Well, it's not here yet, but UVic is working on ways to measure brain fatigue, which could be of use for us with ME.
https://www.uvic.ca/news/topics/2020+knowledge-brain-burnout+news
"The long-term goal: “To have a device that anyone can use, like a blood pressure monitor or a Fitbit, to track your brain health,” says Krigolson. This sci-fi scenario may not be too far off."
https://www.uvic.ca/news/topics/2020+knowledge-brain-burnout+news
"The long-term goal: “To have a device that anyone can use, like a blood pressure monitor or a Fitbit, to track your brain health,” says Krigolson. This sci-fi scenario may not be too far off."