Verbal Working Memory Research Articles

Neurocognitive Operations Underlying Working Memory Abilities: An Analysis of Latency and Time-Based Parameters.

The theory of executive attention (Fuster, 2015) suggests considerable plasticity regarding when specific neurocognitive operations are recruited to bring executive tasks to fruition. We tested the hypothesis that differing neurocognitive operations are recruited upon the initiation of a response, but that other distinct neurocognitive operations are recruited towards the middle or end of a response. The Backward Digit Span Test (BDST) was administered to 58 memory clinic patients (MCI, n = 22; no-MCI, n = 36). Latency to generate all correct 5-span responses was obtained. Statistical analyses found that optimal group classification was achieved using the first and third digit backward. First and third response latencies were analyzed in relation to verbal working memory (WM), visual WM, processing speed, visuospatial operations, naming/lexical access, and verbal episodic memory tests. For the first response, slower latencies were associated with better performance in relation to verbal WM and visuospatial test performance. For the third response, faster latencies were associated with better processing speed and visuospatial test performance. Consistent with the theory of executive attention, these data show that the neurocognitive operations underlying successful executive test performance are not monolithic but can be quite nuanced with differing neurocognitive operations associated with specific time epochs. Results support the efficacy of obtaining time-based latency parameters to help disambiguate successful executive neurocognitive operations in memory clinic patients.

Effects of a 10-week musical instrument training on cognitive function in healthy older adults: implications for desirable tests and period of training.

Previous studies have shown that musical instrument training programs of 16 or more weeks improve verbal memory (Logical Memory Test delayed recall), processing speed (Digit Symbol Coding Test), and executive function (Trail Making Test Part B) of musically untrained healthy older adults. However, it is unclear whether shorter-period instrument training can yield similar effects. We sought to (1) verify those results and (2) clarify if intervention effects could be detected using other measures such as reaction time. Healthy older adults (mean age = 73.28 years) were pseudo-randomly assigned to an untrained control group (n = 30) or an intervention group (n = 30) that received a weekly 10-session musical instrument training program (using melodica). We conducted neuropsychological tests on which intervention effects or association with musical training were reported in previous studies. We newly included two reaction time tasks to assess verbal working memory (Sternberg task) and rhythm entrainment (timing task). Intervention effects were determined using a "group × time" analysis of variance (ANOVA). The intervention effects were detected on the reaction time in Sternberg task and phonological verbal fluency. Although intervention effects had been reported on Logical Memory test, Digit Symbol Coding Test and Trail Making Test in previous studies with longer training periods, the present study did not show such effects. Instead, the test-retest practice effect, indicated by significant improvement in the control group, was significant on these tests. The present results indicated the usefulness of working memory assessments (Verbal Fluency Test and Sternberg task) in detecting the effects of short-term melodica training in healthy older adults. The practice effect detected on those three tasks may be due to the shorter interval between pre- and post-intervention assessments and may have obscured intervention effects. Additionally, the findings suggested the requirement for an extended interval between pre- and post-tests to capture rigorous intervention effects, although this should be justified by a manipulation of training period.

Noun Sequence Statistics Affect Serial Recall and Order Recognition Memory.

Most theories of verbal working memory recognize that language comprehension and production processes play a role in word memory for familiar sequences, but not for novel lists of nouns. Some language emergent theories propose that language processes can support verbal working memory even for novel sequences. Through corpus analyses, we identify sequences of two nouns that resemble patterns in natural language, even though the sequences are novel. We present 2 experiments demonstrating better recall in college students for these novel sequences over the same words in reverse order. In a third experiment, we demonstrate better recognition of the order of these sequences over a longer time scale. These results suggest verbal working memory and recognition of order over a delay are influenced by language knowledge processes, even for novel memoranda that approximate noun lists typically employed in memory experiments.

Verbal working memory capacity modulates semantic and phonological prediction in spoken comprehension.

