The McDonald Criteria was first established in 2001 by neurologist Ian McDonald and a team of researchers as a standard means of diagnosing multiple sclerosis (MS) with sensitivity and speed. (It is also known as the International Panel on MS Diagnosis, and the original and subsequent panels were, at least in part, organized by the National Multiple Sclerosis Society.)
The McDonald Criteria is distinguished by incorporating clinical evaluation with magnetic resonance imaging (MRI) scans in establishing MS. But, like an earlier approach, it too requires:
- Evidence of damage to the central nervous system (CNS; the brain, spinal cord and optic nerves) that is “disseminated in time,” meaning damage that occurs on different dates;
- Evidence of damage “disseminated in space,” or found on two or more parts of the CNS.
A 2010 revision to the McDonald Criteria (which followed a 2005 update) reflected better understanding of MS and improved MRI techniques and made possible a faster diagnosis — one that is, for a first time, potentially based on only one demyelinating relapse or attack provided certain criteria are met. These new criteria are dissemination in time, if two lesions are evident at a first attack, and dissemination in both time and space if only one lesion is evident.
This change was key because of the importance of moving patients with confirmed disease quickly onto disease-modifying therapies that may slow disease progression.
The Schumacher Criteria (1965) was the first official method for diagnosing MS and based on clinical findings. Later, the Poser Criteria (1983) standardized the use of diagnostic tests such as evoked potentials (EP) and a spinal tap, allowing confirmation of damage disseminated in space (DIS) and disseminated in time (DIT). Poser could also distinguish among possible, probably, or definite MS in a patient.
2010 revisions to the McDonald Criteria
Largely, the 2010 revision reflected the need to simplify whether myelin damage seen on an MRI according to DIS and/or DIT was distinctive of MS. The revision also improves the criteria’s applicability to other populations (pediatric, Asian and Latin Americans), since it was developed using a white and Western patient population. Further tests for these populations are specified.
Emphasis in this revision was also placed on the criteria being applied only to patients with clinically isolated syndrome (CIS) suggestive of MS, or with symptoms consistent with a CNS inflammatory demyelination disease, the National MS Society reports.
Essential MRI findings to confirm MS based on one relapse (DIS and DIT)
Under the McDonald Criteria (revised), an MS diagnosis is likely if myelin damage is disseminated in space, as seen in an MRI as: