Julia Karbach

Making Working Memory Work A Meta-Analysis of Executive-Control and Working Memory Training in Older Adults

This meta-analysis examined the effects of process-based executive-function and working memory training (49 articles, 61 independent samples) in older adults (> 60 years). The interventions resulted in significant effects on performance on the trained task and near-transfer tasks; significant results were obtained for the net pretest-to-posttest gain relative to active and passive control groups and for the net effect at posttest relative to active and passive control groups. Far-transfer effects were smaller than near-transfer effects but were significant for the net pretest-to-posttest gain relative to passive control groups and for the net gain at posttest relative to both active and passive control groups. We detected marginally significant differences in training-induced improvements between working memory and executive-function training, but no differences between the training-induced improvements observed in older adults and younger adults, between the benefits associated with adaptive and nonadaptive training, or between the effects in active and passive control conditions. Gains did not vary with total training time.

Making Working Memory Work

This meta-analysis examined the effects of process-based executive-function and working memory training (49 articles, 61 independent samples) in older adults (> 60 years). The interventions resulted in significant effects on performance on the trained task and near-transfer tasks; significant results were obtained for the net pretest-to-posttest gain relative to active and passive control groups and for the net effect at posttest relative to active and passive control groups. Far-transfer effects were smaller than near-transfer effects but were significant for the net pretest-to-posttest gain relative to passive control groups and for the net gain at posttest relative to both active and passive control groups. We detected marginally significant differences in training-induced improvements between working memory and executive-function training, but no differences between the training-induced improvements observed in older adults and younger adults, between the benefits associated with adaptive and nonadaptive training, or between the effects in active and passive control conditions. Gains did not vary with total training time.

Verbal self-instructions in task switching: a compensatory tool for action-control deficits in childhood and old age?

This study examined the influence of verbal self-instructions on age differences in task switching. Task-switching ability, measured as the difference between performance in single-task blocks and in mixed-task blocks in which participants switch between two tasks (mixing costs), increases during childhood and decreases in old age. To measure the influence of language on task switching, we compared conditions in which participants either (a) named the next task to be performed (i.e. task-relevant verbalization), (b) verbalized words not related to the task at hand (i.e. task-irrelevant verbalization), or (c) did not verbalize (control condition). Results indicated that mixing costs were substantially reduced under task-relevant verbalization and increased under task-irrelevant verbalization. Moreover, age-related differences in mixing costs were increased when the use of inner speech was disrupted and were reduced when participants performed task-relevant verbalization. These findings suggest that verbal self-instructions are a useful tool for retrieving the next task goal and for reducing action-control deficits in younger children and older adults.

Working memory and executive functions: Effects of training on academic achievement.

The aim of this review is to illustrate the role of working memory and executive functions for scholastic achievement as an introduction to the question of whether and how working memory and executive control training may improve academic abilities. The review of current research showed limited but converging evidence for positive effects of process-based complex working-memory training on academic abilities, particularly in the domain of reading. These benefits occurred in children suffering from cognitive and academic deficits as well as in healthy students. Transfer of training to mathematical abilities seemed to be very limited and to depend on the training regime and the characteristics of the study sample. A core issue in training research is whether high- or low-achieving children benefit more from cognitive training. Individual differences in terms of training-related benefits suggested that process-based working memory and executive control training often induced compensation effects with larger benefits in low performing individuals. Finally, we discuss the effects of process-based training in relation to other types of interventions aimed at improving academic achievement.

Can Task-Switching Training Enhance Executive Control Functioning in Children with Attention Deficit/-Hyperactivity Disorder?

The key cognitive impairments of children with attention deficit/-hyperactivity disorder (ADHD) include executive control functions such as inhibitory control, task-switching, and working memory (WM). In this training study we examined whether task-switching training leads to improvements in these functions. Twenty children with combined type ADHD and stable methylphenidate medication performed a single-task and a task-switching training in a crossover training design. The children were randomly assigned to one of two groups. One group started with the single-task training and then performed the task-switching training and the other group vice versa. The effectiveness of the task-switching training was measured as performance improvements (relative to the single-task training) on a structurally similar but new switching task and on other executive control tasks measuring inhibitory control and verbal WM as well as on fluid intelligence (reasoning). The children in both groups showed improvements in task-switching, that is, a reduction of switching costs, but not in performing the single-tasks across four training sessions. Moreover, the task-switching training lead to selective enhancements in task-switching performance, that is, the reduction of task-switching costs was found to be larger after task-switching than after single-task training. Similar selective improvements were observed for inhibitory control and verbal WM, but not for reasoning. Results of this study suggest that task-switching training is an effective cognitive intervention that helps to enhance executive control functioning in children with ADHD.

