Dirk Smits

Foto Dirk Smits

 

Publicaties

Aantal : 128
article
The Dutch Self-Concept and Identity Measure (SCIM): Factor structure and I associations with identity dimensions and psychopathology
Bogaerts, Annabel ; Claes, Laurence ; Verschueren, Margaux ; Bastiaens, Tim ; Kaufman, Erin A ; Smits, Dirk ; Luyckx, Koen
Elsevier
Personality and Individual Differences; 2018; Vol. 123; pp. 56 - 64
© 2017 Elsevier Ltd Identity formation is a lifelong developmental process. Neo-Eriksonian researchers have primarily focused on normative identity exploration and commitment, while overlooking clinical identity disturbance and disorder. As a result, developmental and clinical conceptualizations of identity are largely disconnected. The Self-Concept and Identity Measure (SCIM; Kaufman, Cundiff, & Crowell, 2015) is a self-report questionnaire assessing identity consolidation, identity disturbance, and lack of identity. This instrument facilitates identifying both developmentally-appropriate and clinical-pathological identity functioning. Using three samples of Flemish individuals (totaling 1087 participants; between 18 and 67 years; 66.33% female), this study examined the factor structure and reliability of a Dutch version of the SCIM. Furthermore, associations with (1) identity dimensions of exploration and commitment, and (2) symptoms of anxiety, depression, and Borderline Personality Disorder (BPD) were investigated by means of self-report questionnaires. We replicated the three-factor structure of the SCIM in each sample. All scales showed adequate internal consistency coefficients. In line with expectations, differential associations of SCIM scales were obtained with identity dimensions and psychopathological outcomes. The present findings underscore the importance of focusing on Eriksonian notions of identity synthesis and confusion, as well as on more severe forms of identity problems, as captured by SCIM's lack of identity scale.
dissertation
The validation of the Personality Inventory for DSM-5 (PID-5) in a Flemish Non-Clinical and Clinical Sample, and the relation of PID-5 Psychoticism to psychosis
Bastiaens, Tim
Summary The Personality Inventory for DSM-5 (PID-5; Krueger et al., 2012) is a self-report questionnaire that originates from the preparatory work of the DSM-5 Task Force, aligning the classical DSM-IV-TR personality categories with a dimensional representation of personality pathology. Inspired by the non-clinical Five Factor Model (FFM; Costa & McCrae, 1992), its 25 primary scales have been reported to group into five higher order factors, each representing a pathological version of the classic five personality dimensions (i.e., Neuroticism, Extraversion, Agreeableness, Conscientiousness and Openness). The present PhD thesis contributes to the ongoing PID-5 research by investigating the merits of the PID-5 in a clinical population and its advantages over the Dimensional Assessment of Personality Pathology Basic Questionnaire (DAPP-BQ; Livesley & Jackson, 2009) as a representative of the pathological four dimensional model (Openness not included). Indeed, whereas earlier studies have found solid pathological equivalents for four out of five of the classical Big Five personality dimensions, an unequivocal pathological version of the fifth personality dimension Openness, i.e. Psychoticism, remains subject of ongoing research. Also, the conceptual relationship between Psychoticism as a personality factor, syndromal psychosis and cognitive biases as an at-risk factor for syndromal psychosis warrants further investigation. In the present PhD thesis we will start from a separate psychometric evaluation of each of the new instruments that will be used in addressing our research questions. This will include the psychometric evaluation of the PID-5 itself, as well as the psychometric evaluation of the Davos Assessment of Cognitive Biases Scale (DACOBS; van der Gaag et al., in press), an instrument measuring cognitive biases as a mediating personality trait in the development of syndromal psychosis. Thereafter, we will focus on the incremental validity of the fifth personality dimension Psychoticism (above and beyond the four other personality traits) in the prediction of (1) psychopathology in general, and (2) psychosis in particular, and on its conceptual relationship with cognitive biases as an at-risk factor for syndromal psychosis.
conference_proceeding
Do radiographers base the diagnostic acceptability of a radiograph on anatomical structures?
