DIAGNOSTIC-VALUE OF PARACLINICAL TESTS IN MULTIPLE-SCLEROSIS - RELATIVE SENSITIVITIES AND SPECIFICITIES FOR RECLASSIFICATION ACCORDING TO THE POSER COMMITTEE CRITERIA

The yield of paraclinical tests was evaluated in a prospective study o f 189 consecutive patients referred for suspected multiple sclerosis ( 142 patients with multiple sclerosis, 47 non-multiple sclerosis patien ts on discharge), Patients were first classified according to the Pose r criteria by the clinical findings. Subsequently, the results of para clinical tests (cranial MRI, visually evoked potentials (VEPs), somato sensory evoked potentials by tibial nerve stimulation (SSEPs), motor e voked potentials (MEPs), and analysis of CSF for oligoclonal banding a nd IgG-index (CSF)) were taken into account, The percentage of reclass ified patients (reclassification sensitivity, RS) was always lower tha n the percentage of abnormal results (diagnostic sensitivity, DS), and the divergence of RS v DS differed between the tests (60% v 84% in MR T, 31% v 77% in CSF, 29% v 37% in VEPs, 20% v 68% in MEPs, and 12% v 4 6% in SSEPs respectively), False reclassifications of non-multiple scl erosis patients to multiple sclerosis would have occurred with all tes ts (MRI: six of 47 patients, (reclassification specificity 88%); CSF: one (98%); VEPs: two (96%); MEPs: two (96%); SSEPs: four (91%); P < 0. 05). Although MRI had superior diagnostic capacity, 57 of the 142 pati ents with multiple sclerosis were not reclassified by the MRI result, 12 of whom were reclassified by CSF and 18 by one of the evoked potent ial (EP) studies. Of the 98 patients not reclassified by CSF, 53 were reclassified by MRI and 39 by EPs. The results suggest that for tbe ev aluation of paraclinical tests in suspected multiple sclerosis, compar ison of diagnostic sensitivities is inappropriate. In general, a crani al MRI contributes most to the diagnosis; however, due to its comparat ively low specificity and its considerable number of negative results, EP or CSF studies are often useful, to establish the diagnosis of mul tiple sclerosis.