The wearing-off phenomenon and the use of questionnaires to facilitate its recognition in Parkinson's disease.

Long-term treatment of Parkinson's disease (PD) with dopaminergic therapy is associated with a re-emergence of PD symptoms, referred to as wearing-off. Signs of wearing-off encompass motor symptoms, such as slowness of movement and stiffness, and non-motor symptoms, including anxiety and fatigue. Both motor and non-motor symptoms impact significantly on the function and quality of life of PD patients. Early detection and management of wearing-off has been shown to improve patient symptoms; however, identification of wearing-off, particularly the non-motor symptoms, is hampered by a lack of patient education, awareness, patient-physician communication, and limited time for evaluation. Several questionnaires have been developed to aid the detection of wearing-off. This review investigates the development and use of the Wearing-Off Questionnaires (WOQ-32, WOQ-19, and WOQ-9), as well as their sensitivity and specificity in identifying wearing-off. The manuscript also provides an overview of the motor and non-motor signs of wearing-off and highlights the available treatment strategies for managing this potentially debilitating phenomenon.