Dual-task Performance Research Articles

Dual-Task Interference Slows Down Proprioception.

It is well-known that multitasking impairs the performance of one or both of the concomitant ongoing tasks. Previous studies have mainly focused on how a secondary task can compromise visual or auditory information processing. However, despite dual tasking being critical to motor performance, the effects of dual-task performance on proprioceptive information processing have not been studied yet. The purpose of the present study was, therefore, to investigate whether sensorimotor task performance would be affected by the dual task and if so, in which phase of the sensorimotor task performance would this negative effect occur. The kinematic variables of passive and active knee movements elicited by the leg drop test were analyzed. Thirteen young adults participated in the study. The dual task consisted of performing serial subtractions. The results showed that the dual task increased both the reaction time to counteract passive knee-joint movements in the leg drop test and the threshold to detect those movements. The dual task did not affect the speed and time during the active knee movement and the absolute angle error between the final and the target knee angles. Furthermore, the results showed that the time to complete the sensorimotor task was prolonged in dual tasking. Our findings suggest that dual tasking reduces motor performance due to slowing down proprioceptive information processing without affecting movement execution.

Cognition Uniquely Influences Dual-Task Tandem Gait Performance Among Athletes With a Concussion History.

After a concussion, there are unique associations between static balance and landing with cognition. Previous research has explored these unique correlations, but the factor of time, dual-task, and different motor tasks leave gaps within the literature. The purpose of this study was to determine the associations between cognition and tandem gait performance. We hypothesized that athletes with a concussion history would display stronger associations compared with athletes without a concussion history between cognition and tandem gait. Cross-sectional. Level 3. A total of 126 athletes without (56.3% female; age, 18.8 ± 1.3 years; height, 176.7 ± 12.3 cm; mass, 74.8 ± 19.0 kg) and 42 athletes with (40.5% female; age, 18.8 ± 1.3 years; height, 179.3 ± 11.9 cm; mass, 81.0 ± 25.1 kg) concussion history participated. Cognitive performance was assessed with CNS Vital Signs. Tandem gait was performed on a 3-meter walkway. Dual-task tandem gait included a concurrent cognitive task of serial subtraction, reciting months backward, or spelling words backward. Athletes with a concussion history exhibited a larger number of significant correlations compared with athletes without a concussion history for cognition and dual-task gait time (4 significant correlations: rho-range, -0.377 to 0.358 vs 2 significant correlations: rho, -0.233 to 0.179) and dual-task cost gait time (4 correlations: rho range, -0.344 to 0.392 vs 1 correlation: rho, -0.315). The time between concussion and testing did significantly moderate any associations (P = 0.11-0.63). Athletes with a concussion history displayed better dual-task cost response rate (P = 0.01). There were no other group differences for any cognitive (P = 0.13-0.97) or tandem gait (P = 0.20-0.92) outcomes. Athletes with a concussion history display unique correlations between tandem gait and cognition. These correlations are unaffected by the time since concussion. These unique correlations may represent shared neural resources between cognition and movement that are only present for athletes with a concussion history. Time does not influence these outcomes, indicating the moderating effect of concussion on the correlations persists long-term after the initial injury.

The interplay between cognition, functional and dual-task gait in persons with a vestibular disorder versus healthy controls

