Understanding the Comparative Fit Index: It\u27s all about the base!

Despite the sensitivity of fit indices to various model and data characteristics in structural equation modeling, these fit indices are used in a rigid binary fashion as a mere rule of thumb threshold value in a search for model adequacy. Here, we address the behavior and interpretation of the popular Comparative Fit Index (CFI) by stressing that its metric for model assessment is the amount of misspecification in a baseline model and by further decomposition into its fundamental components: sample size, number of variables and the degree of multivariate dependence in the data. Simulation results show how these components influence the performance of CFI and its rule of thumb in practice. We discuss the usefulness of additional qualifications when applying the CFI rule of thumb and potential adjustments to its threshold value as a function of data characteristics. In conclusion, we at a minimum recommend a dual reporting strategy to provide the necessary context and base for meaningful interpretation and even more optimal, a move to using CFI as a real incremental fit index intended to evaluate the relative effect size of cumulative theoretically motivated model restrictions in terms of \% reduction in misspecification as measured by the baseline model

CABE : a cloud-based acoustic beamforming emulator for FPGA-based sound source localization

Microphone arrays are gaining in popularity thanks to the availability of low-cost microphones. Applications including sonar, binaural hearing aid devices, acoustic indoor localization techniques and speech recognition are proposed by several research groups and companies. In most of the available implementations, the microphones utilized are assumed to offer an ideal response in a given frequency domain. Several toolboxes and software can be used to obtain a theoretical response of a microphone array with a given beamforming algorithm. However, a tool facilitating the design of a microphone array taking into account the non-ideal characteristics could not be found. Moreover, generating packages facilitating the implementation on Field Programmable Gate Arrays has, to our knowledge, not been carried out yet. Visualizing the responses in 2D and 3D also poses an engineering challenge. To alleviate these shortcomings, a scalable Cloud-based Acoustic Beamforming Emulator (CABE) is proposed. The non-ideal characteristics of microphones are considered during the computations and results are validated with acoustic data captured from microphones. It is also possible to generate hardware description language packages containing delay tables facilitating the implementation of Delay-and-Sum beamformers in embedded hardware. Truncation error analysis can also be carried out for fixed-point signal processing. The effects of disabling a given group of microphones within the microphone array can also be calculated. Results and packages can be visualized with a dedicated client application. Users can create and configure several parameters of an emulation, including sound source placement, the shape of the microphone array and the required signal processing flow. Depending on the user configuration, 2D and 3D graphs showing the beamforming results, waterfall diagrams and performance metrics can be generated by the client application. The emulations are also validated with captured data from existing microphone arrays.</jats:p

Metaphor Comprehension in Individuals with Autism Spectrum Disorder: Core Language Skills Matter

Poor metaphor comprehension was considered a hallmark of autism spectrum disorder (ASD), but recent research has questioned the extent and the sources of these difculties. In this cross-sectional study, we compared metaphor comprehension in individuals with ASD (N=29) and individuals with typical development (TD; N=31), and investigated the relationship between core language and metaphor comprehension. Individuals with ASD showed more difculty but also a more variable performance in both metaphor and literal items of the task used than individuals with TD did. This indicates that core language ability accounts for metaphor comprehension and should be considered in future research and interventions aiming to improve metaphor comprehension in individuals with ASD.publishedVersio

Measurement Efficiency for Fixed-Precision Multidimensional Computerized Adaptive Tests:Comparing Health Measurement and Educational Testing Using Example Banks

It is currently not entirely clear to what degree the research on multidimensional computerized adaptive testing (CAT) conducted in the field of educational testing can be generalized to fields such as health assessment, where CAT design factors differ considerably from those typically used in educational testing. In this study, the impact of a number of important design factors on CAT performance is systematically evaluated, using realistic example item banks for two main scenarios: health assessment (polytomous items, small to medium item bank sizes, high discrimination parameters) and educational testing (dichotomous items, large item banks, small- to medium-sized discrimination parameters). Measurement efficiency is evaluated for both between-item multidimensional CATs and separate unidimensional CATs for each latent dimension. In this study, we focus on fixed-precision (variable-length) CATs because it is both feasible and desirable in health settings, but so far most research regarding CAT has focused on fixed-length testing. This study shows that the benefits associated with fixed-precision multidimensional CAT hold under a wide variety of circumstances

Do Flexible Administration Procedures Promote Individualized Clinical Assessments?:An Explorative Analysis of How Clinicians Utilize the Funnel Structure of the SCID-5-AMPD Module I: LPFS