Decoster, Robin ; Toomey, Rachel ; Smits, Dirk ; Butler, Marie-Louise
Medical Imaging 2018: Image Perception, Observer Performance, and Technology Assessment; 2018; iss. 10577
article
Self-Reported Cognitive Biases Are Equally Present in Patients Diagnosed With Psychotic Versus Nonpsychotic Disorders
Bastiaens, Tim ; Claes, Laurence ; Smits, Dirk ; Vanwalleghem, Dominique ; De Hert, Marc
Lippincott, Williams Wilkins
Journal of Nervous and Mental Disease; 2018; Vol. 206; iss. 2; pp. 122 - 129
We investigated the relation between subjective cognitive biases measured with the Dutch Davos Assessment of Cognitive Biases (DACOBS-NL) and (1) the presence of a psychotic versus nonpsychotic psychiatric disorder, (2) the current dose of antipsychotic medication and current psychotic symptoms, and (3) the Personality Inventory for the DSM-5 (PID-5) Psychoticism personality trait. Results showed that DACOBS-NL subjective cognitive biases (1) were equally present in patients diagnosed with nonpsychotic disorders compared with patients with a psychotic disorder, (2) could not be explained by the current dose of antipsychotic medication, nor by current psychotic symptoms, and (3) significantly correlated with all PID-5 Personality domains. Moreover, in predicting membership of the psychotic versus nonpsychotic psychiatric disorder group, the addition of the PID-5 domains in step 2 rendered the contribution of the DACOBS-NL subjective cognitive biases in step 1 nonsignificant. Further research is needed to clarify the interplay between cognitive biases and aberrant salience in the prediction of psychotic disorders.
article
Lifetime Self-Harm Behaviors Are Not More Prevalent in Bariatric Surgery Candidates than in Community Controls with Obesity
Mueller, Astrid ; Claes, Laurence ; Smits, Dirk ; Schag, Kathrin ; de Zwaan, Martina
S. Karger AG
Obesity Facts; 2018; Vol. 11; iss. 2; pp. 109 - 115
OBJECTIVE: The study aimed at investigating the lifetime prevalence of 22 self-harm behaviors in bariatric surgery candidates (pre-bariatric surgery group; PSG) compared to community controls with obesity (obese community group; OCG). METHODS: The Self-Harm Inventory (SHI) was administered to the PSG (n = 139, BMI ≥ 35 kg/m2) and to the OCG (n = 122, BMI ≥ 35 kg/m2). RESULTS: Group comparison of cumulative SHI scores indicated a trend towards less endorsed SHI items in the PSG compared to the OCG (medianPSG = 1.00, IQRPSG = 2.00, medianOCG = 1.00, IQROCG = 2.25, U = 7.241, p = 0.033, η2 = 0.02). No significant group differences were found with regard to the rate of suicide attempts (12.4% vs. 9.4% for OCG vs. PSG). At least one type of lifetime self-harm behavior was admitted by 51.8% of the PSG and 63.9% of the OCG (χ2(1) = 3.91, p = 0.048). The results of logistic regressions using Firth's bias reduction method with at least one SHI item endorsed as dependent variable, group as categorical predictor (PSG as baseline), and age or BMI or PHQ-4 as continuous control variable indicated that only PHQ-4 had a positive effect on the odds ratio. CONCLUSION: The results suggest that self-harm (including suicidal attempts) is not more prevalent in bariatric surgery candidates than in community control participants with obesity. Further studies are needed to investigate self-harm in bariatric surgery patients, prior and following surgery, compared to non-operated patients with obesity.
article
The Relationship Between the Personality Inventory for the DSM-5 (PID-5) and the Psychotic Disorder in a Clinical Sample.
Bastiaens, Tim ; Smits, Dirk ; De Hert, Marc ; Thys, Erik ; Bryon, Hendrik ; Sweers, Kim ; Teugels, Teresa ; Van Looy, Joeri ; Verwerft, Tim ; Vanwalleghem, Dominique ; Van Bouwel, Ludi ; Claes, Laurence
Sage
Assessment; 2017; pp. 1073191117693922 -
Recent studies have successfully investigated the validity of the DSM-5 Alternative Model for Personality Disorders. In a final sample of 174 psychiatric patients, the present study examined the relationship between the Personality Inventory for the DSM-5 (PID-5) and syndromal psychosis. Results showed that patients diagnosed with versus without a psychotic disorder significantly differed on all PID-5 domains except Antagonism. Discriminant function analysis indicated that lower Detachment, lower Negative Affect, lower Disinhibition, and higher Psychoticism best discriminated patients with a psychotic disorder from patients with other psychiatric conditions. Subsequent stepwise discriminant analysis on all facet scales of the contributing PID-5 domains revealed that higher Unusual Beliefs, lower Depressivity, and lower Distractibility contributed the most to this differentiation. PID-5 Psychoticism scores showed moderate correlations with current psychotic symptoms and were not influenced by dose of antipsychotic medication. Our results support the ability of the PID-5 to discriminate between patients with and without psychotic disorder.
