Forty-five MS patients (34.8 ± 8.6 yrs old; disease duration 8.9±6.6 yrs) underwent BSRs, EPs (namely Brainstem Auditory Evoked Potentials – BAEPs, median and tibial Somatosensory Evoked Potentials-mSEPs and tSEPs), MRI and CLIN examination. BSR and EP data were ranked and summed up to obtain a cumulative score expressing severity of neurophysiological impairment. Before-after changes were tested with Wilcoxon test.
After 15.1 ± 4.2 months from initial evaluation, no relapses had been reported by any patient. This was in line with the stability of the frequency of CLIN and MRI abnormalities (37.3% and 71.1%, respectively) at the follow up. Despite this, BSRs and EPs revealed a worsening of BS function. In particular, although the proportion of altered BSRs did not change significantly (80.6% vs 90.3%; p = 0.180), a significant worsening of scores was observed for VMR (p = 0.001), AMR (0.018) and TCR (p = 0.013). Similarly to BSRs, the incidence rate of EP abnormalities did not increased significantly (84.4% vs 86.7%, p = 0.564), but the analysis of cumulative score showed a significant worsening for the whole EP set (p = 0.03) as well as for median SEP (68.9% vs 75.6%, p = 0.03), P14 mSEP (33.3% vs 51.1%, p = 0.005), tibial SEP (60% vs 66.7%, p = 0.03).
BSRs and EPs were able to reveal a significant worsening of BS functions in spite of any variation of both BS signs/symptoms and of MRI BS lesion load. This is in agreement with previous reports on BSR/EP ability to detect clinically and radiologically silent BS lesions. Further studies are needed in a larger cohort of patient to assess BSR clinical usefulness in a longitudinal perspective.
FISM GRANT 2011/R/17.