Genotype-Environment Interaction in ADHD: Genetic Predisposition Determines the Extent to Which Environmental Influences Explain Variability in the Symptom Dimensions Hyperactivity and Inattention.

Although earlier research has shown that individual differences on the spectrum of attention deficit hyperactivity disorder (ADHD) are highly heritable, emerging evidence suggests that symptoms are associated with complex interactions between genes and environmental influences. This study investigated whether a genetic predisposition [Note that the term 'genetic predisposition' was used in this manuscript to refer to an estimate based on twin modeling (an individual's score on the latent trait that resembles additive genetic influences) in the particular population being examined.] for the symptom dimensions hyperactivity and inattention determines the extent to which unique-environmental influences explain variability in these symptoms. To this purpose, we analysed a sample drawn from the Twins Early Development Study (TEDS) that consisted of item-level scores of 2168 16-year-old twin pairs who completed both the Strengths and Difficulties Questionnaire (SDQ; Goodman, in J Child Psychol Psychiatry 38:581-586, 1997) and the Strength and Weaknesses of ADHD Symptoms and Normal Behavior (SWAN; Swanson, in Paper presented at the meeting of the American Psychological Association, Los Angeles, 1981) questionnaire. To maximize the psychometric information to measure ADHD symptoms, psychometric analyses were performed to investigate whether the items from the two questionnaires could be combined to form two longer subscales. In the estimation of genotype-environment interaction, we corrected for error variance heterogeneity in the measurement of ADHD symptoms through the application of item response theory (IRT) measurement models. A positive interaction was found for both hyperactivity (e.g., [Formula: see text] = 2.20 with 95% highest posterior density interval equal to [1.79;2.65] and effect size equal to 3.00) and inattention (e.g., [Formula: see text] = 2.16 with 95% highest posterior density interval equal to [1.56;2.79] and effect size equal to 3.07). These results indicate that unique-environmental influences were more important in creating individual differences in both hyperactivity and inattention for twins with a genetic predisposition for these symptoms than for twins without such a predisposition.

From zinc homeostasis to disease progression: Unveiling the neurodegenerative puzzle.

Zinc is a crucial trace element in the human body, playing a role in various physiological processes such as oxidative stress, neurotransmission, protein synthesis, and DNA repair. The zinc transporters (ZnTs) family members are responsible for exporting intracellular zinc, while Zrt- and Irt-like proteins (ZIPs) are involved in importing extracellular zinc. These processes are essential for maintaining cellular zinc homeostasis. Imbalances in zinc metabolism have been linked to the development of neurodegenerative diseases. Disruptions in zinc levels can impact the survival and activity of neurons, thereby contributing to the progression of neurodegenerative diseases through mechanisms like cell apoptosis regulation, protein phase separation, ferroptosis, oxidative stress, and neuroinflammation. Therefore, conducting a systematic review of the regulatory network of zinc and investigating the relationship between zinc dysmetabolism and neurodegenerative diseases can enhance our understanding of the pathogenesis of these diseases. Additionally, it may offer new insights and approaches for the treatment of neurodegenerative diseases.

Using joint probability density to create most informative unidimensional indices: a new method using pain and psychiatric severity as examples.

