Gregor Liegl

The effect of sleep deprivation on pain perception in healthy subjects: a meta-analysis

BACKGROUND There is strong evidence indicating an interaction between sleep and pain. However, the size of this effect, as well as the clinical relevance, is unclear. Therefore, this meta-analysis was conducted to quantify the effect of sleep deprivation on pain perception. METHODS A systematic literature search was conducted using the electronic databases PubMed, Cochrane, Psyndex, Psycinfo, and Scopus. By conducting a random-effect model, the pooled standardized mean differences (SMDs) of sleep deprivation on pain perception was calculated. Studies that investigated any kind of sleep deprivation in conjunction with a pain measurement were included. In cases of several pain measurements within a study, the average effect size of all measures was calculated. RESULTS Five eligible studies (N = 190) for the between-group analysis and ten studies (N = 266) for the within-group analysis were identified. Sleep deprivation showed a medium effect in the between-group analysis (SMD = 0.62; CI95: 0.12, 1.12; z = 2.43; p = 0.015) and a large effect in the within-group analysis (SMD = 1.49; CI95: 0.82, 2.17; z = 4.35; p <0.0001). The test for heterogeneity was not significant in the between-group analysis (Q = 5.29; df = 4; p = 0.2584), but it was significant in the within-group analysis (Q = 53.49; df = 9; p <0.0001). CONCLUSION This meta-analysis confirms a medium effect (SMD = 0.62) of sleep deprivation on pain perception. As this meta-analysis is based on experimental studies in healthy subjects, the clinical relevance should be clarified.

Neural correlates of conversion disorder: overview and meta-analysis of neuroimaging studies on motor conversion disorder

BackgroundConversion Disorders (CD) are prevalent functional disorders. Although the pathogenesis is still not completely understood, an interaction of genetic, neurobiological, and psychosocial factors is quite likely. The aim of this study is to provide a systematic overview on imaging studies on CDs and investigate neuronal areas involved in Motor Conversion Disorders (MCD).MethodsA systematic literature search was conducted on CD. Subsequently a meta-analysis of functional neuroimaging studies on MCD was implemented using an Activation Likelihood Estimation (ALE). We calculated differences between patients and healthy controls as well as between affected versus unaffected sides in addition to an overall analysis in order to identify neuronal areas related to MCD.ResultsPatients with MCD differ from healthy controls in the amygdala, superior temporal lobe, retrosplenial area, primary motor cortex, insula, red nucleus, thalamus, anterior as well as dorsolateral prefrontal and frontal cortex. When comparing affected versus unaffected sides, temporal cortex, dorsal anterior cingulate cortex, supramarginal gyrus, dorsal temporal lobe, anterior insula, primary somatosensory cortex, superior frontal gyrus and anterior prefrontal as well as frontal cortex show significant differences.ConclusionsNeuronal areas seem to be involved in the pathogenesis, maintenance or as a result of MCD. Areas that are important for motor-planning, motor-selection or autonomic response seem to be especially relevant. Our results support the emotional unawareness theory but also underline the need of more support by conduction imaging studies on both CD and MCD.

Patients’ Perceptions of Risky Developments During Psychotherapy

Research on risks and unwanted effects is largely missing in psychotherapy. Using exploratory factor analysis six dimensions of personal therapy situation were identified in a preliminary study, three of them were associated with risky developments during the psychotherapeutic process: (1) (poor) quality of therapeutic relationship, (2) burden caused by psychotherapy, and (3) dependency/isolation. Based on the finding of this study an online survey was performed to examine these three dimensions. Aside from these three factors another variable was associated with risky therapy developments: the online questionnaire also asked for premature terminations of psychotherapy as a consequence of risky conditions for the therapeutic development. Risky conditions were found to be associated with the following variables: (1) the combination of female patient–male therapist, (2) the therapeutic orientation (particularly with the psychodynamic approaches) and (3) the duration of therapy. Fewer humanistic and systemic psychotherapies were found among the high risk-prone group of patients who were at risk in at least three of the four variables which were associated with risky developments. Differences in the findings of the study regarding the four therapeutic orientations stress the importance of an extensive differential indication and a cooperative partnership between patient and therapist, in order to facilitate a positive patient participation towards the choice of therapy method and subsequent successful participation throughout the course of treatment. Further studies should also focus on female patient and male therapist psychotherapies.

