Table 1. Poser’s criteria17 for the diagnosis of multiple sclerosis (MS)

* Symptoms lasting more than 24 hours would constitute an attack even if they were “completely subjective and anamnestic.”
† Evidence of two separate lesions found on neurologic examination. Bilateral optic neuritis would constitute only one lesion provided that the episodes of optic neuritis were separated by less than 15 days.
‡ Includes lesions detected by MRI or evoked potentials.
§ CSF analysis demonstrates the presence of oligoclonal bands or an increased CNS synthesis of immunoglobulin G.
Clinically definite MS
    A1: 2 Attacks* + 2 lesions on examination
    A2: 2 Attacks + 1 lesion on examination + 1 paraclinical lesion
Laboratory-supported definite MS
    B1: 2 Attacks + 1 lesion on examination or 1 paraclinical lesion + abnormal CSF§
    B2: 1 Attack + 2 lesions on examination + abnormal CSF§
    B3: 1 Attack + 1 lesion on examination + 1 paraclinical lesion + abnormal CSF§
Clinically probable MS
    C1: 2 Attacks + 1 lesion on examination
    C2: 1 Attack + 2 lesions on examination
    C3: 1 Attack + 1 lesion on examination + 1 paraclinical lesion
Laboratory-supported probable MS
    D1: 2 Attacks + abnormal CSF§