Close links exist between vestibular function and cognition. Dual-task (DT) tests may have ecological validity to assess the impact of daily life cognitive-motor demands in people with vestibular dysfunction (PwVD), functional gait and falls risk. The present paper aimed at building predictive models for functional gait under DT conditions, while clarifying the impact of vestibular dysfunction, individual characteristics, varying task types and motor-cognitive demands. Case-controlled observational study with 39 PwVD and 62 healthy participants. The Functional Gait Assessment (FGA), with and without an additional motor, numeracy, or literacy task, was completed. Multiple linear regression was used to fit models to predict FGA under single and DT performance. Dual task cost (DTC, %) was calculated to assess DT interference on FGA performance using the equation: 100*(single task score–dual task score)/single-task score. Following Bonferroni corrections for multiple comparisons (corrected alpha level of 0.003), PwVD had poorer performance than controls for all FGA conditions (p < 0.001), motor (− 3.94%; p = 0.002) and numeracy (− 22.77%; p = 0.001) DTCs and spatial working memory (p = 0.002). The literacy DTC was marginally significant (− 19.39% p = 0.005). FGA single and DT motor, numeracy, and literacy models explained 76%, 76%, 66% and 67% of the variance respectively for PwVD. Sustained attention, visual memory and sex contributed to all models; short-term visual recognition memory, balance confidence, and migraine contributed to some models. Cognitive performance is impaired in PwVD. Motor, numeracy and literacy tasks impair functional gait performance. Cognitive assessment and FGA with a numeracy or literacy cognitive component should be included within assessment protocols and considered in the provision of targeted interventions for PwVD.

Cognitive load causes kinematic changes in both elite and non-elite rowers

The current motor literature suggests that extraneous cognitive load may affect performance and kinematics in a primary motor task. A common response to increased cognitive demand, as observed in past studies, might be to reduce movement complexity and revert to previously learned movement patterns, in line with the progression-regression hypothesis. However, according to several accounts of automaticity, motor experts should be able to cope with dual task demands without detriment to their performance and kinematics. To test this, we conducted an experiment asking elite and non-elite rowers to use a rowing ergometer under conditions of varying task load. We employed single-task conditions with low cognitive load (i.e., rowing only) and dual-task conditions with high cognitive load (i.e., rowing and solving arithmetic problems). The results of the cognitive load manipulations were mostly in line with our hypotheses. Overall, participants reduced movement complexity, for example by reverting towards tighter coupling of kinematic events, in their dual-task performance as compared to single-task performance. The between-group kinematic differences were less clear. In contradiction to our hypotheses, we found no significant interaction between skill level and cognitive load, suggesting that the rowers' kinematics were affected by cognitive load irrespective of skill level. Overall, our findings contradict several past findings and automaticity theories, and suggest that attentional resources are required for optimal sports performance.

Dual-Task Performance, Balance and Aerobic Capacity as Predictors of Falls in Older Adults with Cardiovascular Disease: A Comparative Study.

Cardiovascular diseases (CVD) are highly prevalent and strongly associated with the risk of falls in the elderly. Falls are associated with impairments in cognition and functional or gait performance; however, little is known about these associations in the elderly population with CVD. In this study, we aimed to clarify the possible associations of physical capacity and functional and cognitive outcomes with the incidence of falls in older adults with CVD. In this comparative study, 72 elderly patients were divided into fallers (n = 24 cases) and non-fallers (n = 48 controls) according to the occurrence of falls within one year. Machine learning techniques were adopted to formulate a classification model and identify the most important variables associated with the risk of falls. Participants with the worst cardiac health classification, older age, the worst cognitive and functional performance, balance and aerobic capacity were prevalent in the case group. The variables of most importance for the machine learning model were VO2max, dual-task in seconds and the Berg Scale. There was a significant association between cognitive-motor performance and the incidence of falls. Dual-task performance, balance, and aerobic capacity levels were associated with an increased risk of falls, in older adults with CVD, during a year of observation.

Dual Task Performance in Adolescents With Idiopathic Scoliosis.

