Measures Of Short-term Memory Research Articles

The effectiveness of working memory training with individuals with intellectual disabilities - a meta-analytic review.

Working memory (WM) training has been increasingly popular in the last years. Previous studies have shown that individuals with intellectual disabilities (ID) have low WM capacity and therefore would benefit by this type of intervention. The aim of this study was to investigate the effect of WM and cognitive training for individuals with ID. The effects reported in previous studies have varied and therefore a meta-analysis of articles in the major databases was conducted. Inclusion criteria included to have a pretest–posttest design with a training group and a control group and to have measures of WM or short-term memory. Ten studies with 28 comparisons were included. The results reveal a significant, but small, overall pretest–posttest effect size (ES) for WM training for individuals with ID compared to controls. A mixed WM approach, including both verbal and visuo-spatial components working mainly on strategies, was the only significant training type with a medium ES. The most commonly reported training type, visuo-spatial WM training, was performed in 60 percent of the included comparisons and had a non-significant ES close to zero. We conclude that even if there is an overall effect of WM training, a mixed WM approach appears to cause this effect. Given the few studies included and the different characteristics of the included studies, interpretations should be done with caution. However, different types of interventions appear to have different effects. Even if the results were promising, more studies are needed to better understand how to design an effective WM intervention for this group and to understand if, and how, these short-term effects remain over time and transfer to everyday activities.

The heterogeneity of verbal short-term memory impairment in aphasia

Verbal short-term memory (STM) impairment represents a frequent and long-lasting deficit in aphasia, and it will prevent patients from recovering fully functional language abilities. The aim of this study was to obtain a more precise understanding of the nature of verbal STM impairment in aphasia, by determining whether verbal STM impairment is merely a consequence of underlying language impairment, as suggested by linguistic accounts of verbal STM, or whether verbal STM impairment reflects an additional, specific deficit. We investigated this question by contrasting item-based STM measures, supposed to depend strongly upon language activation, and order-based STM measures, supposed to reflect the operation of specific, serial order maintenance mechanisms, in a sample of patients with single-word processing deficits at the phonological and/or lexical level. A group-level analysis showed robust impairment for both item and serial order STM aspects in the aphasic group relative to an age-matched control group. An analysis of individual profiles revealed an important heterogeneity of verbal STM profiles, with patients presenting either selective item STM deficits, selective order STM deficits, generalized item and serial order STM deficits or no significant STM impairment. Item but not serial order STM impairment correlated with the severity of phonological impairment. These results disconfirm a strong version of the linguistic account of verbal STM impairment in aphasia, by showing variable impairment to both item and serial order processing aspects of verbal STM.

Increase in short-term memory capacity induced by down-regulating individual theta frequency via transcranial alternating current stimulation.

Working memory (WM) and short-term memory (STM) supposedly rely on the phase-amplitude coupling (PAC) of neural oscillations in the theta and gamma frequency ranges. The ratio between the individually dominant gamma and theta frequencies is believed to determine an individual’s memory capacity. The aim of this study was to establish a causal relationship between the gamma/theta ratio and WM/STM capacity by means of transcranial alternating current stimulation (tACS). To achieve this, tACS was delivered at a frequency below the individual theta frequency. Thereby the individual ratio of gamma to theta frequencies was changed, resulting in an increase of STM capacity. Healthy human participants (N = 33) were allocated to two groups, one receiving verum tACS, the other underwent a sham control protocol. The electroencephalogram (EEG) was measured before stimulation and analyzed with regard to the properties of PAC between theta and gamma frequencies to determine individual stimulation frequencies. After stimulation, EEG was recorded again in order to find after-effects of tACS in the oscillatory features of the EEG. Measures of STM and WM were obtained before, during and after stimulation. Frequency spectra and behavioral data were compared between groups and different measurement phases. The tACS- but not the sham stimulated group showed an increase in STM capacity during stimulation. WM was not affected in either groups. An increase in task-related theta amplitude after stimulation was observed only for the tACS group. These augmented theta amplitudes indicated that the manipulation of individual theta frequencies was successful and caused the increase in STM capacity.

