More than words: Translating MDS clinical outcome assessments for global use 

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Movement disorders are global, and the clinical outcome assessments (COAs) we use need to work across languages and cultures. But translating a COA is much more complicated than replacing one English word with its counterpart in another language. The goal of the MDS COA Translation Steering Committee is to ensure that all MDS-owned COAs preserve the clinical meaning and measurement properties of the original instrument so that a score obtained in one language can be interpreted with the same confidence as a score obtained in another. 

What does the Translation Steering Committee do? 

Within the MDS COA Program, the Translation Steering Committee oversees the development of official non-English translations of MDS-owned instruments by national teams, particularly the Movement Disorder Society-Sponsored Revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS), MDS Non-Motor Rating Scale (MDS-NMS), and Unified Dyskinesia Rating Scale (UDysRS). The Committee reviews and approves translation projects, helps develop translation teams, monitors projects through the different stages of development, and oversees the clinimetric evaluation needed for official translations. It also contributes recommendations for translating and validating electronic and digital versions of MDS assessments.¹ 

The mission is straightforward: to make rigorous MDS assessments usable by patients, clinicians, and researchers worldwide without compromising the scientific standards of the original instruments. 

What happens when an MDS COA is translated? 

The process is deliberately more rigorous than ordinary translation. 

A typical project begins with translation and back-translation. Teams with expertise in both English and the target language translate the COA, and an independent team translates it back into English. Teams reconcile and review differences to identify places where meaning may have shifted. MDS translation teams include native speakers, individuals fluent in English, and movement disorders specialists, with independent reviewers also contributing. 

Next comes cognitive pretesting, in which patients and raters use the translated instrument and provide feedback about whether the questions, instructions, and response options are understandable and appropriate in their culture. 

For translations requiring full validation, the revised version is then administered to a much larger group of native-language speakers to determine whether the translated scale retains the measurement structure of the original English version (clinimetric analysis). The Translation Steering Committee reviews the project at defined stages before an instrument receives official MDS designation. The recent Norwegian MDS-UPDRS validation, for example, describes these four core steps: translation/back-translation, cognitive pretesting, large-scale validation, and clinimetric analysis.² 

Why isn't word-for-word translation enough? 

Words that appear equivalent in a dictionary do not always carry the same meaning in everyday conversation, and the challenge becomes even greater when a question is intended to distinguish between precise levels of symptom severity. 

Again, the Norwegian MDS-UPDRS translation project is a good example. Norwegian has two official written standards, Bokmål and Nynorsk, as well as many spoken dialects. The translation team selected Bokmål for the official version because it is the written standard used by most Norwegian speakers. During cognitive pretesting, patients and raters generally found the COA clear, but their feedback still led to a wording change in the instructions for the item assessing time spent with dyskinesias, followed by another round of testing.² 

This illustrates why cognitive pretesting is essential. A translation can be linguistically correct and still not communicate exactly what the COA developers intended. The objective is therefore not literal equivalence, but conceptual and clinical equivalence. 

Cultural considerations matter as well. During cognitive pretesting of the recently validated German MDS-NMS, patients generally considered the COA relevant and understandable, but some reported greater difficulty or discomfort answering questions involving sensitive domains such as sexual symptoms, mood, and depression.³ This feedback helps determine whether an item is understood as intended and whether it needs additional linguistic refinement before large-scale validation. 

How do we make sure a translation works? What has the Committee accomplished recently? 

Cognitive interviewing and pretesting allow the translation team to ask not simply, “Can you read this question?” but, more importantly, “Tell me in your own words, what does this question mean to you?" Feedback can lead to changes in wording, instructions, or response options before hundreds of participants are evaluated. 

Full-scale validation then provides assurance that the clinimetric properties of the COA are retained. The translated COA is evaluated to determine whether its underlying structure corresponds sufficiently to that of the original English instrument. The recent projects demonstrate this effort. The French MDS-NMS underwent cognitive pretesting followed by a multicenter validation involving 303 participants with Parkinson's disease,⁴ while the German validation included 300 participants.³ Both supported official translated versions of the MDS-NMS. 

The MDS-COA Program has built an increasingly global portfolio. The MDS-UPDRS alone is now available in more than two dozen non-English languages, while official translations of the UDysRS and the newer MDS-NMS continue to expand. In addition to the recent work highlighted above, several additional translation projects are progressing through different stages. The work depends on a large international network of translation leaders, movement disorders specialists and other clinicians, patients and care partners, statistical experts, and MDS staff. 

What's next? 

Demand for translations will continue to increase as the MDS COA portfolio grows and as clinical research becomes increasingly multinational. One priority is to expand global access while maintaining scientific rigor. Full-scale validation can be particularly challenging for languages spoken by smaller or geographically dispersed patient populations, or in regions with fewer movement disorders centers and research resources. The Committee is therefore examining how translation pathways can continue to uphold MDS standards while recognizing these practical barriers and making high-quality assessments accessible to more language communities. 

Another important frontier is the intersection between translation and digital COAs.¹ As MDS assessments move into electronic, remote, and other digital formats, ensuring that translated versions remain valid and function consistently across platforms will become an increasingly important part of the Committee's work. 

Ultimately, our goal is simple: patients should be assessed in the language they understand and, in a way, appropriate to their culture, while clinicians and researchers can trust that the measurement means the same thing across languages and cultures. We firmly believe that better translations lead to better measurement, broader participation in research, and ultimately better care for people with movement disorders worldwide. We welcome your participation in the MDS-COA program's translation efforts. 

Learn more about translating COAs, or get involved in translation:

COA translation program

 

References 

1. International Parkinson and Movement Disorder Society. Clinical Outcome Assessment Program Committees [Internet]. Milwaukee (WI): International Parkinson and Movement Disorder Society; [cited 2026 Aug 27]. Available from: Movement Disorders Society COA Program  

2. Alves G, Sørenes YS, Frantzen VH, Gjerstad MD, Bjørnestad AL, Maple-Grødem J, et al. Validation of the Norwegian version of the Movement Disorder Society-Unified Parkinson's Disease Rating Scale. Clin Park Relat Disord. 2026;14:100420. doi:10.1016/j.prdoa.2025.100420.  

3. Bendig J, Frank A, Lipska-Dieck A, Wunderlich K, Geißler-Lösch D, Wurster I, et al. Validation of the German Version of the Movement Disorder Society Non-Motor Scale (MDS-NMS). Mov Disord Clin Pract. 2026;13(5):1346-1348. doi:10.1002/mdc3.70486.  

4. Desjardins C, Grimaldi S, Luo S, Yu L, Goetz CG, Stebbins GT, et al. Validation of the French Translation of the Movement Disorder Society Non-Motor Symptoms Scale (MDS-NMS) in Parkinson's Disease. Mov Disord Clin Pract. 2026;13(2):575-579. doi:10.1002/mdc3.70323.