Browsing by Keyword "Rasch analysis"
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Publication Is the Parkinson Anxiety Scale comparable across raters?(Wiley, 2015-04) Forjaz, Maria João; Ayala, Alba; Martínez-Martín, Pablo; Dujardin, Kathy; Pontone, Gregory M; Starkstein, Sergio E; Weintraub, Daniel; Leentjens, Albert F G; Foundation for Parkinson ResearchThe Parkinson Anxiety Scale is a new scale developed to measure anxiety severity in Parkinson's disease specifically. It consists of three dimensions: persistent anxiety, episodic anxiety, and avoidance behavior. This study aimed to assess the measurement properties of the scale while controlling for the rater (self- vs. clinician-rated) effect. The Parkinson Anxiety Scale was administered to a cross-sectional multicenter international sample of 362 Parkinson's disease patients. Both patients and clinicians rated the patient's anxiety independently. A many-facet Rasch model design was applied to estimate and remove the rater effect. The following measurement properties were assessed: fit to the Rasch model, unidimensionality, reliability, differential item functioning, item local independency, interrater reliability (self or clinician), and scale targeting. In addition, test-retest stability, construct validity, precision, and diagnostic properties of the Parkinson Anxiety Scale were also analyzed. A good fit to the Rasch model was obtained for Parkinson Anxiety Scale dimensions A and B, after the removal of one item and rescoring of the response scale for certain items, whereas dimension C showed marginal fit. Self versus clinician rating differences were of small magnitude, with patients reporting higher anxiety levels than clinicians. The linear measure for Parkinson Anxiety Scale dimensions A and B showed good convergent construct with other anxiety measures and good diagnostic properties. Parkinson Anxiety Scale modified dimensions A and B provide valid and reliable measures of anxiety in Parkinson's disease that are comparable across raters. Further studies are needed with dimension C.Publication Living with Chronic Illness Scale: International validation through the classic test theory and Rasch analysis among Spanish-speaking populations with long-term conditions(Wiley, 2021-12) Rodriguez-Blazquez, Carmen; Forjaz, Maria João; Ayala, Alba; Portillo, Mari Carmen; Ambrosio, Leire; EC‐PC Validation Group; Ministerio de Ciencia, Innovación y Universidades (España); Unión Europea. Fondo Europeo de Desarrollo Regional (FEDER/ERDF); Agencia Estatal de Investigación (España)Background: The Living with Chronic Illness (LW-CI) Scale is a comprehensive patient-reported outcome measure that evaluates the complex process of living with long-term conditions. Objective: This study aimed to analyse the psychometric properties of the LW-CI scale according to the classic test theory and the Rasch model among individuals living with different long-term conditions. Design: This was an observational, international and cross-sectional study. Methods: A total of 2753 people from six Spanish-speaking countries living with type 2 diabetes mellitus, chronic obstructive pulmonary disease, chronic heart failure, Parkinson's disease, hypertension and osteoarthritis were included. The acceptability, internal consistency and validity of the LW-CI scale were analysed using the classical test theory, and fit to the model, unidimensionality, person separation index, item local independency and differential item functioning were analysed using the Rasch model. Results: Cronbach's α for the LW-CI scale was .91, and correlation values for all domains of the LW-CI scale ranged from .62 to .68, except for Domain 1, which showed correlation coefficients less than .30. The LW-CI domains showed a good fit to the Rasch model, with unidimensionality, item local independency and moderate reliability providing scores in a true interval scale. Except for two items, the LW-CI scale was free from bias by long-term condition type. Discussion: After some adjustments, the LW-CI scale is a reliable and valid measure showing a good fit to the Rasch model and is ready for use in research and clinical practice. Future implementation studies are suggested. Patient and Public Contribution: Patient and public involvement was conducted before this validation study - in the pilot study phase.Publication Proposing a Parkinson's disease-specific tremor scale from the MDS-UPDRS(Wiley, 2015-07) Forjaz, Maria João; Ayala, Alba; Testa, Claudia M; Bain, Peter G; Elble, Rodger; Haubenberger, Dietrich; Rodriguez-Blazquez, Carmen; Deuschl, Günther; Martínez-Martín, PabloBackground: This article proposes an International Parkinson and Movement Disorder Society (MDS)-UPDRS tremor-based scale and describes its measurement properties, with a view to developing an improved scale for assessing tremor in Parkinson's disease (PD). Methods: This was a cross-sectional, multicenter study of 435 PD patients. Rasch analysis was performed on the 11 MDS-UPDRS tremor items. Construct validity, precision, and test-retest reliability were also analyzed. Results: After some modifications, which included removal of an item owing to redundancy, the obtained MDS-UPDRS tremor scale showed moderate reliability, unidimensionality, absence of differential item