cells / Q000503:physiopathology*; D014960:X Chromosome