Neural correlates of somatoform disorders from a meta-analytic perspective on neuroimaging studies

Somatoform disorders (SD) are common medical disorders with prevalence rates between 3.5% and 18.4%, depending on country and medical setting. SD as outlined in the ICD-10 exhibits various biological, social, and psychological pathogenic factors. Little is known about the neural correlates of SD. The aims of this meta-analysis are to identify neuronal areas that are involved in SD and consistently differ between patients and healthy controls. We conducted a systematic literature research on neuroimaging studies of SD. Ten out of 686 studies fulfilled the inclusion criteria and were analyzed using activation likelihood estimation. Five neuronal areas differ between patients with SD and healthy controls namely the premotor and supplementary motor cortexes, the middle frontal gyrus, the anterior cingulate cortex, the insula, and the posterior cingulate cortex. These areas seem to have a particular importance for the occurrence of SD. Out of the ten studies two did not contribute to any of the clusters. Our results seem to largely overlap with the circuit network model of somatosensory amplification for SD. It is conceivable that functional disorders, independent of the clinical impression, show similar neurobiological processes. While overlaps do occur it is necessary to understand single functional somatic syndromes and their aetiology for future research, terminology, and treatment guidelines.

Guided self-help interventions for irritable bowel syndrome: a systematic review and meta-analysis.

Objective Although irritable bowel syndrome (IBS) is highly prevalent and is accompanied by high costs for respective healthcare systems, the data on treatment effectiveness are limited. Current treatment methods have limitations in terms of side effects and availability. Guided self-help (GSH) might be an easily accessible and cost-effective treatment alternative. This study is the first systematic review and meta-analysis of GSH interventions for IBS. Methods Using electronic databases (MEDLINE, SCOPUS, PsycINFO, and Web of Science), we performed a systematic search for randomized-controlled trials. Using a random-effect model, we calculated the pooled standardized mean differences (SMDs) of GSH on IBS symptom severity (primary outcome) and quality of life (secondary outcome). We additionally examined the moderating effects of online-based interventions and face-to-face therapist contact by applying mixed models. Results A systematic literature search identified 10 eligible randomized-controlled trials, including 886 participants. Compared with the control conditions, the effect size was medium for the decrease in IBS symptom severity (SMD=0.72; 95% confidence interval: 0.34–1.08) and large for the increase in patients’ quality of life (SMD=0.84; 95% confidence interval: 0.46–1.22). Neither treatment format nor face-to-face contact was a predictor of therapy outcomes in between-group analyses. In contrast, within-group analyses led to the conclusion that online-based interventions are more effective than other self-help formats. Conclusion GSH is an effective alternative for the treatment of IBS. As GSH methods are easy to implement, it seems sensible to integrate GSH into clinical practice. Limitations With respect to the high study heterogeneity, the number of studies included was relatively small.

Using Patient Health Questionnaire-9 item parameters of a common metric resulted in similar depression scores compared to independent item response theory model reestimation

OBJECTIVES To investigate the validity of a common depression metric in independent samples. STUDY DESIGN AND SETTING We applied a common metrics approach based on item-response theory for measuring depression to four German-speaking samples that completed the Patient Health Questionnaire (PHQ-9). We compared the PHQ item parameters reported for this common metric to reestimated item parameters that derived from fitting a generalized partial credit model solely to the PHQ-9 items. We calibrated the new model on the same scale as the common metric using two approaches (estimation with shifted prior and Stocking-Lord linking). By fitting a mixed-effects model and using Bland-Altman plots, we investigated the agreement between latent depression scores resulting from the different estimation models. RESULTS We found different item parameters across samples and estimation methods. Although differences in latent depression scores between different estimation methods were statistically significant, these were clinically irrelevant. CONCLUSION Our findings provide evidence that it is possible to estimate latent depression scores by using the item parameters from a common metric instead of reestimating and linking a model. The use of common metric parameters is simple, for example, using a Web application (http://www.common-metrics.org) and offers a long-term perspective to improve the comparability of patient-reported outcome measures.

A meta‐analytic review of brief guided self‐help education for chronic pain

Up to 30% of the population in Western countries suffer from chronic pain. The treatment of chronic pain causes medical and socioeconomic problems. Guided self‐help (GSH) might be an effective supplementary treatment, however, the size of this effect is unclear. This meta‐analysis quantifies the effect of GSH on chronic pain. A systematic literature search was conducted using PubMed, Cochrane, Psyndex, Psycinfo and Scopus. Studies that investigated GSH in chronic pain conditions (children and adults) were included. Disability, quality of life and pain severity were defined as main outcomes. We conducted random effects models to calculate standardized mean differences (SMDs). By applying mixed models and subgroup analyses, we examined the moderating effects of sample characteristics (age; pain region), GSH format (online; face‐to‐face contact) and study characteristics (study quality; control condition). We identified 16 eligible studies, including 739 subjects. Between‐group analyses resulted in a medium, but heterogeneous effect size for pain severity (SMD = 0.51; CI95: 0.21, 0.81). After excluding two samples suggesting small study bias, the effect on pain severity was small but homogeneous (SMD = 0.34; CI95: 0.13, 0.54). We found a small effect size for disability (SMD = 0.30; CI95: 0.10, 0.50). The pooled effect size for quality of life did not reach significance (SMD = 0.24; CI95: −0.07, 0.54). We conclude that GSH has a small but robust effect on pain severity and disability in chronic pain patients. This applies to various GSH formats and patient populations. It seems reasonable to integrate GSH into clinical practice as a supplemental treatment option.

