Poor Working Memory Research Articles

Frontal Glutamate and γ-Aminobutyric Acid Levels and Their Associations With Mismatch Negativity and Digit Sequencing Task Performance in Schizophrenia.

Auditory mismatch negativity (MMN) is a biomarker for schizophrenia thought to reflect glutamatergic N-methyl-d-aspartate receptor function and excitatory-inhibitory neurotransmission balance. However, the association of glutamate level with MMN has not been directly examined in patients with schizophrenia, to our knowledge. To investigate the contributions of glutamate and γ-aminobutyric acid (GABA) to MMN and digit sequencing task (DST) performance, an assessment of verbal working memory, in schizophrenia. Fifty-three control participants from the community and 45 persons with schizophrenia from outpatient clinics completed an electroencephalographic session for MMN, magnetic resonance spectroscopy for glutamate and GABA, and a DST. The study dates were July 2011 to May 2014, and the dates of our analysis were May 2014 to August 2015. Glutamate, GABA, the ratio of glutamine to glutamate, MMN amplitude, and DST. Structural equation modeling was used to test the effects of neurochemistry and MMN amplitude on DST performance. The 45 persons with schizophrenia were a mean (SD) of 37.7 (12.8) years and the control participants were 37.1 (13.1) years. The schizophrenia group had a mean (SD) of 14.7 (12.1) years of illness. Mismatch negativity amplitude (F = 4.39, P = .04) and glutamate (F = 9.69, P = .002) were reduced in the schizophrenia group. Smaller MMN amplitude was significantly associated with lower GABA level (P = .008), lower glutamate level (P = .05), and higher ratio of glutamine to glutamate (P = .003). Reduced MMN amplitude was linked to poor verbal working memory in schizophrenia (P = .002). Modeling revealed that a proxy of glutamatergic function, indexed by the ratio of glutamine to glutamate, influenced a path from the ratio of glutamine to glutamate to MMN to verbal working memory (P = .38 [root-mean-square error of approximation, P < .001] by χ2 test), supporting the contention that MMN serves as an intermediate biomarker linking glutamatergic function to DST performance in schizophrenia. The role of glutamate and GABA in MMN and verbal working memory deficits in schizophrenia has been frequently debated. These data provide in vivo evidence that support glutamatergic and GABAergic regulation of MMN and verbal working memory function in schizophrenia.

Frontal Metabolite Concentration Deficits in Opiate Dependence Relate to Substance Use, Cognition, and Self-Regulation.

ObjectiveProton magnetic resonance spectroscopy (1H MRS) in opiate dependence showed abnormalities in neuronal viability and glutamate concentration in the anterior cingulate cortex (ACC). Metabolite levels in dorsolateral prefrontal cortex (DLPFC) or orbitofrontal cortex (OFC) and their neuropsychological correlates have not been investigated in opiate dependence.MethodsSingle-volume proton MRS at 4 Tesla and neuropsychological testing were conducted in 21 opiate-dependent individuals (OD) on buprenorphine maintenance therapy. Results were compared to 28 controls (CON) and 35 alcohol-dependent individuals (ALC), commonly investigated treatment-seekers providing context for OD evaluation. Metabolite concentrations were measured from ACC, DLPFC, OFC and parieto-occipital cortical (POC) regions.ResultsCompared to CON, OD had lower concentrations of N-acetylaspartate (NAA), glutamate (Glu), creatine +phosphocreatine (Cr) and myo-Inositol (mI) in the DLPFC and lower NAA, Cr, and mI in the ACC. OD, ALC, and CON were equivalent on metabolite levels in the POC and γ-aminobutyric acid (GABA) concentration did not differ between groups in any region. In OD, prefrontal metabolite deficits in ACC Glu as well as DLPFC NAA and choline containing metabolites (Cho) correlated with poorer working memory, executive and visuospatial functioning; metabolite deficits in DLPFC Glu and ACC GABA and Cr correlated with substance use measures. In the OFC of OD, Glu and choline-containing metabolites were elevated and lower Cr concentration related to higher nonplanning impulsivity. Compared to 3 week abstinent ALC, OD had significant DLPFC metabolite deficits.ConclusionThe anterior frontal metabolite profile of OD differed significantly from that of CON and ALC. The frontal lobe metabolite abnormalities in OD and their neuropsychological correlates may play a role in treatment outcome and could be explored as specific targets for improved OD treatment.

