Evoked Potentials Score Predicts Disability in Clinically Isolated Syndrome

Luka Crnosija, MD, neurology resident, University Hospital Centre Zagreb

Luka Crnosija, MD

Study data suggest that evoked potentials (EP) scores can allow for the prediction of disability in those with clinically isolated syndrome (CIS), which is often an early stage of the multiple sclerosis (MS) disease course.¹

These responses indicate electrical potential in a specific pattern recorded from a specific part of the nervous system—in this instance, to evaluate brainstem function. In this study, an EP score of >13 was shown to be associated with a significant risk of sustained accumulation of disability (P = .017). All told, the relative risk reduction for sustained accumulation of disability with an EP score ≤13 was 74%.

Luka Crnosija, MD, neurology resident, University Hospital Centre Zagreb, in Croatia, and colleagues concluded that the results “provide evidence that the EP score could be a potential marker for monitoring disease progression.” Data were also presented by Crnosjia at ECTRIMS 2019, in Stockholm, Sweden.²

Additionally, after controlling for age, sex, the number of T2 lesions at baseline, the hazard of SAD for participants with EP scores >13 was 4.093 times that of those with EP scores ≤13. An EP score of >13 increased the risk of progression, as measured with the composite of Expanded Disability Status Scale (EDSS), 9‐Hole Peg Test (9HPT) and Timed 25‐Foot Walk (T25W) for a b coefficient of 5.577 (95% CI, 1.520­—20.468; P = .01).

In total, 94 participants had data at follow-up, which lasted a mean of 2.9 years. During follow-up, 45.7% (n = 43) of subjects experienced a new relapse and 70.2% (n = 66) had MRI activity. All told, 14.9% (n = 14) had sustained accumulation of disability.

“Nowadays, when different treatment options are available, there is an even greater need to predict the severity of the disease course at an early stage of the disease,” Crnosija and colleagues wrote. “In the last 2 decades, there have been several studies on the use of multimodal EPs in evaluating current and predicting future disability with positive results. Brainstem lesions have been identified as a significant and independent prognostic factor. Considering the latter, adding EPs that evaluate the brainstem could potentially provide a more powerful tool than previously reported protocols.”

The cut-off value of an EP score of 13 had a sensitivity of 64.3% and specificity of 73.7%. EP score was built including visual evoked potentials, auditory evoked potentials, somatosensory evoked potentials of the median and tibial nerves, as well as vestibular evoked myogenic potentials and tongue somatosensory evoked potentials. Each section was granted a score of 0­—3 based on normal responses (score 0), prolonged latencies (score 1), irregular morphology (score 2), or absent response (score 3), totaling an EP score between 0 and 42.

Univariate logistic regression suggested that the total number of T2 lesions on MRI at baseline was predictive of the occurrence of new relapse (b coefficient, 1.027; 95% CI, 1.000­—1.055; P = .047). MRI activity yielded no significant predictors of new relapses.

REFERENCES

1. Crnosija L, Gabelic T, Barun B, Adamec I, Krbot Skoric M, Habek M. Evoked potentials can predict future disability in people with clinically isolated syndrome. Eur J Neurol. 2019. doi: 10.1111/ene.14100.

2. Crnosija L, Gabelic T, Barun B, Adamec I, Krbot Skoric M, Habek M. The evoked potential score predicts disease progression in early multiple sclerosis. Presented at: ECTRIMS; Setember 11-15, 2019; Stockholm, Sweden. Poster P440.