BACKGROUND: Dimension reduction methods do not always reduce their underlying indicators to a single composite score. Furthermore, such methods are usually based on optimality criteria that require discarding some information. We suggest, under some conditions, to use the joint probability density function (joint pdf or JPD) of p-dimensional random variable (the p indicators), as an index or a composite score. It is proved that this index is more informative than any alternative composite score. In two examples, we compare the JPD index with some alternatives constructed from traditional methods. METHODS: We develop a probabilistic unsupervised dimension reduction method based on the probability density of multivariate data. We show that the conditional distribution of the variables given JPD is uniform, implying that the JPD is the most informative scalar summary under the most common notions of information. B. We show under some widely plausible conditions, JPD can be used as an index. To use JPD as an index, in addition to having a plausible interpretation, all the random variables should have approximately the same direction(unidirectionality) as the density values (codirectionality). We applied these ideas to two data sets: first, on the 7 Brief Pain Inventory Interference scale (BPI-I) items obtained from 8,889 US Veterans with chronic pain and, second, on a novel measure based on administrative data for 912 US Veterans. To estimate the JPD in both examples, among the available JPD estimation methods, we used its conditional specifications, identified a well-fitted parametric model for each factored conditional (regression) specification, and, by maximizing the corresponding likelihoods, estimated their parameters. Due to the non-uniqueness of conditional specification, the average of all estimated conditional specifications was used as the final estimate. Since a prevalent common use of indices is ranking, we used measures of monotone dependence [e.g., Spearman's rank correlation (rho)] to assess the strength of unidirectionality and co-directionality. Finally, we cross-validate the JPD score against variance-covariance-based scores (factor scores in unidimensional models), and the "person's parameter" estimates of (Generalized) Partial Credit and Graded Response IRT models. We used Pearson Divergence as a measure of information and Shannon's entropy to compare uncertainties (informativeness) in these alternative scores. RESULTS: An unsupervised dimension reduction was developed based on the joint probability density (JPD) of the multi-dimensional data. The JPD, under regularity conditions, may be used as an index. For the well-established Brief Pain Interference Inventory (BPI-I (the short form with 7 Items) and for a new mental health severity index (MoPSI) with 6 indicators, we estimated the JPD scoring. We compared, assuming unidimensionality, factor scores, Person's scores of the Partial Credit model, the Generalized Partial Credit model, and the Graded Response model with JPD scoring. As expected, all scores' rankings in both examples were monotonically dependent with various strengths. Shannon entropy was the smallest for JPD scores. Pearson Divergence of the estimated densities of different indices against uniform distribution was maximum for JPD scoring. CONCLUSIONS: An unsupervised probabilistic dimension reduction is possible. When appropriate, the joint probability density function can be used as the most informative index. Model specification and estimation and steps to implement the scoring were demonstrated. As expected, when the required assumption in factor analysis and IRT models are satisfied, JPD scoring agrees with these established scores. However, when these assumptions are violated, JPD scores preserve all the information in the indicators with minimal assumption.

Development of standard computerised adaptive test (CAT) settings for the EORTC CAT Core.

AIMS: Computerised adaptive test (CAT) provides individualised patient reported outcome measurement while retaining direct comparability of scores across patients and studies. Optimal CAT measurement requires an appropriate CAT-setting, the set of criteria defining the CAT including start item, item selection criterion, and stop criterion. The European Organisation for Research and Treatment of Cancer (EORTC) CAT Core allows for assessing the 14 functional and symptom domains covered by the EORTC QLQ-C30 questionnaire. The aim was to present a general approach for selecting CAT-settings and to use this to develop a portfolio of standard settings for the EORTC CAT Core optimised for different purposes and populations. METHODS: Using simulations, the measurement properties of CATs of different length and precision were evaluated and compared allowing for identifying the most suitable settings. All CATs were initiated with the most informative QLQ-C30 item. For each domain two fixed-length and two fixed-precision standard CATs were selected focusing on efficiency (brief version) and precision (long), respectively. RESULTS: The brief fixed-length CATs included 3-5 items each while the long versions included 5-8 items. The fixed-precision CATs aimed for reliability of 0.65-0.95 (brief versions) and 0.85-0.98 (long versions), respectively. Median sample size savings using the CATs compared to the QLQ-C30 scales ranged 20%-31%, although savings varied considerably across the domains. CONCLUSION: The EORTC CAT Core standard settings simplify selection of relevant and appropriate CATs. The CATs prioritise either brevity and efficiency or precision, but all provide increased measurement precision and hence, reduced sample size requirements compared to the QLQ-C30 scales. The CATs may be used as they are or modified to accommodate specific requirements.

Extending the PROMIS item bank "ability to participate in social roles and activities": a psychometric evaluation using IRT.