Distinguishing between impairments of working memory and inhibitory control in cases of early dementia

Dementia (most notably, Alzheimer's Disease) is often associated with impairments of both working memory and inhibitory control. However, it is unclear whether these are functionally distinct impairments. We addressed the issue of whether working memory and inhibitory control can be dissociated, using data from a sample of patients who were recruited in a longitudinal study (Crawford et al., 2013, 2015). The first case revealed a preserved working memory capacity together with poor inhibitory control in the anti-saccade task. A longitudinal follow-up revealed that the defective inhibitory control emerged 12-months before the dementia was evident on the mini-mental state examination assessment. A second case revealed a poor working memory together with a well-preserved level of inhibitory control. The dissociation of working memory and inhibitory control was confirmed statistically in 7 additional cases. These findings yield converging evidence that working memory and inhibitory control are distinct cognitive operations and challenges the Kimberg and Farah (2000) cognitive model of working memory.

The nature of anhedonia and avolition in patients with first-episode schizophrenia.

Patients with schizophrenia have intact ability to experience emotion, but empirical evidence suggests that they fail to translate emotional salience into effortful behaviour. Previous research in patients with chronic schizophrenia suggests that working memory is important in integrating emotion and behaviour. This study aimed to examine avolition and anhedonia in patients with first-episode schizophrenia and clarify the role of working memory in emotion-behaviour coupling. We recruited 72 participants with first-episode schizophrenia and 61 healthy controls, and used a validated emotion-inducing behavioural paradigm to measure participants' affective experiences and how experienced emotion coupled with behaviour. Participants were given the opportunity to expend effort to increase or decrease their exposure to emotion-inducing photographs. Participants with schizophrenia having poor working memory were compared with those with intact working memory in their liking and emotion-behaviour coupling. Patients with first-episode schizophrenia experienced intact 'in-the-moment' emotion, but their emotion was less predictive of the effort expended, compared with controls. The emotion-behaviour coupling was significantly weaker in patients with schizophrenia with poor working memory than in those with intact working memory. However, compared with controls, patients with intact working also showed substantial emotion-behaviour decoupling. Our findings provide strong evidence for emotion-behaviour decoupling in first-episode schizophrenia. Although working memory deficits contribute to defective translation of liking into effortful behaviour, schizophrenia alone affects emotion-behaviour coupling.

A Profile of Working Memory Ability in Poor Readers

ObjectiveThis study aimed to provide a comprehensive working memory profile of a group of children with established poor reading ability.MethodsParticipants included a group of established “poor readers” and a group of age‐ and gender‐matched controls with typically developing reading ability. The participants completed a comprehensive battery of assessments examining four components of working memory—the central executive, phonological loop, visuospatial sketchpad, and episodic buffer.ResultsAs predicted, the poor reading group scored significantly lower than the typically developing reading group on measures of the phonological loop and central executive. There were no significant differences between the two groups on measures of the visuospatial sketchpad or episodic buffer. Contrary to predictions, a subgroup of poor readers with poor visuospatial working memory was not found, further highlighting the inconsistent findings in this area of working memory.ConclusionsThe results provide support for past research findings of deficits in the phonological loop and central executive of poor readers. The finding of typical episodic buffer functioning demonstrates the potential to draw on this relative strength in implementing interventions with poor readers. This implicates the importance of increasing awareness of specific working memory deficits in poor readers, and may guide future research into more effective teaching strategies and interventions for this population.

