Hi , excellent question! While there are certainly locations where you may get a lesion and be able to have it correspond to a particular issue, it quite that cut and dry. The nervous system is incredibly complex, myelin can be damaged in some areas, but the signal may continue to travel with no issue (or only have issues when there is a particular trigger, like heat, that affects the conductivity of the signal). So while looking at lesions is a good way to determine disease activity, it's really not an accurate way to gauge what issues you will have.