| 1. |
- Kim, M.-Y., et al.
(författare)
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Respondent burden and patient-perceived validity of the PDQ-39
- 2006
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Ingår i: Acta Neurologica Scandinavica. - : Wiley-Blackwell. - 0001-6314 .- 1600-0404. ; 113:2, s. 132-137
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To evaluate the respondent burden and patient-perceived content validity of the Parkinson's disease (PD)-specific health status questionnaire PDQ-39, and the linguistic validity of its revised Swedish version.MATERIALS AND METHODS: Eighteen PD patients completed the revised Swedish version of the PDQ-39. Respondent burden was assessed by recording the time taken to complete the questionnaire. Content and linguistic validity was evaluated qualitatively.RESULTS: Patients with mild, moderate and advanced PD needed a mean time of 9.5, 11.3 and 20.1 min, respectively, to complete the PDQ-39. One-third of the patients identified irrelevant items and 50% identified important health-related areas that were missing. Revisions had eliminated previous linguistic problems with the Swedish PDQ-39.CONCLUSIONS: Undue respondent burden challenged the appropriateness of the PDQ-39 among patients with more advanced disease. Overall content validity was acceptable but compromised by lack of important content areas. Observations supported the linguistic validity of the revised Swedish PDQ-39.
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| 2. |
- Hagell, Peter
(författare)
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Measuring activities of daily living in Parkinson's disease : On a road to nowhere and back again?
- 2019
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Ingår i: Measurement: Journal of the International Measurement Confederation. - : Elsevier BV. - 0263-2241. ; 132, s. 109-124
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Tidskriftsartikel (refereegranskat)abstract
- Parkinson's disease (PD) is a progressive neurodegenerative disorder associated with increasing disability and limitations in performance of activities of daily living (ADL) despite availability of effective symptomatic therapy. Following an overview of classical test theory (CTT) and Rasch measurement theory (RMT), the case of a clinical PD trial aiming to demonstrate ADL improvements by using the ADL section (part II) of the Unified PD Rating Scale (UPDRS) to measure ADL outcomes is considered and central questions related to its validity and interpretation are addressed. It is found that while CTT did not detect any issues, RMT in combination with conceptual considerations seriously challenged the role of the UPDRS II as an ADL outcome measure. Results are discussed from historical, methodological and clinical perspectives.
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| 3. |
- Hellström, Amanda, et al.
(författare)
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A classical test theory evaluation of the Sleep Condition Indicator accounting for the ordinal nature of item response data
- 2019
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 14:3, s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- Background Insomnia symptoms are common among young adults and affect about 5% to 26% of 19 to 34-year-olds. In addition, insomnia is associated with poor mental health and may affect daily performance. In research, as well as in clinical practice, sleep questionnaires are used to screen for and diagnose insomnia. However, most questionnaires are not developed according to current DSM-5 diagnostic criteria. An exception is the recently developed Sleep Condition Indicator (SCI), an eight-item scale screening for insomnia. Aim The aim of this study was to perform a Classical Test Theory (CTT) based psychometric evaluation of the SCI in a sample of Swedish university students, by taking the ordinal nature of item level data into account. Methods The SCI was translated into Swedish and distributed online to undergraduate students at three Swedish universities, within programs of health, psychology, science or economy. Of 3673 invited students, 634 (mean age 26.9 years; SD = 7.4) completed the questionnaire that, in addition to the SCI, comprised other scales on sleep, stress, lifestyle and students' study environment. Data were analyzed according to CTT investigating data completeness, item homogeneity and unidimensionality. Results Polychoric based explorative factor analysis suggested unidimensionality of the SCI, and internal consistency was good (Cronbach's alpha, 0.91; ordinal alpha, 0.94). SCI scores correlated with the Insomnia Severity Index (-0.88) as well as with sleep quality (-0.85) and perceived stress (-0.50), supporting external construct validity. Conclusions These observations support the integrity of the of the SCI. The SCI demonstrates sound CTT-based psychometric properties, supporting its use as an insomnia screening tool.
