Dual-task Studies Research Articles

Perturbation-based dual task assessment in older adults with mild cognitive impairment.

Dual tasking (i.e., concurrent performance of motor and cognitive task) is significantly impaired in older adults with mild cognitive impairment (OAwMCI) compared to cognitively intact older adults (CIOA) and has been associated with increased fall risk. Dual task studies have primarily examined volitionally driven events, and the effects of mild cognitive impairment on reactive balance control (i.e., the ability to recover from unexpected balance threats) are unexplored. We examined the effect of cognitive tasks on reactive balance control in OAwMCI compared to CIOA. Adults >55 years were included and completed the Montreal Cognitive Assessment (MoCA) to categorize them as OAwMCI (MoCA: 18-24, n = 15) or CIOA (MoCA: ≥25, n = 15). Both OAwMCI [MoCA: 22.4 (2.2), 65.4 (6.1) years, 3 females] and CIOA [MoCA: 28.4 (1.3), 68.2 (5.5) years, 10 females] responded to large magnitude stance slip-like perturbations alone (single task) and while performing perceptual cognitive tasks targeting the visuomotor domain (target and tracking game). In these tasks, participants rotated their head horizontally to control a motion mouse and catch a falling target (target game) or track a moving object (track). Margin of stability (MOS) and fall outcome (harness load cell >30% body weight) were used to quantify reactive balance control. Cognitive performance was determined using performance error (target) and sum of errors (tracking). A 3 × 2 repeated measures ANOVA examined the effect of group and task on MOS, and generalized estimating equations (GEE) model was used to determine changes in fall outcome between groups and tasks. 2 × 2 repeated measures ANOVAs examined the effect of group and task on cognitive performance. Compared to CIOA, OAwMCI exhibited significantly deteriorated MOS and greater number of falls during both single task and dual task (p < 0.05), and lower dual task tracking performance (p < 0.01). Compared to single task, both OAwMCI and CIOA exhibited significantly deteriorated perceptual cognitive performance during dual task (p < 0.05); however, no change in MOS or fall outcome between single task and dual task was observed. Cognitive impairment may diminish the ability to compensate and provide attentional resources demanded by sensory systems to integrate perturbation specific information, resulting in deteriorated ability to recover balance control among OAwMCI.

EXPRESS: The affective consequences of response inhibition determine no-go based crosstalk effects in dual tasks.

Backward crosstalk effects (BCE) are observed in dual-task studies when characteristics of Task 2 influence Task 1 performance. When Task 2 is a go/no-go task, responses in Task 1 are slower when Task 2 is a no-go as compared to a go trial. This no-go BCE has been argued to be due to response inhibition spilling over from Task 2 to Task 1. Growing evidence shows that response inhibition elicits negative affect leading to affective devaluation of associated stimuli. We tested for a functional role of the negative affective consequence of response inhibition in the no-go BCE by investigating its interaction with affective processing in Task 1. In four experiments, Task 1 was a valence categorization task, and Task 2 a go/no-go task. In all experiments, the no-go BCE strongly depended on affective processing in Task 1. While this modulation could be attributed to an affective (mis)match between stimulus features in both tasks in Experiments 1 and 2, Experiments 3 and 4 provided evidence for an affective (mis)match between stimulus valence in Task 1 and affective consequences of Task 2 response inhibition. Results are discussed in the context of current theories of no-go BCE in dual tasks.

Increased dual-task interference during upper limb movements in stroke exceeding that found in aging - a systematic review and meta-analysis.

To determine whether dual-task interference during upper limb tasks is increased in patients after stroke compared to healthy older subjects and to compare magnitude of stroke-induced change in interference to that explained by aging. We conducted a systematic literature search in MEDLINE, CINAHL, Google Scholar and PEDro databases up to October 2023 for studies on upper limb dual-tasks in stroke and elderly healthy subjects. Eleven upper limb dual-task studies in stroke patients and 11 studies in healthy older subjects were identified and systematically reviewed. A meta-analysis was performed on seven stroke studies and on five studies in healthy older subjects that included control groups. Most stroke studies investigated proximal arm movements with kinematic measures, but few studies evaluated manual dexterity. In contrast, studies in healthy older subjects used more distal (finger tapping) tasks. The meta-analysis showed that stroke patients had on average a 19% (CI 95% = 1.0-37.3) increase in dual-task interference compared to age-matched healthy controls (Z = 2.06, p = 0.04). Older healthy subjects showed greater dual-task interference compared to younger subjects (19% greater, CI 95% = 6.5-31.2, Z = 2.98, p = 0.003). Meta-analysis revealed an increase in dual-task interference during upper limb movements in stroke patients, exceeding age-related changes, supporting the presence of subclinical impairments in divided attention post-stroke that may impede motor recovery.