OBJECTIVE: Our objective was to explore whether the extension of the PROMIS item bank Ability to Participate in Social Roles and Activities (APSRA) with new items would result in more effective targeting (i.e., selecting items that are appropriate for each individual's trait level), and more reliable measurements across all latent trait levels. METHODS: A sample of 1,022 Dutch adults completed all 35 items of the original item bank plus 17 new items (in Dutch). The new items presented in this publication have been translated provisionally from Dutch into English for presentation purposes. We evaluated the basic IRT assumptions unidimensionality, local independence, and monotonicity. Furthermore, we examined the item parameters, and assessed differential item functioning (DIF) for sex, education, region, age, and ethnicity. In addition, we compared the test information functions, item parameters, and θ scores, for the original and extended item bank in order to assess whether the measurement range had improved. RESULTS: We found that the extended item bank was compatible with the basic IRT assumptions and showed good reliability. Moreover, the extended item bank improved the measurement in the lower trait range, which is important for reliably assessing functioning in clinical populations (i.e., persons reporting lower levels of participation). CONCLUSION: We extended the PROMIS-APSRA item bank and improved its psychometric quality. Our study contributes to PROMIS measurement innovation, which allows for the addition of new items to existing item banks, without changing the interpretation of the scores and while maintaining the comparability of the scores with other PROMIS instruments.

Factor structure of psychosis screening questionnaire in Ugandan adults.

BACKGROUND: Psychotic disorders are common and contribute significantly to morbidity and mortality of people with psychiatric diseases. Therefore, early screening and detection may facilitate early intervention and reduce adverse outcomes. Screening tools that lay persons can administer are particularly beneficial in low resource settings. However, there is limited research evaluating the validity of psychosis screening instruments in Uganda. We aimed to assess the construct validity and psychometric properties of the Psychosis Screening Questionnaire (PSQ) in Uganda in a population with no history of a psychotic disorder. METHODS: The sample consisted of 2101 Ugandan adults participating as controls in a larger multi-country case-control study on psychiatric genetics who were recruited between February 2018 and March 2020. Participants were individuals seeking outpatient general medical care, caretakers of individuals seeking care, and staff or students recruited from five medical facilities that were age 18 years or older and able to provide consent. Individuals were excluded who had acute levels of alcohol or substance use, including being under inpatient hospitalization or acute medical care for one of these conditions. We used confirmatory factor analysis (CFA) and item response theory (IRT) to evaluate the factor structure and item properties of the PSQ. RESULTS: The overall prevalence screening positive for psychotic symptoms was 13.9% 95% CI (12.4,15.4). "Strange experiences" were the most endorsed symptoms 6.6% 95% CI (5.6,7.8). A unidimensional model seemed to be a good model or well-fitting based on fit indices including the root mean square error of approximation (RMSEA of 0.00), comparative fit index (CFI of 1.000), and Tucker-Lewis Index (TLI of 1.000). The most discriminating items along the latent construct of psychosis were items assessing thought disturbance followed by items assessing paranoia, with a parameter (discrimination) value of 2.53 and 2.40, respectively. CONCLUSION: The PSQ works well in Uganda as an initial screening tool for moderate to high-level of psychotic symptoms.

Interpretation of course conceptual structure and student self-efficacy: an integrated strategy of knowledge graphs with item response modeling.

BACKGROUND: There is a scarcity of studies that quantitatively assess the difficulty and importance of knowledge points (KPs) depending on students' self-efficacy for learning (SEL). This study aims to validate the practical application of psychological measurement tools in physical therapy education by analyzing student SEL and course conceptual structure. METHODS: From the "Therapeutic Exercise" course curriculum, we extracted 100 KPs and administered a difficulty rating questionnaire to 218 students post-final exam. The pipeline of the non-parametric Item Response Theory (IRT) and parametric IRT modeling was employed to estimate student SEL and describe the hierarchy of KPs in terms of item difficulty. Additionally, Gaussian Graphical Models with Non-Convex Penalties were deployed to create a Knowledge Graph (KG) and identify the main components. A visual analytics approach was then proposed to understand the correlation and difficulty level of KPs. RESULTS: We identified 50 KPs to create the Mokken scale, which exhibited high reliability (Cronbach's alpha = 0.9675) with no gender bias at the overall or at each item level (p > 0.05). The three-parameter logistic model (3PLM) demonstrated good fitness with questionnaire data, whose Root Mean Square Error Approximation was < 0.05. Also, item-model fitness unveiled good fitness, as indicated by each item with non-significant p-values for chi-square tests. The Wright map revealed item difficulty relative to SEL levels. SEL estimated by the 3PLM correlated significantly with the high-ability range of average Grade-Point Average (p < 0.05). The KG backbone structure consisted of 58 KPs, with 29 KPs overlapping with the Mokken scale. Visual analysis of the KG backbone structure revealed that the difficulty level of KPs in the IRT could not replace their position parameters in the KG. CONCLUSION: The IRT and KG methods utilized in this study offer distinct perspectives for visualizing hierarchical relationships and correlations among the KPs. Based on real-world teaching empirical data, this study helps to provide a research foundation for updating course contents and customizing learning objectives. TRIAL REGISTRATION: Not applicable.