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| 4. |
- Lindholm, Beata, et al.
(författare)
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The clinical significance of 10-m walk test standardizations in Parkinson’s disease
- 2018
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Ingår i: Journal of Neurology. - : Springer Science and Business Media LLC. - 0340-5354 .- 1432-1459. ; 265:8, s. 1829-1835
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Tidskriftsartikel (refereegranskat)abstract
- Background: The 10-m walk test (10MWT) is a widely used measure of gait speed in Parkinson’s disease (PD). However, it is unclear if different standardizations of its conduct impact test results. Aim of the study: We examined the clinical significance of two aspects of the standardization of the 10MWT in mild PD: static vs. dynamic start, and a single vs. repeated trials. Implications for fall prediction were also explored. Methods: 151 people with PD (mean age and PD duration, 68 and 4 years, respectively) completed the 10MWT in comfortable gait speed with static and dynamic start (two trials each), and gait speed (m/s) was recorded. Participants then registered all prospective falls for 6 months. Results: Absolute mean differences between outcomes from the various test conditions ranged between 0.016 and 0.040 m/s (effect sizes, 0.06–0.14) with high levels of agreement (intra-class correlation coefficients, 0.932–0.987) and small standard errors of measurement (0.032–0.076 m/s). Receiver operating characteristic curves showed similar discriminate abilities for prediction of future falls across conditions (areas under curves, 0.70–0.73). Cut-off points were estimated at 1.1–1.2 m/s. Conclusions: Different 10MWT standardizations yield very similar results, suggesting that there is no practical need for an acceleration distance or repeated trials when conducting this test in mild PD.
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| 5. |
- Hagell, Peter, et al.
(författare)
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A Swedish version of the 16-item Parkinson Fatigue Scale (PFS-16)
- 2012
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Ingår i: Acta Neurologica Scandinavica. - : Wiley-Blackwell. - 0001-6314 .- 1600-0404. ; 125:4, s. 288-292
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Tidskriftsartikel (refereegranskat)abstract
- Background – The PFS-16 is a 16-item fatigue scale for Parkinson’s disease (PD) developed in the UK. However, documented translations and psychometric evaluations are sparse.Aim – To translate the PFS-16 into Swedish and conduct initial testing of its psychometric properties.Methods – Following translation, the PFS-16 was administered twice (2 weeks apart) to 30 people with PD (18 men; mean age/PD duration, 60/6.4 years). The PFS-16 uses five response categories (1 = strongly disagree, 5 = strongly agree), and the total score is the mean over item scores (1–5; 5 = more fatigue). An alternative, dichotomised scoring method has also been suggested (total score, 0–16; 16 = more fatigue). Scaling assumptions, floor/ceiling effects, reliability, and correlations with other variables including the generic fatigue scale Functional Assessment of Chronic Illness Therapy – Fatigue scale (FACIT-F) were tested.Results – Scaling assumptions were generally supported for the original scoring [range of mean (SD) item scores, 2.1–3.3 (1–1.4); corrected item-total correlations, ≥0.40], but not for dichotomised scoring [range of mean (SD) item scores, 0.1–0.6 (0.3–0.5); corrected item-total correlations, ≥0.16]. Reliabilities were ≥0.88. Floor effects were absent (original scoring) and >23% (dichotomised scoring); there were no ceiling effects. Correlations with other variables followed expectations (e.g. −0.88 with FACIT-F scores).Conclusions – These observations support the psychometric properties of the Swedish PFS-16, but cautions against dichotomised scoring.
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| 6. |
- Hagell, Peter, et al.
