To contribute further to SymptoMScreen (SMSS) validation by assessing its responsiveness across levels of multiple sclerosis (MS) severity.

The SMSS is a brief self-report questionnaire for measuring symptom severity in twelve neurologic domains commonly affected by MS. Unlike other measures, as the Expanded Disability Status Scale (EDSS), the SMSS reports the patient’s perspective and shows adequate psychometric properties.

A multicenter, non-interventional study in patients with relapsing-remitting MS was conducted. Total SMSS score ranges from 0-72, with higher scores indicating more severe symptom endorsement. The distribution of the SMSS scores was evaluated across different levels of MS severity including disease duration, number of relapses, EDSS score, and number of disease-modifying therapies. We evaluated mean differences and linear trends with one-way analysis of variance and linear regression.

A total of 197 patients were studied (mean age: 39.6 ± 9.4 years, 70% female, mean disease duration 6.5 ± 4 years, median EDSS score: 1.5 [IQR: 1, 2.5]). The SMSS scores showed a significant linear trend relationship with EDSS severity (p-value < 0.001; means from 7.5 – lower EDSS category– to 28.9 –EDSS value= 4), and number of relapses (≤ 2 versus ≥ 3; p-value = 0.02). We did not find significant relationships with disease duration (levels: ≤ 3 years; 4+ years; p-value = 0.07) and number of MS treatments (levels: 1, 2, 3+; p-value = 0.08). However, the average SMSS scores showed a clear linear trend (12.8 ± 11.2, 16.6 ± 14 for disease duration; 13 ± 13.8, 15.6 ± 12.8, 18.4 ± 13.3 for total number of treatments).

The SymptoMScreen shows appropriate convergent validity with the EDSS and number of relapses as well as a linear trend with other surrogate indicators of severity. Therefore, it may be a useful and reliable instrument for the rapid assessment of MS symptoms in clinical practice.