Scoping review of dual-task interference in individuals with intellectual disability.

Dual-task paradigms can provide insights on the structures and mechanisms underlying information processing and hold diagnostic, prognostic, and rehabilitative value for populations with cognitive deficits such as in individuals with intellectual disability (ID). In this paradigm, two tasks are performed separately (single-task context) and concurrently (dual-task context). The change in performance from single- to dual-task context represents dual-task interference. Findings from dual-task studies have been largely inconsistent on whether individuals with ID present with dual-task-specific deficits. The current review aimed to map the published literature on dual-task methods and pattern of dual-task interference in individuals with ID. A scoping review based on Arksey and O'Malley's five-stage methodological framework was performed. Seventeen electronic databases and registries were searched to identify relevant studies, including gray literature. Charted data from included studies were analyzed quantitatively and qualitatively. PRISMA guidelines informed the reporting of this review. Twenty-two studies involving 1,102 participants (656 with ID and 446 without ID) met the review's inclusion criteria. Participants in the included studies were heterogeneous in sex, age (range 3-59 years), etiology and ID severity. Included studies characterized their ID-sample in different ways, most commonly using intelligence quotient (IQ) scores. Other measures of intellectual function (e.g., mental age, ID severity, verbal and/or visuospatial ability scores) were also used, either solely or in combination with IQ. Methods of dual-task testing varied across studies, particularly in relation to dual-task combinations, equation of single-task performance between groups, measurement and reporting of dual-task performance for each single-task, and task priority instructions. Thematic content of the included studies were: (1) structural interference to dual-tasking; (2) etiology-based differences in dual-tasking; (3) gait and balance dual-task performance; (4) testing executive function using dual-task paradigms; and (5) training effect on dual-task performance. Although the evidence consistently supported the intact dual-tasking ability of individuals with ID, the pattern of dual-task interference was inconsistent. Likewise, the evidence was inconclusive regarding dual-task deficit specific to individuals with ID because of heterogeneity in dual-task study designs among included studies.

The role of habitual learning in premotor attention allocation.

Dual-task studies have demonstrated that goal-directed actions are typically preceded by a premotor shift of visual attention toward the movement goal location. This finding is often taken as evidence for an obligatory coupling between attention and motor preparation. Here, we examined whether this coupling entails a habitual component relating to an expectation of spatial congruence between visual and motor targets. In two experiments, participants had to identify a visual discrimination target (DT) while preparing variably delayed pointing movements to a motor target (MT). To induce distinct expectations regarding the DT position, different groups of participants performed a training phase in which the DT either always appeared at MT, opposite to MT, or at an unpredictable position. In a subsequent test phase, the DT position was randomized to assess the impact of learned expectancy on premotor attention allocation. Although we applied individually determined DT presentation times in the test phase of Experiment 1, a fixed DT presentation time was used in Experiment 2. Both experiments yielded evidence for attentional enhancement at the expected DT position. Although interpretability of this effect was limited in Experiment 1 because of between-group differences in DT presentation time, results of Experiment 2 were much clearer. Specifically, a marked discrimination benefit was observed at the position opposite to MT in participants anticipating the DT at this position, whereas no statistically significant benefit was found at MT. Crucially, this was observed at short movement delays, demonstrating that expectation of spatial incongruence between visual and motor targets allows for decoupling of attentional resources from ongoing motor preparation. Based on our findings, we suggest that premotor attention shifts entail a considerable habitual component rather than being the sole result of motor programming.

Impact of cognitive capacity on physical performance in chronic obstructive pulmonary disease patients: A scoping review.

