Validation of an Estonian version of the Parkinson's Disease Questionnaire (PDQ-39)

Is PDQ-39 a reliable measure of quality of life of patients at advanced stages of Parkinson's disease considered for Deep Brain Stimulation

Purpose

Parkinson's disease (PD) significantly impedes, especially at its advanced stages, the health-related quality of life (QoL) of patients. The Parkinson's disease questionnaire (PDQ-39) is a widely-used measure assessing the impact of the disease on the patients' QoL. To date, the reliability of PDQ-39 has not been selectively evaluated for patients at a particular delineated stage of the PD progression. Against this backdrop, the study aimed firstly to evaluate comprehensively the internal consistency reliability of PDQ-39 and the constituent scales specifically for patients at the advanced stages of PD who were candidates for Deep Brain Stimulation (DBS) surgery, and secondly, to compare the Cronbach's alpha coefficients with those reported in other studies conducted with patients across all stages of the PD progression.

Methods

The sample included 36 Bulgarian patients (29 men and 7 women) at advanced stages of PD (Hoehn and Yahr stage 4), PD duration, M = 11.06, SD = 3.50). The internal consistency reliability of the questionnaire and the constituent scales was assessed using three criteria: Cronbach's alpha coefficients, inter-item and item-total correlations.

Results

The internal consistency reliability indicators were satisfactory for the entire instrument and for most of the scales and similar to those reported in previous studies. None of the scales had low internal consistency reliability results across the three criteria. Except for the Communication scale, seven of the eight scales had Cronbach's alpha values that were satisfactory or marginally below the cut off score. All scales had acceptable inter-item correlations. Three of the scales (Emotional Well-Being, Cognition and Communication) contained more than one item with non-satisfactory item-total correlations. With minor exceptions, the removal of the items with low item-total correlations either did not improve or improved marginally or even decreased the Cronbach's alpha coefficients of the respective scale. The Communication scale was the only scale with a Cronbach's alpha coefficient that was both low and comparatively different to other studies and had as well low item-total correlations for all constituent items, thus showing non-satisfactory results on two of the three internal consistency reliability estimates. In contrast, the Mobility scale met all three internal consistency reliability criteria.

Conclusion

PDQ-39 is a reliable tool for assessing the QoL of patients at advanced stages of PD across multiple health-related domains. The questionnaire can be recommended for inclusion in the best practice guidelines for evaluating DBS candidacy and the efficacy of DBS treatment for patients' QoL.

Psychometric properties of the Parkinson's disease Questionnaire-39 and its short form Parkinson's disease Questionnaire-8: A systematic review and meta-analysis

Parkinson's disease (PD) affects Quality of Life (QoL), since it is responsible for cognitive impairment, non-motor, and motor symptoms. Outcome measures are fundamental for evaluating treatment's effect on QoL over time. This systematic review aimed to identify the psychometric properties of PDQ-39 and PDQ-8 in the different populations in which they were validated. The electronic databases systematically searched are MEDLINE (via PubMed), CINAHL, SCOPUS, and Web of Science; the research was conducted in July 2023. The psychometric properties considered were those of the COnsensus-based Standards for the selection of health Measurement Instruments (COSMIN) checklist. Risk of bias was assessed using the COSMIN checklist. The search identified 1306 articles. 398 duplicates were eliminated; 908 articles were analyzed reading title and abstract; 799 were finally excluded because used PDQ-39 and PDQ-8 as outcome measures or were not dealing with psychometric properties; 66 articles were excluded after reading the full text. 43 articles were included in the review; meta-analysis showed all the Cronbach's alpha values were statistically significant for all the subscales of PDQ-39 and PDQ-8. PDQ-39 demonstrated to be a specific HRQoL questionnaire that is correlated with generic HRQoL questionnaires, in fact in many studies included in the review, correlations with SF-36 were found. In the last studies about psychometric properties of PDQ-8 emerged that it is a practical and informative instrument that can be easily used in clinical settings, especially in busy ones, but also in large-scale studies in which a brief instrument would be preferred.

Neurological Health: Not Merely the Absence of Disease: Current Wellbeing Instruments Across the Spectrum of Neurology

OBJECTIVE

Well-being and quality of life can vary independently of disease. Instruments measuring well-being and quality of life are commonly used in neurology, but there has been little investigation into the extent in which they accurately measure wellbeing/quality of life or if they merely reflect a diseased state of an individual.

