Comprehensive grading of Parkinson's disease using motor and non-motor assessments: addressing a key unmet need.

INTRODUCTION: Parkinson's disease (PD) is expressed through motor and non-motor symptoms (NMS) that differ considerably in presence and severity among patients and over time. Furthermore, the progression pattern of the NMS does not necessarily parallel the course of the motor impairment. Gradation of PD according to the motor impairment and burden of NMS is an unmet need for an appropriate management of patients. Areas covered: A review of the studies on clinical gradation methods applied to PD is carried out in this article. Studies have provided cut-off values for a pragmatic classification of scores from rating scales and questionnaires in mild, moderate, and severe PD, considering motor state, complications, disability, and NMS. Grading systems with Hoehn and Yahr staging, Clinical Impression of Severity Index for PD, NMS Scale, NMS Questionnaire, and MDS-UPDRS, are available. These systems are reviewed in detail and examples in format of simple cards are presented. Expert commentary: Patients can be adequately assessed and properly managed according to their specific needs. A comprehensive method for gradation of PD manifestations severity is, therefore, desirable. In the absence of objective in vivo biomarkers for quantitative standardized information, scale-based clinical gradation systems provide a suitable alternative.