Measuring anxiety in visually-impaired people: a comparison between the linear and the nonlinear IRT approaches

La presente investigación tiene dos intereses principales. En primer lugar, se evalúan algunas cuestiones pendientes acerca de las propiedades psicométricas del CTAC (cuestionario de ansiedad para ciegos y deficientes visuales) mediante la teoría de respuesta a los items (TRI). En segundo lugar, en las tres propiedades evaluadas: precisión de medida, sensibilidad al cambio e índices de ajuste de la persona, el modelo lineal se compara con el modelo de respuesta graduada (GRM) y los resultados obtenidos sirven además como ilustración de las posibilidades y ventajas de los modelos TRI. Los participantes son 670 ciegos o personas con deficiencia visual de diferentes ciudades españolas. Los resultados mostraron que las puntuaciones del CTAC son suficientemente precisas para el uso al que están destinadas, y que los participantes son generalmente consistentes en sus respuestas. Los datos eran apropiados para los dos modelos puestos a prueba llevando a resultados similares en lo referente a las estimaciones en los niveles en el rasgo, con la excepción de los participantes extremos que fueron mejor evaluados por el modelo lineal. El GRM mostró mayores ventajas en la evaluación de la precisión de la medida y ambos modelos mostraron alta sensibilidad al cambio alrededor del punto de corte. Los resultados concernientes al ajuste de la persona también fueron similares en ambos modelos(AU)

The present study has two main interests. First, some pending issues about the psychometric properties of the CTAC (an anxiety questionnaire for blind and visually-impaired people) are assessed using item response theory (IRT). Second, the linear model is compared to the graded response model (GRM) in terms of measurement precision, sensitivity to change, and person fit, and the results are also used to illustrate the functioning and advantages of IRT models. The participants were 670 blind or visually-impaired people from different Spanish cities. The results showed that the CTAC scores are accurate enough for practical purposes, and that respondents are quite consistent in their responses. Model-data fit was acceptable in both cases, and both models lead to similar results regarding the trait estimates, with the exception of extreme respondents who were better assessed with the linear model. The GRM assessed measurement precision better, and both models showed high sensitivity to change around cut-off values. Person-fit results were also similar in both models(AU)

[Aging without seeing: evaluation of the adjustment to loss of sight during old age]. / Envejecer sin ver: evaluación del ajuste a la pérdida visual sobrevenida en la vejez.

INTRODUCTION: The adjustment process to visual impairment can be approached by using theoretical models. The key variables in these models are usually measured by using psychometric instruments. The measurements can be taken from those already existing for the general population or be specifically designed for the visually impaired population. If the chosen measurements are reasonably valid and behave as the model predicts, they can be further used for designing programs that improve the process of adjusting. We describe the identification, adaptation and validation of some theses measurements. METHOD: We selected the psychometrics instruments to be used in the research: the Age-Related Vision Loss Scale (AVL) by Horowitz and Reinhardt; the Nottingham Adjustment Scale (NAS) by Dodds, and the Geriatric Depression Scale (GDS) by Brink and Yesavage. The AVL and NAS were adapted for use in Spain. The referred measurements were applied to a sample of 335 respondents together with the Scale of Subjective Wellbeing (EBS), and their psychometric properties were assessed. RESULTS: The estimated reliabilities were: AVL (0.80), NASA2 (0.87), NASB (0.81), NASC (0.75), NASE (0.87), GDS (0.90). The relationships between the measurements were all in the expected direction, and the magnitude of the convergent-validity coefficients was considered as acceptable. CONCLUSIONS: Our results suggests that the available measurements discussed above are appropriate for assessing the adjustment process, and are useful tools for individual assessment, as well as for designing intervention programs. All the measurements are available in computerized form in www.proyectotarragona.es.

Envejecer sin ver: evaluación del ajuste a la pérdida visual sobrevenida en la vejez / Aging without seeing: evaluation of the adjustment to loss of sight during old age

