The stability of the auditory evoked potentials in normal man and patients with multiple sclerosis.

Sequential records of the early and middle components of the auditory evoked potential in response to a click stimulus have been obtained over a period of 2.5 years in normal subjects and in patients with multiple sclerosis. The latencies of all the components were highly consistent in the control subjects and in the patients who were clinically stable throughout the period of study. In constrast, in some of the patients who had clinical relapses during the study there was variation in the latency and amplitude of some of the components. The significance of this variation is discussed and the poor correlation between the sites of the new lesions as determined clinically and the auditory evoked potential variability is emphasised.