[Relation of optic myelitis (OM) and multiple sclerosis (MS)].

Brainstem auditory evoked potentials (BAEP) were studied on 38 optic myelitis (OM) and 16 of myelopathy with definite abnormal VEP. Forty-two normal subjects were studied for comparison. The results showed that BAEP were abnormal in 42% of the OM and 38% of the latter myelopathy groups. Among the abnormal BAEP 82% showed V wave abnormality, 32% prolongation in I-III or III-V interpeak latency or absence of III wave, and 59% with unilateral lesions. These findings would imply that the lesions were mostly on the white matter and small and localized in character which was compatible with the pathology of MS. 41% of BAEP abnormality in these two groups showed a lesion would be in the brainstem in almost half of these two types of disorders. OM would be most likely a clinical variant type of MS and not a unique disease.