Background: Chronic obstructive pulmonary disease (COPD) is often accompanied by impaired cognitive and physical function. However, the role of cognitive function on motor control and purposeful movement is not well studied. The aim of the review was to determine the impact of cognition on physical performance in COPD. Methods: Scoping review methods were performed including searches of the databases: MEDLINE, EMBASE, Cochrane Systematic Reviews, Cochrane (CENTRAL), APA PsycINFO, and CINAHL. Two reviewers independently assessed articles for inclusion, data abstraction, and quality assessment. Results: Of 11,252 identified articles, 44 met the inclusion criteria. The review included 5743 individuals with COPD (68% male) with the forced expiratory volume in one second range of 24-69% predicted. Cognitive scores correlated with strength, balance, and hand dexterity, while 6-min walk distance (n = 9) was usually similar among COPD patients with and without cognitive impairment. In 2 reports, regression analyses showed that delayed recall and the trail making test were associated with balance and handgrip strength, respectively. Dual task studies (n = 5) reported impaired balance or gait in COPD patients compared to healthy adults. Cognitive or physical Interventions (n = 20) showed variable improvements in cognition and exercise capacity. Conclusions: Cognition in COPD appears to be more related to balance, hand, and dual task function, than exercise capacity.

FİZYOTERAPİ VE REHABİLİTASYONDA YAYINLANAN ÇİFT GÖREV ÇALIŞMALARININ BİBLİYOMETRİK ANALİZİ

OBJECTIVE: Dual-task is the ability to simultaneously perform two motor, behavioral, or cognitive tasks with different objectives at the same time. Most of daily life activities consist of dual-tasks. Dual-task training is commonly used in physiotherapy and rehabilitation. This study aimed to conduct a bibliometric analysis of dual-task studies in physiotherapy and rehabilitation to describe their progress and trends. MATERIAL AND METHODS: Data for bibliometric analysis were collected from the Web of Science. The topic search queries were TS=("dual-task" AND "physiotherapy" OR "dual task" AND "physiotherapy" OR "dual-task" AND “physical therapy” OR "dual task" AND "physical therapy"). RESULTS: As a result of the search, 98 publications were found. Mean number of citations for each publication was 27.29. The United States of America ranked first in terms of collaborative network (n=36) and publications (n=28). Nieuwboer (n=57) was the author who contributed the most to dual-task research (n=5). The keyword with the highest occurrence rate (OR) and total link strength (TLS) was “gait” (OR: 32, TLS: 75). The most commonly referred document among dual-task studies was the study of Folstein et al. (n=21). The document with the highest TLS was the study performed by Silsupadol et al. (n=22). CONCLUSIONS: It was observed that there are severe gaps in the literature in terms of dual-task studies in physiotherapy and rehabilitation. It is suggested that dual-task training should be diversified and applied in different populations.

Lower Kinetic Chain, Meet the Thinking Brain: A Scoping Review of Cognitive Function and Lower Extremity Injury Risk

The classic model of non-contact ACL injury includes environmental, anatomical, hormonal and biomechanical risk factors which directly impact either the amount of stress placed on the ligament or the relative capacity of ligament to withstand the forces placed on it. However, cognition also clearly plays a role in successful athletic performance, yet diminished cognitive function is rarely considered a risk factor for injury. Objective To examine the existing literature to determine the extent to which cognitive function (both cognitive ability and task cognitive load) influences non-contact lower extremity injury risk in male and female athletes with a broad variety of athletic expertise. Study Design Scoping Review Methods An electronic search was conducted of CINAHL, SPORTDiscus, Google Scholar, and MEDLINE using the PRISMA method. Search terms included Boolean combinations of “cognition”, “concussion”, “ImPACT”, “cognitive deficit”, “mild traumatic brain injury (mTBI)”, and “neuropsychological function” as cognitive descriptors and the terms “injury risk” and “lower extremity injury” as injury descriptors. Inclusion criteria included papers written in English published between 2000-2021. Exclusion criteria included neurological and cognitively atypical populations, except for concussion (included). Included articles were appraised using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Results Fifty-six studies utilizing across the spectrum of levels of evidence met inclusion criteria. Forty-one articles had good, fourteen had fair, and one had poor methodological quality. Studies examined baseline cognitive function in healthy athletes (n=7); performance during dual-task paradigms (n=13); and the impact of concussion on dual-task performance (n=4), LE injury risk (n=22), or post-concussion testing (n=10). Six articles examining cognitive function and all dual-task studies (including concussion studies) found altered biomechanics associated with injury or increased processing demands. Studies related to concussion and injury incidence consistently found an increased risk of LE injury following concussion. Half of the studies that examined concussion and post-concussion cognitive testing demonstrated significant effects. Discussion Consistent across participant demographics, tasks, and dependent measures, fifty-one of fifty-six assessed articles concluded that decreased cognitive ability or increased cognitive load led to risky LE mechanics or a direct increase in non-contact LE injury risk. Conclusion The robustness of results across gender, performance level, sport, cognitive ability, task cognitive load suggest that the inclusion of cognitive training in the design of optimal LE injury prevention programs warrants further study. Level of Evidence: Ia