Contributions to Constructing Forced-Choice Questionnaires Using the Thurstonian IRT Model.

Forced-choice questionnaires involve presenting items in blocks and asking respondents to provide a full or partial ranking of the items within each block. To prevent involuntary or voluntary response distortions, blocks are usually formed of items that possess similar levels of desirability. Assembling forced-choice blocks is not a trivial process, because in addition to desirability, both the direction and magnitude of relationships between items and the traits being measured (i.e., factor loadings) need to be carefully considered. Based on simulations and empirical studies using item pairs, we provide recommendations on how to construct item pairs matched by desirability. When all pairs contain items keyed in the same direction, score reliability is improved by maximizing within-block loading differences. Higher reliability is obtained when even a small number of pairs consist of unequally keyed items.

Post-operative KEloids iRradiation (POKER): does the surgery/high-dose interventional radiotherapy association make a winning hand?

PURPOSE: To report the results involving post-operative interventional radiotherapy (POIRT) in a homogenous cohort of patients affected by keloid and treated at a single institution with the same fractionation schedule. PATIENTS AND METHODS: Inclusion criteria were: surgery with a histopathological diagnosis of keloid, subsequent high-dose rate interventional radiotherapy (HDR-IRT)-12 Gy in 4 fractions (3 Gy/fr) twice a day-and follow-up period ≥ 24 months. RESULTS: One-hundred and two patients and a total of 135 keloids were eligible for the analyses. Median follow-up was 64 [IQR: 25-103] months. Thirty-six (26.7%) recurrences were observed, 12-months and 36-months cumulative incidence of recurrence were 20.7% (95% CI 12.2-28.5) and 23.8% (95% CI 14.9-31.7) respectively. History of spontaneous keloids (HR = 7.00, 95% CI 2.79-17.6, p < 0.001), spontaneous cheloid as keloid cause (HR = 6.97, 95% CI 2.05-23.7, p = 0.002) and sternal (HR = 10.6, 95% CI 3.08-36.8, p < 0.001), ear (HR = 6.03, 95% CI 1.71-21.3, p = 0.005) or limb (HR = 18.8, 95% CI 5.14-68.7, p < 0.001) keloid sites were significantly associated to a higher risk of recurrence. CONCLUSIONS: The findings support the use of surgery and POIRT as an effective strategy for controlling keloid relapses. Further studies should focus on determining the optimal Biologically Effective Dose and on establishing a scoring system for patient selection.

Exercise-induced changes in lower limbs skin temperature against plasma ATP among individuals with various type and level of physical activity.

The objective of the study was to examine the lower limbs skin temperature (TSK) changes in response to exhaustive whole-body exercise in trained individuals in reference to changes in plasma adenosine triphosphate (ATP). Eighteen trained participants from distinct sport type ‒ endurance (25.2 ± 4.9 yr) and speed-power (25.8 ± 3.1 yr), and 9 controls (24,9 ± 4,3 yr) ‒ were examined. Lower limbs TSK and plasma ATP measures were applied in parallel in response to incremental treadmill test and during 30-min recovery period. Plasma ATP kinetics were inversely associated to changes in TSK. The first significant decrease in TSK (76-89% of V˙ O2MAX) occurred shortly before a significant plasma ATP increase (86-97% of V˙ O2MAX). During recovery, TSK increased, reaching pre-exercise values (before exercise vs. after 30-min recovery: 31.6 ± 0.4 °C vs. 32.0 ± 0.8 °C, p = 0.855 in endurance; 32.4 ± 0.5 °C vs. 32.9 ± 0.5 °C, p = 0.061 in speed-power; 31.9 ± 0.7 °C vs. 32.4 ± 0.8 °C, p = 0.222 in controls). Plasma ATP concentration did not returned to pre-exercise values in well trained participants (before exercise vs. after 30-min recovery: 699 ± 57 nmol l-1 vs. 854 ± 31 nmol l-1, p < 0.001, η2 = 0.961 and 812 ± 35 nmol l-1 vs. 975 ± 55 nmol l-1, p < 0.001, η2 = 0.974 in endurance and speed-power, respectively), unlike in controls (651 ± 40 nmol l-1 vs. 687 ± 61 nmol·l-1, p = 0.58, η2 = 0.918). The magnitude of TSK and plasma ATP response differed between the groups (p < 0.001, η2 = 0.410 for TSK; p < 0.001, η2 = 0.833 for plasma ATP). We conclude that lower limbs TSK change indirectly corresponds to the reverse course of plasma ATP during incremental exercise and the magnitude of the response depends on the level of physical activity and the associated to it long-term metabolic adaptation.