functioning, satisfactory convergent validity with medication, and better precision than the raw sum score. However, the scale displayed a floor effect and a need for more items measuring lower levels of tremor. Conclusions: The MDS-UPDRS tremor scale provides linear scores that can be used to assess tremor in PD in a valid, reliable way. The scale might benefit from modifications and studies that analyze its responsiveness.Publication Psychometric Properties of the COVID-19 Pandemic Fatigue Scale: Cross-sectional Online Survey Study(JMIR Publications, 2022-09-08) Rodriguez-Blazquez, Carmen; Romay-Barja, Maria; Falcon, Maria; Ayala, Alba; Forjaz, Maria João; Instituto de Salud Carlos IIIBackground: Pandemic fatigue is defined as feelings of demotivation to follow preventive measures against COVID-19, together with decreased trust in government and frequency of information-seeking behaviors. Objective: This study aims to analyze the psychometric properties of the COVID-19-specific pandemic fatigue scale according to classical test theory (CTT) and Rasch model approaches in the general Spanish population. Methods: This was a cross-sectional study in a representative sample of 1018 adults who completed an online survey in November 2020 in the framework of the COVID-19 Snapshot Monitoring (COSMO)-Spain project. The assessments included the 6-item COVID-19 Pandemic Fatigue Scale (CPFS) and other COVID-19-related variables: COVID-19 infection, adherence to preventive behaviors, information-seeking behavior, self-efficacy, worry, and cognitive and affective risk perception. Data quality, acceptability, reliability, and validity were analyzed according to CTT, and the fit to the Rasch model, unidimensionality, appropriateness of the response scale, item local independency, reliability (person-separation index [PSI]), and item-person distribution were also calculated. Results: The mean CPFS score was 17.06 (SD 5.04, range 6-30), with higher scores for women, younger participants, participants who never seek information on COVID-19, those who think they would contract a mild disease in case of infection, those with higher level of worry about coronavirus/COVID-19, and those who felt depressed or felt the coronavirus/COVID-19 is spreading slowly (all P<.01). The Cronbach alpha for the CPFS was 0.74. In the confirmatory factor analysis, one factor was identified (root mean square error of approximation [RMSEA]=.02; comparative fit index [CFI]=.99; χ25=8.06, P=.15). The CPFS showed good fit to the Rasch model (χ 224=42.025, P=.01, PSI=.642), unidimensionality (binomial 95% CI -.005 to .045), and item local independency. Conclusions: Our results suggest that the CPFS has moderate reliability and internal consistency and it is composed of a single dimension. It is a useful tool to ascertain the level of pandemic fatigue in the general population, which may help to guide the communication and information strategies to face the COVID-19 pandemic.Publication Validation of the Spanish Version of the Fear of COVID-19 Scale (FCV-19S) in Long-Term Care Settings(Multidisciplinary Digital Publishing Institute (MDPI), 2022-12-03) Cárdenas Soriano, Pilar; Rodriguez-Blazquez, Carmen; Forjaz, Maria João; Ayala, Alba; Rojo-Perez, Fermina; Fernández-Mayoralas, Gloria; Molina-Martinez, Maria-Angeles; de Arenaza Escribano, Carmen Perez; Rodriguez-Rodriguez, Vicente; Consejo Superior de Investigaciones Científicas (España); Corporación de Radio y Televisión Española; Fundación General (CSIC); Comunidad de Madrid (España); Unión Europea. Fondo Social Europeo (ESF/FSE)Fear of coronavirus disease 2019 (COVID-19) is one of the main psychological impacts of the actual pandemic, especially among the population groups with higher mortality rates. The Fear of COVID-19 Scale (FCV-19S) has been used in different scenarios to assess fear associated with COVID-19, but this has not been done frequently in people living in long-term care (LTC) settings. The present study is aimed at measuring the psychometric properties of the Spanish version of the FCV-19S in residents in LTC settings, following both the classical test theory (CTT) and Rasch model frameworks. The participants (n = 447), aged 60 years or older, were asked to complete the FCV-19S and to report, among other issues, their levels of depression, resilience, emotional wellbeing and health-related quality of life with validated scales. The mean FCV-19S score was 18.36 (SD 8.28, range 7−35), with higher scores for women, participants with lower education (primary or less) and higher adherence to preventive measures (all, p < 0.05). The Cronbach’s alpha for the FCV-19S was 0.94. After eliminating two items due to a lack of fit, the FCV-19S showed a good fit to the Rasch model (χ2 (20) = 30.24, p = 0.019, PSI = 0.87), with unidimensionality (binomial 95% CI 0.001 to 0.045) and item local independency. Question 5 showed differential item functioning by sex. The present study shows that the FCV-19S has satisfactory reliability and validity, which supports its use to effectively measure fear in older people living in LTC settings. This tool could help identify risk groups that may need specific health education and effective communication strategies to lower fear levels. This might have a beneficial impact on adherence to preventive measures.