Clinical correlations of serial somatosensory evoked potentials in multiple sclerosis.

Serial median nerve somatosensory evoked potentials (SEPs) were recorded in 12 patients with definite MS. On the initial tests, there was no clear association between the severity of clinical disease activity and SEP findings. The cervical response was most frequently affected and, when present, was often abnormal in configuration, suggesting absence or delay in the far field P14 component with preservation of cervical N11 and N13 components. Clinical motor and sensory findings in the corresponding limb frequently correlated with abnormalities of the cervical response. When new motor and sensory findings developed in the arms during the study, the SEP deteriorated in some patients but improved in others. Most SEP changes were not accompanied by clinical changes. Overall disability sometimes increased during the study despite improvements in the SEP.