Association between Serum Copper Status and Working Memory in Schoolchildren.

Trace elements such as copper are essential micronutrients. Traditionally, copper has been studied in the context of micronutrient deficiencies. Recent studies in both animals and humans, however, have revealed that elevated blood copper can also have adverse effects on cognitive function since free copper can cross the blood-brain barrier and subsequently impose oxidative stress to neuronal cells. However, most of these human studies were conducted in adult populations with and without cognitive decline, and there are few studies on the effect of excess copper on cognitive function in children. This project seeks to look at the effects of elevated copper levels on cognitive development in a population of school age children (ages 10–14 years with mean age of 12.03 years and standard deviation (SD) of 0.44) from Jintan, China. Briefly, serum copper levels and working memory test scores were collected from a sample of 826 children with a mean serum copper level of 98.10 (SD 0.75). Copper level was considered as a categorical variable (taking the first group as those with as ≤84.3 μg/dL, the second group as >84.3 and ≤110.4 μg/dL, and the third group as >110.4 μg/dL with the cut-off values defined by the first and third quartiles of the sample). Results showed a significant association between high copper levels (>110.4 μg/dL) and poorer working memory in boys but this association was not seen in lower copper levels in either sex. These results suggests that in school age children, like in adults, elevated copper levels have the potential to adversely affect cognition.

Apolipoprotein E-ε4 deficiency and cognitive function in hepatitis C virus-infected patients.

Hepatitis C virus (HCV) causes not only liver damage in certain patients but can also lead to neuropsychiatric symptoms. Previous studies have shown that the type 4 allele of the gene for apolipoprotein E (APOE) is strongly protective against HCV-induced damage in liver. In this study, we have investigated the possibility that APOE genotype is involved in the action of HCV in brain. One hundred HCV-infected patients with mild liver disease underwent a neurological examination and a comprehensive psychometric testing of attention and memory function. In addition, patients completed questionnaires for the assessment of fatigue, health-related quality of life and mood disturbances. Apolipoprotein E gene genotyping was carried out on saliva using buccal swabs. The APOE-ε4 allele frequency was significantly lower in patients with an impairment of working memory, compared to those with a normal working memory test result (P = 0.003). A lower APOE-ε4 allele frequency was also observed in patients with definitely altered attention ability (P = 0.008), but here, the P-value missed the level of significance after application of the Bonferroni correction. Our data suggest that the APOE-ε4 allele is protective against attention deficit and especially against poor working memory in HCV-infected subjects with mild liver disease. Considering the role of apolipoprotein E in the life cycle of the virus, the findings shed interesting new light upon possible pathomechanisms behind the development of neuropsychiatric symptoms in hepatitis C infection.

Prenatal and childhood polybrominated diphenyl ether (PBDE) exposure and attention and executive function at 9–12 years of age

ObjectiveCalifornia children's exposures to polybrominated diphenyl ether flame retardants (PBDEs) are among the highest measured worldwide. We previously reported associations for prenatal and childhood PBDE exposures with decrements in attention, processing speed, fine motor coordination, and cognition in children at ages 5 and 7years. Here, we investigate associations of PBDEs with attention and executive function at ages 9 to 12years in the expanded CHAMACOS cohort. MethodsWe measured PBDEs in prenatal and child age 9year serum samples for families enrolled in the study since pregnancy (“CHAM1”, N=321). In a subsequent cohort for which families were enrolled at child age 9 (“CHAM2”, N=301), we measured PBDEs in maternal and child samples collected at child age 9, and used predictive modeling to estimate prenatal exposure levels. We examined associations of measured and estimated PBDE concentrations on children's attention and executive functioning at ages 9, 10½, and 12years. ResultsGeometric means for prenatal and childhood ΣPBDE levels (sum of PBDE-47, -99, -100, -153) for the expanded CHAMACOS cohort were 26.3 and 63.2ng/g lipid, respectively, and did not differ significantly between CHAM1 and CHAM2 families. We found consistent associations of prenatal exposure to PBDEs with poorer attention and executive function, measured with parent report and direct neuropsychological testing of the child. For example, using GEE models of repeated outcome measures at ages 9 and 12, a 10-fold increase in prenatal ΣPBDE was associated with poorer response consistency on the Conners' Continuous Performance Test II (β=2.9; 95% CI: 0.9, 4.8) and poorer working memory on the Behavioral Rating Inventory of Executive Function (β=2.5; 95% CI: 0.5, 4.4). Child age 9 ΣPBDE levels were associated with poorer parent-reported attention and executive function for girls but not boys. ConclusionsOur results suggest that the prefrontal cortex may be a potential target for PBDE exposure and add to a growing literature showing that these ubiquitous toxicants may adversely affect neurodevelopment.

