Objective: Multiple Sclerosis Spasticity Scale (MSSS)-88 has been developed for self-assessment of spasticity symptoms in patients with multiple sclerosis (MS). The objective of this study was to validate MSSS-88 and evaluate the psychometric properties in patients with MS in Serbia.
Methods: The study comprised 65 MS patients with spasticity. MSSS-88 consists of 88 items grouped in eight sections. Internal consistency of the MSSS-88SR subscales was determined using Cronbach's alpha coefficient. Test/retest reliability with an intra-class correlation coefficient (ICC) for each MSSS-88SR subscale was performed. Clinical validity of MSSS-88SR was determined by correlations with the Numeric Rating Scale (NRS) and the Modified Ashworth Scale (MAS).
Results: The range of Cronbach's alpha for all scales and ICC was 0.91-0.96 and 0.84-0.91, respectively. All ICCs were statistically significant (p<0.05). All evaluated subscales of MSSS-88 were significantly correlated with the NRS scale. The highest correlation coefficients were registered between the WL subscale and the EDSS and MAS, while the strongest relationship was observed between the MSS subscale and the NRS.
Conclusion: The Serbian translated version of this instrument may be useful as a clinical measure for spasticity and functionality in patients with MS.