Mounting evidence suggests that people may use multiple cues to predict different levels of representation (e.g., semantic, syntactic, and phonological) during language comprehension. One question that has been less investigated is the relationship between general cognitive processing and the efficiency of prediction at various linguistic levels, such as semantic and phonological levels. To address this research gap, the present study investigated how working memory capacity (WMC) modulates different kinds of prediction behavior (i.e., semantic prediction and phonological prediction) in the visual world. Chinese speakers listened to the highly predictable sentences that contained a highly predictable target word, and viewed a visual display of objects. The visual display of objects contained a target object corresponding to the predictable word, a semantic or a phonological competitor that was semantically or phonologically related to the predictable word, and an unrelated object. We conducted a Chinese version of the reading span task to measure verbal WMC and grouped participants into high- and low-span groups. Participants showed semantic and phonological prediction with comparable size in both groups during language comprehension, with earlier semantic prediction in the high-span group, and a similar time course of phonological prediction in both groups. These results suggest that verbal working memory modulates predictive processing in language comprehension.

Differences in auditory verbal working memory between adults who do and do not stutter on an N-back task

PurposeThe purpose of this study was to investigate auditory verbal working memory in adults who do (AWS) and do not (AWNS) stutter using a highly demanding linguistic N-back task. MethodsFifteen AWS and 15 AWNS matched in age, gender and educational level were asked to hear series of words and respond by pressing a “yes” button if the word they just heard was the same as the word one, two, or three trials back. Words were either phonologically similar (i.e., Phonological Linguistic Condition) or phonologically dissimilar (i.e., Neutral Linguistic Condition). Accuracy and false alarms rates as well as reaction time on correct target trials, missed target trials and false alarms were collected and analyzed. ResultsDifferences were not found between AWS and AWNS in accuracy. Both groups were more accurate and significantly faster in 1- followed by 2- followed by 3-back trials. However, AWS were significantly slower than AWNS in the 2-back level, regardless of linguistic condition. Furthermore, AWS demonstrated more false alarms compared to AWNS. ConclusionResults revealed differences in auditory verbal working memory and interference control between AWS and AWNS when processing highly linguistically demanding stimuli.

Speed of Information Processing and Verbal Working Memory in Children and Adolescents With Cochlear Implants.

Verbal working memory delays are found in many deaf children with cochlear implants compared with normal-hearing peers, but the factors contributing to these delays are not well understood. This study investigated differences between cochlear implant users and normal-hearing peers in memory scanning speed during a challenging verbal working memory task. To better understand variability in verbal working memory capacity within each sample, associations between memory scanning speed, speech recognition, and language were also investigated. Twenty-five prelingually deaf, early implanted children (age, 8-17 yr) with cochlear implants and 25 normal-hearing peers completed the Wechsler Intelligence Scale for Children, Fifth Edition, Letter-Number Sequencing (LNS) working memory task. Timing measures were made for response latency and average pause duration between letters/numbers recalled during the task. Participants also completed measures of speech recognition, vocabulary, and language comprehension. Children with cochlear implants had longer pause durations than normal-hearing peers during three-span LNS sequences, but the groups did not differ in response latencies or in pause durations during two-span LNS sequences. In the sample of cochlear implant users, poorer speech recognition was correlated with longer pause durations during two-span sequences, whereas poorer vocabulary and weaker language comprehension were correlated with longer response latencies during two-span sequences. Response latencies and pause durations were unrelated to language in the normal-hearing sample. Children with cochlear implants have slower verbal working memory scanning speed than children with normal hearing. More robust phonological-lexical representations of language in memory may facilitate faster memory scanning speed and better working memory in cochlear implant users.

The role of bilingualism in paired-associate and cross-situational word learning.