Frontal lobe dysfunctions in patients with juvenile myoclonic epilepsy

Juvenile myoclonic epilepsy (JME) is a common form of idiopathic generalized epilepsy. Behavioral and cognitive problems are frequently observed in JME. Although the underlying mechanisms are still unknown, recent neuropsychological and neuroimaging studies provide strong evidence for frontal lobe dysfunction. Neuropsychological studies have shown JME patients to be impaired in a number of executive functions such as concept formation, abstract reasoning, mental flexibility, and cognitive speed and planning. They scored below average on measures of attention, immediate verbal memory, working memory, and verbal fluency. The patients with JME performed worse than the group with temporal lobe epilepsy on some frontal tasks. Some specific personality features, such as unreliability and emotional instability, poor social adjustment, high rates of anxiety, mood disorders, phobias and somatization disorders seen in patients with JME have also been described in patients with frontal lobe-lesions. Quantitative magnetic resonance imaging studies have shown regional, frontal cortical and thalamic grey matter abnormalities. These findings support the pathophysiological concept of functional abnormalities in the thalamo-cortical circuit in JME. The additional impact of interictal epileptiform electroencephalography activity on cognitive functions was suggested. Poor working memory and impaired executive and motor performance in JME patients may also be attributed to altered dopamine signaling in the striatum and frontal lobes. JME may be a non-uniform condition. Different genetic and pathophysiologic mechanisms could underlie the clinically observed differences in prognosis, cognitive functioning, personality traits, and frontal lobe deficits.

Working Memory Functioning in Children With Poor Mathematical Skills

Previous research on working memory (WM) in children with poor mathematical skills has yielded heterogeneous results, possibly due to inconsistent consideration of the IQ–achievement discrepancy and additional reading and spelling difficulties. To examine the impact of both, the WM of 68 average-achieving and 68 low-achieving third-graders in mathematics was assessed. Preliminary analyses showed that poor mathematical skills were associated with poor WM. Afterwards, children with isolated mathematical difficulties were separated from those with additional reading and spelling difficulties. Half of each group fulfilled the IQ–achievement discrepancy, resulting in a 2 (additional reading and spelling difficulties: yes/no) by 2 (IQ–achievement discrepancy: yes/no) factorial design. Analyses revealed that not fulfilling the IQ–achievement discrepancy was associated with poor visual WM, whereas additional reading and spelling difficulties were associated with poor central executive functioning in children fulfilling the IQ–achievement discrepancy. Therefore, WM in children with poor mathematical skills differs according to the IQ–achievement discrepancy and additional reading and/or spelling difficulties.

