Genetic Modulation of Training and Transfer in Older Adults: BDNF ValMet Polymorphism is Associated with Wider Useful Field of View

Cognitive Computerized Training for Older Adults and Patients with Neurological Disorders: Do the Amount and Training Modality Count? An Umbrella Meta-Regression Analysis

Numerous applications have been created to train cognition and challenge the brain, a process known as computerized cognitive training (CCT). Despite potential positive results, important questions remain unresolved: the appropriate training duration, the efficacy of CCT depending on its type (commercial or developed in-house for the rehabilitation of specific patients) and delivery mode (at-home or on-site), and the patients most likely to benefit such intervention. This study aims to perform an umbrella meta-analysis and meta-regression to determine if the type of CCT, the delivery mode, the amount of training, and participants' age at inclusion influence the improvement of the cognitive function. To do so, we performed a umbrella meta-analysis. One hundred studies were included in this analysis representing 6407 participants. Statistical improvements were found for the different conditions after the training. We do not find statistical difference between the type of intervention or the delivery mode. No dose-response relationship between the total amount of training and the improvement of cognitive functions was found. CCT is effective in improving cognitive function in patients suffering from neurological conditions and in healthy aging. There is therefore an urgent need for health care systems to recognize its therapeutic potential and to evaluate at a larger scale their integration into the clinical pipeline as preventive and rehabilitation tool.

A Review of Working Memory Training in the Management of Attention Deficit Hyperactivity Disorder

Attention deficit hyperactivity disorder (ADHD) is one of the most common neurodevelopmental disorders among children. Working memory deficits underlie many of the behavioural symptoms of ADHD. Alongside psychostimulant medications, strategies to improve working memory may play an important adjuvant role in the management of ADHD. In this study, we review the role of working memory deficits in ADHD, the evidence surrounding working memory training strategies in the management of the condition, and the factors affecting the success of these strategies in alleviating ADHD symptoms. More specifically, we review several non-pharmacological interventions that target working memory deficits in ADHD, with special emphasis on cognitive working memory training. We conclude that the development of evidence-based interventions such as computerised cognitive training (CCT) could provide an alternative or adjunct to the use of psychostimulants, especially in cases where side effects are a major issue.

Cognitive Deficits in Schizophrenia: Understanding the Biological Correlates and Remediation Strategies

Cognitive deficits are one of the core symptoms of schizophrenia that evolve during the course of schizophrenia, after being originated even before the onset of illness. Existing pharmacological and biological treatment modalities fall short to meet the needs to improve the cognitive symptoms; hence, various cognitive remediation strategies have been adopted to address these deficits. Research evidences suggest that cognitive remediation measures improve the functioning, limit disability bettering the quality of life. The functional outcomes of cognitive remediation in schizophrenia are resultant of neurobiological changes in specific brain areas. Recent years witnessed significant innovations in cognitive remediation strategies in schizophrenia. This comprehensive review highlights the biological correlates of cognitive deficits in schizophrenia and the remedial measures with evidence base.

Urinary brain-derived neurotrophic factor as a biomarker of executive functioning

BACKGROUND/AIMS

Neurotrophins such as brain-derived neurotrophic factor (BDNF) are vital for neuronal survival and adaptive plasticity. With high BDNF gene expression in the prefrontal cortex, BDNF is a potential regulatory factor for building and maintaining cognitive reserves. Recent studies suggest that individual differences in executive functioning, a broad cognitive domain reliant upon frontal lobe structure and function, are governed in part by variance in BDNF polymorphisms. However, as neurogenetic data are not necessarily indicative of in vivo neurochemistry, this study examines the relationship between executive functioning and the neurotransmitter by measuring peripheral BDNF levels.

METHODS

Fifty-two healthy young adults completed a battery of standardized executive function tests. BDNF levels, adjusted for creatinine, were quantified with enzyme-linked immunosorbent assay of urine samples taken at the time of testing.

RESULTS

BDNF concentration was positively associated with cognitive flexibility but had no relationship with working memory, abstract reasoning/planning, self-monitoring/response inhibition, or fluency.

CONCLUSIONS

These results individuate cognitive flexibility as the specific facet of executive functioning associated with in vivo BDNF levels. This study also validates urinary BDNF as a peripheral biomarker of cognition in healthy adults.

Computerized cognitive training in cognitively healthy older adults: a systematic review and meta-analysis of effect modifiers

BACKGROUND

New effective interventions to attenuate age-related cognitive decline are a global priority. Computerized cognitive training (CCT) is believed to be safe and can be inexpensive, but neither its efficacy in enhancing cognitive performance in healthy older adults nor the impact of design factors on such efficacy has been systematically analyzed. Our aim therefore was to quantitatively assess whether CCT programs can enhance cognition in healthy older adults, discriminate responsive from nonresponsive cognitive domains, and identify the most salient design factors.