Daily life activities commonly include many combinations of dual tasks. Although dual task ability has been studied in healthy young adults, dual task performance in adolescents with idiopathic scoliosis (IS) has not been explored. Our objective in this study was to investigate dual task performance in adolescents with IS. We paired 33 adolescents diagnosed with IS and 33 healthy control participants (age range: 11-17years) and administered to both groups the Stroop Color and Word test as a measure of cognitive ability, and both the Expanded Timed Up and Go (ETUG) test and the Tandem Gait test as measures of motor tasks. During the motor tasks, we had participants spell five-letter words in reverse and count down by seven from a randomly presented number between 50 and 100 to assess their dual task (cognitive-motor) performance. All cognitive, motor, and dual cognitive-motor test scores differed significantly between the IS and healthy control groups. The time taken to complete all these tasks was longer for participants with IS compared with controls (p < .05). These results revealed diminished performances on dual cognitive-motor tasks among adolescents with IS when compared to peers without IS. Dual task performance is a new research paradigm in the scoliosis rehabilitation field, and it should be further investigated in future studies.

Fate of the second task in dual-task interference is associated with sensory system interactions with default-mode network

Psychological refractory period (PRP) effect refers to the delay in responding to the second of two tasks occurring in rapid succession. While all the major models of PRP highlight the importance of the frontoparietal control network (FPCN) in prioritizing the neural processing of the first task, the fate of the second task remains poorly understood. Here, we provide novel neural evidence on how the functional connectivity between sensory systems and the default-mode network (DMN) suspends the neural processing of the second task to ensure the efficient completion of the first task in dual-task situation. In a cross-modal PRP paradigm, a visual task could either precede or follow an auditory task. The DMN was generally deactivated during task performance and selectively coupled with the sensory system underlying the second task subjected to the PRP effect. Specifically, the DMN showed neural coupling with the auditory system when the auditory task came after the visual task, and with the visual system vice versa. More critically, the strength of the DMN-Sensory coupling correlated negatively with the size of the PRP effect: the stronger the coupling, the shorter the PRP. Therefore, rather than being detrimental to the dual-task performance, temporary suspension of the second task, via the DMN-Sensory coupling, surprisingly guaranteed the efficient completion of the first task by reducing the interference from the second task. Accordingly, the entry and processing of the second stimuli in the central executive system were speeded up as well.

The content-dependent effect of the N-back task on dual-task performance

Impaired task accuracy under dual-task conditions leads to issues such as falls and traffic accidents. Specific cognitive tasks (e.g., the N-back task) potentially improves dual-task performance. This study aims to establish an effective cognitive-task methodology for clinical practice and identify dual-task combinations in which the N-back task is likely to improve performance. Twenty-one young, healthy adults performed an intervention task (either N-back or control), followed by single- and dual tasks in the disappearing or dexterity condition, to assess its effect on different days. The participants performed force-control and calculation tasks in both disappearing and dexterity conditions. In the disappearing force-control task, target waveforms disappeared after a few practice trials, and the participants recalled them and adjusted their knee extension torque. The dexterity force-control task involved presenting complex waveforms. The participants carefully observed the waveforms, and adjusted their knee extension torque. We measured changes in the excitability of the dorsolateral prefrontal cortex (DLPFC) using near-infrared spectroscopy to determine whether the N-back-task-induced changes contributed to improving dual-task performance. For dual-task performance in the disappearing condition, the N-back task improved the performance of the disappearing force-control task, but the control task did not. The other results were the same regardless of the type of intervention task. The N-back task enhanced a portion of the DLPFC excitability. However, no correlation was observed between changes in dual-task performance and in DLPFC excitability. Our findings may contribute to establishing an effective method for improving dual-task performance using cognitive tasks.

Association between dual-task function and neuropsychological testing in older adults with cognitive impairment