DESIGN

Systematic searches, thematic analysis and narrative synthesis were undertaken. Individual items from instruments represented in ≥ 5 publications were categorised independently, without prior training, by five neurologists and one well-being researcher, as relating to 'disease-effect' or 'Well-being' with a study-created instrument. Items were additionally categorised into well-being domains.

DATA SOURCES

MEDLINE, EMBASE, EMCARE and PsycINFO from 1990 to 2020 were performed, across the 13 most prevalent neurological diseases.

RESULTS

301 unique instruments were identified. Multiple sclerosis had most unique instruments at 92. SF-36 was used most, in 66 studies. 22 instruments appeared in ≥ 5 publications: 19/22 'well-being' outcome instruments predominantly measured disease effect (Fleiss kappa = .60). Only 1/22 instruments was categorised unanimously as relating to well-being. Instruments predominantly measured mental, physical and activity domains, over social or spiritual.

CONCLUSIONS

Most neurological well-being or quality-of-life instruments predominantly measure disease effect, rather than disease-independent well-being. Instruments differed widely in well-being domains examined.

Structured guideline-based physiotherapy reduces difficulties in activities of daily living in Parkinson's disease

BACKGROUND

In the long term, Parkinson's disease (PD) leads to the development of difficulties in daily functional tasks. There remains a paucity of evidence on the effectiveness of physiotherapy on patient-perceived difficulties regarding basic activities of daily living (ADL).

OBJECTIVES

To assess an effect of a versatile physiotherapy intervention on patient-perceived difficulties in basic ADL.

METHODS

The study sample included 24 patients (10 men and 14 women) with PD. Participants were randomly assigned into intervention (IG) and control groups (CG). Two assessments were performed with a gap of 10 weeks. Following first assessment, during an 8-week period, IG participants attended sixteen physiotherapy 60-minutes sessions in groups that were divided into five parts to address the core areas recommended by the European Physiotherapy Guideline for PD (EPGPD): gait, transfers, balance, physical capacity, and manual activities. The main assessment tool was the Modified Patients Specific Functional Scale (ModPSFS), which represents a self-assessment rating on difficulties perceived in 17 different commonly occurring activities.

RESULTS

IG members reported a significant reduction in self-perceived difficulties as assessed by ModPSFS (effect size 1.39; 95%CI 5.1, 26.6 points, p = 0.005).

CONCLUSIONS

2-months conventional physiotherapy with incorporated core areas recommended in EPGPD for PD reduced patient-perceived difficulties in basic ADL.

Perceptions of aquatic physiotherapy and health-related quality of life among people with Parkinson's disease

Background

Enablers for people with Parkinson's disease (PD) participating in aquatic physiotherapy have been identified, and exercise improves health‐related quality of life (HRQoL) but it is unclear whether all enablers and barriers for aquatic physiotherapy specific to the PD population have been explored.

Objective

To describe HRQoL in people with PD who have undertaken aquatic physiotherapy, and explore their perceptions and attitudes regarding the programme.

Methods

Twenty‐one participants who participated in a pilot trial on aquatic physiotherapy were included. Participants completed a survey regarding their experiences. The Parkinson's Disease Questionnaire‐39 (PDQ‐39) and Personal Well‐being Index‐Adult (PWI) were used to quantify HRQoL, whilst focus groups were conducted to explore their perceptions and attitudes. Descriptive statistics were used to summarize HRQoL scores. Focus group data were analysed using the deductive coding method.

Results

Most participants felt that the aquatic programme was worthwhile (n = 20/21, 95%). However, they had poor overall well‐being (mean 41.6, SD 13.5) and HRQoL (mean 31.0, SD 13.2) as measured by the PWI and PDQ‐39. Several barriers to aquatic therapy including safety when getting dressed, fatigue and transport were identified although many enablers were also identified, including an improvement in function, less falls and group socialization.

Conclusions

Aquatic physiotherapy was well‐accepted. Participants felt their function improved and felt safe in the water. HRQoL is lower in individuals with PD when compared to Australian norms; thus, interventions to optimize HRQoL need to be explored further.

Patient or Public Contribution

Patients participated in the aquatic intervention, survey and focus groups.

