The Experts below are selected from a list of 123 Experts worldwide ranked by ideXlab platform
Andrea Fossati - One of the best experts on this subject based on the ideXlab platform.
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post traumatic reactions as individual differences Latent Structure Analysis of the international trauma questionnaire in italian trauma exposed and non trauma exposed adults
Mediterranean Journal of Clinical Psychology, 2019Co-Authors: Antonella Somma, Cesare Maffei, Serena Borroni, Giulia Gialdi, Andrea FossatiAbstract:To evaluate the internal consistency and factor Structure of the Italian translation of the 12-item International Trauma Questionnaire (ITQ), 382 trauma-exposed and 366 non-trauma exposed Italian community-dwelling Italian adults from a total group of 748 volunteers completed the ITQ. The ITQ Post-traumatic Stress Disorder and Disorder of Self-Organization scales showed adequate Cronbach’s a s in both trauma-exposed and non-trauma-exposed participants. Confirmatory factor analyses showed that the a priori model of item-to-scale assignment of the ITQ items was consistently reproduced in both trauma-exposed and non-trauma-exposed participants, even when measurement invariance was formally assessed. Finally, taxometric analyses showed that the Latent distribution of the six ITQ PTSD symptom items should be conceived as a Latent dimension rather than a categorical Latent construct. As a whole, our findings supported to the cross-cultural validity of the ITQ while extending its clinical usefulness.
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a Latent Structure Analysis of diagnostic and statistical manual of mental disorders fourth edition narcissistic personality disorder criteria
Comprehensive Psychiatry, 2005Co-Authors: Andrea Fossati, Theodore P Beauchaine, Federica Grazioli, Ilaria Carretta, Francesca Cortinovis, Cesare MaffeiAbstract:The aim of this study was to examine the Latent Structure of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), Narcissistic Personality Disorder (NPD) criteria in a group of 641 outpatients. The consecutively admitted outpatients were administered the Structured Clinical Interview for DSM-IV Axis II Personality Disorders, Version 2.0, and the Personality Questionnaire. Both confirmatory and exploratory factor analyses (CFA and EFA, respectively) were used to evaluate whether the NPD criteria measure a single Latent trait. Latent class Analysis was used to assess the diagnostic accuracy of the individual DSM-IV NPD criteria. Mean above minus below a cut (MAMBAC) and maximum covariance (MAXCOV) taxometric analyses were used to evaluate whether the Latent distribution of the DSM-IV NPD features is actually discrete. Both CFA and EFA results showed that the 9 DSM-IV NPD criteria loaded on 2 correlated factors. The Latent class Analysis results suggested a 3-class solution for NPD criteria; relevant differences in diagnostic efficiency were observed among the NPD criteria. MAMBAC and MAXCOV analyses provided consistent evidence of taxonic (ie, discrete) Latent Structure for NPD. This study gave only partial support to the validity of the DSM-IV NPD construct. Taxometric analyses indicated that a typological model is appropriate for describing NPD, but CFA and EFA suggested the existence of 2 distinct-albeit correlated-clusters of narcissistic features. As a whole, the DSM-IV criteria discriminated NPD from other personality disorders, but diagnostic accuracy statistics did not replicate the rank order of diagnostic efficiency of NPD criteria proposed by the DSM-IV.
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Latent Structure Analysis of DSM-IV borderline personality disorder criteria.
Comprehensive Psychiatry, 1999Co-Authors: Andrea Fossati, Cesare Maffei, Maria Bagnato, Deborah Donati, Caterina Namia, Liliana NovellaAbstract:Abstract The aim of this study was to evaluate the Structure of DSM-IV borderline personality disorder (BPD) criteria. The study group consisted of 564 consecutively admitted inpatients and outpatients. BPD criteria discriminatory power was tested by using corrected item-tototal and item-to-diagnosis correlations. Weighted least-squares (WLS) confirmatory factor Analysis (CFA) was used to assess the fit of DSM-IV BPD unidimensional model. The categorial model of BPD was tested by exploratory Latent class Analysis (LCA). Item Analysis suggested a hierarchy in BPD criteria discriminatory power, even if with different rank order with respect to the DSM-IV model. CFA showed a unifactorial Structure with congeneric items as the best fitting model for DSM-IV BPD criteria ( ξ 2 = 18.89, df = 27, P > .87). LCA showed evidence for three Latent classes; heterogeneity was observed only among subjects falling below DSM-IV diagnostic threshold for BPD. These results support the categorial model of BPD, even if with several differences with respect to DSM-IV.
J Jensen - One of the best experts on this subject based on the ideXlab platform.
