[Multiple sclerosis in health care in our country: electrophysiological, immunological and clinical analysis]

Among 70 patients referred for suspected multiple sclerosis (MS) a total of 40 met criteria for definite (17), likely (12) or possible (11) diagnosis of the disease. Visual evoked potentials provided evidence of CNS lesion in 13 cases. Abnormalities of somatosensory evoked potentials, particularly on stimulation of the posterior tibial nerve, were present in 90% of patients. Brainstem auditory evoked potentials were of little use, contributing to diagnosis of one subclinical lesion; they were normal in 14 cases with suspected brainstem involvement. A definite diagnosis of MS was made in 4 cases by study of oligoclonal bands. The most frequently involved sites were the optic nerve and the brainstem, followed by the spinal cord. Hemispheral location was demonstrated in only 3 cases. These findings of the first study on MS in our country suggest a different pattern for demyelinating diseases in Chile.