article
Prevalence and Correlates of Self-Harm in the German General Population
Mueller, Astrid ; Claes, Laurence ; Smits, Dirk ; Braehler, Elmar ; de Zwaan, Martina
Public Library of Science (PLoS)
PLoS One; 2016; Vol. 11; iss. 6; pp. -
The study aimed at evaluating the psychometric properties of the German version of the Self- Harm Inventory (SHI) and examining the lifetime prevalence and correlates of self-harm in a representative German population sample (N = 2,507; age mean = 48.79, SD = 18.11; range 14 to 94 years; 55.5% women) using the SHI. All participants answered the German SHI, the short form of the Barratt Impulsiveness Scale (BIS-15), the ultra-brief Patient Health Questionnaire for Depression and Anxiety (PHQ-4), and provided sociodemographic information. The one-factorial structure of the SHI was replicated using a confirmatory factor analysis. Internal consistency coefficients were sufficient and in line with previous studies. Almost half of the sample (49%) acknowledged at least one self-harming behavior over the life-span, most frequently indirect forms of self-harm. The rate of participants who engaged in at least one SHI behavior was higher among men than women (51.6% vs. 46.9%, respectively, χ2 = 5.38, p = 0.020). Higher SHI scores were related to younger age, male gender, living alone, more symptoms of anxiety and depression (PHQ-4), higher impulsivity scores (BIS-15), and suffering from obesity grade 2. Women engaged more often in discreet forms of self-harm than men, e.g., preventing wounds from healing, exercising an injury, starving, and abusing laxatives. In terms of other indirect self-harming behaviors, men admitted more often driving recklessly, being promiscuous and losing a job on purpose, while women reported more frequently engaging in emotionally abusive relationships. With respect to direct self-harm, women were more likely to endorse suicide attempts and cutting, while men admitted more often head-banging. The findings suggest that self-harm constitutes a common problem. Future longitudinal studies are required to examine the natural course, sociodemographic and psychopathological risk factors, as well as possible time-trends of self-harming behaviors in more depth.
article
Validation of the German version of the Perceived Stigmatization Questionnaire/Social Comfort Questionnaire in adult burn survivors
Mueller, Astrid ; Smits, Dirk ; Claes, Laurence ; Jasper, Stefanie ; Berg, Lea ; Ipaktchi, Ramin ; Vogt, Peter M ; de Zwaan, Martina
Elsevier
Burns; 2016; Vol. 42; iss. 4; pp. 790 - 796
OBJECTIVE: To investigate the factor structure, reliability, and validity of the German version of the Perceived Stigmatization Questionnaire/Social Comfort Questionnaire (PSQ/SCQ) in burn victims. METHODS: The PSQ/SCQ was answered by 139 adult burn survivors (age M=49.69, SD=15.16 years). Factor structure was examined using a confirmatory factor analysis (CFA). Validity was investigated through correlations between the PSQ/SCQ scales and questionnaires assessing perceived social support, burn-specific health-related quality of life, symptoms of anxiety/depression, and percent of total body surface area (TBSA) burned. Additionally, the link between perceived stigmatization/social comfort and current partnership status was investigated. RESULTS: The four-factor model showed the best fit to the data with three PSQ factors (Absence of Friendly Behavior, Confused/Staring Behavior, and Hostile Behavior) and one single SCQ factor. All PSQ/SCQ scales showed good internal consistency. Higher PSQ/lower SCQ means were related to less perceived social support, less burn-specific quality of life, and more symptoms of anxiety/depression. With the exception of a positive correlation with the PSQ subscale Confused Behavior and Staring, no other significant correlations were found between the PSQ/SCQ subscales and TBSA burned. While PSQ/SCQ scores were not linked to age or gender, less perceived social stigmatization/more social comfort was reported by participants who were currently living with a partner. CONCLUSIONS: The results indicate a four-factor structure and a good validity of the PSQ/SCQ which is in line with prior research. Further studies should investigate the application of the PSQ/SCQ in individuals with appearance distinctions that are not related to burns.
