Working Memory Impairments In Children Research Articles

Prevalence and risk factors for attention and working memory impairment in children with epilepsy attending the University of Benin Teaching hospital, Benin City: a comparative cross-sectional study

Introduction: children with epilepsy (CWE) experience a wide range of developmental and functional challenges, including cognitive and behavioural problems. Problems with attention and memory are among the most common problems reported. The study sought to determine the prevalence of attention and memory impairment in CWE compared to controls, and to examine the influence of epilepsy-related variables on attention and memory.

Effects of Neurofeedback on the Working Memory of Children with Learning Disorders-An EEG Power-Spectrum Analysis.

Learning disorders (LDs) are diagnosed in children impaired in the academic skills of reading, writing and/or mathematics. Children with LDs usually exhibit a slower resting-state electroencephalogram (EEG), corresponding to a neurodevelopmental lag. Frequently, children with LDs show working memory (WM) impairment, associated with an abnormal task-related EEG with overall slower EEG activity (more delta and theta power, and less gamma activity in posterior sites). These EEG patterns indicate inefficient neural resource management. Neurofeedback (NFB) treatments aimed at normalizing the resting-state EEG of LD children have shown improvements in cognitive-behavioral indices and diminished EEG abnormalities. Given the typical findings of WM impairment in children with LDs, we aimed to explore the effects of an NFB treatment on the WM of children with LDs by analyzing the WM-related EEG power spectrum. EEGs of 18 children (8–11 y.o.) with LDs were recorded, pre- and post-treatment, during performance of a Sternberg-type WM task. Thirty sessions of an NFB treatment (NFB-group, n = 10) or 30 sessions of a placebo-sham treatment (sham-group, n = 8) were administered. We analyzed the before and after treatment group differences for the behavioral performance and the WM-related EEG power spectrum. The NFB group showed faster response times in the WM task post-treatment. They also exhibited a decreased theta power and increased beta and gamma power at the frontal and posterior sites post-treatment. We explain these findings in terms of NFB improving the efficiency of neural resource management, maintenance of memory representations, and improved subvocal memory rehearsal.

Anatomo-functional study of the cerebellum in working memory in children treated for medulloblastoma

IntroductionMedulloblastoma is the most common malignant cerebral tumor during childhood, arising in the posterior fossa. Children treated for medulloblastoma often experience working memory (WM) deficits, affecting their quality of life and school performance. The aim of the present study undertaken to describe the cerebellar involvement in WM deficits observed in these children. Material and methods23 healthy children and 11 children treated for medulloblastoma were included into study. All subjects performed a detailed neuropsychological examination, an anatomical and functional MRI. Stimuli were presented to the participants with alternating sensory modality and nature of communication in a block design during functional magnetic resonance imaging acquisitions. Non-parametric tests were used for analyzing neuropsychological and behavioral data. SPM8 and SUIT (Spatially Unbiased Atlas Template) were used for anatomical and functional MRI data analyses. ResultsPatients had cerebellar resections mainly located in the left posterior lobe. Patients had significantly reduced intelligence quotient, central executive and visuospatial WM. In healthy children group, fMRI showed activations for non-verbal and visuospatial WM in the left posterior cerebellar lobe. ConclusionThis study provides further evidence that left posterior cerebellar lobe plays a critical role in WM. Indeed, lesions of left posterior cerebellar lobe were associated with WM impairment in children treated for cerebellar medulloblastoma. Additionally, fMRI using WM tasks showed activation in the left posterior cerebellar lobe in healthy children. Taken together, these findings may help for improving treatment and rehabilitation of children referred for cerebellar tumor.