METHODS AND FINDINGS

We systematically searched Medline, Embase, and PsycINFO for relevant studies from the databases' inception to 9 July 2014. Eligible studies were randomized controlled trials investigating the effects of ≥ 4 h of CCT on performance in neuropsychological tests in older adults without dementia or other cognitive impairment. Fifty-two studies encompassing 4,885 participants were eligible. Intervention designs varied considerably, but after removal of one outlier, heterogeneity across studies was small (I(2) = 29.92%). There was no systematic evidence of publication bias. The overall effect size (Hedges' g, random effects model) for CCT versus control was small and statistically significant, g = 0.22 (95% CI 0.15 to 0.29). Small to moderate effect sizes were found for nonverbal memory, g = 0.24 (95% CI 0.09 to 0.38); verbal memory, g = 0.08 (95% CI 0.01 to 0.15); working memory (WM), g = 0.22 (95% CI 0.09 to 0.35); processing speed, g = 0.31 (95% CI 0.11 to 0.50); and visuospatial skills, g = 0.30 (95% CI 0.07 to 0.54). No significant effects were found for executive functions and attention. Moderator analyses revealed that home-based administration was ineffective compared to group-based training, and that more than three training sessions per week was ineffective versus three or fewer. There was no evidence for the effectiveness of WM training, and only weak evidence for sessions less than 30 min. These results are limited to healthy older adults, and do not address the durability of training effects.

CONCLUSIONS

CCT is modestly effective at improving cognitive performance in healthy older adults, but efficacy varies across cognitive domains and is largely determined by design choices. Unsupervised at-home training and training more than three times per week are specifically ineffective. Further research is required to enhance efficacy of the intervention. Please see later in the article for the Editors' Summary.

Cognitive training in mental disorders: update and future directions

OBJECTIVE

This article reviews the conceptual basis, definitions, and evolution of cognitive training approaches for the treatment of mental disorders.

METHOD

The authors review the current state of the knowledge on cognitive training in psychiatric illnesses, and its neural and behavioral targets, and summarize the factors that appear to relate to a successful response, including learner characteristics that influence clinical outcome. They also discuss methodological issues relevant to the development and testing of cognitive training approaches, with the goal of creating maximally efficient and effective approaches to training. Finally, they identify gaps in existing knowledge and outline key research directions for the future.

RESULTS

While much of the early research has been conducted in schizophrenia, cognitive training has more recently been applied to a widening range of neuropsychiatric illnesses, including attention deficit hyperactivity disorder, mood disorders, and substance use disorders. Cognitive training harnesses the inherent neuroplastic capacities of the brain, targeting neural system function across psychiatric disorders, thus improving the cognitive processes that play a role in emotion regulation, clinical symptoms, and adaptive community functioning.

CONCLUSIONS

Cognitive training offers considerable promise, especially given the limited efficacy of pharmacological interventions in ameliorating cognitive deficits. However, more research is needed to understand the mechanisms underlying cognitive training, predictors of response, generalization and real-world applicability, and approaches to dissemination in practice settings.

Effects and mechanisms of working memory training: a review

Can cognitive abilities such as reasoning be improved through working memory training? This question is still highly controversial, with prior studies providing contradictory findings. The lack of theory-driven, systematic approaches and (occasionally serious) methodological shortcomings complicates this debate even more. This review suggests two general mechanisms mediating transfer effects that are (or are not) observed after working memory training: enhanced working memory capacity, enabling people to hold more items in working memory than before training, or enhanced efficiency using the working memory capacity available (e.g., using chunking strategies to remember more items correctly). We then highlight multiple factors that could influence these mechanisms of transfer and thus the success of training interventions. These factors include (1) the nature of the training regime (i.e., intensity, duration, and adaptivity of the training tasks) and, with it, the magnitude of improvements during training, and (2) individual differences in age, cognitive abilities, biological factors, and motivational and personality factors. Finally, we summarize the findings revealed by existing training studies for each of these factors, and thereby present a roadmap for accumulating further empirical evidence regarding the efficacy of working memory training in a systematic way.

Are the effects of response inhibition on gambling long-lasting?

A recent study has shown that short-term training in response inhibition can make people more cautious for up to two hours when making decisions. However, the longevity of such training effects is unclear. In this study we tested whether training in the stop-signal paradigm reduces risky gambling when the training and gambling task are separated by 24 hours. Two independent experiments revealed that the aftereffects of stop-signal training are negligible after 24 hours. This was supported by Bayes factors that provided strong support for the null hypothesis. These findings indicate the need to better optimise the parameters of inhibition training to achieve clinical efficacy, potentially by strengthening automatic associations between specific stimuli and stopping.

Online games training aging brains: limited transfer to cognitive control functions

The prevalence of age-related cognitive decline will increase due to graying of the global population. The goal of the present study was to test whether playing online cognitive training games can improve cognitive control (CC) in healthy older adults. Fifty-four older adults (age 60–77) played five different cognitive training games online for 30 min a day over a period of seven weeks (game group). Another group of 20 older adults (age 61–73) instead answered quiz questions about documentaries online (documentary group). Transfer was assessed by means of a cognitive test battery administered before and after the intervention. The test battery included measures of working memory updating, set shifting, response inhibition, attention, and inductive reasoning. Compared with the documentary group, the game group showed larger improvement of inhibition (Stop-Signal task) and inductive reasoning (Raven-SPM), whereas the documentary group showed more improvement in selective attention (UFoV-3). These effects qualify as transfer effects, because response inhibition, inductive reasoning and selective attention were not targeted by the interventions. However, because seven other indicators of CC did not show benefits of game training and some of those that did suffered from potential baseline differences, the study as a whole provides only modest support for the potential of videogame training to improve CC in healthy older adults.