article
DSM-5 section III personality traits and section II personality disorders in a Flemish community sample
Bastiaens, Tim ; Smits, Dirk ; De Hert, Marc ; Vanwalleghem, Dominique ; Claes, Laurence
Elsevier
Psychiatry Research; 2016; Vol. 238; pp. 290 - 298
The Personality Inventory for DSM-5 (PID-5; Krueger et al., 2012) is a dimensional self-report questionnaire designed to measure personality pathology according to the criterion B of the DSM-5 Section III personality model. In the current issue of DSM, this dimensional Section III personality model co-exists with the Section II categorical personality model derived from DSM-IV-TR. Therefore, investigation of the inter-relatedness of both models across populations and languages is warranted. In this study, we first examined the factor structure and reliability of the PID-5 in a Flemish community sample (N=509) by means of exploratory structural equation modeling and alpha coefficients. Next, we investigated the predictive ability of section III personality traits in relation to section II personality disorders through correlations and stepwise regression analyses. Results revealed a five factor solution for the PID-5, with adequate reliability of the facet scales. The variance in Section II personality disorders could be predicted by their theoretically comprising Section III personality traits, but additional Section III personality traits augmented this prediction. Based on current results, we discuss the Section II personality disorder conceptualization and the Section III personality disorder operationalization.
article
The Construct Validity of the Dutch Personality Inventory for DSM-5 Personality Disorders (PID-5) in a Clinical Sample
Bastiaens, Tim ; Claes, Laurence ; Smits, Dirk ; De Clercq, Barbara ; De Fruyt, Filip ; Rossi, Gina ; Vanwalleghem, Dominique ; Vermote, Rudi ; Lowyck, Benedicte ; Claes, Stephan ; De Hert, Marc
SAGE Publications
Assessment; 2016; Vol. 23; iss. 1; pp. 42 - 51
The factor structure and the convergent validity of the Personality Inventory for DSM-5 (PID-5), a self-report questionnaire designed to measure personality pathology as advocated in the fifth edition, Section III of Diagnostic and Statistical Manual of Mental Disorders (DSM-5), are already demonstrated in general population samples, but need replication in clinical samples. In 240 Flemish inpatients, we examined the factor structure of the PID-5 by means of exploratory structural equation modeling. Additionally, we investigated differences in PID-5 higher order domain scores according to gender, age and educational level, and explored convergent and discriminant validity by relating the PID-5 with the Dimensional Assessment of Personality Pathology-Basic Questionnaire and by comparing PID-5 scores of inpatients with and without a DSM-IV categorical personality disorder diagnosis. Our results confirmed the original five-factor structure of the PID-5. The reliability and the convergent and discriminant validity of the PID-5 proved to be adequate. Implications for future research are discussed.
conference_proceeding
Variability amongst radiographers in the categorization of clinical acceptability for digital trauma radiography
Decoster, Robin ; Toomey, Rachel ; Smits, Dirk ; Mol, Harrie ; Verhelle, Filip ; Butler, Marie-Louise
Society of Photo-optical Instrumentation Engineers
MEDICAL IMAGING 2016: IMAGE PERCEPTION, OBSERVER PERFORMANCE, AND TECHNOLOGY ASSESSMENT; 2016; Vol. 9787; pp. -
© 2016 SPIE. Introduction: Radiographers evaluate anatomical structures to judge clinical acceptability of a radiograph. Whether a radiograph is deemed acceptable for diagnosis or not depends on the individual decision of the radiographer. Individual decisions cause variation in the accepted image quality. To minimise these variations definitions of acceptability, such as in RadLex, were developed. On which criteria radiographers attribute a RadLex categories to radiographs is unknown. Insight into these criteria helps to further optimise definitions and reduce variability in acceptance between radiographers. Therefore, this work aims the evaluation of the correlation between the RadLex classification and the evaluation of anatomical structures, using a Visual Grading Analysis (VGA) Methods: Four radiographers evaluated the visibility of five anatomical structures of 25 lateral cervical spine radiographs on a secondary class display with a VGA. They judged clinical acceptability of each radiograph using RadLex. Relations between VGAS and RadLex category were analysed with Kendall's Tau correlation and Nagelkerke pseudo-R. Results: The overall VGA score (VGAS) and the RadLex score correlate (rÏ.,= 0.62, p < / 0.01, R2=0.72) strongly. The observers' evaluation of contrast between bone, air (trachea) and soft tissue has low value in predicting (rÏ.,=0.55, p < / 0.01, R2=0.03) the RadLex score. The reproduction of spinous processes (rÏ.,=0.67, p < / 0.01, R2=0.31) and the evaluation of the exposure (rÏ.,=0.65, p < / 0.01, R2=0.56) have a strong correlation with high predictive value for the RadLex score. Conclusion: RadLex scores and VGAS correlate positively, strongly and significantly. The predictive value of bony structures may support the use of these in the judgement of clinical acceptability. Considerable inter-observer variations in the VGAS within a certain RadLex category, suggest that observers use of observer specific cut-off values.
