Mortlock, Katharine Eirlys ORCID: https://orcid.org/0000-0003-4745-7297, Binns, Alison, Aldebasi, Yousef H. and North, Rachel Valerie ORCID: https://orcid.org/0000-0002-6657-5099 2010. Inter-subject, inter-ocular and inter-session repeatability of the photopic negative response of the electroretinogram recorded using DTL and skin electrodes. Documenta Ophthalmologica 121 (2) , pp. 123-134. 10.1007/s10633-010-9239-9 |
Abstract
The photopic negative response (PhNR) has attracted interest as a flash ERG component reflecting inner retinal activity, with investigators adopting various approaches to analysing the response. This study has two principal aims: first to determine the most reliable technique for assessing the PhNR amplitude; secondly to compare the repeatability characteristics of the PhNR recorded using DTL and skin active electrodes. Electroretinograms were recorded in 31 subjects, using both electrode types, in response to a Ganzfeld red stimulus (Lee filter “bright red”; 1.76 log phot td.s; 4 Hz) presented over a steady blue background (Schott glass filter BG28; 3.9 log scot td). Sixteen subjects returned to assess repeatability. PhNR amplitude was measured from b-wave peak-to-PhNR trough, pre-stimulus baseline to trough, and from peak and baseline to a fixed time-point; a ratio of b-wave/PhNR amplitude was also calculated. Coefficients of variation (CoV), and inter-ocular and inter-session limits of agreement (LoA) were calculated for all measures. The ratio of b-wave/PhNR amplitude showed the lowest CoV (14.3% DTL; 23.2% skin), inter-ocular LoA (22.2% DTL; 25.0% skin), and inter-session LoA (22.8% DTL; 20.3% skin). The peak-to-trough and peak-to-fixed-time measurements were also consistently reliable. Least reliable measures were those measured from baseline. While skin electrode responses were significantly smaller than DTL responses (P < 0.0001), the variability was only slightly increased. This study suggests that peak-to-trough measurements are the most reliable means of measuring the PhNR and ratio calculation further improves repeatability. Skin electrodes provided a viable alternative to DTL electrodes for recording the PhNR.
Item Type: | Article |
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Date Type: | Publication |
Status: | Published |
Schools: | Optometry and Vision Sciences |
Subjects: | R Medicine > RE Ophthalmology |
Uncontrolled Keywords: | Photopic negative response ; PhNR ; Variability ; Repeatability ; Skin electrode ; Electroretinogram ; ERG ; DTL electrode |
Publisher: | Springer-Verlag |
ISSN: | 0012-4486 |
Last Modified: | 19 Oct 2022 09:52 |
URI: | https://orca.cardiff.ac.uk/id/eprint/22459 |
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