The development of predictors of multiple sclerosis (MS) disability is difficult due to the complex interplay of pathophysiological and adaptive processes.

The purpose of this study was to investigate whether combined evoked potential (EP)-measures allow prediction of MS disability after 20 years.

We examined 28 patients with clinically definite MS according to Poser’s criteria with Expanded Disability Status Scale (EDSS) scores, combined visual and motor EPs at entry (T0), 6 (T1), 12 (T2) and 24 (T3) months, and a cranial magnetic resonance imaging (MRI) scan at T0 and T2. EDSS testing was repeated at year 14 (T4) and year 20 (T5). Spearman rank correlation was used. We performed a multivariable regression analysis to examine predictive relationships of the sum of z-transformed EP latencies (s-EP_T0) and other baseline variables with EDSS_T5.

We found that s-EP_T0 correlated with EDSS_T5 (rho=0.72, p<0.0001) and EDSS_T5-T0 (rho=0.50, p=0.006). Backward selection resulted in the prediction model: E (EDSS_T5)=3.91–2.22xtherapy+0.079xage+0.057xs-EP_T0 (Model 1, R²=0.58) with therapy as binary variable (1=any disease-modifying therapy between T3 and T5, 0=no therapy). Neither EDSS_T0 nor T2-lesion or gadolinium (Gd)-enhancing lesion quantities at T0 improved prediction of EDSS_T5. The area under the receiver operating characteristic (ROC) curve was 0.89 for model 1.

These results further support a role for combined EP-measures as predictors of long-term disability in MS.