Urdu Version of the Unified PARKINSON Disease Rating Scale: a Reliability and Validity Study

Parkinson's disease (PD) is a complex disorder with a combination of characteristic motor signs and non-motor symptoms. The natural course of PD is modified by the effect of treatments, and over time, these treatments can also be associated with both motor and non-motor complications. At present, there is no biomarker or other gold standard index to determine the severity of PD as a whole. Therefore, measurement of the different aspects of PD and their severities relies on clinically based rating scales.

The Unified Parkinson's Disease Rating Scale version 3.0 (UPDRS), published in 1987, was developed to provide a comprehensive instrument for the evaluation of impairment and disability related to PD. Further, the scale attempted to utilize the most clinically relevant aspects of several earlier scales that were already familiar to clinicians and researchers, though poorly validated clinimetrically. The development of this "unified" scale was aimed to provide a single scale so that outcomes among different clinical trials could be directly compared. For two decades, the UPDRS was the most used scale for assessment of PD patients and became the reference scale for development of other measures and for the United States and European regulatory agencies.

In 2002, the Movement Disorder Society sponsored Task Force for Rating Scales in PD carried out a review and critique of the UPDRS. Several weaknesses, including ambiguities in wording, the absence of uniform instructions for raters, some metric flaws, and the lack of assessments for many important non-motor symptoms were evident. Therefore, a modified UPDRS, named the Movement Disorder Society-UPDRS (MDS-UPDRS), was proposed to overcome the identified shortcomings. In 2008, the official MDS-UPDRS English version was published along with satisfactory clinimetric results on its performance in a series of over 800 native English-speaking patients and raters. As a result, the MDS-UPDRS has been proposed as the official benchmark scale for PD.

Given the content and structure of the MDS-UPDRS, with inclusion of symptoms impossible to assess objectively (e.g., fatigue, pain, dizziness), a questionnaire for self-evaluation, and a wide body of instructions for raters, the scale has to be cross-culturally adapted and validated. A detailed plan for obtaining equivalent and locally validated non-English versions of the MDS-UPDRS was established by the Steering Committee of the Movement Disorder Society Task Force and Spanish, Italian and Estonian official versions are now available.