Adaptive working-memory training benefits reading, but not mathematics in middle childhood

Working memory (WM) capacity is highly correlated with general cognitive ability and has proven to be an excellent predictor for academic success. Given that WM can be improved by training, our aim was to test whether WM training benefited academic abilities in elementary-school children. We examined 28 participants (mean age = 8.3 years, SD = 0.4) in a pretest-training-posttest-follow-up design. Over 14 training sessions, children either performed adaptive WM training (training group, n = 14) or nonadaptive low-level training (active control group, n = 14) on the same tasks. Pretest, posttest, and follow-up at 3 months after posttest included a neurocognitive test battery (WM, task switching, inhibition) and standardized tests for math and reading abilities. Adaptive WM training resulted in larger training gains than nonadaptive low-level training. The benefits induced by the adaptive training transferred to an untrained WM task and a standardized test for reading ability, but not to task switching, inhibition, or performance on a standardized math test. Transfer to the untrained WM task was maintained over 3 months. The analysis of individual differences revealed compensatory effects with larger gains in children with lower WM and reading scores at pretest. These training and transfer effects are discussed against the background of cognitive processing resulting from WM span training and the nature of the intervention.

Executive control training from middle childhood to adolescence

Executive functions (EFs) include a number of higher-level cognitive control abilities, such as cognitive flexibility, inhibition, and working memory, which are instrumental in supporting action control and the flexible adaptation changing environments. These control functions are supported by the prefrontal cortex and therefore develop rapidly across childhood and mature well into late adolescence. Given that executive control is a strong predictor for various life outcomes, such as academic achievement, socioeconomic status, and physical health, numerous training interventions have been designed to improve executive functioning across the lifespan, many of them targeting children and adolescents. Despite the increasing popularity of these trainings, their results are neither robust nor consistent, and the transferability of training-induced performance improvements to untrained tasks seems to be limited. In this review, we provide a selective overview of the developmental literature on process-based cognitive interventions by discussing (1) the concept and the development of EFs and their neural underpinnings, (2) the effects of different types of executive control training in normally developing children and adolescents, (3) individual differences in training-related performance gains as well as (4) the potential of cognitive training interventions for the application in clinical and educational contexts. Based on recent findings, we consider how transfer of process-based executive control trainings may be supported and how interventions may be tailored to the needs of specific age groups or populations.

Cognitive function in patients with decompensated heart failure: the Cognitive Impairment in Heart Failure (CogImpair‐HF) study

The objective of this study was to examine cognitive and psychological processes systematically in patients with decompensated chronic heart failure (CHF) and to document changes in cognitive function after compensation. Executive functions, episodic memory, and attention are impaired in patients with stable CHF, influencing health behaviour and disease management. Cognitive function and psychological co‐morbidities are associated with hospitalization, disability, and mortality.

Practice-related optimization and transfer of executive functions: a general review and a specific realization of their mechanisms in dual tasks

Improvements in performing demanding and complex task situations are typically related to the optimization of executive functions and efficient behavioral control. The present study systematizes and reviews the optimization of different executive function types: Shifting, Inhibition, Updating, and Dual tasking. In particular, we focus on optimisations of these functions with training and on transfer effects of related training skills to non-trained situations. The aim of the study’s empirical part (see also Appendix) was to investigate the specific mechanisms of executive functions in the context of Dual tasking, leading to improved dual-task performance after practice. More specifically, we tested the Efficient Task Instantiation (ETI) model that includes specific assumptions regarding practice-related improvements of executive task coordination skills: Dual-task performance is improved with practice because of an efficient and conjoint instantiation of sets of relevant task information in working memory at the onset of a dual task. According to our knowledge, the ETI model is one of the first that allows illustrating the contribution of cognitive mechanisms underlying practice-related improvements in performing dual tasks and the impact of task coordination skills on this performance.

Developmental Changes In Switching Between Mental Task Sets: The Influence Of Verbal Labeling In Childhood

Age-related changes in the use of verbal processes for the efficient switching between tasks were investigated in 5-year-old children (N = 32, M age = 5.9 years) and 9-year-old children (N = 32, M age = 9.4 years). Task switching was assessed by means of a cued switching paradigm to examine two switching components: (a) to maintain and select and (b) to switch between task sets. The aim of this study is to determine (a) developmental changes in both switching components during childhood, (b) whether age-related changes in these components are influenced by verbalizations in terms of “thinking aloud” (Ericsson & Simon, 1993) during task performance, and (c) age changes in the content of the self-verbalizations. Results show an age-related impairment of the 5-year-old group on the level of task-set maintenance and selection. Children mainly verbalized the response labels. However, whereas 5-year-olds more often labeled their perceptions (Zelazo, 1999), 9-year-olds used language to maintain the currently relevant task set. Both age groups relied on the same verbal strategy facilitating task switching, supporting the view that language can be used to plan and guide actions (Luria, 1969).