Longitudinal relationships between language and verbal short-term memory skills in children with Down syndrome

Children with Down syndrome are at risk for language difficulties, the nature of which is not well understood. This study compared the longitudinal predictors of language skills in children with Down syndrome with those in typically developing control children matched for initial level of nonverbal mental ability. An age cohort of children with Down syndrome (n=43) and 57 typically developing control children was assessed on measures of vocabulary, grammar, and verbal short-term memory three times at yearly intervals. Children with Down syndrome showed slower development on all measures than the typically developing controls. Longitudinal analyses showed moderate to high stability of language and verbal short-term memory skills. Our results confirm earlier evidence of pervasive language learning difficulties in this group and suggest that early language intervention should be given high priority.

The effects of video-game training on broad cognitive transfer in multiple sclerosis: A pilot randomized controlled trial

Background: Multiple sclerosis (MS) is a neurodegenerative disease of the central nervous system that results in diffuse nerve damage and associated physical and cognitive impairments. Of the few comprehensive rehabilitation options that exist for populations with lower baseline cognitive functioning, those that have been successful at eliciting broad cognitive improvements have focused on a multimodal training approach, emphasizing complex cognitive processing that utilizes multiple domains simultaneously. Method: The current study sought to determine the feasibility of an 8-week, hybrid-variable priority training (HVT) program, with a secondary aim to assess the success of this training paradigm at eliciting broad cognitive transfer effects. Capitalizing on the multimodal training modalities offered by the Space Fortress platform, we compared the HVT strategy-based intervention with a waitlist control group, to primarily assess skill acquisition and secondarily determine presence of cognitive transfer. Twenty-eight participants met inclusionary criteria for the study and were randomized to either training or waitlist control groups. To assess broad transfer effects, a battery of neuropsychological tests was administered pre- and post-intervention. Results: The results indicated an overall improvement in skill acquisition and evidence for the feasibility of the intervention, but a lack of broad transfer to tasks of cognitive functioning. Participants in the training group, however, did show improvements on a measure of spatial short-term memory. Conclusions: The current investigation provided support for the feasibility of a multimodal training approach, using the HVT strategy, within the MS population, but lacked broad transfer to multiple domains of cognitive functioning. Future improvements to obtain greater cognitive transfer efficacy would include a larger sample size, a longer course of training to evoke greater game score improvement, the inclusion of only cognitively impaired individuals, and integration of subjective measures of improvement in addition to objective tests of cognitive performance.

Working memory training improves visual short-term memory capacity.

Since antiquity, philosophers, theologians, and scientists have been interested in human memory. However, researchers today are still working to understand the capabilities, boundaries, and architecture. While the storage capabilities of long-term memory are seemingly unlimited (Bahrick, J Exp Psychol 113:1-2, 1984), working memory, or the ability to maintain and manipulate information held in memory, seems to have stringent capacity limits (e.g., Cowan, Behav Brain Sci 24:87-185, 2001). Individual differences, however, do exist and these differences can often predict performance on a wide variety of tasks (cf. Engle What is working-memory capacity? 297-314, 2001). Recently, researchers have promoted the enticing possibility that simple behavioral training can expand the limits of working memory which indeed may also lead to improvements on other cognitive processes as well (cf. Morrison and Chein, Psychol Bull Rev 18:46-60 2011). However, initial investigations across a wide variety of cognitive functions have produced mixed results regarding the transferability of training-related improvements. Across two experiments, the present research focuses on the benefit of working memory training on visual short-term memory capacity-a cognitive process that has received little attention in the training literature. Data reveal training-related improvement of global measures of visual short-term memory as well as of measures of the independent sub-processes that contribute to capacity (Awh et al., Psychol Sci 18(7):622-628, 2007). These results suggest that the ability to inhibit irrelevant information within and between trials is enhanced via n-back training allowing for selective improvement on untrained tasks. Additionally, we highlight a potential limitation of the standard adaptive training procedure and propose a modified design to ensure variability in the training environment.

Working Memory Measurements and ADHD?