In adulthood, novel words are commonly encountered in the context of sequential language learning, and to a lesser extent, when learning a new word in one's native language. Paired-associate (PAL) and cross-situational word learning (CSWL) paradigms have been studied separately, under distinct theoretical umbrellas, limiting the understanding of the mechanisms underlying the learning process in each. We tested 126 monolinguals and 111 bilinguals on PAL and CSWL, manipulating familiarity and measuring verbal working memory. Results revealed highly similar learning performance across groups, both demonstrating better performance in PAL than in CSWL, similar sensitivity to familiarity, and similar reliance on phonological working memory. We observed a trend such that bilinguals outperformed monolinguals in PAL but not in CSWL, but this trend was weak. Findings indicate limited effects of bilingualism on word learning in adulthood and suggest highly similar word learning mechanisms in learners with different linguistic experiences.

Co-development among reading, math, science, and verbal working memory in the elementary stage.

With a focus on within-person effects, this study investigated mutualism among academic skills (reading, math, science) and between those skills and verbal working memory in a general population sample and groups with high or low skills from Grades 2 to 5 (2010-2016, N = 859-9040, age 6.27-13.13 years, 49% female, ethnically diverse). Mutualism was found between reading and science in all high-ability groups, and between reading/math and verbal working memory only in high-math students. These results remained the same when controlled for socioeconomic status and gender, and with sensitivity analyses. High-skill students (especially high-math students) may improve academic performance through accumulation of academic knowledge and mutualism between academic and cognition. Such mutualism may be driven by high-quality, intensive academic practice.

Are General Anxiety, Reading Anxiety, and Reading Self-Concept Linked to Reading Skills Among Chinese Adolescents With and Without Dyslexia?

This study investigated the cross-sectional relationships between reading-related affective and cognitive factors and reading skills among adolescents with and without dyslexia. Participants were 120 Chinese-speaking eighth graders, including 60 adolescents with dyslexia and 60 typically developing adolescents from Hong Kong, China. Adolescents completed questionnaires on general anxiety, reading anxiety, and reading self-concept. They were also assessed on measures of rapid digit naming, verbal working memory, word reading, reading fluency, and reading comprehension. The results showed that readers with dyslexia reported higher levels of general anxiety and reading anxiety and lower levels of reading self-concept than typical readers. They also showed difficulties in rapid digit naming and verbal working memory. Importantly, controlling for rapid digit naming and verbal working memory, reading self-concept was uniquely associated with word reading and reading fluency for readers with and without dyslexia. Furthermore, reading anxiety and reading self-concept were uniquely associated with reading comprehension for the two groups of readers. The findings point to the importance of considering affective factors when examining the reading skills of Chinese readers and the utility of targeting these factors when supporting the learning of adolescents with and without dyslexia.

Verbal but not visual-spatial working memory contributes to complex arithmetic calculation.

The contribution of working memory to mathematics has been extensively studied. It has been proposed that verbal working memory (VWM) and visual-spatial working memory (VSWM) have distinct contributions, but results have been inconclusive. Here, we hypothesized that VWM and VSWM contribute differentially to separate sub-domains of mathematics. To test this hypothesis, we enrolled 199 primary school students and measured their VWM and VSWM with number/letter/matrix backward span tasks, and tested mathematics performance with simple subtraction, complex subtraction, multi-step calculation and number series completion, while controlling for several aspects of cognition. We found that while letter backward span had a significant contribution to complex subtraction, multi-step computation and number series completion, number backward span only had a significant contribution to multi-step computation, and matrix span had no effect on any math task. These results suggest that only VWM associated with complex mathematics, which might reflect verbal rehearsal. In contrast, VSWM does not appear to associated with mathematics.

Cognitive stimulation of executive functions through computational thinking

The healthy development of cognitive functions, including executive functions, has been shown to depend mainly on the experiences and learning opportunities of people, especially during childhood. Over the past few years, researchers have been studying the impacts of diverse types of interventions on children’s cognitive development in which computational thinking programs are a recent field. This pilot study evaluated the effect of computational thinking training based on the “Programming for Children” program on the executive functions of children aged 10 and 11 years: working memory, inhibition, and planning (N = 30). The results showed that children in the experimental group improved on tests of visuospatial working memory, cognitive inhibition, and sequential planning compared with the control group. However, tests of verbal working memory, memory strategy, and visual spatial planning did not show any observed changes. Although this was an exploratory study, and its findings should be interpreted cautiously due to the small sample size, the findings support the relevance and feasibility of conducting similar larger studies with larger samples.

