Validation of the Serbian Version of Multiple Sclerosis Spasticity Scale 88 (MSSS-88)

Clinical Outcome Assessments for Spasticity: Review, Critique, and Recommendations

BACKGROUND

Spasticity is a common feature in patients with disruptions in corticospinal pathways. However, the term is used ambiguously. Here, spasticity is defined as enhanced velocity-dependent stretch reflexes and placed within the context of deforming spastic paresis encompassing other forms of muscle overactivity.

OBJECTIVE

This scoping review aims at evaluating the clinimetric quality of clinical outcome assessments (COAs) for spasticity across different pathologies and to make recommendations for their use.

METHODS

A literature search was conducted to identify COAs used to assess spasticity. An international expert panel evaluated the measurement properties in the included COAs. Recommendations were based on the MDS-COA program methodology based on three criteria: if the COA was (1) applied to patients with spastic paresis, (2) used by others beyond the developers, and (3) determined to be reliable, valid, and sensitive to change in patients with spasticity.

RESULTS

We identified 72 COAs of which 17 clinician-reported outcomes (ClinROs) and 6 patient-reported outcomes (PROs) were reviewed. The Tardieu Scale was the only ClinRO recommended for assessing spasticity. One ClinRO-Composite Spasticity Index-and two PROs-Spasticity 0-10 Numeric Rating Scale and 88-Item Multiple Sclerosis Spasticity Scale-were recommended with caveats. The Ashworth-derived COAs were excluded after evaluation due to their focus on muscle tone rather than spasticity, as defined in this review.

CONCLUSIONS

The Tardieu Scale is recommended for assessing spasticity, and two PROs are recommended with caveats. Consistent terminology about the various types of muscle overactivity is necessary to facilitate their assessment and treatment. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Assessment and Measurement of Spasticity in MS: State of the Evidence

PURPOSE OF REVIEW

The purpose of this review is to familiarize the reader with assessments and measurement of spasticity in people with multiple sclerosis (MS). Spasticity affects 60-84% of people with MS, worsening as disability worsens and impacting activity, participation, and quality of life. Spasticity manifests in many ways, including spasms, resistance to passive stretch, pain, and perception of tightness, and can affect muscles throughout the body, making assessment and quantification of spasticity challenging but important. Assessment tools include those quantified by clinicians, instrumentation, and patients.

RECENT FINDINGS

Most tools for measuring spasticity are based on clinician scoring, were developed many years ago, and have undergone minimal recent advances. More recent developments are patient-reported outcome measures for spasticity, including the Numeric Rating Scale for Spasticity (NRS-S) and the disease-specific Multiple Sclerosis Spasticity Scale-88 (MSSS), and, most recently, imaging through elastography. MS-related spasticity is common and often disabling. There are various spasticity measurement tools available, each with advantages and limitations. Newer tools are likely to be developed as our understanding of spasticity in MS grows.

Evaluation of the Multiple Sclerosis Spasticity Scale 88: A Short Report

Background:

The Multiple Sclerosis Spasticity Scale 88 (MSSS-88) is designed to capture the patient experience and impact of spasticity, but there is limited evaluation against clinician-rated measures of spasticity.

Objective:

To evaluate the convergent validity and responsiveness of the MSSS-88.

Design:

Longitudinal study.

Setting:

University Laboratory.

Subjects:

Thirty-four people with multiple sclerosis.

Methods:

People with multiple sclerosis (MS; n = 34) completed the self-reported 12-item Multiple Sclerosis Walking Scale, Multiple Sclerosis Spasticity Scale, Barthel Index alongside the clinician-rated Ashworth Scale, and a laboratory-based measure of ankle spasticity. Spasticity measure responsiveness was evaluated in 20 participants at two time points, an average of 8.75 ± 3.8 months apart.

Results:

In people with MS (mean age 55.1 ± 8.1 years; Expanded Disability Scale range 4.5-7.0), spasticity symptom specific subscales of the MSSS-88 (stiffness and spasms) showed strong and significant correlations with the clinician-rated Ashworth Scale (r = 0.52-0.53; P < .01). Responsiveness of the MSSS-88 was comparable to a laboratory-based measure of ankle spasticity.

Conclusions:

Our findings lend additional support to the convergent validity of this measure.

The 88-item Multiple Sclerosis Spasticity Scale: a Rasch validation of the Italian version and suggestions for refinement of the original scale

BACKGROUND

In multiple sclerosis (MS), the impact of spasticity on the patient's life is a key issue, and it is fundamental that existing tools measuring the patient's perspective undergo psychometric analysis and refinement to optimize confidence in their use in clinical practice and research.