Conceptually, it seems that the tasks commonly used in clinical psychology may not be measuring the same construct identified in cognitive literature [15]. Span tasks provide a good example of discrepancies in WM measurement between clinical psychology and cognitive or experimental research. In clinical neuropsychology, span tasks are often one of the most common methods for assessing WM capacity [16]. For example, WM measurement built into instruments commonly used in clinical psychology (e.g., Wechsler Intelligence Scale for Children, Fourth Edition) [17], heavily relies on span tasks, and often combines simple and complex tasks. Simple span tasks are viewed as a measure of short-term memory, the ability to hold information for a limited time [13], rather than WM capacity [18]. In contrast to simple span tasks, complex span tasks require both storage and processing of information, engage the CE, and so are theoretically a more accurate measure of WM processes [16].

Verb representations are closely associated with syntactic constructions in sentence production: Evidence from aphasic patients with short-term memory deficits

Verb representations are closely associated with syntactic constructions in sentence production: Evidence from aphasic patients with short-term memory deficits

Speech segmentation in aphasia

Background: Speech segmentation is one of the initial and mandatory phases of language learning. Although some people with aphasia have shown a preserved ability to learn novel words, their speech segmentation abilities have not been explored.Aims: We examined the ability of individuals with chronic aphasia to segment words from running speech via statistical learning. We also explored the relationships between speech segmentation and aphasia severity, and short-term memory capacity. We further examined the role of lesion location in speech segmentation and short-term memory performance.Methods & Procedures: The experimental task was first validated with a group of young adults (n = 120). Participants with chronic aphasia (n = 14) were exposed to an artificial language and were evaluated in their ability to segment words using a speech segmentation test. Their performance was contrasted against chance level and compared to that of a group of elderly matched controls (n = 14) using group and case-by-case analyses.Outcomes & Results: As a group, participants with aphasia were significantly above chance level in their ability to segment words from the novel language and did not significantly differ from the group of elderly controls. Speech segmentation ability in the aphasic participants was not associated with aphasia severity although it significantly correlated with word pointing span, a measure of verbal short-term memory. Case-by-case analyses identified four individuals with aphasia who performed above chance level on the speech segmentation task, all with predominantly posterior lesions and mild fluent aphasia. Their short-term memory capacity was also better preserved than in the rest of the group.Conclusions: Our findings indicate that speech segmentation via statistical learning can remain functional in people with chronic aphasia and suggest that this initial language learning mechanism is associated with the functionality of the verbal short-term memory system and the integrity of the left inferior frontal region.

Cognitive function and social attainment in adult survivors of retinoblastoma: a report from the St. Jude Lifetime Cohort Study.

Retinoblastoma has a 5-year survival rate exceeding 95%, yet little is known about long-term functional outcomes for these patients. Sixty-nine adult survivors of retinoblastoma (mean age, 33 years; mean years post-diagnosis, 31) who had enrolled in the St. Jude Lifetime Cohort Study completed clinical cognitive evaluations and questionnaires assessing adult social attainment. Scores on all cognitive measures were converted to z-scores (M = 0, SD = 1) using age-adjusted normative data. Multivariable linear regression analyses, adjusted for age at diagnosis and disease laterality, were used to examine associations between disease and treatment exposures and cognitive outcomes. Retinoblastoma survivors performed within normative expectations across most cognitive domains. In multivariable models, adjusted for disease laterality, survivors diagnosed at ≤1 year of age performed significantly better on measures of short-term verbal memory (β = 0.87, P<.01), long-term verbal memory (β = 0.66, P = .02), verbal learning (β = 0.67, P = .02), and verbal reasoning abilities (β = 0.79, P<.01) compared with survivors diagnosed at >1 year of age. In multivariable models, restricted to bilateral survivors and adjusted for age at diagnosis, whole brain radiation exposure was significantly associated with poorer performance on tasks of short-term verbal memory (β = -0.003, P = .03) and long-term verbal memory (β = -0.003, P = .01). Reported social attainment was consistent with adult developmental expectations. Adult survivors of retinoblastoma demonstrate few cognitive or social attainment deficits decades following diagnosis and treatment. Findings suggest the potential for neural reorganization following early insult to the visual system as well as vulnerability of the developing brain to low dose radiation exposure. Early intervention and rehabilitation will be important for these patients.