Language‐related differential item functioning between English and German PROMIS Depression items is negligible

To investigate differential item functioning (DIF) of PROMIS Depression items between US and German samples we compared data from the US PROMIS calibration sample (n = 780), a German general population survey (n = 2,500) and a German clinical sample (n = 621). DIF was assessed in an ordinal logistic regression framework, with 0.02 as criterion for R2‐change and 0.096 for Rajus non‐compensatory DIF. Item parameters were initially fixed to the PROMIS Depression metric; we used plausible values to account for uncertainty in depression estimates. Only four items showed DIF. Accounting for DIF led to negligible effects for the full item bank as well as a post hoc simulated computer‐adaptive test (< 0.1 point on the PROMIS metric [mean = 50, standard deviation =10]), while the effect on the short forms was small (< 1 point). The mean depression severity (43.6) in the German general population sample was considerably lower compared to the US reference value of 50. Overall, we found little evidence for language DIF between US and German samples, which could be addressed by either replacing the DIF items by items not showing DIF or by scoring the short form in German samples with the corrected item parameters reported.

Varying the item format improved the range of measurement in patient-reported outcome measures assessing physical function

BackgroundPhysical function (PF) is a core patient-reported outcome domain in clinical trials in rheumatic diseases. Frequently used PF measures have ceiling effects, leading to large sample size requirements and low sensitivity to change. In most of these instruments, the response category that indicates the highest PF level is the statement that one is able to perform a given physical activity without any limitations or difficulty. This study investigates whether using an item format with an extended response scale, allowing respondents to state that the performance of an activity is easy or very easy, increases the range of precise measurement of self-reported PF.MethodsThree five-item PF short forms were constructed from the Patient-Reported Outcomes Measurement Information System (PROMIS®) wave 1 data. All forms included the same physical activities but varied in item stem and response scale: format A (“Are you able to …”; “without any difficulty”/“unable to do”); format B (“Does your health now limit you …”; “not at all”/“cannot do”); format C (“How difficult is it for you to …”; “very easy”/“impossible”). Each short-form item was answered by 2217–2835 subjects. We evaluated unidimensionality and estimated a graded response model for the 15 short-form items and remaining 119 items of the PROMIS PF bank to compare item and test information for the short forms along the PF continuum. We then used simulated data for five groups with different PF levels to illustrate differences in scoring precision between the short forms using different item formats.ResultsSufficient unidimensionality of all short-form items and the original PF item bank was supported. Compared to formats A and B, format C increased the range of reliable measurement by about 0.5 standard deviations on the positive side of the PF continuum of the sample, provided more item information, and was more useful in distinguishing known groups with above-average functioning.ConclusionsUsing an item format with an extended response scale is an efficient option to increase the measurement range of self-reported physical function without changing the content of the measure or affecting the latent construct of the instrument.

Wie belastend ist die Behandlung von Patienten mit somatoformen Störungen

OBJECTIVES This study examines the influence of self-perceived emotional stress during the treatment of patients with somatoform disorders. It asks whether emotional stress can be influenced by psychosomatic education. METHODS Via online questionnaire general practitioners were asked about the prevalence of patients presenting with somatoform disorders and emotional stress during treatment. RESULTS The prevalence of somatoform disorders in general practices was estimated at around 27.7 %. Practitioners educated in psychosomatic medicine estimate the prevalence of patients with somatoform disorders higher than practitioners without such education (n = 79; r = 0.242; p = 0.032). The treatment of patients presenting with somatoform disorders causes 42.6% more emotional stress among general practitioners compared with the treatment of an average patient (n = 79; t = 16.67; p ≤ 0.001). Doctors with additional education in psychosomatic medicine rate stress 17.2% lower than doctors without such education (n = 79; t = 1.875; p = 0.033). CONCLUSIONS General practitioners experience the treatment of patients presenting with somatoform disorders as emotionally stressful. This emotional stress is mainly explained by increases in time expenditure, but it can be reduced by additional psychosomatic education.