Association between sleep and working memory in children with ADHD: a cross-sectional study

Objective/BackgroundThis study aimed to examine the relationship between sleep problems and working memory in children aged 5–13 years with attention-deficit/hyperactivity disorder (ADHD). Patients/MethodsChildren with ADHD were recruited into a randomized controlled trial from 21 paediatric practices in VIC, Australia. Cross-sectional data for intervention and control children were pooled at 6 months post randomization for the current analyses (n = 189). Children who met the Diagnostic Statistical Manual of Mental Disorders, 4th Edition (DSM-IV) criteria for ADHD and had a parent-reported moderate/severe sleep problem that fulfilled diagnostic criteria for a behavioural sleep disorder were recruited into the study. Sleep was assessed by detailed parent (Children's Sleep Habits Questionnaire) and self-reports (Self-Sleep Report). Working memory was measured using the Working Memory Test Battery for Children (low and very low working memory defined as <25th and <10th percentiles, respectively). Analyses were adjusted for child age and gender, internalizing and externalizing comorbidities, and socio-economic status. ResultsSelf-reported sleep problem severity was associated with poorer working memory; for each standard deviation increase in self-reported sleep problems, working memory scores decreased by −3.8 points (95% confidence interval (CI): −6.7, −0.8; p = 0.01). There was some evidence that self-reported sleep problems were associated with low (p = 0.06) and very low working memory (p = 0.01). There was minimal evidence that parent-reported sleep problems were associated with poorer working memory with the exception of bedtime resistance problems. ConclusionsBehavioural sleep problems and working memory are associated in children with ADHD, particularly when sleep is assessed by self-report.

Same clock, different time read-out: Spontaneous brain oscillations and their relationship to deficient coding of cognitive content

Neuronal oscillations provide an efficient means of communication, fostering functional neural states supporting action and reaction. High in the action hierarchy, cognitive abilities are severely compromised in neuropsychiatric disease such as schizophrenia. Current thinking highlights a clocking mechanism provided by the phase of an ongoing slow oscillation that offers a temporal frame for coding of perceptual and computational elements. Yet unclear is whether and how a dysregulated clocking mechanism accounts for diminished cognitive performance. Neuromagnetic oscillatory activity was related to cognitive performance assessed by the MATRICS Consensus Cognitive Battery in 58 healthy individuals (HC) and 46 schizophrenia patients (SZ). HC showed a correlation between gamma-band oscillations (>40Hz) and working memory performance. This relationship was disrupted in several ways in SZ. First, patients evidenced lower gamma power, poorer working memory performance, and no relationship between these measures. Second, the power spectra were dominated by ~10Hz alpha oscillations with no group differences in amplitude. However, analysis of phase-to-amplitude coupling (PAC) revealed exaggerated clocking of gamma activity by alpha phase in SZ, associated with poor working memory performance. Third, despite entrainment by the same 10Hz clock, gamma amplitude was abnormally distributed across the duty cycle in SZ, a potential consequence of compromised interneuron inhibition. Fourth, SZ showed over-engagement of a fronto-parietal network measured by gamma phase coherence, suggesting a brain state hindering cognitive output.Such an endogenous temporal organization may be a core dysfunction in SZ: a segregation/integration input imbalance fostering reduced cognitive performance and compromised behavioral output.

Course of neurological soft signs in first-episode schizophrenia: Relationship with negative symptoms and cognitive performances.

This prospective study examined the course of neurological soft signs (NSS) in patients with first-episode schizophrenia and its relationship with negative symptoms and cognitive functions. One hundred and forty-five patients with first-episode schizophrenia were recruited, 29 were classified as having prominent negative symptoms. NSS and neuropsychological measures were administered to all patients and 62 healthy controls at baseline. Patients were then followed-up prospectively at six-month intervals for up to a year. Patients with prominent negative symptoms exhibited significantly more motor coordination signs and total NSS than patients without prominent negative symptoms. Patients with prominent negative symptoms performed worse than patients without negative symptoms in working memory functions but not other fronto-parietal or fronto-temporal functions. Linear growth model for binary data showed that the prominent negative symptoms were stable over time. Despite general improvement in NSS and neuropsychological functions, the prominent negative symptoms group still exhibited poorer motor coordination and higher levels of NSS, as well as poorer working memory than patients without prominent negative symptoms. Two distinct subtypes of first-episode patients could be distinguished by NSS and prominent negative symptoms.

Deficient interference control during working memory updating in adults with ADHD: An event-related potential study

ObjectiveLittle is known about the underlying mechanisms of poor working memory (WM) performance of adults with attention deficit hyperactivity disorder (ADHD). This study investigates interference and load effects during WM updating by use of event-related potentials. MethodForty ADHD patients and 41 controls performed verbal n-back tasks under conditions of low and high WM load. Intrusion probes, i.e., lures, were implemented to challenge interference control abilities during WM processing. ResultsStimulus-dependent N200 amplitude modulation and behavioral performance in lure trials were reduced in adults with ADHD compared to healthy controls. Also, P300 amplitudes tended to be less sensitive to WM load in patients with ADHD. ConclusionOur findings provide electrophysiological evidence for inaccurate discrimination of stimulus categories. Particularly, deficient interference control may lead to overt WM deficits in adult subjects with ADHD. SignificanceThe current findings contribute to a deeper understanding of the neural substrates of executive dysfunction in adult ADHD, focusing on the domain of WM.

Balancing Proliferation and Connectivity in PTEN-associated Autism Spectrum Disorder.

Germline mutations in PTEN, which encodes a widely expressed phosphatase, was mapped to 10q23 and identified as the susceptibility gene for Cowden syndrome, characterized by macrocephaly and high risks of breast, thyroid, and other cancers. The phenotypic spectrum of PTEN mutations expanded to include autism with macrocephaly only 10years ago. Neurological studies of patients with PTEN-associated autism spectrum disorder (ASD) show increases in cortical white matter and a distinctive cognitive profile, including delayed language development with poor working memory and processing speed. Once a germline PTEN mutation is found, and a diagnosis of phosphatase and tensin homolog (PTEN) hamartoma tumor syndrome made, the clinical outlook broadens to include higher lifetime risks for multiple cancers, beginning in childhood with thyroid cancer. First described as a tumor suppressor, PTEN is a major negative regulator of the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (mTOR) signaling pathway-controlling growth, protein synthesis, and proliferation. This canonical function combines with less well-understood mechanisms to influence synaptic plasticity and neuronal cytoarchitecture. Several excellent mouse models of Pten loss or dysfunction link these neural functions to autism-like behavioral abnormalities, such as altered sociability, repetitive behaviors, and phenotypes like anxiety that are often associated with ASD in humans. These models also show the promise of mTOR inhibitors as therapeutic agents capable of reversing phenotypes ranging from overgrowth to low social behavior. Based on these findings, therapeutic options for patients with PTEN hamartoma tumor syndrome and ASD are coming into view, even as new discoveries in PTEN biology add complexity to our understanding of this master regulator.

Causes of academic and behavioral difficulties among Japanese-Brazilian students: cognitive, linguistic and parental education factors

As in other countries with large immigrant populations, in Japan there is increasing interest in students from culturally and linguistically diverse backgrounds who experience learning and behavioral difficulties in the classroom. The causes of the problems have not been identified owing to a lack of appropriate and comparable assessments. In this study we focused on Japanese-Brazilian elementary school students, the largest ethnic minority group of students in Japan, and explored whether evaluation of their learning and behavior is influenced by the following aspects: language proficiency, cognitive capacity and family environment. We conducted a set of tasks to assess the students’ vocabulary and syntactic development in Japanese and Portuguese, and to evaluate their executive functions as an indicator of nonverbal cognitive development. Questionnaires were administered to teachers and parents in order to gain information about the children’s classroom performance and family environment, such as parents’ educational background and place of birth. Three key findings from our data include the following. (1) Some students in mainstream classrooms were ‘at-risk’ in their level of cognitive capacity. (2) Even among those with typical cognitive capacity, academic performance and classroom behavior were still rated lower than at grade level for the native population. (3) Teachers’ ratings of the two aspects were associated with different factors: low academic performance was significantly influenced by poor working memory, while problematic behavior was affected by Japanese grammatical skill and father’s educational background. This study used quantitative data to confirm that clear information about students’ linguistic, cognitive and environmental profiles, could be used to ensure that appropriate support is provided to students experiencing difficulties.