Individual differences in cognitive resources and elementary school mathematics achievement: Examining the roles of storage and attention

Using data from the NICHD Study of Early Child Care and Youth Development, a longitudinal study of 1,364 children, the present research investigated early cognitive correlates of children's mathematics achievement. Individual differences in mathematics performance prior to kindergarten and growth in achievement across elementary school were modeled as a function of two measures of attention—performance-based and informant-reported—and a measure of short-term memory. At the age of 54months, children with poor capacities for attention and short-term memory storage had lower mathematics achievement than their peers with larger capacities. These early differences persisted through the fifth grade. Interestingly, the informant-based measure of attention did not predict mathematics achievement or its growth across time. The findings implicate the utility of early performance-based assessments of cognitive resources – storage and attention – in identifying students potentially at-risk for poor mathematical outcomes.

Musical practice and cognitive aging: two cross-sectional studies point to phonemic fluency as a potential candidate for a use-dependent adaptation.

Because of permanent use-dependent brain plasticity, all lifelong individuals' experiences are believed to influence the cognitive aging quality. In older individuals, both former and current musical practices have been associated with better verbal skills, visual memory, processing speed, and planning function. This work sought for an interaction between musical practice and cognitive aging by comparing musician and non-musician individuals for two lifetime periods (middle and late adulthood). Long-term memory, auditory-verbal short-term memory, processing speed, non-verbal reasoning, and verbal fluencies were assessed. In Study 1, measures of processing speed and auditory-verbal short-term memory were significantly better performed by musicians compared with controls, but both groups displayed the same age-related differences. For verbal fluencies, musicians scored higher than controls and displayed different age effects. In Study 2, we found that lifetime period at training onset (childhood vs. adulthood) was associated with phonemic, but not semantic, fluency performances (musicians who had started to practice in adulthood did not perform better on phonemic fluency than non-musicians). Current frequency of training did not account for musicians' scores on either of these two measures. These patterns of results are discussed by setting the hypothesis of a transformative effect of musical practice against a non-causal explanation.

Verbal and visuospatial working memory as predictors of children's reading ability.

Children with reading difficulties often demonstrate weaknesses in working memory (WM). This research study explored the relation between two WM systems (verbal and visuospatial WM) and reading ability in a sample of school-aged children with a wide range of reading skills. Children (N = 157), ages 9-12, were administered measures of short-term memory, verbal WM, visuospatial WM, and reading measures (e.g., reading fluency and comprehension). Although results indicated that verbal WM was a stronger predictor in reading fluency and comprehension, visuospatial WM also significantly predicted reading skills, but provided more unique variance in reading comprehension than reading fluency. These findings suggest that visuospatial WM may play a significant role in higher level reading processes, particularly in reading comprehension, than previously thought.

Longitudinal and concurrent links between memory span, anxiety symptoms, and subsequent executive functioning in young children.

It has been conjectured that basic individual differences in attentional control influence higher-level executive functioning and subsequent academic performance in children. The current study sets out to complement the limited body of research on early precursors of executive functions (EFs). It provides both a cross-sectional, as well as a longitudinal exploration of the relationship between EF and more basic attentional control mechanisms, assessed via children's performance on memory storage tasks, and influenced by individual differences in anxiety. Multiple measures of verbal and visuospatial short-term memory (STM) were administered to children between 3 and 6 years old, alongside a non-verbal measure of intelligence, and a parental report of anxiety symptoms. After 9 months, children were re-tested on the same STM measures, at which time we also administered multiple measures of executive functioning: verbal and visuospatial working memory (WM), inhibition, and shifting. A cross-sectional view of STM development indicated that between 3 and 6 years the trajectory of visuospatial STM and EF underwent a gradual linear improvement. However, between 5 and 6 years progress in verbal STM performance stagnated. Hierarchical regression models revealed that trait anxiety was negatively associated with WM and shifting, while non-verbal intelligence was positively related to WM span. When age, gender, non-verbal intelligence, and anxiety were controlled for, STM (measured at the first assessment) was a very good predictor of overall executive performance. The models were most successful in predicting WM, followed by shifting, yet poorly predicted inhibition measures. Further longitudinal research is needed to directly address the contribution of attentional control mechanisms to emerging executive functioning and to the development of problematic behavior during early development.