OBJECTIVE

We examined-by Rasch analysis (RA)-the main metric characteristics of the 88-item Multiple Sclerosis Spasticity Scale (MSSS-88) to: (i) further validate its Italian version (MSSS-88-IT), previously validated through classical test theory methods only and (ii) independently verify the measurement properties of the original scale.

METHODS

MSSS-88 data from a convenience sample of 232 subjects with MS underwent RA, mainly examining item fit, reliability indices, test information function, dimensionality, local item independence, and differential item functioning (DIF).

RESULTS

Most items fitted the Rasch model, but 13/88 items showed a misfit in infit and/or outfit values. Rasch reliability indices were high (> 0.80). Test information functions in most subscales showed a sharp decrease in measurement precision as the ability level departs from the quite limited central range of maximal information. The unidimensionality of each subscale was confirmed. Thirteen item pairs showed local dependency (residual correlations > 0.30) and three items presented DIF.

CONCLUSION

Reliability, dimensionality and some internal construct validity characteristics of the MSSS-88-IT were confirmed. But, drawbacks of the original MSSS-88 emerged related to some item misfit, redundancy, or malfunctioning. Thus, further large independent studies are recommended, to verify the robustness of previous findings and examine the appropriateness of a few targeted item replacements.

The cross-cultural adaptation and psychometric validation of the MSSS-88 for use in Italian patients with multiple sclerosis

PURPOSE

To cross-culturally translate the Multiple Sclerosis Spasticity Scale into Italian and to evaluate its psychometric properties in patients with multiple sclerosis.

METHODS

The Italian version of Multiple Sclerosis Spasticity Scale was developed in accordance with international standards and subsequently administered to 232 Italian adults with multiple sclerosis. The following psychometric properties were analyzed: internal consistency through Cronbach's α and item-to-total correlation, dimensionality with factor analysis, and convergent and criterion validity through hypotheses-testing, comparing the Multiple Sclerosis Spasticity Scale with other outcome measures (Fatigue Severity Scale, Multiple Sclerosis Quality of Life, Modified Ashworth Scale, Barthel Index, and Expanded Disability Status Scale) and analyzing related constructs. Finally, we correlated the MSSS-88 subscales with each other.

RESULTS

The final Multiple Sclerosis Spasticity Scale version was well-understood by all subjects. The internal consistency was good (Cronbach's α ≥0.90). Factor analysis revealed that each subscale was unidimensional. Convergent and criterion validity were supported by acceptable correlations with other disease-specific questionnaires, according to the a priori expectations.

CONCLUSIONS

The final Italian Multiple Sclerosis Spasticity Scale version showed robust psychometric properties. Therefore, it can be recommended as an assessment tool for clinical and research use to evaluate spasticity in Italian patients with multiple sclerosis. Implications for rehabilitation The Multiple Sclerosis Spasticity Scale was developed to measure patients' perception of the impact of spasticity on life of subjects with multiple sclerosis. In a sample of Italian subjects with multiple sclerosis, the Multiple Sclerosis Spasticity Scale revealed good internal consistency and convergent and criterion validity. Factor analysis demonstrated that each subscale was unidimensional. Each subscale can be used to assess the impact of spasticity in Italian patients with multiple sclerosis.

Lower Endurance and Strength of Core Muscles in Patients with Multiple Sclerosis

Background

Multiple sclerosis (MS) is a chronic inflammatory disorder of the central nervous system associated with a variety of symptoms and functional deficits. Balance impairment is a common concern in patients with MS. Core muscle stabilization is considered a main component of balance. The strength and endurance of core muscles have not been compared between patients with MS and healthy people. The objective of this study was to compare core muscle strength and endurance between ambulatory patients with MS and a healthy group.

Methods

Thirty-three patients with MS with Expanded Disability Status Scale scores ranging from 1.0 to 4.5 and 33 matched healthy people participated in this cross-sectional group comparison study. The primary outcome measure was endurance of core muscles assessed by functional endurance tests, and the secondary outcome was isometric strength of core muscles assessed using a dynamometer.

Results

Patients with MS had lower performance on endurance tests (P < .001) and strength tests (P < .05) compared with the control group.

Conclusions

These results show decreased core muscle strength and endurance in ambulatory individuals with MS compared with a matched control group. Future studies are required to assess how core muscle impairment affects balance and how it would be affected by rehabilitation and exercise programs.