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validation of the bech rafaelsen mania scale using Latent Structure Analysis
Acta Psychiatrica Scandinavica, 1997Co-Authors: Rasmus Wentzer Licht, J JensenAbstract:The essential criteria of internal validity have not been sufficiently evaluated for any mania rating scale, although the fulfilment of such criteria is a prerequisite for summing the item scores to give a total score reflecting the severity of mania, and for comparing total scores across patient groups that differ with regard to variables such as age and sex. This study investigated the internal validity of the Bech-Rafaelsen Mania Scale (MAS), based on the ratings of 100 consecutively admitted drug-free DSM-III-R manic patients. Application of logistic Latent Structure models did not statistically confirm the additivity of the MAS. However, a modified MAS (the MAS-M) arising from the analyses fulfilled the measurement model. Transferability of the MAS-M across age and sex was also confirmed. The MAS-M showed an acceptable concurrent validity and an adequate sensitivity in discriminating between responders and non-responders among patients participating in a drug trial. The MAS-M presented here is the first mania rating scale that has been shown to fulfil statistical criteria for internal validity.
Kozo Takayama - One of the best experts on this subject based on the ideXlab platform.
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Latent Structure Analysis of wet granulation tableting process based on structural equation modeling
Chemical & Pharmaceutical Bulletin, 2021Co-Authors: Hiroki Katayama, Shoko Itakura, Hiroaki Todo, Kenji Sugibayashi, Kozo TakayamaAbstract:Quality by design (QbD) is an essential concept for modern manufacturing processes of pharmaceutical products. Understanding the science behind manufacturing processes is crucial; however, the complexity of the manufacturing processes makes implementing QbD challenging. In this study, structural equation modeling (SEM) was applied to understand the causal relationships between variables such as process parameters, material attributes, and quality attributes. Based on SEM Analysis, we identified a model composed of the above-mentioned variables and their Latent factors without including observational data. Difficulties in fitting the observed data to the proposed model are often encountered in SEM Analysis. To address this issue, we adopted Bayesian estimation with Markov chain Monte Carlo simulation. The tableting process involving the wet-granulation process for acetaminophen was employed as a model case for the manufacturing process. The results indicate that SEM Analysis could be useful for implementing QbD for the manufacturing processes of pharmaceutical products.
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Latent Structure Analysis in the pharmaceutical process of tablets prepared by wet granulation
Drug Development and Industrial Pharmacy, 2016Co-Authors: Naoto Uehara, Yoshinori Onuki, Yoshihiro Hayashi, Yasuko Obata, Hiroshi Mochida, Saori Otoguro, Kozo TakayamaAbstract:AbstractBackground: Granule characteristics are some of the important intermediate qualities that determine tablet properties. However, the relationships between granule and tablet characteristics are poorly understood. The aim of this study was to elucidate relationships among formulation factors, granule characteristics, and tablet properties using a non-linear response surface method (RSM) incorporating a thin-plate spline interpolation (RSM-S) and a Bayesian network (BN).Method: Tablets containing lactose (Lac), cornstarch (CS), and microcrystalline cellulose (MCC) were prepared by wet granulation. Ten formulations were prepared by an extreme vertices design. The angle of repose (Y1), compressibility (Y2), cohesion force (Y3), internal friction angle (Y4), and mean particle size (Y5) were measured as granule characteristics. Tensile strength (TS) and disintegration time (DT) were measured as tablet properties.Results: RSM-S results showed that TS increased with increasing amounts of MCC and Lac. DT de...
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Latent Structure Analysis of the process variables and pharmaceutical responses of an orally disintegrating tablet.
Chemical & Pharmaceutical Bulletin, 2012Co-Authors: Yoshihiro Hayashi, Yoshinori Onuki, Etsuko Oshima, Jin Maeda, Yasuko Obata, Kozo TakayamaAbstract:A multivariate statistical technique was applied to the design of an orally disintegrating tablet and to clarify the causal correlation among variables of the manufacturing process and pharmaceutical responses. Orally disintegrating tablets (ODTs) composed mainly of mannitol were prepared via the wet-granulation method using crystal transition from the δ to the β form of mannitol. Process parameters (water amounts (X(1)), kneading time (X(2)), compression force (X(3)), and amounts of magnesium stearate (X(4))) were optimized using a nonlinear response surface method (RSM) incorporating a thin plate spline interpolation (RSM-S). The results of a verification study revealed that the experimental responses, such as tensile strength and disintegration time, coincided well with the predictions. A Latent Structure Analysis of the pharmaceutical formulations of the tablet performed using a Bayesian network led to the clear visualization of a causal connection among variables of the manufacturing process and tablet characteristics. The quantity of β-mannitol in the granules (Q(β)) was affected by X(2) and influenced all granule properties. The specific surface area of the granules was affected by X(1) and Q(β) and had an effect on all tablet characteristics. Moreover, the causal relationships among the variables were clarified by inferring conditional probability distributions. These techniques provide a better understanding of the complicated Latent Structure among variables of the manufacturing process and tablet characteristics.
