Search

Pain is a common and debilitating symptom of Parkinson's disease (PD) and has no specific treatment. King's Parkinson's disease Pain Scale (KPPS) is the only specific scale for pain measurement in PD with established psychometric properties. The minimal clinically important difference (MCID) of KPPS, an important parameter for the design and interpretation of therapeutic interventions, has not yet been measured. The aim of our study was to assess the MCID of KPPS.Two hundred and seven PD patients were evaluated by KPPS before and after receiving the intervention. The Clinical Global Impression of Improvement Scale was used as an anchor, and a Receiver Operating Characteristic (ROC) curve was used to determine the optimal MCID cut-off point for KPPS. The distribution-based approach applied one-third standard deviation (SD), 0.5 SD, and one standard error of measurement (SEM) of the total score of KPPS to determine the MCID.The MCID achieved from the ROC curve was 3 points (sensitivity: 74.4%; specificity: 81.9%). For the distribution-based method, the MCIDs corresponding to 0.3 SD, 0.5 SD, and one SEM were 5.65, 9.41, and 2.54 points, respectively.KPPS is a valid scale for measuring pain in PD with demonstrable MCID. IMPLICATIONS FOR REHABILITATIONThe King's Parkinson's disease Pain Scale (KPPS) is a valid scale for measuring pain in patients with Parkinson's disease (PD) with demonstrable minimal clinically important difference (MCID).The MCID obtained in the current study will assist clinicians and researchers when interpreting KPPS change score to determine clinically meaningful changes of pain in both PD progression and response to interventions.

Purpose Patients with idiopathic Parkinson's disease (PD) suffer from different non-motor symptoms, including pain. The present study aimed to measure the psychometric properties of the Brief Pain Inventory (BPI) in patients with PD during ON- and OFF-states. Methods We recruited 460 patients with PD and 100 non-PD controls. The pain was assessed by the BPI, King's Parkinson's disease Pain Scale (KPPS), Neuropathic Pain Symptom Inventory (NPSI), Visual Analogue Scale-Pain (VAS-pain), and short-form McGill Pain Questionnaire-2 (SF-MPQ-2) in both medication states. Internal consistency and test-retest reliability was examined using Cronbach's alpha coefficient and intra-class correlation coefficient (ICC). Dimensionality and convergent validity of BPI were also investigated. Diagnostic accuracy and discriminative validity were determined by Receiver Operating Characteristics (ROC) curve analysis and Area Under the Curve (AUC). Results Cronbach's alpha was satisfactory (α = 0.91-0.97) in both states. The ICC values were 0.85-0.96 in ON- and OFF-state. Factor analysis revealed two factors. A high correlation was obtained between BPI subscales and other scales. AUC >0.91, sensitivity, and specificity> 0.77 were observed for discriminating different pain levels. Furthermore, appropriate diagnostic accuracy was found (AUC, sensitivity, and specificity >0.67) between non-PD control and PD patients. Conclusion The BPI has acceptable psychometric features as well as diagnostic accuracy for patients with PD.Implications for rehabilitationPain as a non-motor symptom in PD can affect daily and social activities.The BPI is used to assess pain severity and interference in activities.For better treatment, pain should be assessed in off-state like to on-state.BPI has satisfactory reliability and validity in different medication states in PD.