[Multiple sclerosis. From lesion to symptoms].

Clinical manifestations of multiple sclerosis cannot be exactly correlated with lesions identified by brain imaging, electrophysiology or even anatomy. It is generally accepted that a continuous conduction is possible within some demyelinated fibers, and a conduction block may occur in the CNS white matter without demyelinization. These data explain the possible occurrence of brief, repetitive deficits besides the classical relapses. Among the latter, at least some are not correlated with demyelinization. The knowledge of these mechanisms suggest the possibility of therapy to restore the conduction without a direct action on the demyelinating process.