Study Protocol: Strategies and Techniques for the Rehabilitation of Cognitive and Motor Deficits in Patients with Multiple Sclerosis.

MS clinical features vary between patients. In approximately 60% of cases, cognitive deficits are associated with motor disabilities, with consequences on both walking and maintaining balance and cognitive efficiency. Multimodal programs are very infrequent for MS patients and cognitive rehabilitation is not provided by the Italian health system, which only favors access to motor rehabilitation. Dual-task studies showed how motor and cognitive skills are closely associated. Therefore, physiotherapy exercises may favor an indirect improvement in cognition. The aim of this study is to understand which rehabilitative approach may increase both cognitive and motor efficiency, avoiding the waste of time and resources. In this multi-site single-blind parallel controlled clinical trial, we will compare three rehabilitative approaches: cognitive training, motor training and combined cognitive-motor training. We also aim to evaluate: whether self-perception and objective improvement correspond; the impact of each rehabilitation program on patients' QoL, mood and self-perception; and long-term effects. A total of 60 patients will be randomly assigned to one of the three treatments for two 45-min sessions/week for 12 weeks. All participants will undergo a complete cognitive, motor, clinical assessment together with mood, self-perception, and QoL questionnaires before, immediately after and 6 months after the training period.

Capacity limits in sentence comprehension: Evidence from dual-task judgements and event-related potentials

There is an ongoing controversy over whether readers can access the meaning of multiple words, simultaneously. To date, different experimental methods have generated seemingly contradictory evidence in support of serial or parallel processing accounts. For example, dual-task studies suggest that readers can process a maximum of one word at a time (White, Palmer & Boynton, 2018), while ERP studies have demonstrated neural priming effects that are more consistent with parallel activation (Wen, Snell & Grainger, 2019). To help reconcile these views, I measured neural responses and behavioral accuracy in a dual-task sentence comprehension paradigm. Participants saw masked sentences and two-word phrases and had to judge whether or not they were grammatical. Grammatically correct sentences (This girl is neat) produced smaller N400 responses compared to scrambled sentences (Those girl is fled): an N400 sentence superiority effect. Critically, participants' grammaticality judgements on the same trials showed striking capacity limitations, with dual-task deficits closely matching the predictions of a serial, all-or-none processing account. Together, these findings suggest that the N400 sentence superiority effect is fully compatible with serial word recognition, and that readers are unable to process multiple sentence positions simultaneously.

Effect of individualized cognitive and postural task difficulty levels on postural control during dual task condition

BackgroundPrevious dual task studies suggested that the difficulty of the concurrent cognitive and motor tasks may not be challenging to the same degree for each person. This study approaches this problem by setting individualized difficulty levels for tasks to examine the dual task interference. Research questionDo the features of postural sway depend on increased individualized difficulty levels of concurrent cognitive and postural activities? Methods20 young healthy participants (10 male, 10 female) took part in the study. Before the experiments, cognitive task difficulty (No-, Medium-, High) has been set individually. Subjects performed postural tasks (quiet stance, voluntary sway) concurrently with or without a cognitive task which based on simple arithmetic calculations. Postural sway features were examined. ResultsPostural sway features were affected by individualized difficulty level of concurrent cognitive and postural activities. In voluntary sway, as a more challenging postural task, higher reductions were observed for such sway features as COP velocity and range in AP direction. SignificanceThis study signaled task-specific changes in postural sway features. When the difficulty levels were set individually, the effect of motor and cognitive dual task was more apparent when the balance requirement of the primary motor task increased.