IntroductionDespite the current high prevalence of dementia, more than half of older adult patients never receive an evaluation. Current evaluation methods are lengthy, cumbersome, and not viable for busy clinics. This indicates that, despite recent improvements, a quick and objective routine test for screening cognitive decline in older adults is still needed. Poor dual-task gait performance has been previously associated with decreased executive and neuropsychological function. However, gait tests are not always viable for clinics or older patients. MethodsThe aim of this study was to assess the relationship between a novel upper-extremity function (UEF) dual-task performance and neuropsychological test results in older adults. For UEF dual-tasks, participants performed a consistent elbow flexion and extension, while counting backwards in increments of threes or ones. Wearable motion sensors were attached to the forearm and upper-arm to measure accuracy and speed of elbow flexion kinematics to calculate a UEF cognitive score. ResultsWe recruited older adults at three stages: cognitively normal (CN) (n = 35), mild cognitively impaired (MCI) of the Alzheimer's type (n = 34), and Alzheimer's disease (AD) (n = 22). The results demonstrate significant correlations between UEF cognitive score and mini-mental state examination (MMSE), Mini-Cog, Category fluency, Benson complex figure copy, Trail making test, and Montreal cognitive assessment (MOCA) (r values between −0.2355 and −0.6037 and p < 0.0288). DiscussionUEF dual-task was associated with executive function, orientation, repetition, abstraction, verbal recall, attention and calculation, language and visual construction. Of the associated brain domains, UEF dual-task was most significantly associated with executive function, visual construction, and delayed recall. The results from this study convey potential for UEF dual-task as a safe and convenient cognitive impairment screening method.

Dyspnea induced by inspiratory loading limits dual-tasking in healthy young adults.

Dyspnea is a common and multidimensional experience of healthy adults and those with respiratory disorders. Due to its neural processing, it may limit or interfere with cognition, which may be examined with a dual-task paradigm. The aim of this study was to compare single-task performance of Stroop Colour and Word Test (SCWT) or inspiratory threshold loading (ITL) to their combined dual-task performance. Secondly, whether mood was related to dyspnea or cognitive performance was also evaluated. A virtual pre-post design examined single (SCWT and ITL) and dual-task (SCWT+ITL) performance. For ITL, a Threshold Trainer™ was used to elicit a "somewhat severe" rating of dyspnea. The SCWT required participants to indicate whether a colour-word was congruent or incongruent with its semantic meaning. The Depression, Anxiety and Stress Scale-21 (DASS-21) was completed to assess mood. Breathing frequency, Borg dyspnea rating, and breathing endurance time were ascertained. Thirty young healthy adults (15F, 15M; median age = 24, IQR [23-26] years) completed the study. SCWT+ITL had lower SCWT accuracy compared to SCWT alone (98.6%, [97.1-100.0] vs 99.5%, [98.6-100.0]; p = 0.009). Endurance time was not different between ITL and SCWT+ITL (14.5 minutes, [6.9-15.0]) vs 13.7 minutes, [6.1-15.0]; p = 0.59). DASS-21 scores positively correlated with dyspnea scores during ITL (rho = 0.583, p<0.001) and SCWT+ITL (rho = 0.592, p<0.001). ITL significantly reduced dual-task performance in healthy young adults. Lower mood was associated with greater perceived dyspnea during single and dual-task ITL. Considering the prevalence of dyspnea in respiratory disorders, the findings of this dual task paradigm warrant further exploration to inform dyspnea management during daily activities.

How to prevent cognitive overload in the walking-arithmetic dual task among patients with Parkinson’s disease