Tools to assess the quality of life in patients with Parkinson's disease: a systematic review

INTRODUCTION

The clinical, social, and economic implications of Parkinson's disease (PD) are significant; disability occurs leading to a low quality of life (QoL). Information on the QoL of patients with PD and studies on the relationship between QoL and motor and cognitive function are necessary for both research and clinical use to make informed decisions in healthcare and rehabilitation. The aim of this study was to determine which scales are most used to assess QoL in patients with PD.

AREA COVERED

A literature search was conducted in MEDLINE, Scopus, CINAHL, PsycINFO, and Web of Science. Two authors independently identified eligible studies based on predefined inclusion criteria and extracted the data. Study quality and the risk of bias were assessed using the COSMIN checklist.

EXPERT OPINION

116 suitable studies were included, and 42 different instruments were identified. The most frequently used scales were the 39-items and 8-items Parkinson's Disease Questionnaire (PDQ-39) (PDQ-8). These findings suggest further investigation of existing PD outcome measures would benefit patients, researchers, and clinicians. Validated, universal outcome measures are required to allow comparisons across practice; therefore, we recommend that future researchers use a common set of outcome assessments based on the results of this review.

Quality of life in Parkinson's disease: Italian validation of the Parkinson's Disease Questionnaire (PDQ-39-IT)

Translation and cross-cultural adaptation of the 39-item Parkinson's Disease Questionnaire (PDQ-39) to the Italian culture was performed by Oxford University Innovation in 2008, but this version has never been validated. Therefore, we performed the process of validation of the Italian version of the PDQ-39 (PDQ-39-IT) following the "Consensus-Based Standards for the Selection of Health Status Measurement Instruments" checklist. The translated PDQ-39-IT was tested with 104 patients diagnosed with Parkinson's disease (PD) who were recruited between June and October 2017. The mean age of the participants was 65.7 ± 10.2 years, and the mean duration of symptoms was 7.4 ± 5.3 years. The internal consistency of the PDQ-39-IT was assessed by Cronbach's alpha and ranged from 0.69 to 0.92. In an assessment of test-retest reliability in 35 of the 104 patients, the infraclass correlation coefficient (ICC) ranged from 0.85 to 0.96 for the various subitems of the PDQ-39-IT (all p < 0.01). Spearman's rank correlation coefficient for the validity of the PDQ-39-IT and the Italian version of the 36-Item Short Form (SF-36) was - 0.50 (p < 0.01). The results show that the PDQ-39-IT is a reliable and valid tool to assess the impact of PD on functioning and well-being. Thus, the PDQ-39-IT can be used in clinical and research practice to assess this construct and to evaluate the overall effect of different treatments in Italian PD patients.

Health-related quality of life in Parkinson's disease: a cross-sectional study focusing on non-motor symptoms

BACKGROUND

The objective of this study was to investigate factors affecting health-related quality of life (HRQoL) among Estonian persons with Parkinson's disease (PD).

METHODS

268 persons with PD were evaluated using: the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS); the Hoehn and Yahr scale (HY); the Schwab and England Activities of Daily Living scale (SE-ADL); the Beck Depression Inventory (BDI); the Mini Mental State Examination (MMSE); the Parkinson's Disease Questionnaire (PDQ-39). Additional questions on clinical and socio-demographic variables were asked during a semi-structured interview. Predictors of HRQoL were tested using multiple regression analysis.

RESULTS

The main predictors of low HRQoL were depression and motor and non-motor aspects of daily living. 59.9 % of the variation in the PDQ-39 summary index (SI) score was explained by the predictive variables identified in this study. None of the socio-demographic variables (age, gender, urban/rural living, marital status, living alone/with others, education level) were significant predictors of HRQoL. Prevalence of non-motor Parkinson's symptoms were high (99.6 %); cognitive impairment, sleep and urinary problems were the most common. All non-motor symptoms correlated significantly with low HRQoL, except the features of impulse control disorders (ICDs).

CONCLUSIONS

Depression and motor and non-motor daily living experiences were found to be significant and independent factors of low HRQoL in persons with PD. Depression was the strongest determinant of low HRQoL. Our results highlight the importance of recognition and management of non-motor symptoms, as these features had more impact on patients' HRQoL than clinically assessed motor symptoms.

Safety and efficacy of recombinant human erythropoietin treatment of non-motor symptoms in Parkinson's disease

BACKGROUND

Numerous animal studies and clinical trials have demonstrated that erythropoietin (EPO) has therapeutic effects in ischemic and degenerative diseases. However, few clinical trials have investigated the effect of EPO in Parkinson's disease (PD) patients. This study was an exploratory pilot study to investigate the effects of recombinant human EPO (rhEPO) on motor and non-motor symptoms (NMS) in PD patients.

