Differences In Dual-task Cost Research Articles

Cognitive-Motor Dual-Task Costs on Postural Sway During Sit-to-Stand Movement in Children With Cerebral Palsy.

The purpose of this study was to investigate the cognitive-motor dual-task costs (DTCs) on postural sway of children with typical development (TD) and children with cerebral palsy (CP) during the sit-to-stand movement. Twenty children with TD (mean age = 9.35 years) and 17 children with CP (mean age = 8.29 years) randomly performed 3 test conditions: simple motor task, low-complexity cognitive-motor dual-task, and high-complexity cognitive-motor dual-task. The sit-to-stand movement was divided into 3 phases for data analysis: preparation (P1), rising (P2), and stabilization (P3). For each of these phases, the DTCs were calculated by the percentage change in the center of pressure area of sway, velocity of sway, and duration variables between the simple and dual-task conditions. Analysis of variance was applied to test the group, task conditions, and interaction effects. Children with CP had lower DTC than children with TD in area of sway in P1 and P2 variables; anteroposterior velocity of sway in P1, P2, and P3; and duration in P3. Children with TD had higher DTC in the high-complexity cognitive-motor dual-task than in the low complexity one. Children with CP did not show adaptations between the dual-task conditions, showing no differences in DTCs. The simultaneous performance of a motor task and a cognitive task seems to affect children with CP and children with TD differently, but the effects depend on the specific demands of each task. These results demonstrate the importance of rehabilitation actions to place demands involving a variety of postural sway strategies. DTCs are different for children with TD and children with CP. Assessment and rehabilitation strategies must take into account the postural sway behavior of these children.

Tennis expertise reduces costs in cognition but not in motor skills in a cognitive-motor dual-task condition

Dual-process theories predict performance reductions under dual-task situations (= situations where two tasks have to be processed and executed simultaneously), because limited cognitive resources have to be shared between concurrent tasks. Increases in expertise should reduce the attentional resources needed to perform a motor task, leading to reduced dual-task costs. The current studies investigated whether expert tennis players (performance ratings of 1 to 14 in the German system) show smaller costs compared to intermediate players (performance ratings of 15 to 23). Two studies assessed single- and dual-task performance in a within-subject design in the same tennis task, returning balls into a target field. Two different cognitive tasks were used, a 3-back working memory task in study 1, and a vocabulary-learning task (episodic memory) in study 2. As predicted, performance in both cognitive tasks was reduced during dual-tasking, while the accuracy of tennis returns remained stable under cognitive challenge. These findings indicate that skilled tennis players show a task-prioritization strategy in favor of the tennis task in a dual-task situation. In study 1, intermediate players showed higher overall dual-task costs than experts, but the group differences in dual-task costs did not reach significance in study 2. This may have been due to less pronounced expertise-differences between the groups in study 2. The findings replicate and extend previous expertise studies in sports to the domain of tennis. We argue that an athlete's ability to keep up cognitive and motor performances in challenging dual-task situations may be a valid indicator of skill level.

Mild Traumatic Brain Injury Is Associated With Increased Dual-Task Cost During Ambulation: A Preliminary Study.

The aim of the study was to determine the impact of dual-task conditions on mobility after mild traumatic brain injury. Eleven adults with mild traumatic brain injury within 1 wk of injury and 10 age- and sex-matched healthy controls completed gait trials with a single-task condition and three separate dual-task conditions: counting by 1 (low), serial subtraction by 3 (medium), and alternating letters and numbers (high). Dual-task cost was calculated as dual-task cost = ([dual-task performance] - [single-task performance]) / [single-task performance] × 100%. Participants with mild traumatic brain injury ambulated slower than control subjects (P < 0.001). Significant differences in dual-task cost were noted for both group (P < 0.001) and dual-task condition (P = 0.005). Dual-task cost was greater for those with mild traumatic brain injury compared with controls with significant group differences for the low and high cognitive loads (P < 0.05). Only 1 of the 11 individuals with mild traumatic brain injury and 1 of the 10 controls demonstrated gait speed less than 80 cm/sec, which is predictive of community mobility, during any dual-task condition. Dual-task cost exceeded 11.9%, previously determined to be the minimal detectable change in healthy adults, for 9 of the 11 individuals with mild traumatic brain injury compared with 3 of the 10 controls. Dual-task cost may be a more sensitive measure for impairment during dual-task conditions than gait speed after mild traumatic brain injury.

Association between the level of attention and dual-task costs on postural sway and cognitive yield in children, adolescents, and young adults.