BackgroundParticipants with Parkinson’s disease (PD) may experience difficulty during certain dual-task (DT) tests. Thus, it is necessary to keep the cognitive load within the limits of their ability.ObjectiveTo identify cognitive overload and its influence on the walking and auditory addition and subtraction (AAS, all values within the range of 0–20) DT performance of patients with PD.Study designA cross-sectional observational study with convenience sampling.SettingOutpatient clinic of the Department of Neurology.SubjectsSixteen patients with PD and 15 sex- and age- matched people elderly healthy controls (HCs).MethodsVerbal calculation responses and gait parameters were collected from the two groups in the 2-min single arithmetic task (2-min SAT), 2-min single walking task (2-min SWT), and 2-min walking–arithmetic dual task (2-min WADT).ResultsThe group differences in the lower-limb gait parameters increased in the 2-min WADT (P < 0.01), and those in the arm, trunk, and waist parameters did not change (P > 0.05). In the 2-min SAT, the calculation speed of the PD group was significantly lower than that of the HC group (P < 0.01). In the 2-min WADT, both groups made more errors (P < 0.05), especially the PD group (P = 0.00). PD group miscalculations occurred in the first half of the 2-min SAT but were uniformly distributed in the 2-min WADT. The HC group and PD group had subtraction self-correction rates of 31.25% and 10.25%, respectively. The PD group tended to make subtraction errors when the value of the first operand was 20 or 13.46 ± 2.60 and when the value of the second and third operands were 7.75 ± 2.51 (P = 0.3657) and 8.50 ± 4.04 (P = 0.170), respectively.ConclusionsCognitive overload was observed in patients with PD. This was mainly reflected in the failure of gait control and accurate calculation, indicated by gait parameters of the lower limbs and accuracy of calculation. To impose a constant cognitive load, the amount added or subtracted, especially in subtraction with borrowing, should not be mixed during a sequential arithmetic problem in the DT, and equations with the value of the first operand equal to 20 or approximately 13, the value of the second operand approximately 7, or the value of the third operand of approximately 9 should be excluded in the AAS DT.Trial registrationClinical trial registration number: ChiCTR1800020158.

Influence of cognitive and motor tasks using smartphone during gait: EMG and gait performance analysis – Dual-task study

Previous studies reported changes in spatiotemporal gait parameters during dual-task performance while walking using a smartphone compared to walking without a smartphone. However, studies that assess muscle activity while walking and simultaneously performing smartphone tasks are scarce. So, this study aimed to assess the effects of motor and cognitive tasks using a smartphone while simultaneously performing gait on muscle activity and gait spatiotemporal parameters in healthy young adults. Thirty young adults (22.83 ± 3.92 years) performed five tasks: walking without a smartphone (single-task, ST); typing on a smartphone keyboard in a sitting position (secondary motor single-task); performing a cognitive task on a smartphone in a sitting position (cognitive single-task); walking while typing on a smartphone keyboard (motor dual-task, mot-DT) and walking while performing a cognitive task on a smartphone (cognitive dual-task, cog-DT). Gait speed, stride length, stride width and cycle time were collected using an optical motion capture system coupled with two force plates. Muscle activity was recorded using surface electromyographic signals from bilateral biceps femoris, rectus femoris, tibialis anterior, gastrocnemius medialis, gastrocnemius lateralis, gluteus maximus and lumbar erector spinae. Results showed a decrease in stride length and gait speed from the single-task to cog-DT and mot-DT (p < 0.05). On the other hand, muscle activity increased in most muscles analyzed from single- to dual-task conditions (p < 0.05). In conclusion, performing a cognitive or motor task using a smartphone while walking promote a decline in spatiotemporal gait parameters performance and change muscle activity pattern compared to normal walking.

Toplumda yaşayan yaşlılarda kognitif ve motor fonksiyonlar ile ikili görev performansı arasındaki ilişki: cinsiyet farkları

Dual-task performances may be impaired with the impairment in motor performance and cognitive functions due to aging. The aim of the present cross-sectional study is to investigate the gender differences in dual-task performance. A total of 82 community-dwelling older adults (41 males and 41 females) aged between 65 and 75 years were included. Motor performance was evaluated with the sit-to-stand test, the timed up and go test, 10 m walking test and cognitive functions were evaluated with Montreal Cognitive Assessment Test. Dual-task performances were evaluated as motor-motor and cognitive-motor performance. Mean age was 70.12±3.18 years for females and 69.80±3.21 years for males. Both groups were similar with regard to age, education status, exercise habits, and working status. In dual-task performances, females were found to complete motor-motor tasks in a shorter time as compared to males (p=0.001). Cognitive-motor task performances were found to be better in males (p=0.038). It is considered that gender differences in dual-task performances could be understood better in the light of the results of the present study and treatment may be arranged in accordance with these gender differences.