What Part of Working Memory is not Working in ADHD? Short-Term Memory, the Central Executive and Effects of Reinforcement

Deficits in Working Memory (WM) are related to symptoms of Attention-Deficit/Hyperactivity Disorder (ADHD). In children with ADHD visuospatial WM is most impaired. WM is composed of Short-Term Memory (STM) and a Central Executive (CE). Therefore, deficits in either or both STM and the CE may account for WM impairments in children with ADHD. WM-component studies investigating this find deficits in both STM and the CE. However, recent studies show that not only cognitive deficits, but also motivational deficits give rise to the aberrant WM performance of children with ADHD. To date, the influence of these motivational deficits on the components of WM has not been investigated. This study examined the effects of a standard (feedback-only) and a high level of reinforcement (feedback + 10 euros) on the visuospatial WM-, visuospatial STM-, and the CE performance of 86 children with ADHD and 62 typically-developing controls. With standard reinforcement the STM, CE, and WM performance of children with ADHD was worse than that of controls. High reinforcement improved STM and WM performance more in children with ADHD than in controls, but was unable to normalize their performance. High reinforcement did not appear to improve the CE-related performance of children with ADHD and controls. Motivational deficits have a detrimental effect on both the visuospatial WM performance and the STM performance of children with ADHD. Aside from motivational deficits, both the visuospatial STM and the CE of children with ADHD are impaired, and give rise to their deficits in visuospatial WM.

Phonological working memory impairments in children with specific language impairment: Where does the problem lie?

PurposeThe purpose of this study was to determine which factors contribute to the lexical learning deficits of children with specific language impairment (SLI). MethodParticipants included 40 7–8-year old participants, half of whom were diagnosed with SLI and half of whom had normal language skills. We tested hypotheses about the contributions to word learning of the initial encoding of phonological information and the link to long-term memory. Children took part in a computer-based fast-mapping task which manipulated word length and phonotactic probability to address the hypotheses. The task had a recognition and a production component. Data were analyzed using mixed ANOVAs with post-hoc testing. ResultsResults indicate that the main problem for children with SLI is with initial encoding, with implications for limited capacity. There was not strong evidence for specific deficits in the link to long-term memory. ConclusionsWe were able to ascertain which aspects of lexical learning are most problematic for children with SLI in terms of fast-mapping. These findings may allow clinicians to focus intervention on known areas of weakness. Future directions include extending these findings to slow mapping scenarios.Learning outcomes: The reader will understand how different components of phonological working memory contribute to the word learning problems of children with specific language impairment.

An event-related functional MRI study on working memory impairment in children with primary nocturnal enuresis

Objective To assess the working memory and explore the activation of brain areas for children with primary nocturnal enuresis (PNE) with fMRI scan. Methods Twenty three right-handed children with PNE and 20 age-matched right-handed healthy children as the controls were recruited.Intelligence tests were performed by means of Wechsler Young Children Scales of Intelligence (C-WISC) in children with PNE and normal controls. The full intelligence quotient (FIQ), verbal IQ (VIQ),performances IQ (PIQ) and the memory/caution (M/C) factor of PNE children and the controls were measured. After Intelligence tests, an enent-related fMRI scan was performed using the categorial N-Back working memory task. Percent of correct responses (PCR) and mean reaction time to correct response (mRT) were recorded and analyzed by the student t test. The fMRI data were analyzed using Statistical Parametric Mapping 2 (SPM2), the differences in activation were compared between two groups. Results The data of 15 PNE children and 15 healthy children were evaluated. The FIQ, VIQ and PIQ in PNE group were in a normal range and no statistical significance with the control group ( P ＞ 0. 05). M/C factor in the PNE group(90.4 ±10.2)was significantly lower than that in the control group (99. 6 ± 11.9) (t =2. 260,P ＜ 0. 05). In the N-Back test, PNE children had significantly less PCR [(72.7±6.3 ) % vs. ( 86. 3 ±6. 7) %, t = 5. 727,P ＜ 0. 01] and longer mRT [ (625. 8 ± 72.5) ms vs. (534. 8 ± 63. 3 ) ms, t = 3. 684,P ＜ 0.01] than the healthy controls. The activation regions of PNE patients and healthy children were mainly in the dorsal right frontal lobe, right parietal lobe, left temporal lobe gyrus fusiformis and bilateral cerebellum posterior lobe. The activation level in left posterior cerebellar lobe in PNE children was significant lower than that in healthy controls (P＜0.01). Conclusion The children with PNE have deficits in working memory which might be associated with the dysfunction of the left cerebellum. Key words: Nocturnal enuresis; Magnetic resonance imaging; Memory disorders