article
Persoonlijkheidsstoornissen in de DSM-5
Bastiaens, Tim ; Claes, Laurence ; Smits, Dirk ; De Hert, Marc
Uitgeverij Acco
Tijdschrift Klinische Psychologie; 2015; Vol. 45; iss. 4; pp. 278 - 288
In april 2014 verscheen bij testuitgeverij Boom de Nederlandse vertaling van de vijfde editie van de Diagnostic and Statistical Manual of Mental Disorders (DSM-5; American Psychiatric Association [APA], 2013; APA/Nederlandse Vereniging voor Psychiatrie [NVvP], 2014), met daarin twee onderdelen (Sectie II/Sectie III) over persoonlijkheidsstoornissen. In deze bijdrage bespreken we de belangrijkste veranderingen in de classificatie van persoonlijkheidsstoornissen ten opzichte van DSM-IV-TR (APA, 2000). Ook blikken we kort vooruit op toekomstige ontwikkelingen binnen het internationale en Nederlandse taalgebied.
article
Validation of the German version of the Burn Specific Health Scale-Brief (BSHS-B)
Mueller, Astrid ; Smits, Dirk ; Jasper, Stefanie ; Berg, Lea ; Claes, Laurence ; Ipaktchi, Ramin ; Vogt, Peter M ; de Zwaan, Martina
Elsevier
Burns; 2015; Vol. 41; iss. 6; pp. 1333 - 1339
BACKGROUND: The Burn Specific Health Scale-Brief (BSHS-B) is recognized as a valid self-rating scale to evaluate quality of life after burn. AIM: To validate the translated German version of the BSHS-B. METHOD: One hundred and forty one burn survivors (65.2% men) with a mean age of 49.62 years (SD=15.16) and a mean duration after burn of 45.01 months (SD=26.18) answered the BSHS-B. Factor structure was tested by using confirmatory factor analysis, reliability (internal consistency) of the scales was determined by means of Cronbach's α. Construct validity was explored through correlations between the BSHS-B and the Short-Form 8 Health Survey (SF-8). In addition, the know-groups technique was used to determine to which degree the BSHS-B discriminates between patients with low and high burn severity based on the abbreviated burn severity index (ABSI). The Hospital Anxiety and Depression Scale (HADS) was used to examine criterion validity. RESULTS: The nine BSHS-B subscales showed good internal consistency. A second-order confirmatory factor analysis revealed the following main components: (1) Affect and Relationship, (2) Function and (3) Skin Involvement. The second-order factors were positively correlated with the SF-8 and negatively correlated with symptoms of anxiety and depression. Patients with low ABSI scored higher on all three BSHS-B domains than those with high ABSI. CONCLUSIONS: The results indicate good psychometric properties of the German BSHS-B. Further studies are needed to investigate the utility of the questionnaire in clinical routine practice, evaluation of burn management programs, and burn-specific research.
