Abstract
Ocular current stimulation (CS) exhibits potential for the treatment of neurodegenerative ocular diseases. For direct CS stimulation between the eye and the ipsilateral tempus we found no CS effect on the characteristic waves (a-, b’-, and b-wave) of the full field electroretinogram (ffERG). To investigate whether the orientation of the generated electric field has an influence on the CS effect, this study replicated the previous ffERG study with stimulation between the eye and the visual cortex.
In the study 17 (7m, 22.0±1.9years) healthy volunteers were stimulated with an anodal, cathodal, and sham direct CS of 800μA for 5min in three sessions (randomized, different days). A cut-sized ring rubber electrode (30cm2) was placed around the eye. A square rubber electrode (25cm2) was placed at the visual cortex (Oz position). For ERG recording, Ag/AgCl ring-shaped skin-electrodes were placed at the lower eyelid, the ipsilateral earlobe, and the forehead. Before (ERG1) and during (ERG2) CS, the ffERG was measured (white flash ≤5ms, 3cds/m2, 2Hz, 2000samples-per-second). For statistical analysis, the CS effect within (paired samples t-test, α=0.05) and between the CS sessions were investigated (repeated measures ANOVA for difference between ERG1 and ERG2 measurement, α=0.05).
The comparison of the data distribution showed no signs of an CS effect for the latencies, whereupon the statistical analysis of the latencies was waived. The paired samples t-test showed no significant amplitude difference between ERG1 and ERG2 measurement for all characteristic amplitudes and CS sessions (Bonferroni correction pt-test*≤0.0055; p-values a-/b’-/b-wave: anodal 0.680/0.498/0.790, cathodal 0.032/0.425/0.593, sham 0.265/0.219/0.562). The ANOVA for repeated measurements showed no significant CS effect between the CS session (Bonferroni correction pANOVA*≤0.0167; p-values a-/b’-/b-wave: 0.414/0.866/0.685).
It can be concluded that the retinal cells generating the ffERG are not affected during an ocular direct CS of the entire visual pathway.
In the study 17 (7m, 22.0±1.9years) healthy volunteers were stimulated with an anodal, cathodal, and sham direct CS of 800μA for 5min in three sessions (randomized, different days). A cut-sized ring rubber electrode (30cm2) was placed around the eye. A square rubber electrode (25cm2) was placed at the visual cortex (Oz position). For ERG recording, Ag/AgCl ring-shaped skin-electrodes were placed at the lower eyelid, the ipsilateral earlobe, and the forehead. Before (ERG1) and during (ERG2) CS, the ffERG was measured (white flash ≤5ms, 3cds/m2, 2Hz, 2000samples-per-second). For statistical analysis, the CS effect within (paired samples t-test, α=0.05) and between the CS sessions were investigated (repeated measures ANOVA for difference between ERG1 and ERG2 measurement, α=0.05).
The comparison of the data distribution showed no signs of an CS effect for the latencies, whereupon the statistical analysis of the latencies was waived. The paired samples t-test showed no significant amplitude difference between ERG1 and ERG2 measurement for all characteristic amplitudes and CS sessions (Bonferroni correction pt-test*≤0.0055; p-values a-/b’-/b-wave: anodal 0.680/0.498/0.790, cathodal 0.032/0.425/0.593, sham 0.265/0.219/0.562). The ANOVA for repeated measurements showed no significant CS effect between the CS session (Bonferroni correction pANOVA*≤0.0167; p-values a-/b’-/b-wave: 0.414/0.866/0.685).
It can be concluded that the retinal cells generating the ffERG are not affected during an ocular direct CS of the entire visual pathway.
| Original language | English |
|---|---|
| Pages (from-to) | 1674-1675 |
| Number of pages | 2 |
| Journal | Brain Stimulation |
| Volume | 14 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - 2021 |