Thermal threshold for knee osteoarthritis people evaluated with infrared thermography: A scoping review.

INTRODUCTION: Knee degenerative processes, such as osteoarthritis, are disabling. An early intervention is generally more effective making important a timely diagnosis. A pre-diagnosis tool could be the thermal camera that allows the detection of joint inflammation. Consequently, the objective of the present study was to evaluate the literature and propose a thermal attention threshold for infrared thermography data in people with knee osteoarthritis. METHODS: four electronic databases were searched with specific keywords until the 25th of March 2024. Only original articles about joint inflammation due to osteoarthritis evaluated through digital infrared thermal images were included. A quality assessment analysis was performed. The attention threshold was extracted through the median of the extracted data. The findings were narratively discussed. RESULTS: A total of 9 studies have been included after the eligibility criteria selection. The studies presented some differences in terms of acquisition protocol, thermal imaging camera, data extrapolation, and analysis. Despite these differences, the studies presented similar thermal data. CONCLUSION: A knee thermography of or above 31.3 °C could indicate osteoarthritis, highlighting the necessity of further, more specific, and accurate analysis.

Non-invasive evaluation of vascular permeability in formalin-induced orofacial pain model using infrared thermography.

Enhanced vascular permeability at the site of injury is a prominent feature in acute inflammatory pain models, commonly assessed through the Evans Blue test. However, this invasive test requires euthanasia, thereby precluding further investigations on the same animal. Due to these limitations, the integration of non-invasive tools such as IRT has been sought. Here, we aimed to evaluate the use of thermography in a common orofacial pain model that employs formalin as a chemical irritant to induce local orofacial inflammation. Male Hannover rats (290-300 g, N = 43) were used. In the first approach, radiometric images were taken before and after formalin administration, assessing temperature changes and extravasated Evans Blue. The second approach included capturing pre- and post-formalin test radiometric images, followed by cytokine measurements in excised vibrissae tissue. Rats were anesthetized for vibrissae tissue collection, allowing correlations between thermographic patterns, nocifensive behavior duration, and cytokine levels in this area. Our findings revealed a positive correlation between local temperature, measured via thermography, and vascular permeability in the contralateral (r2 = 0.3483) and ipsilateral (r2 = 0.4502) side, measured using spectrophotometry. The obtained data supports the notion that thermography-based temperature assessment can effectively evaluate vascular permeability in the orofacial region.

Applicability of thermography as a potential non-invasive technique to assess the body-thermal status of heat-stressed and water-deprived goats (Capra hircus).

To evaluate the use of infrared thermography to assess the thermal status of heat-stressed and water-deprived Capra hircus, full-body surface temperature (TS) and six other body-thermal variables [core, rectal (TR), and skin (TSK) temperatures, respiratory and heart rates, and total body-thermal gradient (core-to-ambient, BTG)] were measured after three days of euhydration (EU), dehydration (DE), and rehydration (RE). Results revealed that the combined effect of heat stress and water deprivation had affected all tested variables including the TS, and once these animals gained access to water in the RE stage variables returned to their EU levels. Moreover, there were positive correlations between TS and all variables with the exception of BTG. From these six variables, only three variables (i.e. the TR, TSK, and BTG) during the DE stage and two variables (i.e. the TSK and BTG) throughout the experimental stages showed higher constancy (R2 ≥ 0 75, P < 0 001; agreement intervals ±1 96 95 % CI) with TS. However, BTG appeared more closely correlated with TS, representing the body-thermal status more realistically than other variables. In effect, the mean and thresholds of the BTG were predicted using the recorded TS and were within 0.02 °C of original estimates. Collectively, these findings show that infrared thermography is appropriate for assessing body-thermal status, and thus the welfare, of these animals under the three conditions studied, and conclude that full-body TS can be a surrogate proxy for BTG in these animals. Further experiments are needed to adequately examine the reproducibility of these results under biometeorologically-simulated environments and natural habitats.