article
Clinicians' Attitudes Towards Outcome and Process Monitoring: A Validation of the Outcome Measurement Questionnaire
Smits, Dave F ; Claes, Laurence ; Stinckens, Nele ; Smits, Dirk JM
Springer Verlag
Administration and Policy in Mental Health and Mental Health Services Research; 2015; Vol. 42; iss. 5; pp. 634 - 641
Valid and reliable instruments to measure monitoring attitudes of clinicians are scarce. The influence of sociodemographics and professional characteristics on monitoring attitudes is largely unknown. First, we investigated the factor structure and reliability of the Outcome Measurement Questionnaire among a sample of Flemish mental health professionals (n = 170). Next, we examined the relationship between clinicians' sociodemographic and professional characteristics and monitoring attitudes. Construct validity was determined using a confirmatory factor analysis. Internal consistency was ascertained using Cronbach's alpha. Mean level differences in monitoring attitudes related to clinicians' gender, work setting, level of education and psychotherapeutic training, were investigated using ANOVAs. The relationships between clinicians' age, clinical experience and attitudes were calculated using the Pearson correlation coefficient. A model with one general factor and a method factor referring to reverse-worded items best fitted our data. Internal consistency was good. Clinicians with psychotherapeutic training reported more favorable monitoring attitudes than those without such training. Compared to clinicians working in subsidized outpatient services, private practitioners and clinicians from inpatient mental health clinics had more positive attitudes. Results highlight the need for sustained and targeted training, with particular focus on transforming measurement data into meaningful clinical support tools.
article
Structural Characteristics and External Correlates of the Working Alliance Inventory-Short Form
Smits, Dave ; Luyckx, Koen ; Smits, Dirk ; Stinckens, Nele ; Claes, Laurence
American Psychological Association
Psychological Assessment; 2015; Vol. 27; iss. 2; pp. 545 - 551
Controversy remains on the psychometric properties of the Working Alliance Inventory-Short Form (WAI-S). In the present study we first examined the factor structure and reliability of WAI-S scores in a sample of 557 Flemish mental health consumers. Subsequently, we investigated the relationship between early alliance quality and client's psychological dysfunctioning (symptomatic distress, interpersonal functioning and personality pathology). Participants completed the Outcome Questionnaire and the Dimensional Assessment of Personality Pathology-Short Form at start of treatment. The WAI-S was completed after the third treatment session. The structure of the WAI-S was examined using confirmatory factor analysis. Four different factor models were compared. Internal consistencies of the scales were ascertained using the Cronbach's alpha coefficient. Pearson correlations were calculated to determine the relationships between alliance ratings and the independent variables. CFA resulted in a two-factor model, with a Bond component (Contact) and a Task-Goal (Contract) component. Reliability of the WAI-S subscale scores proved to be very good. Symptomatic distress, interpersonal dysfunctioning and personality traits were associated to the Contract component of the alliance, but not to the Contact component. Clinical implications, limitations and suggestions for further research are formulated.
article
Psychometric Properties of the Multidimensional Perfectionism Scale of Hewitt in a Dutch-Speaking Sample: Associations With the Big Five Personality Traits
De Cuyper, Kathleen ; Claes, Laurence ; Hermans, Dirk ; Pieters, Guido ; Smits, Dirk
Taylor Francis (Routledge)
Journal of Personality Assessment; 2015; Vol. 97; iss. 2; pp. 182 - 190
We administered the Dutch Multidimensional Perfectionism Scale of Hewitt and Flett (1991, 2004) in a large student sample (N = 959) and performed a confirmatory factor analysis to test the factorial structure proposed by the original authors. The existence of a method factor referring to the negatively keyed items in the questionnaire was investigated by including it in the tested models. Next, we investigated how the 3 perfectionism dimensions are associated with the Five-factor model (FFM) of personality. The 3-factor structure originally observed by the authors was confirmed, at least when a method factor that refers to the negatively keyed items was included in the model. Self-oriented and socially prescribed perfectionism were both distinguished by low extraversion and low emotional stability. Self-oriented perfectionism's positive relationship with both conscientiousness and openness to experience differentiated the 2 perfectionism dimensions from each other. Other-oriented perfectionism was not well-characterized by the Big Five personality traits.