Task-prioritization and balance recovery strategies used by young healthy adults during dual-task walking

BackgroundMaintaining dynamic balance is an essential task during walking, with foot-placement playing a critical role. Dual-task studies analyzing steady-state walking with cognitive loads have found healthy adults prioritize cognitive task performance at the expense of maintaining control of their balance. However, few studies have focused on the influence of cognitive loads on more difficult motor tasks, such as walking with unexpected foot-placement perturbations. Individuals often recover from a loss of balance using an ankle or hip strategy; however, how cognitive loads affect these balance recovery strategies remains unknown. Research questionHow do individuals prioritize cognitive resources and does the balance recovery strategy used change following mediolateral foot-placement perturbations during steady-state walking when performing cognitive tasks of increasing difficulty? MethodsFifteen young healthy adults walked during unperturbed and perturbed conditions with increasing cognitive loads (no cognitive load, attentive listening, spelling short words backwards and spelling long words backwards). No specific task-prioritization instructions were given. Medial and lateral foot-placement perturbations were applied prior to heel-strike during random steps. ResultsCognitive performance decreased between the unperturbed and perturbed conditions. While balance control decreased during perturbed relative to unperturbed walking, the additional cognitive load had little effect on balance control during the perturbations. Lastly, the balance recovery strategy used, as measured by peak joint moments at the ankle and hip, was unaffected by the additional cognitive loads. SignificanceIndividuals appear to prioritize their balance control over cognitive performance when experiencing foot-placement perturbations and do not change their balance recovery strategy with the addition of a cognitive load. These results highlight the flexibility of task-prioritization in young adults and provide a foundation for future studies analyzing neurologically impaired populations.

Dual-Task Interference in Children with Down Syndrome and Chronological and Mental Age-Matched Healthy Controls.

Background. On the assumption that motor actions result from the interaction between cognitive, perceptual, and neurological mechanisms, neuromotor dysfunction–such as in children with Down Syndrome (DS)–is expected to affect the central coordination processes required for dual-task (DT) performance. There are few dual-task (DT) studies in individuals with DS, so the current study examined the effects of dual-tasking (DT) on walking performance in children with DS. Method. In this study, a motor-cognitive DT was used in 12 children with DS (10.5 ± 1.08 years, 6 female), 12 typically developed (TD) children with the same mental age (TD-MA: 5.98 ± 1.21 years, 6 female), and 12 with the same chronological age (TD-CA: 10.5 ± 1.07 years, 6 female). Children were asked to enumerate animals for one minute while walking straight ahead. Results. All groups showed lower performances under the DT condition than the single-task (ST) condition. Children with DS appear to have the most difficulties in motor and cognitive tasks and ST- and DT-conditions. Concerning the DT costs (DTC), difficulties were mainly observed with the motor task, with motor DTC being greater than cognitive DTC. Conclusion. The interplay of different systems seems to play a crucial role in walking, especially in children with DS. DT walking paradigms with directional changes are recommended for future studies, as this is more appropriate for the everyday demands of children.

Capacity-free automatic processing of facial expressions of emotion.

Are facial expressions of emotion processed automatically? Some authors have not found this to be the case (Tomasik et al., 2009). Here we revisit the question with a novel experimental logic-the backward correspondence effect (BCE). In three dual-task studies, participants first categorized a sound (Task 1) and then indicated the location of a target face (Task 2). In Experiment 1, Task 2 required participants to search for one facial expression of emotion (angry or happy). We observed positive BCEs, indicating that facial expressions of emotion bypassed the central attentional bottleneck and thus were processed in a capacity-free, automatic manner. In Experiment 2, we replicated this effect but found that morphed emotional expressions (which were used by Tomasik) were not processed automatically. In Experiment 3, we observed similar BCEs for another type of face processing previously shown to be capacity-free: identification of familiar faces (Jung et al., 2013). We conclude that facial expressions of emotion are identified automatically when sufficiently unambiguous. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

An fNIRS Investigation of Discrete and Continuous Cognitive Demands During Dual-Task Walking in Young Adults.

