Middle latency auditory evoked potentials improve the detection of abnormalities along auditory pathways in multiple sclerosis patients.

Brain-stem and middle latency auditory evoked potentials (BAEPs and MLAEPs) have been studied in 34 multiple sclerosis (MS) patients. We were able to detect a central nervous system auditory pathway involvement in 17 (50%) of the patients: 38% by BAEPs alone (I-V inter-peak latency) and 47% by MLAEPs alone (Na and Pa peak latency). Five patients had abnormal MLAEPs with normal BAEPs whereas the opposite was detectable in only 1 patient. In addition, most MLAEP parameters in the MS group statistically differed from those obtained in the control group. Therefore, our results demonstrated that the auditory pathway impairment could frequently be located at a rostral level along the auditory radiation. In conclusion, even if only Na and Pa components were considered, MLAEPs succeeded in improving the sensitivity of the auditory evoked potential examination without increasing the false positive rate.