Been to neurologist had clear blood tests, eeg and mri. suffering from something undiagnosed which is similar to dementia and ms what else can be done?

There are further : Tests that can be done at research centers. If it were me, i would contact mayo clinic which is researching this and i would contact dr. Ronald petersen and ask to see him or one of his many colleagues that specialize in cognitive dysfunction. Make sure you have been checked for lyme's disease and lupus.Best wishes.

Consider getting a: Second opinion or perhaps see a psychiatrist. It could be a psychological issue. I wonder if u were tested for vitamin b 12 deficiency, syphilis, auto immune/ thyroid condition etc. Cut down or quit smoking. Take care!

See a psychiatrist.: You appear to be suffering from cognitive impairment, weakness with tests that look normal. I don't know the extent of your cognitive impairment but i assume from the blood tests that other metabolic problems have been ruled out, like thyroid disorders, endocrine problems, pseudodementia ( severe depression), or fronto temporal dementia. A psychiatric evaluation might be helpful.