Introduction: Dual-task studies have demonstrated that walking is attention-demanding for younger adults. However, numerous studies have attributed this to task type rather than the amount of required to accomplish the task. This study examined four tasks: two discrete (i.e., short intervals of attention) and two continuous (i.e., sustained attention) to determine whether greater attentional demands result in greater dual-task costs due to an overloaded processing capacity.Methods: Nineteen young adults (21.5 ± 3.6 years, 13 females) completed simple reaction time (SRT) and go/no-go (GNG) discrete cognitive tasks and n-back (NBK) and double number sequence (DNS) continuous cognitive tasks with or without self-paced walking. Prefrontal cerebral hemodynamics were measured using functional near-infrared spectroscopy (fNIRS) and performance was measured using response time, accuracy, and gait speed.Results: Repeated measures ANOVAs revealed decreased accuracy with increasing cognitive demands (p = 0.001) and increased dual-task accuracy costs (p < 0.001). Response times were faster during the single compared to dual-tasks during the SRT (p = 0.005) and NBK (p = 0.004). DNS gait speed was also slower in the dual compared to single task (p < 0.001). Neural findings revealed marginally significant interactions between dual-task walking and walking alone in the DNS (p = 0.06) and dual -task walking compared to the NBK cognitive task alone (p = 0.05).Conclusion: Neural findings suggest a trend towards increased PFC activation during continuous tasks. Cognitive and motor measures revealed worse performance during the discrete compared to continuous tasks. Future studies should consider examining different attentional demands of motor tasks.

Dual-task speech performance in multiple sclerosis

BackgroundAlthough extant dual-task studies suggest cognitive-motor interference may magnify existing non-speech motor impairments in multiple sclerosis (MS), cognitive-speech motor interference in MS has not been studied. This study evaluated the presence of cognitive-speech motor interference in MS and explored within subject differences in speech measures from the single-to dual-task condition for individuals with MS with co-occurring dysarthria and impaired cognition. MethodsIn this dual-task study, 21 individuals with MS and 21 controls read aloud a sentence (single-task) and completed a cognitive-linguistic task while simultaneously reading aloud a sentence (dual-task). Speech measures included speech and articulation rate, silent pause frequency and duration, and total sentence duration. ResultsBoth groups had significantly slower speech in the dual-task condition. Relative to participants with dysarthria, speech rate and sentence duration difference scores approached significance or were significantly greater for participants with MS with dysarthria and cognitive impairment. These difference scores were associated with executive function and processing speed deficits and fewer years of education. ConclusionSignificant negative compounding effects for speech rate and sentence duration suggest that the dual-task paradigm shows promise for identifying individuals with MS with cognitive impairment and dysarthria at increased risk of problems with effective communication. Further research is warranted to replicate this work and evaluate the consequences of these speech aberrancies on communication effectiveness that ultimately may affect employment, social relationships, and quality of life.

The influence of cognitive load on balance control during steady-state walking

For an individual to successfully walk, they must maintain control of their dynamic balance. However, situations that require increased cognitive attention may impair an individual’s ability to actively control their balance. While dual-task studies have analyzed walking-while-talking conditions, few studies have focused specifically on the influence of cognitive load on balance control. The purpose of this study was to assess how individuals prioritize their cognitive resources and control dynamic balance during dual-task conditions of varying difficulty. Young healthy adults (n = 15) performed two single-task conditions (spelling-while-standing and treadmill walking with no cognitive load) and three dual-task conditions (treadmill walking with increasing cognitive load: attentive listening and spelling short and long words backwards). Cognitive performance did not change between the single- and dual-task as measured by spelling percent error and response rate (p = 0.300). Balance control, assessed using the range of whole-body angular momentum, did not change between the no load and listening conditions, but decreased during the short and long spelling conditions (p < 0.001). These results highlight that in young adults balance control decreases during dual-task treadmill walking with increased cognitive loads, but their cognitive performance does not change. The decrease in balance control suggests that participants prioritized cognitive performance over balance control during these dual-task walking conditions. This work offers additional insight into the automaticity of walking and task-prioritization in healthy young individuals and provides the basis for future studies to determine differences in neurologically impaired populations.

