Psychometric features of brief pain inventory for Parkinson's disease during medication states.

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.

Validity and Reliability of the Persian Version of Parkinson's Disease Sleep Scale-2.

OBJECTIVE: Sleep problems are nonmotor symptoms in Parkinson's disease that should be carefully evaluated for better management and treatment. Parkinson's Disease Sleep Scale (PDSS-2) is one of the most reliable tools for measuring sleep difficulties in people with Parkinson's disease. This study investigated the psychometric properties of the Persian version of PDSS-2. METHODS: Four hundred and fifty-six people with Parkinson's disease with a mean age ±standard deviation of 60.7 ± 11.3 years were engaged in this study. Acceptability was assessed by floor and ceiling effects. Dimensionality was measured by exploratory factor analysis. The convergent validity of PDSS-2 with the Hospital Anxiety and Depression Scale (HADS) was assessed. Internal consistency and test-retest reliability were assessed with Cronbach's alpha and intraclass correlation coefficient (ICC), respectively. RESULTS: No noticeable ceiling and floor effect was detected. The dimensionality analysis showed three factors. A high correlation was obtained between PDSS-2 and HADS (anxiety subscale). Excellent internal consistency with α = 0.94, and good test-retest reliability with ICC = 0.89 were obtained. CONCLUSION: This study showed that the Persian version of Parkinson's Disease Sleep Scale has acceptable validity and reliability for measuring sleep disturbances in people with Parkinson's disease.

Clinimetrics of the Freezing of Gait Questionnaire for Parkinson Disease During the "off" State.

INTRODUCTION: Freezing of gait, a common PD motor symptom, could increase the risk of falling. This study aimed to investigate the clinimetric attributes of the Freezing of Gait Questionnaire (FOGQ) for people with Parkinson disease in the "off" state. METHODS: A total of 115 patients with Parkinson disease (PD; mean age, 60.25 years) were included. Acceptability, internal consistency (by the Cronbach alpha, and test-retest by Intraclass Correlation [ICC]), and reliability of the Persian-translated version of the FOGQ were examined. Dimensionality was estimated by Exploratory Factor Analysis (EFA). Fall efficacy scale-international, unified Parkinson disease rating scale-II, Berg balance scale, functional reach test, and Parkinson disease questionnaire-39 were applied to determine the convergent validity. Diagnostic accuracy for obtaining optimal cutoff point, separating faller and non-faller groups, was analyzed by Receiver Operating Characteristics (ROC) curve analysis and Area Under the Curve (AUC). All tests were carried out in an "off" state. RESULTS: The Cronbach alpha was high (α=0.92). The test-retest showed high reliability (ICC=0.89). The FOGQ was unidimensional according to the EFA and had acceptable convergent validity with moderate to high correlation with other clinical scales. The optimal cutoff point to discriminate fallers from non-fallers during the "off" state was 9/10, with an AUC of 0.92. CONCLUSION: Our results suggest that the FOGQ has appropriate reliability, validity, and discriminative ability for measuring FOG in patients with PD during the "off" state.

King's Parkinson's disease pain scale cut-off points for detection of pain severity levels: A reliability and validity study.

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.

Psychometric features of Neuropathic Pain Symptom Inventory in Iranian people with Parkinson's disease.

OBJECTIVE: Neuropathic pain is a type of pain reported in people with Parkinson's disease. There are various scales to evaluate the characteristics of this kind of pain. The purpose of this study was to investigate the psychometric properties of the Neuropathic Pain Symptom Inventory (NPSI), a specific scale that measures neuropathic pain in Iranian people with Parkinson's disease. METHOD: Four hundred forty-seven individuals with Parkinson's disease were recruited in the study. Acceptability, internal consistency (Cronbach's alpha), and test-retest reliability (intraclass correlation coefficient, ICC) of NPSI were calculated. Dimensionality was examined through exploratory factor analysis. For convergent validity, correlations of NPSI with Douleur Neuropathic 4, Brief Pain Inventory, King's Pain Parkinson disease Scale, and Visual Analog Scale-Pain were used. Discriminative validity and sensitivity to change between On- and Off- medication states were analyzed. RESULTS: A marked floor effect was observed for this scale (64.2%). Cronbach's alpha and ICC were 0.90 and 0.87, respectively. Items of NPSI were placed in 4 factors. A moderate to the strong association (rs = 0.55 to 0.85) between NPSI and other scales was obtained. The results of discriminative validity and sensitivity to change indicate the ability of NPSI to show differences between medication states. CONCLUSION: The results of this study suggest that NPSI has acceptable reliability, validity, and sensitivity to change, indicating that this scale is suitable for measuring neuropathic pain in Iranian people with Parkinson's disease.

