The unified Parkinson's disease rating scale (UPDRS) is used to follow the longitudinal course of Parkinson's disease. The UPD rating scale is the most commonly used scale in the clinical study of Parkinson's disease. The unified Parkinson's disease rating scale (UPDRS) is used to follow the longitudinal course of Parkinson's disease. The UPD rating scale is the most commonly used scale in the clinical study of Parkinson's disease. The UPDRS is made up of these sections: