Working Memory Training Studies Research Articles

Evaluating the effect of action-like video game play and of casual video game play on anxiety in adolescents with elevated anxiety: protocol for a multi-center, parallel group, assessor-blind, randomized controlled trial

BackgroundAdolescence is a critical period for the onset and maintenance of anxiety disorders, which raises the importance of intervening early; one possibility of doing so is via digital interventions. Within that research field, at least two important research paths have been explored in the past years. On the one hand, the anxiolytic effect of casual video games has been tested as such gaming activity may distract away from anxious thoughts through the induction of flow and redirection of attention toward the game and thus away of anxious thoughts. On the other hand, the bidirectional link between weak attentional control and higher anxiety has led to the design of interventions aiming at improving attentional control such as working memory training studies. Taking stock that another genre of gaming, action video games, improves attentional control, game-based interventions that combines cognitive training and action-like game features would seem relevant. This three-arm randomized controlled trial aims to evaluate the feasibility and the efficacy of two video game interventions to document how each may potentially alleviate adolescent anxiety-related symptoms when deployed fully on-line.MethodsThe study aims to recruit 150 individuals, 12 to 14 years of age, with high levels of anxiety as reported by the parents’ online form of the Screen for Child Anxiety Related Disorders questionnaire. This trial contrasts a child-friendly, “action-like” video game designed to improve attentional control abilities in a progressive and stepwise manner (Eco-Rescue), a casual puzzle video game selected to act as a positive distraction tool (Bejeweled) and finally a control group with no assigned training intervention to control for possible test-retest effects (No-training). Participants will be assigned randomly to one of the three study arms. They will be assessed for main (anxiety) and secondary outcomes (attentional control, affective working memory) at three time points, before training (T1), one week after the 6-week training (T2) and four months after completing the training (T3).DiscussionThe results will provide evidence for the feasibility and the efficacy of two online video game interventions at improving mental health and emotional well-being in adolescents with high levels of anxiety. This project will contribute unique knowledge to the field, as few studies have examined the effects of video game play in the context of digital mental health interventions for adolescents.Trial registrationThe trial is registered on ClinicalTrials.gov (NCT05923944, June 20, 2023).

Training working memory for two years—No evidence of transfer to intelligence.

Working memory (WM) training has been proposed as a promising intervention to enhance cognitive abilities, but convincing evidence for transfer to untrained abilities is lacking. Prevalent limitations of WM training studies include the narrow assessment of both WM and cognitive abilities, the analysis of manifest variables subject to measurement error, and training dosages too low to likely cause changes in the cognitive system. To address these limitations, we conducted a 2-year longitudinal study to investigate the effects of working memory training on latent factors of working memory capacity, fluid intelligence and crystallized intelligence. One hundred twelve students initially attending 9th grade practiced a heterogenous set of validated WM tasks on a biweekly basis. A control group of 113 students initially attending 9th grade participated in the pretest and posttest. Broad and prototypical measures of fluid and crystallized intelligence served as measures of nearer and farer transfer. We found substantial and reliable training effects on the practiced WM tasks, as well as on a latent WM factor constituted by them. However, no transfer of training effects to fluid or crystallized intelligence were observed. These results add to the literature questioning the utility and validity of WM training as means of improving cognitive abilities. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Exploring Individual Differences as Predictors of Performance Change During Dual-N-Back Training.

In working memory training studies, individual trajectories are known to vary considerably between participants. A better understanding of how individual differences affect training outcomes is important because it might inform the development of more effective training interventions. This study explored how measures of working memory, intelligence, sustained attention, training motivation, mindset, psychological well-being, perceived stress, and sleep quality affect initial training performance and rate of change. A total of 217 upper secondary students completed 12 weeks of adaptive dual-n-back in a classroom setting. We analyzed their self-reported training data using latent growth curve modeling. We found that working memory and intelligence predicted both, initial training performance and rate of performance change. Sustained attention and sleep quality predicted initial performance, but not the rate of change. Furthermore, we observed that participants who completed the intervention scored significantly higher on measures of working memory and intelligence and reported lower levels of perceived stress and higher levels of sleep quality at baseline compared to dropouts. In general, our study supports the magnification account with higher ability individuals starting out at a higher performance level and showing a higher rate of performance change, and moreover, being more likely to adhere to the training protocol.

Child Motivation and Family Environment Influence Outcomes of Working Memory Training in Extremely Preterm Children

Cognitive training can improve working memory in children at risk of working memory difficulties; however, response to training can vary and doubt exists if working memory improvements can be sustained long- term. This study aimed to explore whether child motivation and family environment are associated with working memory trajectories in children born extremely preterm or extremely low birth weight. Forty-five 7-year-old children completed Cogmed Working Memory Training® at home over 5–7 weeks. Children and their families completed working memory tests and child motivation and family environment questionnaires at baseline, with working memory further tested 2 weeks, 12 months and 24 months post-training. Latent growth modelling was used to explore whether child motivation and family environment factors were associated with working memory trajectories. Children’s desire for challenge, training competence, and being from a single-parent household were associated with short-term improvements in verbal short-term memory. Children from poorer functioning families were associated with short-term improvements in working memory. There was little evidence that child motivation or family environment was associated with long-term working memory changes. Child motivation and the training environment may be important for understanding training effects in children born extremely preterm or extremely low birth weight, and warrant closer examination in working memory training studies.

Divergent Research Methods Limit Understanding of Working Memory Training.

Working memory training has been a hot topic over the last decade. Although studies show benefits in trained and untrained tasks as a function of training, there is an ongoing debate on the efficacy of working memory training. There have been numerous meta-analyses put forth to the field, some finding overall broad transfer effects while others do not. However, discussion of this research typically overlooks specific qualities of the training and transfer tasks. As such, there has been next to no discussion in the literature on what training and transfer tasks features are likely to mediate training outcomes. To address this gap, here, we characterized the broad diversity of features employed in N-back training tasks and outcome measures in published working memory training studies. Extant meta-analyses have not taken into account the diversity of methodology at this level, primarily because there are too few studies using common methods to allow for a robust meta-analysis. We suggest that these limitations preclude strong conclusions from published data. In order to advance research on working memory training, and in particular, N-back training, more studies are needed that systematically compare training features and use common outcome measures to assess transfer effects.

Working Memory Training in Children: A Review of Basic Methodological Criteria.

Working memory is a process of great relevance during childhood due to its role in diverse complex skills. Like the rest of executive functions, it is highly sensitive to environmental influences, so it is assumed that it could be modified through targeted interventions. A large number of working memory training studies in children aim to achieve transfer effects both on this process and on those with which it is related. Although some promising results have been found, the efficacy of working memory training cannot be affirmed; methodological quality of studies is one of the main reasons for this. Compliance with basic methodological criteria (inclusion of a control group that must preferably be active, random assignment of participants to groups) has a great impact on the internal validity of the studies. Furthermore, the need to control for the effects of motivational factors associated with the intervention is added and emphasized. This study reviews the fulfillment of these criteria in process-based working memory training literature in children, analyzing its impact on internal validity. Limitations of the field in relation to the lack of compliance with the proposed criteria are discussed and alternatives are suggested in order to improve the quality of future studies.

The Effects of Transcranial Direct Current Stimulation (tDCS) on Working Memory Training in Healthy Young Adults.

Working memory (WM) is a fundamental cognitive ability to support complex thought, but it is limited in capacity. WM training has shown the potential benefit for those in need of a higher WM ability. Many studies have shown the potential of transcranial direct current stimulation (tDCS) to transiently enhance WM performance by delivering a low current to the brain cortex of interest, via electrodes on the scalp. tDCS has also been revealed as a promising intervention to augment WM training in a few studies. However, those few tDCS-paired WM training studies, focused more on the effect of tDCS on WM enhancement and its transferability after training and paid less attention to the variation of cognitive performance during the training procedure. The current study attempted to explore the effect of tDCS on the variation of performance, during WM training, in healthy young adults. All the participants received WM training with the load-adaptive verbal N-back task, for 5 days. During the training procedure, active/sham anodal high-definition tDCS (HD-tDCS) was used to stimulate the left dorsolateral prefrontal cortex (DLPFC). To examine the training effect, pre- and post-tests were performed, respectively, 1 day before and after the training sessions. At the beginning of each training session, stable-load WM tasks were performed, to examine the performance variation during training. Compared to the sham stimulation, higher learning rates of performance metrics during the training procedure were found when WM training was combined with active anodal HD-tDCS. The performance improvements (post–pre) of the active group, were also found to be higher than those of the sham group and were transferred to a similar untrained WM task. Further analysis revealed a negative relationship between the training improvements and the baseline performance. These findings show the potential that tDCS may be leveraged as an intervention to facilitate WM training, for those in need of a higher WM ability.

