scholarly journals A hierarchy of functional states in working memory

Author(s):  
Paul S. Muhle-Karbe ◽  
Nicholas E. Myers ◽  
Mark G. Stokes

AbstractExtensive research has examined how information is maintained in working memory (WM), but it remains unknown how WM is used to guide behaviour. We addressed this question by combining human electrophysiology with pattern analyses, cognitive modelling, and a task requiring maintenance of two WM items and priority shifts between them. This enabled us to discern neural states coding for immediately and prospectively task-relevant items, and to examine their contribution to WM-based decisions. We identified two qualitatively different states: a functionally active state encoded only immediately task-relevant items and closely tracked the quality of evidence integration on the current trial. In contrast, prospectively relevant items were encoded in a functionally latent state that did not engage with ongoing processing but tracked memory precision at longer time scales. These results delineate a hierarchy of functional states, whereby latent memories supporting general maintenance are transformed into active decision-circuits to guide flexible behaviour.

2021 ◽  
Author(s):  
Alaa Abd-alrazaq ◽  
Dari Alhuwail ◽  
Eiman Al-Jafar ◽  
Arfan Ahmed ◽  
Shuja Mohd Reagu ◽  
...  

BACKGROUND Memory, one of the main cognitive functions, is known to decline by age. Serious games have been used for improving memory among the elderly. The effectiveness of serious games in improving memory has been investigated by several systematic reviews; however, they are limited by design and methodological weaknesses. OBJECTIVE This study aims to assess the effectiveness of serious games in improving memory among the elderly with cognitive impairment. METHODS A systematic review of randomized controlled trials (RCTs) was carried out. The search sources included searching 8 databases, screening reference lists of the included studies and relevant reviews, and checking studies that cited the included studies. Two reviewers independently carried out the study selection, data extraction, risk of bias assessment, and quality of evidence appraisal. Extracted data were synthesized using a narrative approach and a statistical approach (i.e., meta-analysis), as appropriate. RESULTS Out of 466 citations retrieved, 18 studies met the eligibility criteria of this review. Of those, 15 RCTs were eventually included in 10 meta-analyses. We found that serious games are more effective than no or passive interventions in improving non-verbal memory (P=0.002) and working memory (P=0.02), but not verbal memory (P=0.13). The review also showed that serious games are more effective than conventional exercises in improving verbal memory (P=0.004), but not for non-verbal memory (P=0.12) and working memory (P=0.49). Serious games were as effective as conventional cognitive activities in improving verbal memory (P=0.07), non-verbal memory (P=0.94), and working memory (P=0.08) among the elderly with cognitive impairment. Lastly, the effect of adaptive serious games on working memory was comparable to non-adaptive serious games (P=0.08). CONCLUSIONS Serious games have the potential to improve verbal, non-verbal, and working memory among elderly people with cognitive impairment. However, our findings should be interpreted cautiously given that most meta-analyses were based on a few studies (≤3) and judged to have a low quality of evidence. Therefore, serious games should be offered as supplemental to existing proven and safe interventions, rather than a complete substitute until further, more robust evidence is available. Future studies should investigate the short and long-term effects of serious games on memory and other cognitive abilities among people from different age groups with or without cognitive impairment.


2017 ◽  
Vol 10 (5) ◽  
pp. 229-239 ◽  
Author(s):  
Gang-Zhu Xu ◽  
Yan-Feng Li ◽  
Mao-De Wang ◽  
Dong-Yuan Cao

Background: We systematically reviewed randomized controlled trials (RCTs) of complementary and alternative interventions for fatigue after traumatic brain injury (TBI). Methods: We searched multiple online sources including ClinicalTrials.gov, the Cochrane Library database, MEDLINE, CINAHL, Embase, the Web of Science, AMED, PsychINFO, Toxline, ProQuest Digital Dissertations, PEDro, PsycBite, and the World Health Organization (WHO) trial registry, in addition to hand searching of grey literature. The methodological quality of each included study was assessed using the Jadad scale, and the quality of evidence was evaluated using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system. A descriptive review was performed. Results: Ten RCTs of interventions for post-TBI fatigue (PTBIF) that included 10 types of complementary and alternative interventions were assessed in our study. There were four types of physical interventions including aquatic physical activity, fitness-center-based exercise, Tai Chi, and aerobic training. The three types of cognitive and behavioral interventions (CBIs) were cognitive behavioral therapy (CBT), mindfulness-based stress reduction (MBSR), and computerized working-memory training. The Flexyx Neurotherapy System (FNS) and cranial electrotherapy were the two types of biofeedback therapy, and finally, one type of light therapy was included. Although the four types of intervention included aquatic physical activity, MBSR, computerized working-memory training and blue-light therapy showed unequivocally effective results, the quality of evidence was low/very low according to the GRADE system. Conclusions: The present systematic review of existing RCTs suggests that aquatic physical activity, MBSR, computerized working-memory training, and blue-light therapy may be beneficial treatments for PTBIF. Due to the many flaws and limitations in these studies, further controlled trials using these interventions for PTBIF are necessary.