article
Post-processing, is it a burden or a blessing? Part 1 evaluation of clinical image quality
Decoster, Robin ; Mol, Harrie ; Smits, Dirk
Elsevier
Radiography; 2015; Vol. 21; iss. 1; pp. E1 - E4
© 2014 The College of Radiographers. Background: The dynamic range of modern detectors tolerates a higher detector dose or Detector Air Kerma (DAK) without negative effect on image quality. Necessary image quality is closely related to the clinical question: in order to keep the patient dose as low as possible, image quality criteria are needed for each type of radiography. The purpose of this study was to investigate the relation between image quality, described as an overall judgement versus the visibility of well-defined structures, and DAK in clinically accepted radiographs. Methods and materials: 168 AP radiographs of the knee and 152 radiographs of the pelvis were collected randomly in 19 radiologic centres. Six radiologists with at least five-years experience scored the overall image quality and the visibility of seven different anatomic structures, in a controlled environment on a five-point scale, using a Visual Grading Analysis (VGA). The relation between the DAK and the VGA Score (VGAS) was evaluated. Results: The VGAS was 3.92 for the knee and 3.71 for the pelvis. The VGAS for CR and DR were significantly different (. p < / 0.01). Intra-observer variability was not significant and inter-observer correlations were high and significant. Only for the pelvis radiographs produced with computed radiography, a rather weak but significant correlation was found between DAK and VGAS. Conclusion: The VGA revealed an image quality higher than diagnostically necessary in both datasets, and high inter-observer correlation. Based on the DAK-range, it could be hypothesized that below a certain noise level no further visible improvement of the image quality was reached.
article
Post-processing, is it a burden or a blessing? Part 2 CNR saturation as a new hypothesis
Decoster, Robin ; Mol, Harrie ; Smits, Dirk
Elsevier
Radiography; 2015; Vol. 21; iss. 1; pp. E5 - E8
© 2014 The College of Radiographers. Background: Higher Detector Air Kerma (DAK) lowers the noise level, delivering crisp and sharp radiographs, favoured by the radiologist. Expecting a linear relation between DAK and image quality, a higher DAK should deliver a higher image quality. Lowering the DAK and consequently also the signal, delivers more visible noise that can mask a detail. However, previous analyses of clinically approved radiographs demonstrated a lack of such a relation. The aim is to investigate the contribution of post-processing on the Contrast-Noise Ratio (CNR) as an attempt to clarify the absence of relationship between image quality and DAK in a set of clinical radiographs. Methods and Materials: A TOR18FG phantom, enveloped with 5cm of PMMA, is exposed to a large range of dose levels. To investigate the impact of post-processing on a low and high contrast element, the radiographs were analysed with and without post-processing. The effect of post-processing is evaluated by calculating the CNR for contrast both elements. Results: The post-processing nullifies the relation between DAK and CNR for the low contrast element. It has a smaller influence on the high contrast element, weakening the DAK-CNR relationship above 4μGy. Conclusion: The hypothesis of CNR saturation, a stagnation of CNR in function of DAK, may explain the absence of a relation between DAK and image quality found in the previous study. These findings indicate that post-processing should be handled with care and raises the question how and if guidelines for the daily practice concerning DAK and image quality can be defined.
article
The Relationship Between Parental Expressed Emotions and Non-suicidal Self-injury: The Mediating Roles of Self-criticism and Depression
Baetens, Imke ; Claes, Laurence ; Hasking, Penelope ; Smits, Dirk ; Grietens, Hans ; Onghena, Patrick ; Martin, Graham
Springer Verlag
Journal of Child and Family Studies; 2015; Vol. 24; iss. 2; pp. 491 - 498
© 2013, Springer Science+Business Media New York. Perceived parental expressed emotions have a substantial effect on adolescents’ well-being and non-suicidal self-injury (NSSI). The present study examines the mediating effects of self-criticism and depression in the relationship between perceived parental expressed emotions and NSSI. In total, 358 adolescents between the ages of twelve and twenty were examined. The brief NSSI assessment tool was used to assess NSSI. Depressive symptoms and self-criticism were examined with the Children’s Depression Inventory (CDI-NL) and the Self Rating Scale. Finally, the self-report questionnaire of the level of expressed emotions was used to assess perceived parental expressed emotions. The lifetime prevalence of NSSI in the current study was 13.41 %. Results of a mediation analysis show the relationship between self-criticism and NSSI is mediated by depressive symptoms. Furthermore, results of a path model analysis, explaining 20 % of the variance in NSSI frequency, show a direct effect of perceived parental environment (perceived lack of emotional support and perceived parental criticism) on NSSI frequency, as well as indirect paths via adolescent risk factors (depressive symptoms and self-criticism). Perceived lack of parental emotional support had a direct effect on frequency of NSSI, as well as an indirect effect via depressive symptoms. Perceived parental criticism on the other hand, had no direct effect on frequency of NSSI, but showed an indirect effect through self-criticism. This study improves our understanding of the underlying mechanisms involved in NSSI by interrelating significant family and adolescent risk factors. Limitations and clinical implications of these findings are discussed.