Effects of Combining Physical and Cognitive Training on Older Adults’ Physical Performance and Functional Abilities: A Systematic Review

Background: The combination of physical and cognitive training effectively enhances the physical function of the elderly by preventing and reducing the incidence of falls as well as increasing independence in daily activities. However, the optimal combination of strategies to achieve the best physical performance and functional capacity in healthy elderly is still being explored. Objective: This study aimed to explore effective combinations to improve physical function. Methods: A comprehensive database search was done through Web of Science, Medline, Embase and PubMed, and was supplemented with Google scholar since September 2022. Titles and abstracts were used to search for keywords, and data were extracted using the Participants; Interventions; Comparisons, and Outcomes (PICO). Results: The 23 included studies recruited subjects aged 65 and older, comprising 872 females and 497 males, while some research did not identify the gender of 216 participants. Among the included studies, 16 were of high quality while 7 were of low quality. Ten studies showed a significant improvement in gait among older adults who underwent combined physical-cognitive training, while two studies found no positive effect on dual-task gait performance. All five studies showed a significant improvement in strength. Out of the four studies conducted, only one showed no improvement in endurance. All five studies showed improved mobility, while only one study found no effect on agility. However, eight out of the eleven papers showed a significant improvement in balance for older adults who underwent combined cognitive and physical training. The three papers that effectively reduced the fear of falling were also significant. Two studies showed that those who received combined training exhibited a significantly better quality of life compared to those who did not. Conclusion: Combined motor-cognitive training is an advanced, feasible and effective method that can promote the improvement of gait, balance and overall health in the elderly. This type of training has a more significant impact on the elderly’s fall response compared to general physical or cognitive training. Additionally, it contributes to promoting functional independence.

The effect of Dual-Task modality on midfrontal theta power and driving performance across the adult lifespan

Driving is a complex activity, entailing concurrent preparation and execution of motor behavior, and processing of cognitive information. Dual-tasking often leads to performance decrements, especially when the subtasks require similar neural resources, e.g., controlling the steering wheel, handling the pedals and shifting gears. With higher age, the ability to simultaneously perform different tasks deteriorates, as more mental resources are required for accurate coordination of movements. Therefore, using electroencephalography, we measured the neural correlates of dual-task driving in 81 healthy younger (n = 27), middle-aged (n = 25) and older adults (n = 29). A visuocognitive and a visuomotor dual-task were combined with a simulated lane-keeping task, with the latter dual-task requiring more similar resources. As expected, steering precision decreased to a higher extent when combined with a visuomotor dual-task in all participants, compared to no deterioration in the visuocognitive dual-task. Yet, this visuomotor dual-task performance decrease was more prominent with increasing age. Remarkably, although midfrontal theta power increased in all groups when a visuomotor dual-task was added, indicating the recruitment of additional mental resources, this increase was less prominent for middle-aged and older adults. This could signify a plateau effect of theta power in which a saturation of mental resources is reached, leading to an increased dual-task cost. Therefore, reducing driver task demands by limiting the need for motor control processing, e.g., by switching to automatic gear shifting, could be beneficial for driving safety.

Cortical thickness is related to cognitive-motor automaticity and attention allocation in individuals with Alzheimer’s disease: a regions of interest study