The current study examined clinicians' utilization of the SCID-5-AMPD-I funnel structure. Across 237 interviews, conducted as part of the NorAMP study, we found that clinicians administered on average 2-3 adjacent levels under each subdomain, effectively administering only about 50% of available items. Comparing administration patterns of interviews, no two interviews contained the exact same set of administered items. On average, when comparing individual interviews, only about half of the administered items in each interview were administered in both interviews. Cross-classified mixed effects models were estimated to examine the factors affecting item administration. Results indicated that the interplay between patient preliminary scores and item level had a substantial impact on item administration, suggesting clinicians tend to administer items corresponding to expected patient severity. Overall, our findings suggest clinicians utilize the SCID-5-AMPD-I funnel structure to conduct efficient and individually tailored assessments informed by relevant patient characteristics. Adopting similar non-fixed administration procedures for other interviews could potentially provide similar benefits compared to traditional fixed-form administration procedures. The current study can serve as a template for verifying and evaluating future adoptions of non-fixed administration procedures in other interviews.</p

A Psychometric Evaluation of the DSM-IV Criteria for Antisocial Personality Disorder:Dimensionality, Local Reliability, and Differential Item Functioning Across Gender

This study aims at evaluating the psychometric properties of the antisocial personality disorder (ASPD) criteria in a large sample of patients, most of whom had one or more personality disorders (PD). PD diagnoses were assessed by experienced clinicians using the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, 4th edition, Axis II PDs. Analyses were performed within an item response theory framework. Results of the analyses indicated that ASPD is a unidimensional construct that can be measured reliably at the upper range of the latent trait scale. Differential item functioning across gender was restricted to two criteria and had little impact on the latent ASPD trait level. Patients fulfilling both the adult ASPD criteria and the conduct disorder criteria had similar latent trait distributions as patients fulfilling only the adult ASPD criteria. Overall, the ASPD items fit the purpose of a diagnostic instrument well, that is, distinguishing patients with moderate from those with high antisocial personality scores

A multi-center psychometric evaluation of the Severity Indices of Personality Problems 118 (SIPP-118):Do we really need all those facets?

PURPOSE: The Severity Indices of Personality Problems 118 (SIPP-118) is a self-report questionnaire that aims to measure core components of (mal)adaptive personality functioning that can change over time. In this study, we aimed to assess the facet strength of the 16 facets across three large clinical samples.METHODS: Data from Norwegian and Dutch psychiatric patients were analyzed in this international multi-center study (N1 = 2814, N2 = 4751, N3 = 2217). Bi-factor modeling was used to assess to what degree the SIPP items tap into an overall general factor. The incremental value (distinctiveness) of the facets was studied using proportional reduction in mean squared error (PRMSE) based statistics.RESULTS: The estimated model showed adequate fit. The explained common variance (ECV) attributable to the general factor equaled 50% for all three samples. All but two facets (stable self-image and frustration tolerance) showed sufficient levels of distinctiveness. The findings were observed to be comparable across the three samples.CONCLUSION: Our findings showed that the general factor was relatively weak, and the facets had a clear incremental value.</p

A Psychometric Analysis of the Structured Clinical Interview for the DSM-5 Alternative Model for Personality Disorders Module I (SCID-5-AMPD-I):Level of Personality Functioning Scale

The current study aims to examine the psychometric properties of the Structured Clinical Interview for the DSM-5 Alternative Model for Personality Disorders Module I (SCID-5-AMPD-I) assessing the Level of Personality Functioning Scale (LPFS) in a heterogeneous sample of 282 nonpsychotic patients. Latent variable models were used to investigate the dimensionality of the LPFS. The results indicate that the LPFS, as assessed by the SCID-5-AMPD-I, can be considered as a unidimensional construct that can be measured reliably across a wide range of the latent trait. Threshold parameters for the 12 indicators of the LPFS increased gradually over the latent scale, indicating that the five LPFS levels were ordered as predicted by the model. In general, the increase of threshold parameters was relatively small for the shift from Level 2 to Level 3. A better distinction among the different severity levels might be obtained by fine-tuning the interview guidelines or the Level 2 indicators themselves

Ultra-thin biocompatible implantable chip for bidirectional communication with peripheral nerves

To realize optimal recording and stimulation of peripheral nerve cells, a CMOS chip is made with a multitude of electrodes which can be individually addressed in order to select after implantation the 16 best positioned electrodes. Since the Foreign Body Reaction should be minimal for optimum electrode-nerve contact, the CMOS chip is thinned down to 35um and fully packaged resulting in a 75um thin encapsulated chip. The chip is embedded in a biocompatible stack consisting of polymers and inorganic diffusion barriers deposited using atomic layer deposition (ALD). A biocompatible metallization is realized using gold and platinum sandwiched between polymers and ALD layers for flexible interconnects, and iridium oxide (IrOx) is selected as electrode material for optimal charge injection during stimulation. After this dedicated packaging based on the FITEP technology platform (Flexible Implantable Thin Electronic Package), the CMOS chip is still fully functional, which was tested dry (in air) as well as during submersion in saline. The form factor of the packaged chip is optimized for intra-fascicular implantation with minimum tissue damage. First acute in vivo stimulation tests proved that the stimulation capabilities of the IrOx electrodes are very good