What is the role of brainstem auditory evoked potential (BAEP) testing in the workup of multiple sclerosis?

Updated: Oct 25, 2019
  • Author: Andrew B Evans, MD; Chief Editor: Selim R Benbadis, MD  more...
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BAEP evaluation should be considered if the clinical symptoms implicate a lesion outside the brainstem. In this case, an abnormal BAEP would further support the diagnosis of MS. If, however, the clinical sign (eg, diplopia) points to the brainstem, a BAEP abnormality is merely confirmatory. In various studies, about 20% of the patients tested for a second lesion have an abnormal BAEP, and about half of these go on to develop MS in the next 1-3 years.

Purves et al reported that pattern-shift visual evoked potentials (VEPs) were abnormal in 45% of patients without brainstem signs, somatosensory evoked potentials (SEPs) were abnormal in 35%, and BAEPs were abnormal in 14%. [28] When the 3 modalities were considered together, 97% of patients with definite MS, 86% of patients with probable MS, and 63% of patients with possible MS had abnormal findings on at least 1 of these tests. [28] Similar findings were reported by Ferrer et al. [29]

Kjaer reported a 38% rate of abnormal BAEPs in MS patients with silent lesions, whereas 50% of these patients had an abnormal VEP and only 13% an abnormal SEP. [30] Kjaer also reported 22 patients with only spinal symptoms, 55% of whom showed an abnormal BAEP. [31]

Chiappa found that the BAEP was positive in 21% of clinically unsuspected cases of MS. [32] Most authors have concluded that of the 3 tests, BAEP yields the smallest percentage of patients; however, it still adds to the detection rate because it is abnormal in a different subset of patients.

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