Alzheimer's disease (AD) is characterized by a distinct pattern of cortical thinning and resultant changes in cognition and function. These result in prominent deficits in cognitive-motor automaticity. The relationship between AD-related cortical thinning and decreased automaticity is not well-understood. We aimed to investigate the relationship between cortical thickness regions-of-interest (ROI) and automaticity and attention allocation in AD using hypothesis-driven and exploratory approaches. We performed an ROI analysis of 46 patients with AD. Data regarding MR images, demographic characteristics, cognitive-motor dual task performance, and cognition were extracted from medical records. Cortical thickness was calculated from MR T1 images using FreeSurfer. Data from the dual task assessment was used to calculate the combined dual task effect (cDTE), a measure of cognitive-motor automaticity, and the modified attention allocation index (mAAI). Four hierarchical multiple linear regression models were conducted regressing cDTE and mAAI separately on (1) hypothesis-generated ROIs and (2) exploratory ROIs. For cDTE, cortical thicknesses explained 20.5% (p = 0.014) and 25.9% (p = 0.002) variability in automaticity in the hypothesized ROI and exploratory models, respectively. The dorsal lateral prefrontal cortex (DLPFC) (β = - 0.479, p = 0.018) and superior parietal cortex (SPC) (β = 0.467, p = 0.003), and were predictors of automaticity. For mAAI, cortical thicknesses explained 20.7% (p = 0.025) and 28.3% (p = 0.003) variability in attention allocation in the hypothesized ROI and exploratory models, respectively. Thinning of SPC and fusiform gyrus were associated with motor prioritization (β = - 0.405, p = 0.013 and β = - 0.632, p = 0.004, respectively), whereas thinning of the DLPFC was associated with cognitive prioritization (β = 0.523, p = 0.022). Cortical thinning in AD was related to cognitive-motor automaticity and task prioritization, particularly in the DLPFC and SPC. This suggests that these regions may play a primary role in automaticity and attentional strategy during dual-tasking.

Modulation of the executive control network by anodal tDCS over the left dorsolateral prefrontal cortex improves task shielding in dual tasking

Task shielding is an important executive control demand in dual-task performance enabling the segregation of stimulus–response translation processes in each task to minimize between-task interference. Although neuroimaging studies have shown activity in left dorsolateral prefrontal cortex (dlPFC) during various multitasking performances, the specific role of dlPFC in task shielding, and whether non-invasive brain stimulation (NIBS) may facilitate task shielding remains unclear. We therefore applied a single-blind, crossover sham-controlled design in which 34 participants performed a dual-task experiment with either anodal transcranial direct current stimulation (atDCS, 1 mA, 20 min) or sham tDCS (1 mA, 30 s) over left dlPFC. Task shielding was assessed by the backward-crosstalk effect, indicating the extent of between-task interference in dual tasks. Between-task interference was largest at high temporal overlap between tasks, i.e., at short stimulus onset asynchrony (SOA). Most importantly, in these conditions of highest multitasking demands, atDCS compared to sham stimulation significantly reduced between-task interference in error rates. These findings extend previous neuroimaging evidence and support modulation of successful task shielding through a conventional tDCS setup with anodal electrode over the left dlPFC. Moreover, our results demonstrate that NIBS can improve shielding of the prioritized task processing, especially in conditions of highest vulnerability to between-task interference.

Effects of noninvasive brain stimulation on dual-task performance in different populations: A systematic review.

Increasing research has investigated the use of noninvasive brain stimulation (NIBS) on augmenting dual-task (DT) performance. To investigate the effects of NIBS on DT performance in different populations. Extensive electronic database search (from inception to November 20, 2022) was conducted in PubMed, Medline, Cochrane Library, Web of Science and CINAHL to identify randomized controlled trials (RCTs) that investigated the effects of NIBS on DT performance. Main outcomes were balance/mobility and cognitive function under both single-task (ST) and DT conditions. Fifteen RCTs were included, involving two types of intervention techniques: transcranial direct current stimulation (tDCS) (twelve RCTs) and repetitive transcranial magnetic stimulation (rTMS) (three RCTs); and four different population groups: healthy young adults, older adults, Parkinson's disease (PD), and stroke. For tDCS, under DT condition, significant improvement in speed was only observed in one PD and one stroke RCT, and stride time variability in one older adults RCT. Reduction in DTC in some gait parameters was demonstrated in one RCT. Only one RCT showed significant reduction in postural sway speed and area during standing under DT condition in young adults. For rTMS, significant improvements in fastest walking speed and time taken to Timed-up-and-go test under both ST and DT conditions were observed at follow-up in one PD RCT only. No significant effect on cognitive function in any RCT was observed. Both tDCS and rTMS showed promising effects in improving DT walking and balance performance in different populations, however, due to the large heterogeneity of included studies and insufficient data, any firm conclusion cannot be drawn at present.

