In this review, we examine studies that use item response theory (IRT) to explore the psychometric properties of clinical measures. Next, we consider how IRT has been used in clinical research for: scale linking, computerized adaptive testing, and differential item functioning analysis. Finally, we consider the scale properties of IRT trait scores. We conclude that there are notable differences...

For specific applications of infrared thermography (IRT) in the field of human medicine diagnosis, well defined standard operating procedures are used (e.g. controlled ambient conditions). In contrast, when IRT is used in the veterinary and animal science field, examinations are not always performed under controlled ambient conditions. This leads to unavoidable influences to the surface tempera...

We have measured serum immunoreactive trypsin (IRT) and serum pancreatic isoamylase (PIA) activities using commercially available kits in 37 cystic fibrosis (CF) patients and 46 hospital controls of similar age range. Immunoreactive trypsin was more often abnormal than PIA (26/37 v 18/37 abnormal respectively); IRT will be particularly useful as an additional diagnostic test in older children, ...

BACKGROUND Patients-Reported Outcomes (PRO) are increasingly used in clinical and epidemiological research. Two main types of analytical strategies can be found for these data: classical test theory (CTT) based on the observed scores and models coming from Item Response Theory (IRT). However, whether IRT or CTT would be the most appropriate method to analyse PRO data remains unknown. The statis...

We investigated the effect of 8 weeks of high intensity interval training (HIT) and isoinertial resistance training (IRT) on cardiovascular fitness, muscle mass-strength and risk factors of metabolic syndrome in 12 healthy older adults (68 yy ± 4). HIT consisted in 7 two-minute repetitions at 80%-90% of V˙O2max, 3 times/w. After 4 months of recovery, subjects were treated with IRT, which inclu...

Item response theory (IRT) has a number of potential advantages over classical test theory in assessing self-reported health outcomes. IRT models yield invariant item and latent trait estimates (within a linear transformation), standard errors conditional on trait level, and trait estimates anchored to item content. IRT also facilitates evaluation of differential item functioning, inclusion of ...

Figure 1. Salivary gland scintigraphy performed before (March 2005) and after (August 2005) iodine-131 internal radiation therapy (I-131 IRT). Anterior images obtained at 10 and 20 minutes after intravenous injection of Tc-99m, and at 5 minutes after washout by Vitamin C are shown. Original scintigraphy was performed as a dynamic study with 1 min/frame. Significantly higher accumulation was obs...

Item response theory (IRT) models are a class of statistical models used by researchers to describe the response behaviors of individuals to a set of categorically scored items. The most common IRT models can be classified as generalized linear fixedand/or mixed-effect models. Although IRT models appear most often in the psychological testing literature, researchers in other fields have success...

Changes in the skin temperature (Tsk) are known to be connected with diseases and subsequently infrared thermography (IRT) has been proposed to be a diagnostic aid, e.g. in musculoskeletal disorders (MSD). However, mostly due to conflicting results of previous studies, IRT lost credibility. Now interest in IRT is growing again but valid methodological studies are needed in order to avoid new di...