Validity and Reliability of Short-Form McGill Pain Questionnaire-2 (SF-MPQ-2) in Iranian People with Parkinson's Disease.

PURPOSE: Pain is one of the nonmotor symptoms of Parkinson's disease (PD) that, in order to be better managed, requires to be evaluated. Evaluations are done using pain assessment scales such as the Short-Form McGill Pain Questionnaire-2 (SF-MPQ-2). The goal of this study was to assess the psychometric properties of SF-MPQ-2 to measure pain in people with PD. METHODS: Four hundred and twenty-eight PD patients with a mean (SD) age of 60.11 (11.44) years were included. Accessibility was measured through floor and ceiling effects. Dimensionality was estimated by exploratory factor analysis. The association between SF-MPQ-2 and other scales such as Neuropathic Pain Symptom Inventory, Douleur Neuropathic 4, Brief Pain Inventory, King's Pain Parkinson's Disease Scale, and Visual Analog Scale-Pain was considered to calculate convergent validity. Internal consistency and test-retest reliability were assessed by Cronbach's alpha and intraclass correlation coefficient (ICC), respectively. RESULTS: A noticeable floor effect was found. Dimensionality results indicated four factors for this scale. A strong relationship was found between the SF-MPQ-2 total score and other scales (r = 0.55 to 0.85). In reliability analysis, Cronbach's alpha and ICC were 0.93 and 0.94 for SF-MPQ-2, respectively. CONCLUSION: The results of this study showed that SF-MPQ-2 has adequate validity and reliability to measure pain in people with Parkinson's disease.

Barthel Index and modified Rankin Scale: Psychometric properties during medication phases in idiopathic Parkinson disease.

BACKGROUND: Independence in activities of daily living (ADL) is one of the most important aspects in planning treatment for people with Parkinson disease (PD). The Barthel Index (BI) and modified Rankin Scale (mRS) are commonly used in neurological diseases. OBJECTIVE: This study was conducted to confirm the validity and reliability of the BI and mRS in PD during ON and OFF medication phases. METHODS: We included 260 individuals with a diagnosis of idiopathic PD. The disability in ADL was measured by the BI, mRS, Parkinson's Disease Questionnaire-39 (PDQ-39), Unified Parkinson Disease Rating Scale-Activities of Daily Living (UPDRS-ADL), and Schwab and England ADL scale (SE). Test-retest, inter-rater reliability, and internal consistency were assessed by the intra-class correlation (ICC) and Cronbach α coefficients. Dimensionality was evaluated by factor analysis. Convergent validity was assessed by the SE, Berg Balance Scale (BBS), PDQ-39 and UPDRS-ADL. RESULTS: For the 260 participants (187 [71.9%] males; mean [SD] age 60.3 [12.3] years), both the BI and mRS achieved an acceptable level of test-retest and inter-rater reliability (ICC=0.77 to 0.91) in ON and OFF medication phases. The Cronbach α for BI was 0.85 and 0.88, respectively. We found 1 and 2 factors for BI in ON and OFF phases, respectively. Investigation of convergent validity showed moderate to high correlation for the BI with the UPDRS-ADL, SE, PDQ-39 (ADL), BBS and mRS scores in ON and OFF phases (ρ=0.51-0.74) and mRS with SE, UPDRS-ADL, PDQ-39 (ADL) and BBS scores (ρ=0.48-0.82). CONCLUSION: The BI and mRS showed acceptable validity and reliability to measure the degree of disability in patients with PD in daily activities in both ON and OFF medication phases.