The impact of music making on neural efficiency & dual-task walking performance in healthy older adults

ABSTRACT Music making is linked to improved cognition and related neuroanatomical changes in children and adults; however, this has been relatively under-studied in aging. The purpose of this study was to assess neural, cognitive, and physical correlates of music making in aging using a dual-task walking (DTW) paradigm. Study participants (N = 415) were healthy adults aged 65 years or older, including musicians (n = 70) who were identified by current weekly engagement in musical activity. A DTW paradigm consisting of single- and dual-task conditions, as well as portable neuroimaging (functional near-infrared spectroscopy), was administered. Outcome measures included neural activation in the prefrontal cortex assessed across task conditions by recording changes in oxygenated hemoglobin, cognitive performance, and gait velocity. Linear mixed effects models examined the impact of music making on outcome measures in addition to moderating their change between task conditions. Across participants (53.3% women; 76 ± 6.55 years), neural activation increased from single- to dual-task conditions (p < 0.001); however, musicians demonstrated attenuated activation between a single cognitive interference task and dual-task walking (p = 0.014). Musicians also displayed significantly smaller decline in behavioral performance (p < 0.001) from single- to dual-task conditions and faster gait overall (p = 0.014). Given evidence of lower prefrontal cortex activation in the context of similar or improved behavioral performance, results indicate the presence of enhanced neural efficiency in older adult musicians. Furthermore, improved dual-task performance in older adult musicians was observed. Results have important clinical implications for healthy aging, as executive functioning plays an essential role in maintaining functional ability in older adulthood.

Muscular and Prefrontal Cortex Activity during Dual-Task Performing in Young Adults

Postural control depends on attentional resources besides automatic processes. The dual-task paradigm is a possible approach to analyzing the interference and performance between motor and/or cognitive tasks. Various studies showed that, when individuals simultaneously perform two tasks, the postural stability can decline during a dual-task compared with a single-task due to the attentional resources required performing the tasks. However, little is known about the cortical and muscular activity pattern during dual-task performance. Therefore, this study aims to analyze the muscular and prefrontal activity under dual-task performance in healthy young adults. Thirty-four healthy young adults (mean age ± SD = 22.74 ± 3.74 years) were recruited to perform a postural task (standing posture) and a dual-task (maintaining standing posture while performing a cognitive task). Lower-limb muscle activity was bilaterally collected from five muscles using surface electromyography (sEMG), and the co-contraction index (CCI) was also calculated for selected muscle pairings. The oxy- and deoxyhemoglobin concentrations (prefrontal cortex activity) were recorded using functional near-infrared spectroscopy (fNIRS). Data were compared between single- and dual-task performance. Prefrontal activity increased (p < 0.05), and muscle activity decreased in most analyzed muscles (p < 0.05), from the single-task to cognitive dual-task performing. The co-contraction index patterns changed from single- to dual-task conditions in most selected muscle pairs (p < 0.05). We conclude that the cognitive task negatively interfered with motor performance once the muscle activity decreased and the prefrontal cortex activity increased under a dual-task, suggesting that young adults prioritized cognitive task performance, and they allocated more attentional resources to the cognitive task over the motor performance. Understanding the neuromotor changes can help adopt a better clinical practice to prevent injuries. However, future studies are recommended to assess and monitor muscular and cortical activity during the dual-task performance to provide additional information about the cortical and muscular activity patterns in postural control while performing a dual-task.