The diagnostic criteria for multiple sclerosis: From Charcot to McDonald.

The history of diagnostic criteria for multiple sclerosis (MS) from Charcot to McDonald is reviewed. Although the criteria have evolved positively with each revision we think there is still room for improvement. It is proposed that the 2010 revision to the McDonald criteria should be used for research or drug trials and comprise two categories: 'MS' and 'Not MS'. McDonald 2010 could be used optionally for routine clinical purposes. The categories 'probable' and 'possible' are permissible for everyday clinical activity, particularly where there is limited access to MRI, but they would not be appropriate for research or drug trials. Future updates should make it mandatory to perform MRI of the brain, and possibly spinal cord, and the definition of 'an attack' should be revised to include information from physical examination or MRI. Finally, we suggest that certain paroxysmal symptoms (e.g. Lhermitte phenomenon) should be incorporated in any further revision.