Retinal oscillatory potentials recorded by dermal electrodes

Abstract

Dermal electrodes allowed the recording of retinal oscillatory potentials with similar shape and timing as tracings obtained with conventional corneal electrodes. Normative data is presented. We concluded that dermal electrodes were a reproducible and more comfortable method of testing.

Correlation with age and sex of flash-evoked electroretinogram and retinal oscillatory potentials recorded with skin electrodes

“…Analog to digital conversion was at 50 KHz on 200 msec (ERG) or 100 msec (OPs) epochs, and amplifiers were set at 0.53-1000Hz and 160-1000 Hz respectively, with 2.56 samples/msec or 5.12 samples/msec final resolution (OTE-Biomedica Neuroaverager 1239 system). Methods are described in detail elsewhere [6].…”

“…Amplitude and implicit time values were defied for three ERG components (photopic a; scotopic a; and b), and eight OP wavelets (hereafter named P1, N1, P2, N2, P3, N3, P4, and N4 upon polarity and order of appearance; see Sannita and associates [6] adapted condition. ERG amplitude was measured with respect to prestimulus baseline, while the OP amplitude was measured peak-to-peak in order to minimize biases in baseline definition.…”

“…Application in human neuropharmacology is conditioned however by the limited tolerance of corneal or conjunctival electrodes that should not be removed during experimental sessions designed to include multiple pre-and postdrug controls. Dermal electrodes [3,4,5,6] should be a convenient alternative to conventional devices, while allowing comfortable recording also on healthy children and in the elderly. These subjects are in fact often excluded from normative electrophysiological studies when corneal electrodes are to be used [7,8,9,10,11], and biased control data might be referred to in human neuropharmacology despite the relevance within this context of age-related modifications.…”

Retinal Early Receptor Potential in Retinitis pigmentosa: Correlations with Visual Field and Fluoroangiography Estimates

“…The skin electrode technique proposed for recording of flash ERG and oscillatory poten tials in man [7][8][9][10] appears adequate for rec ording the ERPs as well, despite the limited amplitude of these evoked phenomena. Due to M eanstSD in patients with retinitis pigmentosa compared to those of normal controls.…”

“…The ERP was recorded by symmetrical dermal Ag/ AgCI electrodes positioned at the level of the inferior orbital margin, according to the methodologies used to record the flash ERG and retinal oscillatory potentials (reference: linked mastoids: ground electrode at the vertex [7][8][9][10], The pupils were dilated with 5% trap- icamide and 10% phenylephrine. Both eyes were stim ulated simultaneously (full-field white flashes; intensity: 20 J).…”