METHODS

A total of 26 PD patients at the Hanyang University Hospital were enrolled in the study. The participants were randomly assigned to rhEPO and placebo groups. The rhEPO group was infused intravenously (40,000 IU each) twice a week for 5 weeks. Clinical improvement was estimated using the Unified Parkinson's Disease Rating Scale-III (UPDRS-III), the NMS Scale (NMSS) and the 39-Item Parkinson's Disease Questionnaire (PDQ-39). [(18)F] N-(3-fluoropropyl)-2β-carbon ethoxy-3β-(4-iodophenyl) nortropane (FP-CIT) photon emission tomography (PET) scanning was performed on each participant at baseline and again after 12 months.

RESULTS

The rhEPO administration significantly improved the NMSS and PDQ-39 scores at 12 months. The UPDRS-III, which reflects motor function, did not change significantly after the rhEPO treatment. With the NMSS, the domains of cardiovascular autonomic function, sleep/fatigue, mood/cognition and attention/memory showed significant changes. None of the participants experienced any serious adverse effects.

DISCUSSION

We found that rhEPO had beneficial effects on NMS but not on motor function. Dopaminergic refractory NMS, such as cardiovascular autonomic dysfunction and cognition, showed improvement after the administration of rhEPO. Our results suggest that rhEPO might be a good candidate for the treatment of NMS in PD patients.

Health-related quality of life of australians with Parkinson disease: a comparison with international studies

PURPOSE

This study describes the health-related quality of life (HRQOL) of Australians living with Parkinson disease (PD) and compares the findings to international reports.

METHODS

The Parkinson's Disease Questionnaire-39 (PDQ-39) was used to measure HRQOL in 210 individuals with PD living in Australia. In parallel, a tailored literature search identified previous studies on HROQL in people with PD. A quantitative meta-analysis with a random-effects model was used to compare the HRQOL of individuals with PD living in Australia and other countries.

RESULTS

The mean PDQ-39 summary index (SI) score for this sample of Australians with PD was 20.9 (SD 12.7). Ratings for the dimension of social support and stigma were significantly lower than ratings for bodily discomfort, mobility, activities of daily living, cognition, and emotional well-being. Comparing the Australian and international PD samples revealed a significant heterogeneity in overall HRQOL (I(2)=97%). The mean PDQ-39 SI scores for Australians were lower, indicating better HRQOL relative to samples from other countries.

CONCLUSIONS

This Australian sample with PD perceived their HRQOL as poor, although it was less severely compromised than that of international samples. While further research is required, these findings can inform the clinical decision-making processes of physiotherapists.

Quality of life in patients with Parkinson's disease: Translation and psychometric evaluation of the Iranian version of PDQ-39

BACKGROUND

Health related quality of life is an important outcome measure in studies involving patients with chronic neurological conditions. Disease specific patient reported outcome measures (PROMs) are increasingly used as primary end points in clinical trials. The most widely used disease specific PROM is the 39 item Parkinson's Disease Questionnaire (PDQ-39). The aim of this study was to determine validity and reliability of Persian PDQ-39.

METHODS

Two hundred Parkinson's disease patients attending neurologic clinics of teaching hospitals were recruited. PD patients completed a translated version of the PDQ-39. Internal consistency reliability of the questionnaire was assessed by Cronbach's alpha coefficient. Reproducibility was assessed across the 3-week interval using the intraclass correlation coefficient. To assess convergent validity, results on the PDQ-39 were correlated with those gained on the SF-36. Discriminate validity of questionnaire was assessed by comparing PDQ-39 scores and the severity and the duration of disease.

RESULTS

A value of 0.93 (Cronbach's α) was gained for the summary score (PDQ-SI), indicating high levels of internal reliability. Alpha value of seven domains was greater than 0.70. The intraclass correlation coefficient ranged from 0.47 to 0.90. The range of correlation coefficients between domains of SF-36 and PDQ-SI was from -0.40 to -0.61. There was a statistically significant difference between severity of disease and mean scores of PDSI.

CONCLUSIONS

This study provides evidence that the Persian version of PDQ-39 is a valid and reliable measure of quality of life in PD.