[Visual somatosensory and auditory evoked potentials in multiple sclerosis].
In a group of 15 patients with multiple sclerosis and in a control group of 20 healthy subjects visual evoked potentials produced with flashes or checkerboard pattern, auditory evoked potentials after stimulation with three different tones, and somatosensory evoked potentials after stimulation of the left, right or both median nerves, and reactions to stroboscopic stimulation at seven different frequencies were investigated. Recording was done with unipolar leads from frontal, central, occipital and temporal regions on the left and right side. In patients with multiple sclerosis the cortical responses to all these stimuli had lower amplitude than in healthy subjects, and the reponses to stroboscopic stimulation were also abnormal in the group of patients. Different clinical signs related to various defects of sensory functions showed a high correlation with electrophysiological anomalies. Non-linear discrimination analysis was carried out using 13 variants (the amplitudes were calculated from peak to peak and correlation coefficients were calculated between identical regions on the left and right side) comparing the group of patients with the control group. Using this method it was possible to establish the correct diagnosis in all cases of multiple sclerosis and 85% of healthy subjects could have been included into the asymptomatic group. Since the methods used in these investigations are easy and can be easily automated the authors think that they could be very useful in the clinical diagnosis of multiple sclerosis.