Background

Pain is one of the most common non-motor symptoms in Parkinson's disease (PD). Using an appropriate and specific measuring tool would be helpful in managing the pain. King's Parkinson's disease Pain Scale (KPPS) is an instrument designed to specifically measure pain in people with PD.

Purpose

This study aimed to examine the psychometric properties of the Persian version of KPPS (KPPS-P) and its cut-off points for pain severity levels.

Methods

A total of 480 people with PD (with a mean (SD) age of 60.89 (10.98)) were recruited. The acceptability of KPPS-P was calculated. The structural validity and discriminant validity for different levels of pain was explored via the factor analysis, and Receiver Operating Characteristics (ROC) curves, respectively. Internal consistency, test-retest, and inter-rater reliability were estimated by Cronbach's alpha and Interclass Correlation coefficient (ICC). Convergent validity was established between KPPS-P and other scales including Visual Analog Scale-Pain, Douleur Neuropathic 4, Brief Pain Inventory, Short-form McGill Pain Questionnaire-2, and Parkinson's Disease-8.

Results

A significant floor effect was observed. The exploratory factor analysis revealed 4 factors. Cronbach's alpha and ICC values were higher than 0.80. The correlation range between KPPS-P and other scales was 0.35-0.76. Cut-off points of 0, 17, and 68 were obtained to discriminate pain severity levels between no pain, mild, moderate, and severe pain, respectively, with sensitivity and specificity above 0.80.

Conclusion

Our results indicate that the Persian version of KPPS not only has acceptable psychometric properties to assess pain in PD but also has the ability to distinguish between different levels of pain severity.

中文翻译：

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国王帕金森氏病疼痛量表临界点检测疼痛严重程度的水平：可靠性和有效性研究

背景

疼痛是帕金森氏病（PD）中最常见的非运动症状之一。使用适当而特定的测量工具将有助于控制疼痛。帕金森氏病疼痛量表（KPPS）是一种专门用于测量PD患者疼痛的仪器。

目的

这项研究的目的是检查波斯语版本KPPS（KPPS-P）的心理测量特性及其对疼痛严重程度的临界点。

方法

总共招募了480名PD患者（平均（SD）年龄为60.89（10.98））。计算KPPS-P的可接受性。通过因子分析和受试者工作特征（ROC）曲线分别探讨了不同疼痛程度的结构效度和判别效度。内部一致性，重测和评定者间的可靠性通过Cronbach's alpha和类别间相关系数（ICC）进行估算。在KPPS-P和其他量表（包括视觉模拟量表疼痛，Douleur神经病4，简短疼痛量表，简短形式的麦吉尔疼痛问卷2和帕金森氏病8）之间建立了收敛效度。

结果

观察到明显的地板效应。探索性因素分析揭示了4个因素。Cronbach的alpha和ICC值均高于0.80。KPPS-P与其他量表之间的相关范围是0.35-0.76。获得的分界点分别为0、17和68，以区分疼痛严重程度为无疼痛，轻度，中度和重度疼痛，敏感性和特异性均高于0.80。

结论

我们的结果表明，波斯语版本的KPPS不仅具有可接受的心理测验特性来评估PD的疼痛，而且还能够区分不同程度的疼痛严重程度。