Biomedical subjects

Patrick Onghena

Publications and source records attributed to Patrick Onghena.

13 recordsLinked to original sources

PubMed2005

Reduction of pain-related fear in complex regional pain syndrome type I: the application of graded exposure in vivo.

Fear of (re)injury/movement has been identified as a potential predictor of chronic disability in complex regional pain syndrome type I (CRPS-I). In order to reduce pain-related fears and pain disability, graded exposure in vivo (GEXP) is likely to be an appropriate treatment. Indeed, there is evidence that in chronic pain patients reporting substantial fear of (re)injury/movement, GEXP is successful in reducing pain disability. However, the efficacy of exposure-based protocols in the treatment of CRPS-I patients for reducing pain disability has not been tested. The main research question of this study was whether the reduction of pain-related fear through GEXP also resulted in a decrease of disability in a subgroup of patients with CRPS-I who report substantial pain-related fear. A single-case experimental ABCD-design was used with random determination of the start of the intervention. Eight patients with CRPS-I were included in the study. To assess daily changes in pain intensity, pain-related fear, pain catastrophizing, and activity goal achievement, a diary was used. Standardized questionnaires of pain-related fear, pain disability, and self-reported signs and symptoms of CRPS-I were administered before and after each intervention, and at 6-month follow-up. The current study supports a GEXP approach to chronic CRPS-I. The GEXP was successful in decreasing levels of self-reported pain-related fear, pain intensity, disability, and physiological signs and symptoms. These results support the hypothesis that the meaning people attach to a noxious stimulus influences its experienced painfulness, and that GEXP activates cortical networks and reconciles motor output and sensory feedback.

Activities of Daily Living↗

PubMed2005

Parametric and nonparametric bootstrap methods for meta-analysis.

In a meta-analysis, the unknown parameters are often estimated using maximum likelihood, and inferences are based on asymptotic theory. It is assumed that, conditional on study characteristics included in the model, the between-study distribution and the sampling distributions of the effect sizes are normal. In practice, however, samples are finite, and the normality assumption may be violated, possibly resulting in biased estimates and inappropriate standard errors. In this article, we propose two parametric and two nonparametric bootstrap methods that can be used to adjust the results of maximum likelihood estimation in meta-analysis and illustrate them with empirical data. A simulation study, with raw data drawn from normal distributions, reveals that the parametric bootstrap methods and one of the nonparametric methods are generally superior to the ordinary maximum likelihood approach but suffer from a bias/precision tradeoff. We recommend using one of these bootstrap methods, but without applying the bias correction.

Bias↗

PubMed2004

Psychosocial functioning of young children with learning problems.

BACKGROUND: In this study, psychosocial functioning of different groups of young children with learning problems was investigated using a diverse set of psychosocial variables (including behaviour problems, academic motivation, social preference, and self-concept). METHODS: For this purpose, children with low academic achievement, with a specific learning disability based on an IQ-achievement discrepancy, and with a specific learning disability based on an achievement discrepancy, were selected out of 276 children of the first grade of regular primary schools. By means of multivariate analyses, their psychosocial functioning was compared to the functioning of children without learning problems. RESULTS: The total set of psychosocial variables was able to discriminate between children with and without learning problems, with medium effect size. Attention problems as reported by the teachers turned out to be the most important single psychosocial predictor for group discrimination. However, results varied according to the type of learning problem and the type of psychosocial problem. Children with a specific reading/spelling disability and children with low general academic achievement differed most from their peers without learning problems with regard to their psychosocial functioning. Poor cognitive self-concept was related primarily to low academic achievement, poor learning motivation might be specific for math problems, and a low social preference score seemed most characteristic of children with a specific learning disability. CONCLUSIONS: Studying several psychosocial variables simultaneously in different groups of children with learning problems leads to a further refinement of the current knowledge.

Child↗

PubMed2004

The effects of early prevention programs for families with young children at risk for physical child abuse and neglect: a meta-analysis.

In this article, a meta-analysis is presented on 40 evaluation studies of early prevention programs for families with young children at risk for physical child abuse and neglect with mostly nonrandomized designs. The main aim of all programs was to prevent physical child abuse and neglect by providing early family support. For the meta-analysis, a multilevel approach was used. A significant overall positive effect was found, pointing to the potential usefulness of these programs. The study demonstrated a significant decrease in the manifestation of abusive and neglectful acts and a significant risk reduction in factors such as child functioning, parent-child interaction, parent functioning, family functioning, and context characteristics.

Age Factors↗

PubMed2004

Longitudinal relations between parenting and child adjustment in young children.