Does working memory training enhance intelligence?

Working memory (WM) is a capacity-limited cognitive system that strongly relates to higher-order cognitive abilities including fluid intelligence. It has been suggested that WM training can increase memory capacity, which in turn, improves general intellectual abilities. To evaluate these claims, the present review critically re-assessed nine meta-analysis studies, and revealed that the effect of WM training on fluid intelligence (Gf), executive function, and academic performance is relatively small (averaged Hedges’ adjusted g < .20). Moreover, there were several methodological issues regarding the study design (placebo effect, small sample size), analytical approach (inadequate group comparison, lack of correction for multiple comparisons), and theoretical framework (lack of theoretical account of the training mechanisms) in previous WM training studies. We propose a set of recommendations for future training studies that go beyond training the WM ability per se. This includes theoretically possible methods to enhance intellectual abilities by, for example, learning strategies to effectively encode and recall information into long-term memory.

Longitudinal tDCS: Consistency across Working Memory Training Studies

There is great interest in enhancing and maintaining cognitive function. In recent years, advances in noninvasive brain stimulation devices, such as transcranial direct current stimulation (tDCS), have targeted working memory in particular. Despite controversy surrounding outcomes of single-session studies, a growing field of working memory training studies incorporate multiple sessions of tDCS. It is useful to take stock of these findings because there is a diversity of paradigms employed and the outcomes observed between research groups. This will be important in assessing cognitive training programs paired with stimulation techniques and identifying the more useful and less effective approaches. Here, we treat the tDCS+ working memory training field as a case example, but also survey training benefits in other neuromodulatory techniques (e.g., tRNS, tACS). There are challenges associated with the broad parameter space including: individual differences, stimulation intensity, duration, montage, session number, session spacing, training task selection, timing of follow up testing, near and far transfer tasks. In summary, although the field of assisted cognitive training is young, some design choices are more favorable than others. By way of heuristic, the current evidence supports including more training/tDCS sessions (5+), applying anodal tDCS targeting prefrontal regions, including follow up testing on trained and transfer tasks after a period of no contact. What remains unclear, but important for future translational value is continuing work to pinpoint optimal values for the tDCS parameters on a per cognitive task basis. Importantly the emerging literature shows notable consistency in the application of tDCS for WM across various participant populations compared to single session experimental designs.

Working Memory Training Does Not Improve Performance on Measures of Intelligence or Other Measures of “Far Transfer”

It has been claimed that working memory training programs produce diverse beneficial effects. This article presents a meta-analysis of working memory training studies (with a pretest-posttest design and a control group) that have examined transfer to other measures (nonverbal ability, verbal ability, word decoding, reading comprehension, or arithmetic; 87 publications with 145 experimental comparisons). Immediately following training there were reliable improvements on measures of intermediate transfer (verbal and visuospatial working memory). For measures of far transfer (nonverbal ability, verbal ability, word decoding, reading comprehension, arithmetic) there was no convincing evidence of any reliable improvements when working memory training was compared with a treated control condition. Furthermore, mediation analyses indicated that across studies, the degree of improvement on working memory measures was not related to the magnitude of far-transfer effects found. Finally, analysis of publication bias shows that there is no evidential value from the studies of working memory training using treated controls. The authors conclude that working memory training programs appear to produce short-term, specific training effects that do not generalize to measures of “real-world” cognitive skills. These results seriously question the practical and theoretical importance of current computerized working memory programs as methods of training working memory skills.

Neural correlates of working memory training in HIV patients: study protocol for a randomized controlled trial.

