I've just found this - sorry to be so late.

I've been tracking the work of Francisco Gonzalex-Lima, who has been using MB for MCI. The key seems to be that cytochrome oxidase is downregulated in an anoxic event, and that, in turn impairs the electron transport chain. In low dose (0.5 to 4mg per kg) MB can act as an electron donor (in higher dose it does the reverse). Once the ECT has been assisted, cytochrome goes back to normal.

He's been published quite a lot (easily found on PubMed) and the science seems sound.

Any thoughts?