Brainstem auditory evoked potential and blink reflex in multiple sclerosis.

Brainstem auditory evoked potential (BAEP) and blink reflex (BR) were abnormal in 40% and 26% of 130 patients with MS. Overall, BR was affected in 53% of patients with abnormal BAEP involving I-III and 41% of those involving III-V interval. In 23 patients with unilateral BR involvement, BAEP was affected ipsilaterally in 10, contralaterally in 0 and bilaterally in 8. In 12 patients with bilateral BR abnormalities, BAEP was involved unilaterally in 1 and bilaterally in 8. We conclude: (1) pontine lesions may prolong either I-III or III-V interwave latency of BAEP, and (2) unilateral abnormalities of BAEP tend to implicate the uncrossed auditory pathways.