article
Het woud der verwachtingen
Smits, Dirk
Thema: Tijdschrift voor Hoger Onderwijs en Management; 2014; Vol. 2014; iss. 5; pp. 49 - 53
De hogescholen in Vlaanderen hebben de opdracht om ‘praktijkgericht onderzoek’ te doen. Hoe kun je dat het beste financieren? Dirk Smits inventariseert de huidige praktijk en doet aanbevelingen voor de toekomst. ‘Doordat de interne middelen sterk onder druk staan, blijft een deel van het potentieel van het praktijkgericht onderzoek momenteel onderbenut.’
other
Kwantitatief en kwalitatief onderzoek: Een inleiding in belangrijke concepten: Statistiek in woorden
Smits, Dirk
We starten met een overzicht van verschillen tussen kwantitatief en kwalitatief onderzoek. Vervolgens worden een aantal belangrijke concepten uit beide onderzoeksbenaderingen besproken vanuit een helicopterperspectief. Doel is dat je na de sessie een gemotiveerde keuze kan maken tussen beide benaderingen afhankelijk van je onderzoeksvraag.
other
Kenmerken van een goede onderzoeksvraag
Smits, Dirk ; De Meester, Kurt ; Dieussaert, Kristien
Een onderzoek begint met een idee. Maar hoe kom je tot een onderzoeksidee? Hoe vertaal je het oorspronkelijk idee in een onderzoeksvraag. De onderzoeksvraag heeft richting aan en is tegelijk de toetssteen voor je onderzoeksproces. In deze sessie lichten we onderzoeksidee, aanleiding, doelstelling, probleemstelling en uiteindelijke onderzoeksvraag toe.
article
The Dutch Version of the Emotion Reactivity Scale Validation and Relation with Various Behaviors in a Sample of High School Students
Claes, Laurence ; Smits, Dirk ; Bijttebier, Patricia
Hogrefe
European Journal of Psychological Assessment; 2014; Vol. 30; iss. 1; pp. 73 - 79
In the present study we investigated the psychometric properties of the Dutch version of the Emotion Reactivity Scale (ERS; Nock, Wedig, Holmberg, & Hooley, 2008). A sample of 615 high school students completed the ERS, together with the Adult Temperament Questionnaire, the Utrecht Coping List, the Self-Injury Questionnaire, and the Eating Disorder Inventory-2. Confirmatory factor analyses confirmed the one- and the three factor structure of the ERS. Both solutions showed stability across sex. However, given the high correlations between the three ERS subscales (ranging from r = .87 to r = .94), the more parsimonious 1-factor solution was preferred. The resulting ERS total scale had an internal consistency coefficient of .95 and was positively related to the temperament trait Negative Affectivity and negatively to Effortful Control. Additionally, it correlated significantly and positively with less adequate coping skills (such as Passive Depressive Reaction Patterns and Avoidance) and negatively with adequate coping skills (such as Active Problem Solving). Finally, the ERS scale discriminated between high school students with and without nonsuicidal self-injurious and eating-disorder related behaviors. The ERS is a reliable and valid questionnaire to measure emotion reactivity. © 2013 Hogrefe Publishing.
article
Kijken naar het spel van kleuters. Het Toverbos
Malfait, Catherine ; jeannin, Niki ; Smits, Dirk
Redactie HJK
HJK: De wereld van het jonge kind; 2013; iss. 3; pp. 16 - 19
Het spel van een kind toont waar het mee bezig is. Waar volwassenen over ervaringen en gevoelens praten, uiten kinderen deze in hun spel. Spelen helpt hen om emoties te verwerken. Met de methode Het Toverbos kun je door middel van spel de sociaal-emotionele ontwikkeling van het kind bevorderen. In dit artikel focussen we op deze methodiek, en hoe die in het klasgebeuren kan geïntroduceerd worden.
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