Executive functions in preschool children with moderate hyperphenylalaninemia and phenylketonuria: a prospective study

BackgroundThe risk of neuropsychological disorders appears to be high in hyperphenylalaninemia (HPA). The hypothesis of executive function impairment is prominent in accounting for the neuropsychological phenotype in phenylketonuria (PKU) and is suspected in moderate hyperphenylalaninemia (MHP). However, the issue of early onset of executive disorders remains. The aim of this study was to explore the hypothesis of early executive dysfunction in HPA patients and the possible links with certain metabolic variables according to the new international classifications for patients with PKU and MHP. A group of 23 HPA children (12 PKU, 11 MHP) aged 3 to 5 years was included and compared to 50 control children. The two groups were comparable in terms of socio-demographics (age, sex, parental education level). Executive functions were assessed using performance-based tests and daily life questionnaires (parents and teachers).ResultsPreschool HPA patients have comparable executive scores to control subjects. In contrast, PKU patients score significantly worse than MHP patients on 3 executive tests (verbal working memory, visual working memory and cognitive inhibition. There is no executive complaints in daily life (parents and teachers) for the 2 groups of patients. In addition, 3 correlations were identified between executive scores and Phe levels at inclusion, mean Phe level and variability of Phe levels throughout life.ConclusionsThus, there appears to be evidence of early executive dysfunction in PKU preschool-children, but not in MHP children. Occasionally, certain metabolic indicators can predict executive difficulties in young children with PKU.

Neuropsychiatric outcomes following strokes involving the cerebellum: a retrospective cohort study.

Given the wide-ranging involvement of cerebellar activity in motor, cognitive, and affective functions, clinical outcomes resulting from cerebellar damage can be hard to predict. Cerebellar vascular accidents are rare, comprising less than 5% of strokes, yet this rare patient population could provide essential information to guide our understanding of cerebellar function. To gain insight into which domains are affected following cerebellar damage, we retrospectively examined neuropsychiatric performance following cerebellar vascular accidents in cases registered on a database of patients with focal brain injuries. Neuropsychiatric testing included assessment of cognitive (working memory, language processing, and perceptual reasoning), motor (eye movements and fine motor control), and affective (depression and anxiety) domains. Results indicate that cerebellar vascular accidents are more common in men and starting in the 5th decade of life, in agreement with previous reports. Additionally, in our group of twenty-six patients, statistically significant performance alterations were not detected at the group level an average of 1.3 years following the vascular accident. Marginal decreases in performance were detected in the word and color sub-scales of the Stroop task, the Rey Auditory Verbal Learning Test, and the Lafayette Grooved Pegboard Test. It is well established that the acute phase of cerebellar vascular accidents can be life-threatening, largely due to brainstem compression. In the chronic phase, our findings indicate that recovery of cognitive, emotional, and affective function is likely. However, a minority of individuals may suffer significant long-term performance impairments in motor coordination, verbal working memory, and/or linguistic processing.

Individual Differences in Holistic and Compositional Language Processing.

Individual differences in cognitive abilities are ubiquitous across the spectrum of proficient language users. Although speakers differ with regard to their memory capacity, ability for inhibiting distraction, and ability to shift between different processing levels, comprehension is generally successful. However, this does not mean it is identical across individuals; listeners and readers may rely on different processing strategies to exploit distributional information in the service of efficient understanding. In the following psycholinguistic reading experiment, we investigate potential sources of individual differences in the processing of co-occurring words. Participants read modifier-noun bigrams like absolute silence in a self-paced reading task. Backward transition probability (BTP) between the two lexemes was used to quantify the prominence of the bigram as a whole in comparison to the frequency of its parts. Of five individual difference measures (processing speed, verbal working memory, cognitive inhibition, global-local scope shifting, and personality), two proved to be significantly associated with the effect of BTP on reading times. Participants who could inhibit a distracting global environment in order to more efficiently retrieve a single part and those that preferred the local level in the shifting task showed greater effects of the co-occurrence probability of the parts. We conclude that some participants are more likely to retrieve bigrams via their parts and their co-occurrence statistics whereas others more readily retrieve the two words together as a single chunked unit.