We studied the predictive relations between reports of parenting behavior on the one hand and academic achievement and reported behavior problems of young children on the other hand. Data were gathered for 352 children and their parents from kindergarten to 2nd grade. The results indicated that in the academic domain, low supportive and high controlling parenting practices were modestly related to poor subsequent math achievement. Children's externalizing and attention problem behavior was clearly predictive of high levels of control in mothers and low levels of support in fathers. The combination of high parental support and control was especially associated with high levels of problem behavior. However, when previous parenting and child adjustment were taken into account, the magnitude of the predictive power of parenting for child adjustment, and of child adjustment for parenting, remained limited.

Adult↗

PubMed2003

Strategic aspects of numerosity judgment: the effect of task characteristics.

In previous investigations we documented that people use several strategies to determine different numerosities of blocks that are presented in a square grid. One of these strategies is the clever subtraction strategy, wherein the number of empty squares in the grid is subtracted from the total number of squares in the grid. In the present study we investigated participants' flexibility in strategy use when varying the shape of the grid. Analysis of the results in terms of the theoretical framework of Lemaire and Siegler (1995) regarding strategic change shows that this contextual variable affected the frequency, execution time, and accuracy of subjects' use of the subtraction strategy. The usefulness of this framework for analyzing the nature of the adaptation to contextual variations is discussed. From a methodological point of view, this study documents the potential of Beem's (1993, 1999) segmented linear regression models for assessing subjects' strategy use in cognitive tasks.

Adaptation, Psychological↗

PubMed2003

Hierarchical linear models for the quantitative integration of effect sizes in single-case research.

In this article, the calculation of effect size measures in single-case research and the use of hierarchical linear models for combining these measures are discussed. Special attention is given to meta-analyses that take into account a possible linear trend in the data. We show that effect size measures that have been proposed for this situation appear to be systematically affected by the duration of the experiment and fail to distinguish between effects on level and slope. To avoid these flaws, we propose to perform a multivariate meta-analysis on the standardized ordinary least squares regression coefficients from the study-specific regression equations describing the response variable.

Algorithms↗

PubMed2003

Estimating the mean effect size in meta-analysis: bias, precision, and mean squared error of different weighting methods.

Although use of the standardized mean difference in meta-analysis is appealing for several reasons, there are some drawbacks. In this article, we focus on the following problem: that a precision-weighted mean of the observed effect sizes results in a biased estimate of the mean standardized mean difference. This bias is due to the fact that the weight given to an observed effect size depends on this observed effect size. In order to eliminate the bias, Hedges and Olkin (1985) proposed using the mean effect size estimate to calculate the weights. In the article, we propose a third alternative for calculating the weights: using empirical Bayes estimates of the effect sizes. In a simulation study, these three approaches are compared. The mean squared error (MSE) is used as the criterion by which to evaluate the resulting estimates of the mean effect size. For a meta-analytic dataset with a small number of studies, the MSE is usually smallest when the ordinary procedure is used, whereas for a moderate or large number of studies, the procedures yielding the best results are the empirical Bayes procedure and the procedure of Hedges and Olkin, respectively.

Behavioral Research↗

PubMed2002

Can pain-related fear be reduced? The application of cognitive-behavioural exposure in vivo.

Although cognitive-behavioural treatments of patients with chronic pain generally are reported to be effective, customization might increase their effectiveness. One possible way to customize treatment is to focus the intervention on the supposed mechanism underlying the transition from acute to chronic pain disability. Evidence is accumulating in support of the conjecture that pain-related fear and associated avoidance behaviours are crucial in the development and maintenance of chronic pain disability. It seems timely to apply this knowledge to the cognitive-behavioural management of chronic pain. Two studies are presented here. Study 1 concerns a secondary analysis of data gathered in a clinical trial that was aimed at the examination of the supplementary value of coping skills training when added to an operant-behavioural treatment in patients with chronic back pain. The results show that, compared with a waiting list control, an operant-behavioural treatment with or without pain-coping skills training produced very modest and clinically negligible decreases in pain-related fear. Study 2 presents the effects of more systematic exposure in vivo treatment with behavioural experiments in two single patients reporting substantial pain-related fear. Randomization tests for AB designs revealed dramatic changes in pain-related fear and pain catastrophizing. In both cases, pain intensity also decreased significantly, but at a slower pace. Differences before and after treatment revealed clinically significant improvements in pain vigilance and pain disability.

Adult↗

PubMed1992

Antidepressant-induced analgesia in chronic non-malignant pain: a meta-analysis of 39 placebo-controlled studies.

For 39 controlled studies on the analgesic effect of antidepressants, a meta-analysis was conducted to get an estimation of the effect size, and to obtain a sight on the possible modes of action and the methodology used. The mean size of the analgesic effect was 0.64. It means that the average chronic pain patient who received an antidepressant treatment had less pain than 74% of the chronic pain patients who received a placebo. This quantification, however, is only as good as the studies on which it is based, and it could be differentiated for each of the pain syndromes and antidepressants examined. Real analgesic qualities of antidepressive agents seemed to offer the most plausible and economical explanation for the effect, but the predominant importance of serotonin reuptake blocking was not confirmed. Finally, the meta-analysis appeared to be fruitful for the generation of new hypotheses, for making some recommendations for future research, and for proposing some provisional guidelines for the clinical use of antidepressants in chronic non-malignant pain.