BackgroundPotent combined antiretroviral therapy decreased the incidence and severity of HIV-associated neurocognitive disorders (HAND); however, no specific effective pharmacotherapy exists for HAND. Patients with HIV commonly have deficits in working memory and attention, which may negatively impact many other cognitive domains, leading to HAND. Since HAND may lead to loss of independence in activities of daily living and negative emotional well-being, and incur a high economic burden, effective treatments for HAND are urgently needed. This study aims to determine whether adaptive working memory training might improve cognitive functions and neural network efficiency and possibly decrease neuroinflammation. This study also aims to assess whether subjects with the LMX1A-rs4657412 TT(AA) genotype show greater training effects from working memory training than TC(AG) or CC(GG)-carriers.Methods/Design60 HIV-infected and 60 seronegative control participants will be randomized to a double-blind active-controlled study, using adaptive versus non-adaptive Cogmed Working Memory Training® (CWMT), 20–25 sessions over 5–8 weeks. Each subject will be assessed with near- and far-transfer cognitive tasks, self-reported mood and executive function questionnaires, and blood-oxygenation level-dependent functional MRI during working memory (n-back) and visual attention (ball tracking) tasks, at baseline, 1-month, and 6-months after CWMT. Furthermore, genotyping for LMX1A-rs4657412 will be performed to identify whether subjects with the TT(AA)-genotype show greater gain or neural efficiency after CWMT than those with other genotypes. Lastly, cerebrospinal fluid will be obtained before and after CWMT to explore changes in levels of inflammatory proteins (cytokines and chemokines) and monoamines.DiscussionImproving working memory in HIV patients, using CWMT, might slow the progression or delay the onset of HAND. Observation of decreased brain activation or normalized neural networks, using fMRI, after CWMT would lead to a better understanding of how neural networks are modulated by CWMT. Moreover, validating the greater training gain in subjects with the LMX1A-TT(AA) genotype could lead to a personalized approach for future working memory training studies. Demonstrating and understanding the neural correlates of the efficacy of CWMT in HIV patients could lead to a safe adjunctive therapy for HAND, and possibly other brain disorders.Trial registrationClinicalTrial.gov, NCT02602418.

Can impaired working memory functioning be improved by training? A meta-analysis with a special focus on brain injured patients.

Deficits in working memory (WM) are commonly observed after brain injuries and cause severe impairments in patients' everyday life. It is still under debate if training can enhance or rehabilitate WM in case of malfunction. The current meta-analysis investigates this issue from a clinical point of view. It addresses under which conditions and for which target group WM training may be justifiable. Relevant WM training studies were identified by searching electronic literature databases with a comprehensive search term. In total, 103 studies, which added up to 112 independent group comparisons (N = 6,113 participants), were included in the analysis. Overall, WM training caused a moderate and long-lasting improvement in untrained WM tasks. Moreover, improvement of WM functioning led to sustainable better evaluation of everyday life functioning, however, effect sizes were small. Concerning transfer effects on other cognitive domains, long-lasting improvements with small effect sizes were observed in cognitive control and reasoning/intelligence. In contrast, small immediate, but no long-term effects were found for attention and long-term memory. Studies with brain injured patients demonstrated long-lasting improvements in WM functions with moderate to large effect sizes. A main moderator variable of intervention efficacy is the number of training sessions applied. WM training produces long-lasting beneficial effects which are strongly pronounced in patients with acquired brain injuries. This finding supports the application of WM training in clinical settings. To determine optimal training conditions, future studies must systematically investigate the characteristics of interventions as they are at present inevitably confounded.

Working Memory Load-Dependent Brain Response Predicts Behavioral Training Gains in Older Adults

In the domain of working memory (WM), a sigmoid-shaped relationship between WM load and brain activation patterns has been demonstrated in younger adults. It has been suggested that age-related alterations of this pattern are associated with changes in neural efficiency and capacity. At the same time, WM training studies have shown that some older adults are able to increase their WM performance through training. In this study, functional magnetic resonance imaging during an n-back WM task at different WM load levels was applied to compare blood oxygen level-dependent (BOLD) responses between younger and older participants and to predict gains in WM performance after a subsequent 12-session WM training procedure in older adults. We show that increased neural efficiency and capacity, as reflected by more "youth-like" brain response patterns in regions of interest of the frontoparietal WM network, were associated with better behavioral training outcome beyond the effects of age, sex, education, gray matter volume, and baseline WM performance. Furthermore, at low difficulty levels, decreases in BOLD response were found after WM training. Results indicate that both neural efficiency (i.e., decreased activation at comparable performance levels) and capacity (i.e., increasing activation with increasing WM load) of a WM-related network predict plasticity of the WM system, whereas WM training may specifically increase neural efficiency in older adults.