Introducción. El proceso de ajuste a la discapacidad visual puede aproximarse y describirse utilizando modelos teóricos que facilitan su comprensión. Estos modelos suelen evaluarse usando instrumentos de medida de las variables que los componen. Pueden proceder de los existentes para la población en general, o haber sido diseñados expresamente para la población con discapacidad visual. Introducción. La comprobación de la validez de los instrumentos de medida del proceso de ajuste a la discapacidad visual constituye un paso previo necesario para el diseño de programas de intervención inspirados en sus modelos teóricos de referencia. Introducción. En este artículo se exponen los resultados de la adaptación y la validación de las pruebas que permiten realizar una evaluación con suficientes garantías de fiabilidad y validez. Método. Se seleccionaron los instrumentos de medida a utilizar en la investigación: a) la escala Age related Vision Loss (AVL) de Horowitz y Reinhardt; b) la escala Nottingham de Ajuste (NAS) de Dodds, y c) la Escala Geriátrica de Depresión (GDS) de Brink y Yesavage. Las escalas AVL y NAS se adaptaron a la lengua y cultura españolas. Estos instrumentos, junto con la Escala de Bienestar Subjetivo (EBS), se administraron a una muestra de 335 personas. Se evaluaron la fiabilidad interna y la validez de las medidas. Resultados. Las fiabilidades estimadas fueron de: AVL (0,80), NASA2 (0,87), NASB (0,81), NASC (0,75), NASE (0,87) y GDS (0,90). Para la mayor parte de las relaciones entre las escalas los coeficientes de validez convergente se consideran apropiados. Conclusiones. Los instrumentos de evaluación analizados sirven para medir el proceso de ajuste a la discapacidad en personas mayores y de orientación al profesional de la psicología para el diseño y el seguimiento de programas de intervención. Las pruebas están disponibles para su descarga en http://www.proyectotarragona.es(AU)

Introduction. The adjustment process to visual impairment can be approached by using theoretical models. The key variables in these models are usually measured by using psychometric instruments. The measurements can be taken from those already existing for the general population or be specifically designed for the visually impaired population. If the chosen measurements are reasonably valid and behave as the model predicts, they can be further used for designing programs that improve the process of adjusting. Introduction. We describe the identification, adaptation and validation of some theses measurements. Method. We selected the psychometrics instruments to be used in the research: the Age-Related Vision Loss Scale (AVL) by Horowitz and Reinhardt; the Nottingham Adjustment Scale (NAS) by Dodds, and the Geriatric Depression Scale (GDS) by Brink and Yesavage. The AVL and NAS were adapted for use in Spain. The referred measurements were applied to a sample of 335 respondents together with the Scale of Subjective Wellbeing (EBS), and their psychometric properties were assessed. Results. The estimated reliabilities were: AVL (0.80), NASA2 (0.87), NASB (0.81), NASC (0.75), NASE (0.87), GDS (0.90). The relationships between the measurements were all in the expected direction, and the magnitude of the convergent-validity coefficients was considered as acceptable. Conclusions. Our results suggests that the available measurements discussed above are appropriate for assessing the adjustment process, and are useful tools for individual assessment, as well as for designing intervention programs. Conclusions. All the measurements are available in computerized form in www.proyectotarragona.es(AU)

[Assessment of depressive symptoms in old visually-impaired people: a study of the Geriatric Depression Scale]. / Evaluación de la sintomatología depresiva en población mayor con pérdida visual: un estudio de la Escala de Depresión Geriátrica.

This study has two main purposes: (a) to assess the functioning of the Geriatric Depression Scale in its Spanish version in old visually-impaired people, and (b) to assess the relevance of measuring depressive symptoms within a comprehensive assessment of psychological adjustment related to vision impairment in that population. Respondents were 329 people affiliated to the ONCE who were a representative sample of the target population. The assessment of the first goal let us to establish two cut-off points, and led to new methodological developments that combine Item Response Theory and Classical Test Theory. The results indicated that the scale is particularly useful in the target population and that it is very relevant in the assessment of psychological adjustment related to visual impairment in old people.

Evaluación de la sintomatología depresiva en población mayor con pérdida visual: un estudio de la Escala de Depresión Geriátrica / Assessment of depressive symptoms in old visually-impaired people: a study of the Geriatric Depression Scale

El presente estudio tiene dos objetivos principales: (a) evaluar la adecuación y funcionamiento de la Escala de Depresión Geriátrica en su versión española en la población mayor con déficit visual, y (b) evaluar la relevancia que tiene la medida de la sintomatología depresiva dentro de un proceso global de evaluación del ajuste a la pérdida visual en esta población. Participaron 329 personas afiliadas a la ONCE que forman una muestra representativa de la población de interés. La evaluación del primer objetivo lleva al establecimiento de puntos de corte e implica nuevos desarrollos metodológicos que combinan la Teoría de Respuesta al Ítem y la teoría clásica de los tests. Los resultados indican que la escala resulta particularmente útil en la población de interés y que tiene un peso importante en la evaluación del ajuste a la pérdida visual en la población de mayores con déficit visual (AU)

This study has two main purposes: (a) to assess the functioning of the Geriatric Depression Scale in its Spanish version in old visually-impaired people, and (b) to assess the relevance of measuring depressive symptoms within a comprehensive assessment of psychological adjustment related to vision impairment in that population. Respondents were 329 people affiliated to the ONCE who were a representative sample of the target population. The assessment of the first goal let us to establish two cut-off points, and led to new methodological developments that combine Item Response Theory and Classical Test Theory. The results indicated that the scale is particularly useful in the target population and that it is very relevant in the assessment of psychological adjustment related to visual impairment in old people (AU)