Analgesia↗

PubMedDate not supplied

Fear of movement/(re)injury in chronic low back pain: education or exposure in vivo as mediator to fear reduction?

Clinical research of graded exposure in vivo with behavioral experiments in patients with chronic low back pain who reported fear of movement/(re)injury shows abrupt changes in self-reported pain-related fears and cognitions. The abrupt changes are more characteristics of insight learning rather than the usual gradual progression of trial and error learning. The educational session at the start of the exposure might have contributed to this insight. The current study examines the contribution of education and graded exposure versus graded activity in the reduction of pain-related fear and associated disability and physical activity. Six consecutive patients with chronic low back pain who reported substantial fear of movement/(re)injury were included in the study. After a no-treatment baseline measurement period, all the patients received a single educational session, followed again by a no-treatment period. Patients were then randomly assigned to either a graded exposure with behavioral experiments or an operant graded activity program. A diary was used to assess daily changes in pain intensity, pain-related fear, pain catastrophizing, and activity goal achievement. Standardized questionnaires of pain-related fear, pain vigilance, pain intensity, and pain disability were administered before and after each intervention and at the 6-month follow-up. An activity monitor was carried at baseline, during the interventions, and 1 week at 6-month follow-up. Randomization tests of the daily measures showed that improvements in pain-related fear and catastrophizing occurred after the education was introduced. The results also showed a further improvement when exposure in vivo followed the no-treatment period after the education and not during the operant graded activity program. Performance of relevant daily activities, however, were not affected by the educational session and improved significantly only in the exposure in vivo condition. All improvements remained at half-year follow-up only in patients receiving the exposure in vivo. These patients also reported a significant decrease in pain intensity at follow-up.

Activities of Daily Living↗

PubMedDate not supplied

Customization of pain treatments: single-case design and analysis.

The aim of this paper is to acquaint pain researchers and practitioners with recent developments in the single-case experimental approach and their potential to allow for tailoring the treatment and its evaluation to the specific complaints, aptitudes, or profile of the individual patient, without violating the canons of good science and practice. After contrasting the single-case experimental approach and the case-study approach, we show the possibilities of customization in design, measurement, and test statistics. This is done by distinguishing 2 types of single-case designs--alternation designs and phase designs--and 2 types of replication strategies--simultaneous replications and sequential replications. In addition, tailor-made randomization tests are proposed for alternation, phase, and simultaneous replication designs and the combining of P values to perform a meta-analysis on designs that are sequentially replicated. With our emphasis on: 1) randomization in the design; 2) the possibilities for a statistical test (together with the determination of power and the calculation of effect sizes); 3) the importance of reliable and valid measurement; and 4) the role of replication, we demonstrate how internal validity, statistical-conclusion validity, construct validity, and external validity concerns can be dealt with within a single-case experimental approach framework. Finally, the many research examples and references to clinical work illustrate the usefulness of the approach.

Data Interpretation, Statistical↗

PubMedDate not supplied

Daily hassles reported by chronic fatigue syndrome and fibromyalgia patients in tertiary care: a controlled quantitative and qualitative study.

BACKGROUND: This study aimed at providing insight in the frequency, emotional impact and nature of daily hassles, experienced by patients suffering from chronic fatigue syndrome (CFS) and/or fibromyalgia (FM), compared with patients with a chronic organic disease. METHODS: One hundred and seventy-seven CFS/FM patients, 26 multiple sclerosis (MS) and 26 rheumatoid arthritis (RA) patients were investigated within 2-6 months after diagnosis. All patients completed a self-report questionnaire assessing daily hassles and associated distress, a visual analogue scale assessing fatigue and pain and a depression and anxiety questionnaire. RESULTS: CFS/FM patients show a higher frequency of hassles, higher emotional impact and higher fatigue, pain, depression and anxiety levels compared with MS/RA patients. Three hassle themes dominate in the CFS/FM group: dissatisfaction with oneself, insecurity and a lack of social recognition. In contrast, hassles reported by MS/RA patients show a much larger diversity and are not focused on person-dependent problems. CONCLUSIONS: Patients recently diagnosed as suffering from CFS and/or FM are highly preoccupied and distressed by daily hassles that have a severe impact on their self-image, as well as their personal, social and professional functioning. An optimal therapeutic approach of CFS and FM should take account of this heavy psychosocial burden, which might refer to core themes of these patients' illness experience.

Adult↗