According to our goal of investigating the long-term tACS efficiency, participants will undergo 30 stimulation sessions. Endpoints will be assessed before, immediately after and 2 and 6 months after the end of treatment. To our knowledge, this would be the longest stimulation duration and follow-up period investigating the effect of tACS. It would allow us not only to collect information on long-term effects, but also to compare it with short-term interventions (i.e., 10 days). The study will be considered completed after the last follow-up measurement of the last patient.
To examine the retinal blood vessel dynamics, we want to use a CE-approved "Dynamic Vessel Analyzer" in an additional "open label" feasibility study on a sample of patients (N=20) from an outpatient care center to determine the effect of electrical stimulation on the blood supply. These patients will undergo 10 electrostimulation sessions using a device which is equivalent to the devices used for the other two-arms. As part of our study we will have two measurement points to investigate the effect of the electrical stimulation on the blood supply, namely before and after therapy.