When was the last MRI? You said 6 month MRI. They see 4 new lesions so they must have compared it to the last one. Was the last one, or this one, part of the protocol for Tysabri?

Maybe you can figure a time line that way. Better yet ask the Neuro. They can tell how old the lesions are and look up your records to see when you didn't have them.

Some lesions are so tiny they don't show until they get large enough to be seen on MRI, yet they were there all the time, for years unseen.

I think an MRI can change daily, if done each day. People take up the contrast dye different each time too. Also, maybe they waited longer after the injection of dye to take the sequence pictures. So many variables.

They have doctors that can work with memory issues, retrain, show tips and practice help, to improve memory. Ask the Doctor to see one of these specialists. Don't get discouraged, there is always help. Good luck