(författare)
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Apomorphine formulation influences subcutaneous complications in continuous apomorphine pump therapy for Parkinson’s disease
- 2017
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Ingår i: Movement Disorders.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Objective: To explore if the occurrence and severity of subcutaneous (sc) nodules is influenced by the pharmaceutical formulation of apomorphine used for sc infusion in advanced Parkinson’s disease (PD).Background: Apomorphine infusion is an effective therapy in advanced PD, but a limitation is troublesome sc nodules. Various chemically non-identical apomorphine formulations are available. Anecdotal clinical experience has suggested that shifting from one of these (Apo-Go PumpFill; apoGPF) to another (Apomorphine PharmSwed; apoPS, developed in Sweden) may influence the occurrence and severity of sc nodules.Methods: In this multicenter open-label prospective observational study, 15 people with advanced PD (mean PD- duration, 13.4 years; median Hoehn & Yahr, IV) on apoGPF since a mean of 2.1 years and with troublesome sc nodules were switched to apoPS. Ongoing interventions to treat existing nodules (ultrasound, massage, Hirudoid cream) continued, and apomorphine as well as other drugs was managed according to clinical routines. Data were collected between May 2015 and March 2017; at baseline, at the time of switching (about 2 weeks later), and up to 1.7-4.2 (mean, 2.5) months post-switch follow-up. Primary outcomes were total nodule numbers, size (mm diameter for the 5 worst nodules), consistency (scored 0-3 for the 5 worst nodules), and associated skin changes (scored 0-4 for the 5 worst nodules) and pain (scored 0-5). Patients also rated their perceived PD severity and motor complications (UPDRS IV). Patient preferences 5-12 months post-switch (2-9 months after follow-up) were also recorded.Results: Apomorphine and L-dopa doses did not change over the observation period (P≥0.400). Baseline nodule numbers (7.4 vs. 4.6; P<0.003), size (92.9 vs. 54.1 mm; P=0.016), consistency (11 vs. 5; P=0.003), skin changes (3 vs. 1.5; P=0.205), and average pain (1 vs. 0; P=0.020) improved 11 weeks post-switch. Patient-reported PD severity (P=0.020) and motor fluctuations improved (P=0.051), whereas dyskinesias tended to increase (P=0.205). At 5-12 months post-switch, 13 patients had decided to remain on apoPS; mainly due to improved nodules.Conclusions: These observations suggest that apoPS may have a better safety profile compared to apoGPF in terms of sc nodule occurrence and severity. There is a need for larger, randomized controlled studies for firmer conclusions.
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| 7. |
- Hagell, Peter, et al.
(författare)
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Health status measurement in Parkinson's disease : validity of the PDQ-39 and Nottingham Health Profile
- 2003
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Ingår i: Movement Disorders. - : John Wiley & Sons Inc.. - 0885-3185 .- 1531-8257. ; 18:7, s. 773-783
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Tidskriftsartikel (refereegranskat)abstract
- We assessed the feasibility and psychometric properties of two commonly used health status questionnaires in Parkinson's disease (PD): the generic Nottingham Health Profile (NHP) and the disease-specific 39-item Parkinson's disease Questionnaire (PDQ-39), from a cross-sectional postal survey of PD patients (N = 81), using traditional and Rasch measurement methodologies. Overall response rate was 88%. Both questionnaires were found feasible, although the NHP performed less well. The PDQ-39 had fewer floor effects and was better able to separate respondents into distinct groups than the NHP, whereas the latter exhibited less ambiguous dimensionality and better targeting of respondents with non-extreme scores. Reliability and validity indices were similar, and potential differential item functioning by age and gender groups was found for both questionnaires. PDQ-39 response alternatives indicated ambiguity. With few exceptions, questionnaire scales were unable to meet recommended standards fully. While preliminary, this study illustrates the need for thorough evaluation of outcome measures and has implications beyond the questionnaires used here. Although promising, both questionnaires warrant further developmental work and stronger support of measurement validity before they could be considered fully suitable for valid use in PD, in particular in earlier stages of the disease.
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| 8. |
- Hagell, Peter, et al.