Working memory deficits can be overcome: Impacts of training and medication on working memory in children with ADHD

AbstractThis study evaluated the impact of two interventions—a training program and stimulant medication—on working memory (WM) function in children with attention deficit hyperactivity disorder (ADHD). Twenty‐five children aged between 8 and 11 years participated in training that taxed WM skills to the limit for a minimum of 20 days, and completed other assessments of WM and IQ before and after training, and with and without prescribed drug treatment. While medication significantly improved visuo‐spatial memory performance, training led to substantial gains in all components of WM across untrained tasks. Training gains associated with the central executive persisted over a 6‐month period. IQ scores were unaffected by either intervention. These findings indicate that the WM impairments in children with ADHD can be differentially ameliorated by training and by stimulant medication. Copyright © 2009 John Wiley & Sons, Ltd.

A Meta-Analysis of Working Memory Impairments in Children With Attention-Deficit/Hyperactivity Disorder

To determine the empirical evidence for deficits in working memory (WM) processes in children and adolescents with attention-deficit/hyperactivity disorder (ADHD). Exploratory meta-analytic procedures were used to investigate whether children with ADHD exhibit WM impairments. Twenty-six empirical research studies published from 1997 to December, 2003 (subsequent to a previous review) met our inclusion criteria. WM measures were categorized according to both modality (verbal, spatial) and type of processing required (storage versus storage/manipulation). Children with ADHD exhibited deficits in multiple components of WM that were independent of comorbidity with language learning disorders and weaknesses in general intellectual ability. Overall effect sizes for spatial storage (effect size = 0.85, CI = 0.62 - 1.08) and spatial central executive WM (effect size = 1.06, confidence interval = 0.72-1.39) were greater than those obtained for verbal storage (effect size = 0.47, confidence interval = 0.36-0.59) and verbal central executive WM (effect size = 0.43, confidence interval = 0.24-0.62). Evidence of WM impairments in children with ADHD supports recent theoretical models implicating WM processes in ADHD. Future research is needed to more clearly delineate the nature, severity, and specificity of the impairments to ADHD.

Age-related working memory impairments in children with prefrontal dysfunction associated with phenylketonuria

The prefrontal cortex of the brain has been shown to play a crucial role in working memory, and age-related changes in prefrontal function may contribute to the improvements in working memory that are observed during childhood. We examined the developmental trajectory of working memory in school-age children with early-treated phenylketonuria (PKU), a metabolic disorder that results in prefrontal dysfunction. Using a recognition procedure, we evaluated working memory for letters, abstract objects, and spatial locations in 20 children with PKU and 20 typically developing control children. Children in both groups ranged from 6 to 17 years of age. Our findings revealed poorer performance across all three types of materials for children with PKU. In addition, there was a significant difference in the developmental trajectory of working memory for children with PKU as compared with controls. Specifically, deficits were not apparent in younger children with PKU. Instead, deficits were observed only in older children, suggesting the presence of a developmental deficit rather than a developmental delay in the working memory of children with PKU.

Age-related working memory impairments in children with prefrontal dysfunction associated with phenylketonuria

The prefrontal cortex of the brain has been shown to play a crucial role in working memory, and age-related changes in prefrontal function may contribute to the improvements in working memory that are observed during childhood. We examined the developmental trajectory of working memory in school-age children with early-treated phenylketonuria (PKU), a metabolic disorder that results in prefrontal dysfunction. Using a recognition procedure, we evaluated working memory for letters, abstract objects, and spatial locations in 20 children with PKU and 20 typically developing control children. Children in both groups ranged from 6 to 17 years of age. Our findings revealed poorer performance across all three types of materials for children with PKU. In addition, there was a significant difference in the developmental trajectory of working memory for children with PKU as compared with controls. Specifically, deficits were not apparent in younger children with PKU. Instead, deficits were observed only in older children, suggesting the presence of a developmental deficit rather than a developmental delay in the working memory of children with PKU.