Earlier and more frequent diagnosis of multiple sclerosis using the McDonald criteria: Figure 1

The McDonald criteria allow multiple sclerosis (MS) to be diagnosed in patients with a clinically isolated syndrome (CIS) who have MRI evidence of dissemination in time and space.1–3 There have been successive versions of the criteria in 2001,1 20052 and 20103 with different requirements for dissemination in time and space. Although each version has been shown to have a high sensitivity and specificity for the development of clinically-definite MS (CDMS), few studies have investigated how much sooner4 and how more often5 MS can be diagnosed in patients with CIS using the McDonald criteria. We recruited 178 patients with CIS presenting to Moorfields Eye Hospital and the National Hospital for Neurology and Neurosurgery between 1995 and 2004. The study was approved by ethics committees at both hospitals. Patients were seen at baseline, then for follow-up after 3 months, 1 year, 3 years and 6 years. At each study visit informed consent was obtained. Patients were assessed with a detailed review of neurological symptoms and neurological examination. Relapses were recorded at study visits, but patients were also encouraged to contact the research team at the time of new neurological symptoms. MRI of the brain and whole spine was obtained at each visit on the same 1.5 T Signa scanner, as described elsewhere.6 Each scan was reviewed by a neuroradiologist blinded to the patient's clinical status. The number, location and activity (ie, gadolinium enhancement) of T2 lesions was recorded. During follow-up CDMS was defined according …