# DTL versus skin electrodes in recording of multifocal pattern electroretinogram and multifocal photopic negative response

## TL;DR

This study compares DTL and skin electrodes for recording eye responses in young and old adults, finding that skin electrodes provide lower signal quality but could be useful for certain patient groups.

## Contribution

The study provides a direct comparison of DTL and skin electrodes for mfERGPhNR and mfPERG recordings in different age groups.

## Key findings

- Skin electrode recordings had significantly reduced amplitudes and signal-to-noise ratios compared to DTL electrodes.
- Skin electrodes produced shorter peak times for N1 and P1 components compared to DTL electrodes.
- Young participants had shorter peak times than older participants, but similar amplitudes and SNRs.

## Abstract

To compare the photopic negative response of the multifocal ERG (mfERGPhNR) and the multifocal pattern electroretinogram (mfPERG) using DTL electrode (EDTL) vs skin electrode (ESKIN) in healthy young and old adults.

Ten “Young” [20–27 years] and eight “Old” [60–72 years] participants took part in this study. The electrophysiological responses were recorded binocularly using EDTL and ESKIN. 5-way ANOVAs were applied to investigate the following factors on mfERGPhNR: i) ELECTRODE, ii) DILATATION, iii) AGE, iv) EYE, and v) ECCENTRICITY. For mfPERG, the same factors, except dilatation, were investigated applying 4-way ANOVAs. These were conducted for amplitude and peak time of different components as well as signal-to-noise-ratio (SNR).

Amplitudes of mfERGPhNR [mfPERG]-based ESKIN recording were reduced to 32–38% [37–38%] compared to EDTL, \documentclass[12pt]{minimal}
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\begin{document}$$p < 0.001$$\end{document}p<0.001]. Both age groups had comparable amplitudes and SNRs, but Young had shorter peak times, by 1.5–2.2 ms for N1 and P1, \documentclass[12pt]{minimal}
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\begin{document}$$p < 0.05$$\end{document}p<0.05 [3.7–4.2 ms for N1, P1, N2, \documentclass[12pt]{minimal}
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\begin{document}$$p < 0.05$$\end{document}p<0.05]. Compared to dilated recordings, undilated mfERGPhNR amplitudes were reduced to 47–87%, \documentclass[12pt]{minimal}
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\begin{document}$$p < 0.01$$\end{document}p<0.01, and peak times were delayed by 2.0–11.8 ms, \documentclass[12pt]{minimal}
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mfPERG & mfERGPhNR traces were similar for EDTL and ESKIN. However, for skin electrodes, amplitudes and SNRs were lower and peak times shorter. ESKIN thus seem to be a viable alternative in patients in whom the use of corneal electrodes is precluded, e.g., children and disabled patients, but at the expense of SNR and with reference to ESKIN normative data.