Lexical ambiguity resolution & bilingual language experience: Evidence from Albanian-Greek bilingual children of immigrant families

The present study aims at exploring lexical ambiguity resolution in bilingual children employing homonym meaning activation. Specifically, we are examining the processing of Greek homonyms in relation to the language input, verbal ability and cognitive capacity of 10–12 years old bilingual children raised in an immigrant context, in which Albanian is their heritage language and Greek is the majority language. We systematically assessed sentence context effects in homonym meaning activation using a cross-modal priming task. Primes were sentences biasing towards the dominant, subordinate, or neither meaning of a sentence-final homonym while visual targets were related to either meaning of the homonym. To measure the bilingual language experience and address variability issues in the dataset, we administered a background questionnaire that focused on acquisition history, bi-literacy practices and self-reported competence in each language along with a standardized test for verbal ability in Greek. The study's findings show that frequency and context are significant parameters in the examination of ambiguity resolution and underline the contribution of verbal working memory to lexical processing. Additionally, our results highlight the role of the bilingual language experience in the function of the mental lexicon and the potential benefits of bi-literacy development.

Semantic Feature Analysis (SFA) treatment in L1 and L2 in bilingual aphasia: Effects of cognitive and language factors

ABSTRACT Background Semantic Feature Analysis (SFA) treatment has been proven to be effective in alleviating word finding difficulties in individuals with aphasia. However, there is no consensus on the impact of SFA on naming abilities and general language skills in bilingual persons with aphasia (BiPWAs), nor on factors that determine the success of the SFA treatment. Aims This study aimed to investigate the efficacy of SFA treatment in a group of L1-Russian – L2-Hebrew chronic stage BiPWAs and to evaluate the contribution of background factors, language and cognitive measures on the treatment success. Methods & Procedures The current study included two groups of BiPWAs. In the experimental group (n=10), six individuals received SFA therapy in both languages and four individuals in L2. The delayed-treatment group (n=10) did not receive therapy and served as a control group. All BiPWAs completed the Bilingual Aphasia Test (BAT) in both languages, as well as a battery of 10 cognitive tests and linguistic background questionnaires. Outcome & Results The results indicated a direct effect of SFA treatment on naming as well as within-language generalization and cross-language transfer. Importantly, we found significant improvements of general language skills in the treated and untreated languages in BiPWAs who received SFA treatment, while no such improvement was observed in the control group. Non-verbal inhibition and verbal working memory in L1-Russian predicted success of SFA treatment in BiPWAs. Conclusions SFA therapy has positive effects on naming ability of BiPWAs. In addition, SFA therapy affects general language skills in BiPWAs. Yet, within-language generalization, cross-linguistic transfer, and maintenance of the treatment results vary across individuals. The success of SFA treatment in BiPWAs is predicted by cognitive functions rather than background factors of bilingualism.

Effects of Cognitive Functions on Speech Recognition in Noise in Cochlear Implant Recipients

Introduction: There are substantial differences in speech recognition performance of adult cochlear implant (CI) recipients. This study investigated the effects of cognitive function on speech recognition in CI recipients. Methods: The verbal working memory of 36 adults with unilateral CIs was tested using digit span tests. Attention and inhibition abilities were assessed by using the Stroop test (both congruent and incongruent tasks). Speech recognition in noise was measured using the Turkish matrix test. Results: A moderate negative correlation was observed between the critical signal-to-noise ratio obtained via speech recognition in noise test and the digit span test scores (backward and digit span total scores). There was no correlation between Stroop test scores and speech recognition in noise in CI recipients. Conclusion: The findings indicated that verbal working memory correlated well with speech recognition outcomes in adult CI recipients and that higher working memory capacity led to better speech recognition performance in noise.