HBMIRT: A SAS macro for estimating uni- and multidimensional 1- and 2-parameter item response models in small (and large!) samples.

Item response theory (IRT) has evolved as a standard psychometric approach in recent years, in particular for test construction based on dichotomous (i.e., true/false) items. Unfortunately, large samples are typically needed for item refinement in unidimensional models and even more so in the multidimensional case. However, Bayesian IRT approaches with hierarchical priors have recently been shown to be promising for estimating even complex models in small samples. Still, it may be challenging for applied researchers to set up such IRT models in general purpose or specialized statistical computer programs. Therefore, we developed a user-friendly tool - a SAS macro called HBMIRT - that allows to estimate uni- and multidimensional IRT models with dichotomous items. We explain the capabilities and features of the macro and demonstrate the particular advantages of the implemented hierarchical priors in rather small samples over weakly informative priors and traditional maximum likelihood estimation with the help of a simulation study. The macro can also be used with the online version of SAS OnDemand for Academics that is freely accessible for academic researchers.

A Stan tutorial on Bayesian IRTree models: Conventional models and explanatory extension.

IRTree models have been receiving increasing attention. However, to date, there are limited sources that provide a systematic introduction to Bayesian modeling techniques using modern probabilistic programming frameworks for the implementation of IRTree models. To facilitate the research and application of IRTree models, this paper introduces how to perform two families of Bayesian IRTree models (i.e., response tree models and latent tree models) in Stan and how to extend them in an explanatory way. Some suggestions on executing Stan codes and checking convergence are also provided. An empirical study based on the Oxford Achieving Resilience during COVID-19 data was conducted as an example to further illustrate how to apply Bayesian IRTree models to address research questions. Finally, strengths and future directions are discussed.

An item response theory approach to the measurement of working memory capacity.

Complex span tasks are perhaps the most widely used paradigm to measure working memory capacity (WMC). Researchers assume that all types of complex span tasks assess domain-general WM. However, most research supporting this claim comes from factor analysis approaches that do not examine task performance at the item level, thus not allowing comparison of the characteristics of verbal and spatial complex span tasks. Item response theory (IRT) can help determine the extent to which different complex span tasks assess domain-general WM. In the current study, spatial and verbal complex span tasks were examined using IRT. The results revealed differences between verbal and spatial tasks in terms of item difficulty and block difficulty, and showed that most subjects with below-average ability were able to answer most items correctly across all tasks. In line with previous research, the findings suggest that examining domain-general WM by using only one task might elicit skewed scores based on task domain. Further, visuospatial complex span tasks should be prioritized as a measure of WMC if resources are limited.

Co-occurring dominance and ideal point processes: A general IRTree framework for multidimensional item responding.

Responding to rating scale items is a multidimensional process, since not only the substantive trait being measured but also additional personal characteristics can affect the respondents' category choices. A flexible model class for analyzing such multidimensional responses are IRTree models, in which rating responses are decomposed into a sequence of sub-decisions. Different response processes can be involved in item responding both sequentially across those sub-decisions and as co-occurring processes within sub-decisions. In the previous literature, modeling co-occurring processes has been exclusively limited to dominance models, where higher trait levels are associated with higher expected scores. However, some response processes may rather follow an ideal point rationale, where the expected score depends on the proximity of a person's trait level to the item's location. Therefore, we propose a new multidimensional IRT model of co-occurring dominance and ideal point processes (DI-MIRT model) as a flexible framework for parameterizing IRTree sub-decisions with multiple dominance processes, multiple ideal point processes, and combinations of both. The DI-MIRT parameterization opens up new application areas for the IRTree model class and allows the specification of a wide range of theoretical assumptions regarding the cognitive processing of item responding. A simulation study shows that IRTree models with DI-MIRT parameterization provide excellent parameter recovery and accurately reflect co-occurring dominance and ideal point processes. In addition, a clear advantage over traditional IRTree models with purely sequential processes is demonstrated. Two application examples from the field of response style analysis highlight the benefits of the general IRTree framework under real-world conditions.