The strengths and weaknesses in verbal short-term memory and visual working memory in children with hearing impairment and additional language learning difficulties

ObjectivesTo compare verbal short-term memory and visual working memory abilities of six children with congenital hearing-impairment identified as having significant language learning difficulties with normative data from typically hearing children using standardized memory assessments. MethodsSix children with hearing loss aged 8–15 years were assessed on measures of verbal short-term memory (Non-word and word recall) and visual working memory annually over a two year period. All children had cognitive abilities within normal limits and used spoken language as the primary mode of communication. The language assessment scores at the beginning of the study revealed that all six participants exhibited delays of two years or more on standardized assessments of receptive and expressive vocabulary and spoken language. ResultsThe children with hearing-impairment scores were significantly higher on the non-word recall task than the “real” word recall task. They also exhibited significantly higher scores on visual working memory than those of the age-matched sample from the standardized memory assessment. ConclusionsEach of the six participants in this study displayed the same pattern of strengths and weaknesses in verbal short-term memory and visual working memory despite their very different chronological ages. The children’s poor ability to recall single syllable words in relation to non-words is a clinical indicator of their difficulties in verbal short-term memory. However, the children with hearing-impairment do not display generalized processing difficulties and indeed demonstrate strengths in visual working memory. The poor ability to recall words, in combination with difficulties with early word learning may be indicators of children with hearing-impairment who will struggle to develop spoken language equal to that of their normally hearing peers. This early identification has the potential to allow for target specific intervention that may remediate their difficulties.

Lactobacillus helveticus–fermented milk improves learning and memory in mice

ObjectivesTo investigate the effects of Calpis sour milk whey, a Lactobacillus helveticus–fermented milk product, on learning and memory.MethodsWe evaluated improvement in scopolamine-induced memory impairment using the spontaneous alternation behaviour test, a measure of short-term memory. We also evaluated learning and working memory in mice using the novel object recognition test, which does not involve primary reinforcement (food or electric shocks). A total of 195 male ddY mice were used in the spontaneous alternation behaviour test and 60 in the novel object recognition test.ResultsForced orally administered Calpis sour milk whey powder (200 and 2000 mg/kg) significantly improved scopolamine-induced cognitive impairments (P < 0.05 and P < 0.01, respectively) and object recognition memory (2000 mg/kg; P < 0.05).DiscussionThese results suggest that Calpis sour milk whey may be useful for the prevention of neurodegenerative disorders, such as Alzheimer's disease, and enhancing learning and memory in healthy human subjects; however, human clinical studies are necessary.

Abstract 26: Long-term Blood Pressure Variability though Young Adulthood and Cognitive Function in Midlife; The Coronary Artery Risk Development in Young Adults (CARDIA)Study

Background: Blood pressure variability (BPV) consists of short-term BPV (e.g., diurnal BPV) and long-term BPV (e.g., visit-to-visit BPV). The prospective association of long-term BPV though young adulthood with cognition in midlife is unknown. Methods: CARDIA is a multicenter community-based study that included participants (ppts) aged 18 to 30 years at baseline (Year 0: Y 0 ) in 1985-86 with follow-up examinations at Y 2 , Y 5 , Y 7 , Y 10 , Y 15 , Y 20 , and Y 25 . BP was measured at each exam, and visit-to-visit BPV was assessed by standard deviation (SD), coefficient of variation (CV), maximum minus minimum BP difference (MMD), and average real variability (ARV) across 7 visits (Y 0-20 ). Cognitive function was assessed at Y 25 by the Digit Symbol Substitution Test (DSST, a measure of psychomotor speed; n=2,318), the Rey Auditory Verbal Learning Test (RAVLT, a measure of short-term verbal memory; n=2,321), and the modified Stroop test (executive function; n=2,307). We performed separate multivariable-adjusted linear regression models, and also adjusted for baseline BP (Y 0 ), change of BP (Y 20 -Y 0 ), or cumulative BP from Y 0 to Y 20 (mmHg х year) to determine whether BPV is associated with cognition independent of long-term BP level. Results: At the Y 25 examination, included ppts had a mean age of 50 years, 57% were women and 43% were black. BPV measured by higher SD and ARV in both systolic and diastolic BP was significantly associated with lower DSST and lower RAVLT. SD and ARV remained significant even after further adjustment for baseline BP, change of BP, or cumulative BP (Table). Measures of BPV were not associated with the Stroop test. Associations between the CV and MMD measures of BPV with cognitive function were similar to those of SD (not shown). Conclusions: Long-term BPV over 20-years through young adulthood is associated with worse psychomotor speed and verbal memory in midlife, independent of BP levels. These results may have implications for understanding the pathogenesis of cognitive dysfunction in older adults.