Dual-task studies of working memory and arithmetic performance: A meta-analysis.

We performed a meta-analysis of dual-task experiments to assess the robustness of the effects of conducting working memory secondary tasks on arithmetic performance. Four hundred effect sizes from 21 studies from 1,049 participants were analyzed across a variety of specifications. Results revealed that increases in working memory load resulted in slower (7% to 19% reduction) speed of solving of arithmetic problems. Of the potential moderators, working memory load type (i.e., central executive, phonological loop, and visuospatial sketchpad), arithmetic task type (e.g., addition verification, approximate addition, exact multiplication), and authors' predictions for significance which served as a proxy for cross-talk were statistically significant across specifications, but participants' age was not. Working memory load type was the most substantial moderator, with central executive tasks leading to the greatest slowing of performance, suggesting that the cognitive complexity of a working memory task may exert a larger influence on performance than the domain-specific overlapping processing demands of similar tasks. We discuss the apparent discrepancy between these findings and findings from correlational studies of the relation between arithmetic performance and working memory, which have reported similar correlations across working memory domains, on average. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Minding the load or loading the mind: The effect of manipulating working memory on coherence monitoring

Working memory plays an important role in complex cognitive tasks. For example, in the context of reading, it has been argued that working memory provides a workspace for maintenance and integration of different text units and relevant background knowledge. However, the amount of information that needs to held in mind is often at odds with the very restricted capacity traditionally posited by models of working memory. Moreover, direct evidence concerning the role of working memory during reading is ambiguous and largely based on correlational studies. To address these issues, we conducted two dual-task studies in which we manipulated working memory capacity during reading, and examined the effects of working memory capacity on the processes (rather than the products) of reading comprehension. Both experiments focused specifically on the process of coherence monitoring, a crucial component of comprehension, by comparing participants’ responses (i.e., reading times) for texts with and without inconsistencies. Moreover, in Experiment 2 we additionally examined the interaction between working memory load and availability of information by varying textual distance between inconsistent sentences. Both experiments showed that the external working memory load interfered with coherence monitoring, as reflected by reduced responses to inconsistencies. Experiment 2 further revealed that, in addition to working memory capacity, coherence monitoring is influenced by availability. Interestingly, the effect of availability was only significant in the no-load conditions, suggesting that load reduces the inconsistency effect regardless of availability. Together, these findings suggest that although readers may progress through a text relatively effortlessly by using activated portions of long-term memory, the process of coherence monitoring requires at least some working memory capacity.

The Varying Effects of Dual Tasks on the Performance of Motor Skills across Practice

Numerous previous studies using the dual-task methodology have indicated that the effect of attentional direction on the performance of motor skill differs as a function of skill levels. Whereas previous studies relied mostly on inter-individual comparisons, this study focused on how the effects of different attentional conditions change within individuals with practice. Participants were instructed to learn a short and a long keying sequence (three versus six keys) and then practiced under two block-wise alternating dual-task conditions. In each trial, a tone, either low- or high-pitched, was presented at one of the three/six keys and participants had to indicate either the pitch of the tone (extraneous dual task) or the key with which the tone was presented (skill-focused dual task) after finishing the execution of the keying sequence. Motor task performance was assessed by reaction time (RT) and movement duration (MD), and the concurrent cognitive task performance was assessed by the error rate. RT was faster in the skill-focused dual-task condition at the beginning of practice, whereas a generally shorter MD was found in the extraneous dual-task condition. The error rate in the extraneous dual task decreased with practice, whereas in the skill-focused dual task, it increased with practice. These results show that the effects of attentional direction differ not only as a function of the amount of practice but also as a function of the stage of information processing. Furthermore, our results indicate that the direction of attention alone does not explain the different patterns of performance at different skill levels seen across dual-task studies; rather, the skill levels, the nature of cognitive demands, the difficulty level of dual tasks, and the complexity of the motor skill could all drive performance differences.