BACKGROUND Depression and anxiety are two common normal responses to a chronic disease such as glaucoma. This study analysed the measurement properties of the depression screening instrument - Patient Health Questionnaire-9 (PHQ-9) using Rasch analysis to determine if it can be used as a measure. METHODS In this hospital-based cross-sectional study, the PHQ-9 was administered to primary glauc...

PURPOSE Both the long form visual functioning scale (LFVFS(39)) and visual functioning scale (VFS) are measures of visual functioning (VF) that represent the Rasch-scaled versions of the NEI-VFQ(39) and the Indian vision function questionnaire (IND-VFQ), respectively. The objectives of this study were to investigate if the 15-item LFVFS(39) and 13-item VFS of the IND-VFQ meet the assumptions of...

OBJECTIVE To build a new activity-based, "bed to community", aetiology-independent measure of balance within the neurological rehabilitation setting by merging some existing scales. METHODS Balance scales were selected using a conceptual framework and subsequently administered to a convenience sample of adult patients with balance problems due to different neurological aetiologies. Data were ...

People with chronic conditions, such as epilepsy, are at a high risk for depression; however depression is often under-recognized and undertreated. Depression scales, including one specific to people with epilepsy, have been used for screening in this population, although none have been assessed with Rasch measurement theory. This study used Rasch analyses in order to evaluate and compare the p...

BACKGROUND There is currently no interval-level measure of foot-related disability and this has hampered research in this area. The Manchester Foot Pain and Disability Index (FPDI) could potentially fill this gap. OBJECTIVE To assess the fit of the three subscales (function, pain, appearance) of the FPDI to the Rasch unidimensional measurement model in order to form interval-level scores. M...

BACKGROUND The purpose of this study is to use Rasch analysis to explore the validity of considering self-report scores from Wisconsin Upper Respiratory Symptom Survey (WURSS-21) as a single global illness severity domain. The WURSS-21 is a widely used questionnaire instrument that assesses symptom severity and functional impact of common cold and flu-like illness. METHODS This study applies ...

Traditional methods of developing tests have been driven by item content specification and have relied on the use of summed ordinal scores in an attempt to create a quantitative index of ability. There are fundamental problems with this approach to test development. The first problem is that the summing of qualitative ordinal counts to create a total score does not result in a number that is a ...

This study elaborates the Rasch differential item functioning (DIF) model formulation under the marginal maximum likelihood estimation context. Also, the Rasch DIF model performance was examined and compared with the Mantel–Haenszel (MH) procedure in small sample and short test length conditions through simulations. The theoretically known relationship of the DIF estimators between the Rasch DI...

BACKGROUND Investigations using classical test theory support the psychometric properties of the original version of the Multiple Sclerosis Impact Scale (MSIS-29v1), a disease-specific measure of multiple sclerosis (MS) impact (physical and psychological subscales). Later, assessments of the MSIS-29v1 in an MS community-based sample using Rasch analysis led to revisions of the instrument's resp...