No evidence of intelligence improvement after working memory training: A randomized, placebo-controlled study.

Numerous recent studies seem to provide evidence for the general intellectual benefits of working memory training. In reviews of the training literature, Shipstead, Redick, and Engle (2010, 2012) argued that the field should treat recent results with a critical eye. Many published working memory training studies suffer from design limitations (no-contact control groups, single measures of cognitive constructs), mixed results (transfer of training gains to some tasks but not others, inconsistent transfer to the same tasks across studies), and lack of theoretical grounding (identifying the mechanisms responsible for observed transfer). The current study compared young adults who received 20 sessions of practice on an adaptive dual n-back program (working memory training group) or an adaptive visual search program (active placebo-control group) with a no-contact control group that received no practice. In addition, all subjects completed pretest, midtest, and posttest sessions comprising multiple measures of fluid intelligence, multitasking, working memory capacity, crystallized intelligence, and perceptual speed. Despite improvements on both the dual n-back and visual search tasks with practice, and despite a high level of statistical power, there was no positive transfer to any of the cognitive ability tests. We discuss these results in the context of previous working memory training research and address issues for future working memory training studies.

Dual n-back training increases the capacity of the focus of attention

Working memory (WM) training has been reported to benefit abilities as diverse as fluid intelligence (Jaeggi et al., Proceedings of the National Academy of Sciences of the United States of America, 105:6829-6833, 2008) and reading comprehension (Chein & Morrison, Psychonomic Bulletin & Review, 17:193-199, 2010), but transfer is not always observed (for reviews, see Morrison & Chein, Psychonomics Bulletin & Review, 18:46-60, 2011; Shipstead et al., Psychological Bulletin, 138:628-654, 2012). In contrast, recent WM training studies have consistently reported improvement on the trained tasks. The basis for these training benefits has received little attention, however, and it is not known which WM components and/or processes are being improved. Therefore, the goal of the present study was to investigate five possible mechanisms underlying the effects of adaptive dual n-back training on working memory (i.e., improvements in executive attention, updating, and focus switching, as well as increases in the capacity of the focus of attention and short-term memory). In addition to a no-contact control group, the present study also included an active control group whose members received nonadaptive training on the same task. All three groups showed significant improvements on the n-back task from pretest to posttest, but adaptive training produced larger improvements than did nonadaptive training, which in turn produced larger improvements than simply retesting. Adaptive, but not nonadaptive, training also resulted in improvements on an untrained running span task that measured the capacity of the focus of attention. No other differential improvements were observed, suggesting that increases in the capacity of the focus of attention underlie the benefits of adaptive dual n-back training.

Does working memory training work? The promise and challenges of enhancing cognition by training working memory

A growing body of literature shows that one's working memory (WM) capacity can be expanded through targeted training. Given the established relationship between WM and higher cognition, these successful training studies have led to speculation that WM training may yield broad cognitive benefits. This review considers the current state of the emerging WM training literature, and details both its successes and limitations. We identify two distinct approaches to WM training, strategy training and core training, and highlight both the theoretical and practical motivations that guide each approach. Training-related increases in WM capacity have been successfully demonstrated across a wide range of subject populations, but different training techniques seem to produce differential impacts upon the broader landscape of cognitive abilities. In particular, core WM training studies seem to produce more far-reaching transfer effects, likely because they target domain-general mechanisms of WM. The results of individual studies encourage optimism regarding the value of WM training as a tool for general cognitive enhancement. However, we discuss several limitations that should be addressed before the field endorses the value of this approach.