Item selection methods in multidimensional computerized adaptive testing for forced-choice items using Thurstonian IRT model.

Multidimensional computerized adaptive testing for forced-choice items (MFC-CAT) combines the benefits of multidimensional forced-choice (MFC) items and computerized adaptive testing (CAT) in that it eliminates response biases and reduces administration time. Previous studies that explored designs of MFC-CAT only discussed item selection methods based on the Fisher information (FI), which is known to perform unstably at early stages of CAT. This study proposes a set of new item selection methods based on the KL information for MFC-CAT (namely MFC-KI, MFC-KB, and MFC-KLP) based on the Thurstonian IRT (TIRT) model. Three simulation studies, including one based on real data, were conducted to compare the performance of the proposed KL-based item selection methods against the existing FI-based methods in three- and five-dimensional MFC-CAT scenarios with various test lengths and inter-trait correlations. Results demonstrate that the proposed KL-based item selection methods are feasible for MFC-CAT and generate acceptable trait estimation accuracy and uniformity of item pool usage. Among the three proposed methods, MFC-KB and MFC-KLP outperformed the existing FI-based item selection methods and resulted in the most accurate trait estimation and relatively even utilization of the item pool.

Psychometric benefits of self-chosen rating scales over given rating scales.

Rating scales are susceptible to response styles that undermine the scale quality. Optimizing a rating scale can tailor it to individuals' cognitive abilities, thereby preventing the occurrence of response styles related to a suboptimal response format. However, the discrimination ability of individuals in a sample may vary, suggesting that different rating scales may be appropriate for different individuals. This study aims to examine (1) whether response styles can be avoided when individuals are allowed to choose a rating scale and (2) whether the psychometric properties of self-chosen rating scales improve compared to given rating scales. To address these objectives, data from the flourishing scale were used as an illustrative example. MTurk workers from Amazon's Mechanical Turk platform (N = 7042) completed an eight-item flourishing scale twice: (1) using a randomly assigned four-, six-, or 11-point rating scale, and (2) using a self-chosen rating scale. Applying the restrictive mixed generalized partial credit model (rmGPCM) allowed examination of category use across the conditions. Correlations with external variables were calculated to assess the effects of the rating scales on criterion validity. The results revealed consistent use of self-chosen rating scales, with approximately equal proportions of the three response styles. Ordinary response behavior was observed in 55-58% of individuals, which was an increase of 12-15% compared to assigned rating scales. The self-chosen rating scales also exhibited superior psychometric properties. The implications of these findings are discussed.

Assessing health-related quality of life using the Wound-QoL-17 and the Wound-QoL-14-Results of the cross-sectional European HAQOL study using item response theory.

For assessing health-related quality of life in patients with chronic wounds, the Wound-QoL questionnaire has been developed. Two different versions exist: the Wound-QoL-17 and the Wound-QoL-14. For international and cross-cultural comparisons, it is necessary to demonstrate psychometric properties in an international study. Therefore, the aim of this study was to test both questionnaires in a European sample, using item response theory (IRT). Participants were recruited in eight European countries. Item characteristic curves (ICC), item information curves (IIC) and differential item functioning (DIF) were calculated. In both questionnaires, ICCs for most items were well-ordered and sufficiently distinct. For items, in which adjacent response categories were not sufficiently distinct, response options were merged. IICs showed that items on sleep and on pain, on worries as well as on day-to-day and leisure activities had considerably high informational value. In the Wound-QoL-14, the item on social activities showed DIFs regarding the country and age. The same applied for the Wound-QoL-17, in which also the item on stairs showed DIFs regarding age. Our study showed comparable results across both versions of the Wound-QoL. We established a new scoring method, which could be applied in international research projects. For clinical practice, the original scoring can be maintained.