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Latent Structure Analysis in Pharmaceutical Formulations Using Kohonen's Self-Organizing Map and a Bayesian Network
Journal of Pharmaceutical Sciences, 2011Co-Authors: Shingo Kikuchi, Yoshinori Onuki, Akihito Yasuda, Yoshihiro Hayashi, Kozo TakayamaAbstract:ABSTRACT A Latent Structure Analysis of pharmaceutical formulations was performed using Kohonen's self-organizing map (SOM) and a Bayesian network. A hydrophilic matrix tablet containing diltiazem hydrochloride (DTZ), a highly water-soluble model drug, was used as a model formulation. Nonlinear relationship correlations among formulation factors (oppositely charged dextran derivatives and hydroxypropyl methylcellulose), Latent variables (turbidity and viscosity of the polymer mixtures and binding affinity of DTZ to polymers), and release properties [50% dissolution times ( t 50s ) and similarity factor] were clearly visualized by self-organizing feature maps. The quantities of dextran derivatives forming polyion complexes were strongly related to the binding affinity of DTZ to polymers and t 50s . The Latent variables were classified into five characteristic clusters with similar properties by SOM clustering. The probabilistic graphical model of the Latent Structure was successfully constructed using a Bayesian network. The causal relationships among the factors were quantitatively estimated by inferring conditional probability distributions. Moreover, these causal relationships estimated by the Bayesian network coincided well with estimations by SOM clustering, and the probabilistic graphical model was reflected in the characteristics of SOM clusters. These techniques provide a better understanding of the Latent Structure between formulation factors and responses in DTZ hydrophilic matrix tablet formulations.
Per Bech - One of the best experts on this subject based on the ideXlab platform.
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the bech rafaelsen mania scale in clinical trials of therapies for bipolar disorder a 20 year review of its use as an outcome measure
CNS Drugs, 2002Co-Authors: Per BechAbstract:Over the last two decades the Bech-Rafaelsen Mania Scale (MAS) has been used extensively in trials that have assessed the efficacy of treatments for bipolar disorder. The extent of its use makes it possible to evaluate the psychometric properties of the scale according to the principles of internal validity, reliability, and external validity. Studies of the internal validity of the MAS have demonstrated that the simple sum of the 11 items of the scale is a sufficient statistic for the assessment of the severity of manic states. Both factor Analysis and Latent Structure Analysis (the Rasch Analysis) have been used to demonstrate this. The total score of the MAS has been standardised such that scores below 15 indicate hypomania, scores around 20 indicate moderate mania, and scores around 28 indicate severe mania. The inter-observer reliability has been found to be high in a number of studies conducted in various countries. The MAS has shown an acceptable external validity, in terms of both sensitivity and responsiveness. Thus, the MAS was found to be superior to the Clinical Global Impression scale with regard to responsiveness, and sensitivity has been found to be adequate, with the MAS able to demonstrate large drug-placebo differences. Based on pretreatment scores, trials of antimanic therapies can be classified into: (i) ultrashort (1 week) therapy of severe mania; (ii) short-term therapy (3 to 8 weeks) of moderate mania; (iii) short-term therapy of hypomanic or mixed bipolar states; and (iv) long-term (12 months) therapy of bipolar states. The responsiveness of MAS is such that the scale has been able to demonstrated that typical antipsychotics are effective as an ultrashort therapy of severe mania; that lithium and anticonvulsants are effective in the short-term therapy of moderate mania; and that atypical antipsychotics, electroconvulsive therapy (ECT) and transcranial magnetic stimulation seem to have promising effects in the short-term therapy of moderate mania. In contrast, the scale has been used to demonstrate that calcium antagonists (e.g. verapamil) are ineffective in the treatment of mania. MAS has also been used to add to the literature on the evidence-based effect of lithium as a short-term therapy for hypomania or mixed bipolar states and as a long-term therapy of bipolar states.
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the hamilton scales and the hopkins symptom checklist scl 90 a cross national validity study in patients with panic disorders
British Journal of Psychiatry, 1992Co-Authors: Per Bech, Peter Allerup, W Maier, Margot Albus, Philip W Lavori, J L AyusoAbstract:The HRSD, HRSA, SCL-90 scales were psychometrically investigated in a cross-national sample of patients with varieties of non-psychotic symptoms of anxiety and depression. Across the cultural backgrounds the scores obtained from the original versions of these scales are not sufficient statistics. However, Latent Structure Analysis has identified homogeneous subscales for depression (the HRSD) and for discomfort (an SCL subscale). High concurrent validity was found between the subscales of depression, anxiety and discomfort. In international research, inhomogeneity among scale items can be confounded with group differences which are usually ascribed to drug differences.
