This is encouraging because a previous study showed minimal effect on dreaming using tDCS.

In both experiments a significantly greater number of imagery reports were found on awakening after tDCs (cathodal–frontal, anodal–parietal), compared to the blank control conditions. However, in Experiment 2 the frequency of imagery reports from the tDCs (cathodal–frontal, anodal–parietal) was not significantly different from the other two tDC conditions, suggesting a non-specific effect of tDCs. Overall, it was concluded that tDCs (cathodal–frontal, anodal–parietal) increased the frequency of dream reports with visual imagery, possibly via a general arousing effect and/or recreating specific cortical neural activity involved in dreaming.

via Induction of visual dream reports after transcranial direct current stimulation (tDCs) during Stage 2 sleep – JAKOBSON – 2012 – Journal of Sleep Research – Wiley Online Library. Full pdf.