Hanging on the telephone: Maintaining visuospatial bootstrapping over time in working memory.

Visuospatial bootstrapping (VSB) refers to the phenomenon in which performance on a verbal working memory task can be enhanced by presenting the verbal material within a familiar visuospatial configuration. This effect is part of a broader literature concerning how working memory is influenced by use of multimodal codes and contributions from long-term memory. The present study aimed to establish whether the VSB effect extends over a brief (5-s) delay period, and to explore the possible mechanisms operating during retention. The VSB effect, as indicated by a verbal recall advantage for digit sequences presented within a familiar visuospatial configuration (modelled on the T-9 keypad) relative to a single-location display, was observed across four experiments. The presence and size of this effect changed with the type of concurrent task activity applied during the delay. Articulatory suppression (Experiment 1) increased the visuospatial display advantage, while spatial tapping (Experiment 2) and a visuospatial judgment task (Experiment 3) both removed it. Finally, manipulation of the attentional demands placed by a verbal task also reduced (but did not abolish) this effect (Experiment 4). This pattern of findings demonstrates how provision of familiar visuospatial information at encoding can continue to support verbal working memory over time, with varying demands on modality-specific and general processing resources.

Cognitive processes associated with working memory in children with developmental language disorder

The current study examined how individual differences in language, nonverbal, and attention abilities relate to working memory in children with developmental language disorder (DLD) relative to age-matched typically developing (TD) peers using an interference-based model of working memory as our theoretical framework. Our experimental paradigm involved varying the domain (verbal/nonverbal) of recall items and an interference processing task, testing effects of interference. We examined the relative importance of language, nonverbal, and attention skills in predicting working memory performance by using Bayesian leave-one-out cross-validation to compare models with varied combinations of these skills as predictors. We then statistically tested selected models. Selected models were similar between groups for nonverbal, but not verbal, working memory. Language, nonverbal, and attention skills were associated with performance regardless of whether the working memory task was verbal or nonverbal for the DLD group, yet only attention was associated with verbal working memory for the TD group. A broader set of cognitive processes was involved in verbal recall in children with DLD than in TD peers, potentially reflecting diminished specialization of cognitive processes underlying language. The interference-based model of working memory accounted for interrelationships among language, processing speed, and inhibition of interference, revealing new insights into verbal processing.

Dual-functional Network Regulation Underlies the Central Executive System in Working Memory

The frontoparietal network (FPN) and cingulo-opercular network (CON) may exert top-down regulation corresponding to the central executive system (CES) in working memory (WM); however, contributions and regulatory mechanisms remain unclear. We examined network interaction mechanisms underpinning the CES by depicting CON- and FPN-mediated whole-brain information flow in WM. We used datasets from participants performing verbal and spatial working memory tasks, divided into encoding, maintenance, and probe stages. We used general linear models to obtain task-activated CON and FPN nodes to define regions of interest (ROI); an online meta-analysis defined alternative ROIs for validation. We calculated whole-brain functional connectivity (FC) maps seeded by CON and FPN nodes at each stage using beta sequence analysis. We used Granger causality analysis to obtain the connectivity maps and assess task-level information flow patterns. For verbal working memory, the CON functionally connected positively and negatively to task-dependent and task-independent networks, respectively, at all stages. FPN FC patterns were similar only in the encoding and maintenance stages. The CON elicited stronger task-level outputs. Main effects were: stable CON → FPN, CON → DMN, CON → visual areas, FPN → visual areas, and phonological areas → FPN. The CON and FPN both up-regulated task-dependent and down-regulated task-independent networks during encoding and probing. Task-level output was slightly stronger for the CON. CON → FPN, CON → DMN, visual areas → CON, and visual areas → FPN showed consistent effects. The CON and FPN might together underlie the CES’s neural basis and achieve top-down regulation through information interaction with other large-scale functional networks, and the CON may be a higher-level regulatory core in WM.