(författare)
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Measurement properties of the SF-12 Health Survey in Parkinson's disease
- 2011
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Ingår i: Journal of Parkinson's Disease. - : IOS Press. - 1877-7171 .- 1877-718X. ; 1:2, s. 185-196
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Tidskriftsartikel (refereegranskat)abstract
- The 12-item Short-Form Health Survey (SF-12) is an abbreviated version of the SF-36, one of the most widely used patient-reported health outcome rating scales. Similar to the SF-36, it yields summary scores of physical and mental health (PCS and MCS, respectively). However, SF-36 derived PCS and MCS scores have not been found valid in neurological disorders such as Parkinson's disease (PD). Here we used modern psychometric methodology (Rasch analysis) to test the SF-12 in PD, and explored the appropriateness of a total SF-12 score representing overall health. SF-12 data from 150 non-demented people with PD (56% men; mean age/PD-duration, 70/5 years) were analyzed regarding Rasch model fit for the PCS, MCS, as well as for the full SF-12. Data showed some signs of misfit to the Rasch model for all three scales (overall item-trait interaction, P ≥ 0.003; reliability, ≥ 0.85). For example, all scales exhibited signs of dependency between item responses, and the PCS measured with relatively low precision. Model fit (but not measurement precision) was improved following deletion of one PCS and one MCS item (overall item-trait interaction, P ≥ 0.387; reliability, ≥ 0.82). These observations suggest that the SF-12 can be used as a coarse health survey tool in PD and that a total SF-12 may be useful as a measure of overall health. However, its appropriateness as an outcome measure can be questioned and it is somewhat unclear exactly what the derived scores represent. As such, the SF-12 should probably be considered an assessment tool (or index) rather than a measurement instrument.
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| 9. |
- Hagell, Peter, et al.
(författare)
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Measuring fatigue in Parkinson's disease : a psychometric study of two brief generic fatigue questionnaires.
- 2006
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Ingår i: Journal of Pain and Symptom Management. - : Elsevier. - 0885-3924 .- 1873-6513. ; 32:5, s. 420-32
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Tidskriftsartikel (refereegranskat)abstract
- This study evaluated and compared the measurement properties of the 13-item Functional Assessment of Chronic Illness Therapy-Fatigue Scale (FACIT-F) and the 9-item Fatigue Severity Scale (FSS) in 118 consecutive Parkinson's disease (PD) patients, using traditional and Rasch measurement methodologies. Both questionnaires exhibited excellent data quality and reliability (coefficient alpha>or=0.9), and acceptable rating scale functionality, and both discriminated between fatigued and nonfatigued patients. Factor and Rasch analyses provided general support for unidimensionality of both FACIT-F and FSS, although they do not appear to measure identical aspects of fatigue. No signs of differential item functioning (DIF) were found for the FACIT-F, whereas potential age DIF was detected for two FSS items. These results support the measurement validity of both questionnaires in PD, although the FACIT-F displayed better measurement precision and modest psychometric advantages over the FSS. Availability of psychometrically sound fatigue measures that are applicable across disorders provides a sound basis for advancing the understanding of this common and distressing complaint.
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| 10. |
- Hagell, Peter
(författare)
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Nursing and multidisciplinary interventions for Parkinson's disease : what is the evidence?
- 2007
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Ingår i: Parkinsonism & Related Disorders. - : Elsevier. - 1353-8020 .- 1873-5126. ; 13:Suppl 3, s. 501-508
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Tidskriftsartikel (refereegranskat)abstract
- This paper reports the interim results of an ongoing systematic review of the available evidence for the effectiveness of nursing care for people with Parkinson's disease (PD). Five clinical and four health-economic evaluations suggest that the clinical and cost effectiveness of nursing care for PD remain inconclusive. This is in contrast to clinical experience and may be due to issues related to study designs, study interventions, and the outcome measures used. More studies are needed and may benefit from considering specific interventions evaluated using outcome measures that are valid and responsive representations of their expected outcomes.
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