2011 ◽  
Vol 7 (1) ◽  
pp. 8-14
Author(s):  
Robert Moore ◽  
Susan Gordon-Hickey

The purpose of this article is to propose 4 dimensions for consideration in hearing aid fittings and 4 tests to evaluate those dimensions. The 4 dimensions and tests are (a) working memory, evaluated by the Revised Speech Perception in Noise test (Bilger, Nuetzel, & Rabinowitz, 1984); (b) performance in noise, evaluated by the Quick Speech in Noise test (QSIN; Killion, Niquette, Gudmundsen, Revit, & Banerjee, 2004); (c) acceptance of noise, evaluated by the Acceptable Noise Level test (ANL; Nabelek, Tucker, & Letowski, 1991); and (d) performance versus perception, evaluated by the Perceptual–Performance test (PPT; Saunders & Cienkowski, 2002). The authors discuss the 4 dimensions and tests in the context of improving the quality of hearing aid fittings.


2013 ◽  
Author(s):  
Kimberly D. Becker ◽  
Dana Darney ◽  
Celene Domitrovich ◽  
Catherine Bradshaw ◽  
Nicholas S. Ialongo

2019 ◽  
Author(s):  
Ashley DiPuma ◽  
Kelly Rivera ◽  
Edward Ester

Working memory (WM) performance can be improved by an informative cue presented during storage. This effect, termed a retro-cue benefit, can be used to explore mechanisms of attentional prioritization in WM. Directing attention to a single item stored in memory is known to increase memory precision while decreasing the likelihood of incorrect item reports and random guesses, but it is unclear whether similar benefits manifest when participants direct attention to multiple items stored in memory. We tested this possibility by quantifying memory performance when participants were cued to prioritize one or two items stored in working memory. Consistent with prior work, cueing participants to prioritize a single memory item yielded higher recall precision, fewer swap errors, and fewer guesses relative to a neutral cue condition. Conversely, cueing participants to prioritize two memory items yielded fewer swap errors relative to a neutral condition, but no differences in recall precision or guess rates. Although swap rates were less likely during the cue-two vs. neutral conditions, planned comparisons revealed that when participants made swap errors during cue-two trials they were far more likely to confuse two prioritized stimuli than they were to confuse a prioritized stimulus vs. a non-prioritized stimulus. Our results suggest that it is possible to prioritize multiple items stored in memory, with the caveat that doing so may increase the probability of confusing prioritized items.


2021 ◽  
Vol 10 (7) ◽  
pp. 1478
Author(s):  
Alexandra Voinescu ◽  
Jie Sui ◽  
Danaë Stanton Fraser

Neurological disorders are a leading cause of death and disability worldwide. Can virtual reality (VR) based intervention, a novel technology-driven change of paradigm in rehabilitation, reduce impairments, activity limitations, and participation restrictions? This question is directly addressed here for the first time using an umbrella review that assessed the effectiveness and quality of evidence of VR interventions in the physical and cognitive rehabilitation of patients with stroke, traumatic brain injury and cerebral palsy, identified factors that can enhance rehabilitation outcomes and addressed safety concerns. Forty-one meta-analyses were included. The data synthesis found mostly low- or very low-quality evidence that supports the effectiveness of VR interventions. Only a limited number of comparisons were rated as having moderate and high quality of evidence, but overall, results highlight potential benefits of VR for improving the ambulation function of children with cerebral palsy, mobility, balance, upper limb function, and body structure/function and activity of people with stroke, and upper limb function of people with acquired brain injury. Customization of VR systems is one important factor linked with improved outcomes. Most studies do not address safety concerns, as only nine reviews reported adverse effects. The results provide critical recommendations for the design and implementation of future VR programs, trials and systematic reviews, including the need for high quality randomized controlled trials to test principles and mechanisms, in primary studies and in meta-analyses, in order to formulate evidence-based guidelines for designing VR-based rehabilitation interventions.


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