Updating and working memory training: Immediate improvement, long-term maintenance, and generalisability to non-trained tasks

Despite the popularity of working memory (WM) and updating training, recent reviews have questioned their efficacy. We evaluated a computer-based training programme based on the Running Span and Keep Track paradigms. We assigned 111 7-year-olds with poor WM and mathematical performances to updating training, one of the two control groups, or a fourth group, who were administered Cogmed, a commercially available programme. At the immediate posttest, updating training produced only marginal improvements relative to control, but this was sustained and became significant six months post-training. Cogmed training resulted in substantial improvement at immediate posttest, but became marginal at delayed posttest. Neither type of training resulted in better performance in mathematics or generalised to other WM tasks that differed more markedly from those used during training. These findings suggest that relations between WM or updating capacity and mathematics performance may be moderated by factors that do not benefit directly from improved capacity.

Can verbal working memory training improve reading?

The aim of the current study was to determine whether poor verbal working memory is associated with poor word reading accuracy because the former causes the latter, or the latter causes the former. To this end, we tested whether (a) verbal working memory training improves poor verbal working memory or poor word reading accuracy, and whether (b) reading training improves poor reading accuracy or verbal working memory in a case series of four children with poor word reading accuracy and verbal working memory. Each child completed 8 weeks of verbal working memory training and 8 weeks of reading training. Verbal working memory training improved verbal working memory in two of the four children, but did not improve their reading accuracy. Similarly, reading training improved word reading accuracy in all children, but did not improve their verbal working memory. These results suggest that the causal links between verbal working memory and reading accuracy may not be as direct as has been assumed.

ICT and collaborative co-learning in preschool children who face memory difficulties

Recent development in the role of education in pre-school children includes the use of Information and Communication Technologies (ICTs). ICT nowadays is considered as a tool that can foster the knowledge and the collaborative co-learning for this crucial age and the support of specific areas in kindergarten according to the educational perspective and the areas of needs they serve, is thought important. In this study we present a brief overview of the most representative studies of the last decade (2003–2014), which concentrates on the collaborative co learning and other ICT applications in kindergarten children who face memory difficulties. The effectiveness of ICT in literature, in maths and in children who face learning difficulties is examined. Additionally, the effectiveness of collaborative intervention and diagnostic tools for children with poor working memory in kindergarten children is examined. Concluding, this review, points out certain technological breakthroughs of several researches that focus on the support of children with such deficits.

Individual differences in biophysiological toughness: sustaining working memory during physical exhaustion.

Recent evidence suggests that increased dehydroepiandrosterone sulfate (DHEAS), in combination with decreased cortisol levels have been correlated with enhanced performance outcomes in stressful military environments. This study was implemented to replicate these findings in a group of active duty Air Force members to provide information on the usefulness of these biomarkers indices in the training and operational environment. Seventeen active duty males participated in the 4 sessions of this study. Sessions 1 and 2 were training days for the cognitive testing. Session 3 was a baseline measure of physical fitness, utilizing the VO2 Maximal Treadmill test. Session 4 was centered around a modified-Astrand treadmill protocol designed to induce physical exhaustion. Blood draws for biomarker analysis, cognitive testing (NovaScan), psychomotor vigilance, and physiological measures were collected before, during, and following the treadmill protocol. Results showed that prolonged increases in cortisol negatively correlate with working memory performance. DHEAS release from baseline to poststress was negatively related to the changes in cortisol for 20 minutes following stress. These results indicate that the ratio of DHEAS to cortisol buffers, the effect of cortisol increases that are related to poor working memory performance because of physical exhaustion.