Effects of classroom bilingualism on task‐shifting, verbal memory, and word learning in children

We examined the effects of classroom bilingual experience in children on an array of cognitive skills. Monolingual English-speaking children were compared with children who spoke English as the native language and who had been exposed to Spanish in the context of dual-immersion schooling for an average of 2 years. The groups were compared on a measure of non-linguistic task-shifting; measures of verbal short-term and working memory; and measures of word learning. The two groups of children did not differ on measures of non-linguistic task-shifting and verbal short-term memory. However, the classroom-exposure bilingual group outperformed the monolingual group on the measure of verbal working memory and a measure of word learning. Together, these findings indicate that while exposure to a second language in a classroom setting may not be sufficient to engender changes in cognitive control, it can facilitate verbal memory and verbal learning.

Associations of HLA alleles with specific language impairment

BackgroundHuman leukocyte antigen (HLA) loci have been implicated in several neurodevelopmental disorders in which language is affected. However, to date, no studies have investigated the possible involvement of HLA loci in specific language impairment (SLI), a disorder that is defined primarily upon unexpected language impairment. We report association analyses of single-nucleotide polymorphisms (SNPs) and HLA types in a cohort of individuals affected by language impairment.MethodsWe perform quantitative association analyses of three linguistic measures and case-control association analyses using both SNP data and imputed HLA types.ResultsQuantitative association analyses of imputed HLA types suggested a role for the HLA-A locus in susceptibility to SLI. HLA-A A1 was associated with a measure of short-term memory (P = 0.004) and A3 with expressive language ability (P = 0.006). Parent-of-origin effects were found between HLA-B B8 and HLA-DQA1*0501 and receptive language. These alleles have a negative correlation with receptive language ability when inherited from the mother (P = 0.021, P = 0.034, respectively) but are positively correlated with the same trait when paternally inherited (P = 0.013, P = 0.029, respectively). Finally, case control analyses using imputed HLA types indicated that the DR10 allele of HLA-DRB1 was more frequent in individuals with SLI than population controls (P = 0.004, relative risk = 2.575), as has been reported for individuals with attention deficit hyperactivity disorder (ADHD).ConclusionThese preliminary data provide an intriguing link to those described by previous studies of other neurodevelopmental disorders and suggest a possible role for HLA loci in language disorders.

Cognitive deficits specific to depression-prone smokers during abstinence.

Cigarette smoking is associated with a higher prevalence of depressive symptoms and individuals with elevated symptoms of depression have more difficulty quitting smoking. Depression is accompanied by cognitive deficits similar to those observed during nicotine withdrawal. Depressed smokers may smoke to alleviate these cognitive symptoms, which are exacerbated upon smoking abstinence. We hypothesized that following overnight abstinence, depression-prone smokers (DP+; past history and current depression symptoms; n = 34) would exhibit deficits in short-term and working memory, and experience greater attentional bias for affective stimuli, compared with smokers with no history or current symptoms of depression (DP-; n = 34). All participants underwent two laboratory sessions, once while smoking abstinent and once while smoking ad libitum (order counterbalanced, abstinence biochemically verified). Smokers completed measures of short-term memory (STM; word recognition task), working memory (N-back task), and attentional bias (Emotional Stroop task). The DP+ group showed declines in STM during abstinence compared with smoking, whereas the DP- group did not (interaction p = .02). There were small decrements in working memory accuracy during abstinence (p = .05), but this did not interact with depression status. During the Emotional Stroop task, the DP+ group showed an attentional bias toward positive versus neutral stimuli during abstinence compared with smoking (interaction p = .01). This study provides initial evidence that depressive symptoms may moderate abstinence-induced deficits in STM and shift attentional bias toward emotionally salient stimuli during abstinence. These cognitive changes may prompt relapse and may help identify novel targets for nicotine dependence treatment aimed at attenuating these deficits to improve cessation rates.