Effects of Working Memory Training on Cognitive Functions and Neural Systems

Working memory (WM) is the limited capacity storage system involved in the maintenance and manipulation of information over short periods of time. WM plays a key role in a wide range of higher order cognitive functions and its impairment is observed in a wide range of psychiatric or neurological disorders, making it clinically important. Intensive adaptive training of WM has been shown to enhance individual WM. In this article, we review the studies and describe the methodologies of WM training, along with the psychological, clinical, and neuroimaging findings related to WM training. Training of WM is associated with a wide range of cognitive improvements in non-clinical and clinical subjects, although, on certain points, the results are divided. In clinical studies, training of WM was associated with an improvement of clinical symptoms outside the laboratory. Neuroimaging studies of WM training revealed the effect of WM training on the neural systems of the fronto-parietal network, which play a key role in WM. Still, a number of important issues remain uninvestigated, and we anticipate that future studies will solve these issues.

Working memory and proactive interference: Developmental effects in 8-13 year old healthy children

Event Abstract Back to Event Working memory and proactive interference: Developmental effects in 8-13 year old healthy children Sandra Loosli1*, Johanna Posth1, Benjamin Rahm2, Josef M. Unterrainer3, Irina Mader4, Cornelius Weiller1 and Christoph P. Kaller1 1 University of Freiburg, Department of Neurology, Germany 2 University of Frankfurt/Main, Institute of Medical Psychology, Germany 3 University of Mainz, Department of Medical Psychology and Medical Sociology, Germany 4 University of Freiburg, Department of Neuroradiology, Germany Working memory (WM) refers to a dynamic processing system for the maintenance and manipulation of information. It is essential for higher-order processes such as language comprehension, planning, problem solving or fluid intelligence and is also related directly to school performance, such as reading ability or mathematical skills. An important factor determining WM capacity is the ability to suppress proactive interference (PI). PI refers to impaired recall due to interference from material presented previously. Resistance to PI in WM increases considerably during childhood, however, the associated neuronal processes still remain elusive. Studies involving the Recent-Probes-Task have shown that in adults suppression of PI goes along with activations in the left inferior-frontal gyrus (LIFG). Here, adults as well as 8-9 and 12-13 year old children were compared in an event-related fMRI-study to investigate the course of PI development. Behavioral results revealed effects of PI across all subjects, i.e. participants responded slower and made more errors when the current stimulus was already presented one trial before. Resistance to PI improved gradually with age but was associated with higher costs in reaction times in older subjects. Compared with the non-recent-condition, the recent-condition activated stronger the LIFG pars triangularis and the anterior cingulate cortex (ACC). This activation increased with age, hence corresponding to the developmental effects in the behavioral data. These results show that effects of PI change during childhood and that they may be partially modulated by the activity of the LIFG. In future studies, an application with respect to educational settings lies for instance in the conduction of WM training studies which focus especially on interference processes. By means of training, susceptibility to PI could possibly be reduced and lead potentially to improvements in WM and scholastic abilities. Conference: EARLI SIG22 - Neuroscience and Education, Zurich, Switzerland, 3 Jun - 5 Jun, 2010. Presentation Type: Poster Presentation Topic: General cognitive abilities Citation: Loosli S, Posth J, Rahm B, Unterrainer JM, Mader I, Weiller C and Kaller CP (2010). Working memory and proactive interference: Developmental effects in 8-13 year old healthy children. Front. Neurosci. Conference Abstract: EARLI SIG22 - Neuroscience and Education. doi: 10.3389/conf.fnins.2010.11.00051 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 31 May 2010; Published Online: 31 May 2010. * Correspondence: Sandra Loosli, University of Freiburg, Department of Neurology, Freiburg, Germany, sandra.loosli@uniklinik-freiburg.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Sandra Loosli Johanna Posth Benjamin Rahm Josef M Unterrainer Irina Mader Cornelius Weiller Christoph P Kaller Google Sandra Loosli Johanna Posth Benjamin Rahm Josef M Unterrainer Irina Mader Cornelius Weiller Christoph P Kaller Google Scholar Sandra Loosli Johanna Posth Benjamin Rahm Josef M Unterrainer Irina Mader Cornelius Weiller Christoph P Kaller PubMed Sandra Loosli Johanna Posth Benjamin Rahm Josef M Unterrainer Irina Mader Cornelius Weiller Christoph P Kaller Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.