As in the recently studied sighted woman who had blind alters, "Through EEGs, the doctors were able to ascertain that the brain activity normally associated with sight wasn't present while a blind alter was in control of the woman's body, even though her eyes were open. When a sighted alter assumed control, the usual brain activity returned."
https://bigthink.com/robby-berman/are-we-all-multiple-personalities-of-universal-consciousness
Watch the related video here: https://youtu.be/J07XGg6Rnzo