TY - JOUR
T1 - Clinical electrophysiology of two rod pathways
T2 - Normative values and clinical application
AU - Scholl, H.
AU - Langrová, H.
AU - Weber, B.
AU - Zrenner, E.
AU - Apfelstedt-Sylla, E.
N1 - Funding Information:
Acknowledgements We thank D.C. Hood and L.T. Sharpe for discussions; K. White for help on the manuscript; A. Gal for providing the data on the rhodopsin mutation; K. Götz for technical assistance; J. Kremers, P. Strasser, and M. Herzog for their aid with data analysis. This work was supported by fortüne grant 707-0-0 (Tübingen, Germany) to H.P.N.S., by fortüne grant 514-0-0 (Tübingen, Germany) to H.L., by a grant from the Deutsche For-schungsgemeinschaft (Ap 57/3–1) to E.A.-S., and by a grant from the Deutsche Forschungsgemeinschaft (We 1259/10–1) to B.H.F.W.
PY - 2001
Y1 - 2001
N2 - Background: The scotopic 15-Hz flicker electroretinogram (ERG) has two limbs (slow and fast ERG rod signals), and these have been attributed to two retinal rod pathways (the ON rod bipolar and A II amacrine pathway and the rod-cone gap-junction pathway). The aim of this study was to provide normative values of the scotopic 15-Hz flicker ERG, to estimate the inter-individual variability, and to apply this method to a clinical setting. Methods: Twenty-two normal subjects, one patient with retinitis pigmentosa (RP), and two patients with Stargardt's macular dystrophy (SMD) participated in the study. The SMD patients were screened for mutations in the 50 exons of the ABCA4 (formerly ABCR) gene. We measured ERG response amplitudes and phases to flicker intensities ranging from -3.37 to -0.57 log scotopic trolands s at a flicker frequency of 15 Hz. Results: The normal scotopic 15-Hz. flicker ERG showed a biphasic amplitude pattern with a minimum at about -1.57 log scotopic trolands s, where there was an abrupt phase shift of about 180 deg. The inter-individual variability in ERG amplitude ranged from 47% to 67% for the slow and from 41% to 64% for the fast rod signal. Both the RP patient and the SMD patients (who were compound heterozygotes for mutations in the ABCA4 gene) showed reduced amplitudes for the two rod ERG pathways. Conclusion: The inter-individual variability might be explained by anatomical differences between individual retinae. In the RP patient, the amplitude reductions corresponded well with the standard rod ERG. In the SMD patients, however, the scotopic 15-Hz flicker ERG revealed rod dysfunction, whereas the standard rod ERG was within normal limits; The scotopic 15-Hz flicker method may be more sensitive than the standard rod ERG.
AB - Background: The scotopic 15-Hz flicker electroretinogram (ERG) has two limbs (slow and fast ERG rod signals), and these have been attributed to two retinal rod pathways (the ON rod bipolar and A II amacrine pathway and the rod-cone gap-junction pathway). The aim of this study was to provide normative values of the scotopic 15-Hz flicker ERG, to estimate the inter-individual variability, and to apply this method to a clinical setting. Methods: Twenty-two normal subjects, one patient with retinitis pigmentosa (RP), and two patients with Stargardt's macular dystrophy (SMD) participated in the study. The SMD patients were screened for mutations in the 50 exons of the ABCA4 (formerly ABCR) gene. We measured ERG response amplitudes and phases to flicker intensities ranging from -3.37 to -0.57 log scotopic trolands s at a flicker frequency of 15 Hz. Results: The normal scotopic 15-Hz. flicker ERG showed a biphasic amplitude pattern with a minimum at about -1.57 log scotopic trolands s, where there was an abrupt phase shift of about 180 deg. The inter-individual variability in ERG amplitude ranged from 47% to 67% for the slow and from 41% to 64% for the fast rod signal. Both the RP patient and the SMD patients (who were compound heterozygotes for mutations in the ABCA4 gene) showed reduced amplitudes for the two rod ERG pathways. Conclusion: The inter-individual variability might be explained by anatomical differences between individual retinae. In the RP patient, the amplitude reductions corresponded well with the standard rod ERG. In the SMD patients, however, the scotopic 15-Hz flicker ERG revealed rod dysfunction, whereas the standard rod ERG was within normal limits; The scotopic 15-Hz flicker method may be more sensitive than the standard rod ERG.
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U2 - 10.1007/s004170000232
DO - 10.1007/s004170000232
M3 - Article
C2 - 11372548
AN - SCOPUS:0035074335
SN - 0721-832X
VL - 239
SP - 71
EP - 80
JO - Graefe's Archive for Clinical and Experimental Ophthalmology
JF - Graefe's Archive for Clinical and Experimental Ophthalmology
IS - 2
ER -