Cesare Maffei - One of the best experts on this subject based on the ideXlab platform.
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post traumatic reactions as individual differences Latent Structure Analysis of the international trauma questionnaire in italian trauma exposed and non trauma exposed adults
Mediterranean Journal of Clinical Psychology, 2019Co-Authors: Antonella Somma, Cesare Maffei, Serena Borroni, Giulia Gialdi, Andrea FossatiAbstract:To evaluate the internal consistency and factor Structure of the Italian translation of the 12-item International Trauma Questionnaire (ITQ), 382 trauma-exposed and 366 non-trauma exposed Italian community-dwelling Italian adults from a total group of 748 volunteers completed the ITQ. The ITQ Post-traumatic Stress Disorder and Disorder of Self-Organization scales showed adequate Cronbach’s a s in both trauma-exposed and non-trauma-exposed participants. Confirmatory factor analyses showed that the a priori model of item-to-scale assignment of the ITQ items was consistently reproduced in both trauma-exposed and non-trauma-exposed participants, even when measurement invariance was formally assessed. Finally, taxometric analyses showed that the Latent distribution of the six ITQ PTSD symptom items should be conceived as a Latent dimension rather than a categorical Latent construct. As a whole, our findings supported to the cross-cultural validity of the ITQ while extending its clinical usefulness.
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a Latent Structure Analysis of diagnostic and statistical manual of mental disorders fourth edition narcissistic personality disorder criteria
Comprehensive Psychiatry, 2005Co-Authors: Andrea Fossati, Theodore P Beauchaine, Federica Grazioli, Ilaria Carretta, Francesca Cortinovis, Cesare MaffeiAbstract:The aim of this study was to examine the Latent Structure of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), Narcissistic Personality Disorder (NPD) criteria in a group of 641 outpatients. The consecutively admitted outpatients were administered the Structured Clinical Interview for DSM-IV Axis II Personality Disorders, Version 2.0, and the Personality Questionnaire. Both confirmatory and exploratory factor analyses (CFA and EFA, respectively) were used to evaluate whether the NPD criteria measure a single Latent trait. Latent class Analysis was used to assess the diagnostic accuracy of the individual DSM-IV NPD criteria. Mean above minus below a cut (MAMBAC) and maximum covariance (MAXCOV) taxometric analyses were used to evaluate whether the Latent distribution of the DSM-IV NPD features is actually discrete. Both CFA and EFA results showed that the 9 DSM-IV NPD criteria loaded on 2 correlated factors. The Latent class Analysis results suggested a 3-class solution for NPD criteria; relevant differences in diagnostic efficiency were observed among the NPD criteria. MAMBAC and MAXCOV analyses provided consistent evidence of taxonic (ie, discrete) Latent Structure for NPD. This study gave only partial support to the validity of the DSM-IV NPD construct. Taxometric analyses indicated that a typological model is appropriate for describing NPD, but CFA and EFA suggested the existence of 2 distinct-albeit correlated-clusters of narcissistic features. As a whole, the DSM-IV criteria discriminated NPD from other personality disorders, but diagnostic accuracy statistics did not replicate the rank order of diagnostic efficiency of NPD criteria proposed by the DSM-IV.
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Latent Structure Analysis of DSM-IV borderline personality disorder criteria.
Comprehensive Psychiatry, 1999Co-Authors: Andrea Fossati, Cesare Maffei, Maria Bagnato, Deborah Donati, Caterina Namia, Liliana NovellaAbstract:Abstract The aim of this study was to evaluate the Structure of DSM-IV borderline personality disorder (BPD) criteria. The study group consisted of 564 consecutively admitted inpatients and outpatients. BPD criteria discriminatory power was tested by using corrected item-tototal and item-to-diagnosis correlations. Weighted least-squares (WLS) confirmatory factor Analysis (CFA) was used to assess the fit of DSM-IV BPD unidimensional model. The categorial model of BPD was tested by exploratory Latent class Analysis (LCA). Item Analysis suggested a hierarchy in BPD criteria discriminatory power, even if with different rank order with respect to the DSM-IV model. CFA showed a unifactorial Structure with congeneric items as the best fitting model for DSM-IV BPD criteria ( ξ 2 = 18.89, df = 27, P > .87). LCA showed evidence for three Latent classes; heterogeneity was observed only among subjects falling below DSM-IV diagnostic threshold for BPD. These results support the categorial model of BPD, even if with several differences with respect to DSM-IV.