Postural stability requires attentional resources. Dual-task paradigms are used to investigate the attentional demand of the studied tasks. However, no studies have been conducted on the subjects' level of attention, analyzing its association with dual-task costs (DTC). To evaluate the attentional level and DTC on postural sway and cognitive yield in children, adolescents, and young adults, investigating age-related differences, and to analyze if the participants' attention level is associated with DTC. Postural sway and cognitive-yield of 30 children, 24 adolescents, and 32 young adults were assessed in a dual-task paradigm. We calculated DTC on postural sway and cognitive yield. Attention level was tested using Psychological Battery for Attention Assessment. We tested the association between DTC and attention level. Young adults showed higher DTC on area and velocity of postural sway than children and adolescents. No differences in DTC on cognitive yield were found between the groups. Children showed lower attention levels than adolescents and young adults. Attention level was negatively associated with DTC on cognitive yield in young adults. Focused Attention is responsible for 24.4% of the variance in DTC on cognitive yield. Age impacts DTC on postural stability, but not on cognitive performance. The smaller changes in sway found in children/adolescents when dual-tasking, potentially reflect less developed attentional levels and postural control, which make them performing postural tasks closed to their stability boundaries, and, therefore, make them prioritize stability protection more than adults. Similar DTC on cognition between groups may reflect an equalization of the chosen cognitive task at everyone's difficulty level. The lower attention levels of children may reflect an attentional system in development, with prioritization o postural tasks when dual-tasking to maintain stability. Although attention level increases throughout age, attention only predicted DTC on cognition. Better Focused Attention's levels predicted lower DTC on cognitive yield for young adults.

Assessment of Cognitive-Motor Performance Costs, Task Prioritization, and Adaptation to Dishwashing Under Increased Demand in Older Women With Arthritis.

Background and ObjectivesHand arthritis can limit upper-limb instrumental activities of daily living (IADLs) and require the recruitment of additional cognitive and motor resources to support performance. We devised a dual-task protocol for dishwashing to examine cognitive-motor performance costs and prioritizations under increased demands, processes of adaptation, and individual differences in performance costs.Research Design and MethodsSixty women with hand arthritis (aged 60–91) completed a standardized dishwashing protocol. Motor demand was increased via the properties of the soap dispenser. Cognitive demand was increased using audial attention and response inhibition tasks. The protocol was completed twice per lab visit on 3 occasions. Response time and dishwashing time provided measures of cognitive and motor task performance. Prioritization was determined by comparing the magnitude of dual-task cost (DTC) across tasks. Adaptation to the dishwashing protocol and novel dispenser was assessed by change in DTC across lab visits. Individual differences in cognitive and physical ability were assessed with the trail making B test and gait speed.ResultsEstimates from linear mixed-effects models revealed that response time increased, whereas dishwashing time decreased, during the dual-task study stages. Cognitive-motor prioritization effects were most pronounced among women with lower cognitive and physical ability. Evidence of prioritization and individual differences in DTC diminished across lab visits.Discussion and ImplicationsThe pattern of results suggests that older women with arthritis prioritize the motor over cognitive components of dishwashing, a common IADL. Adaptation across lab visits resulted in improved performance, reduced evidence of prioritization, and attenuated differences in DTC across physical and cognitive abilities.

Influence of a Cell-Phone Conversation on Balance Performance in Women with Fibromyalgia: A Cross-Sectional Descriptive Study.

Background Altered balance is a common and debilitating symptom of fibromyalgia. Previous studies have investigated balance under single-task conditions that do not reflect real-life situations. The present study evaluated the impact of a simultaneous cell-phone conversation on balance performance in a case-control cohort from Spain. Methods A cross-sectional case-control study was performed in 34 women recruited from local self-help organizations and university facilities (n = 18 fibromyalgia cases; n = 16 healthy, pain-free controls). Participants performed the 30 s postural stability test, as implemented in the Biodex Balance System, under two conditions: (a) as a single task and (b) as a dual task, i.e., while holding a simultaneous cell-phone conversation with a technician. Intergroup differences in dual task costs were calculated. Findings Compared with controls, women with fibromyalgia showed higher dual-task costs in balance variables, such as overall sway (pp value = 0.039) and anterior/posterior sway (p value = 0.007). In the dual-task condition, overall (p value = 0.004) and anterior/posterior (p value = 0.012) sway indices significantly decreased in women with fibromyalgia but not in controls. Interpretation In women with fibromyalgia, balance performance was adversely impacted by the holding of a simultaneous cell-phone conversation. The inability to conduct two tasks simultaneously may be related to reduced attention and may increase the risk of falling in this population.

Chronic Pain Characteristics and Gait in Older Adults: The MOBILIZE Boston Study II

ObjectiveTo investigate a proposed cognitively-mediated pathway whereby pain contributes to gait impairments by acting as a distractor in community-living older adults. DesignA cross-sectional study of a population-based cohort of older adults. SettingUrban and suburban communities in a large metropolitan area. ParticipantsCommunity-living participants (N=302) 70 years and older recruited from a previous population-based cohort. InterventionsNot applicable. Main Outcome MeasuresGait parameters including gait speed, stride length, double support and swing characteristics, and variability were assessed under single- and dual-task conditions involving cognitive challenges (eg, counting backward). A joint pain questionnaire assessed pain distribution in the back and major joints. We examined pain-gait relationships using multivariable linear regression and bootstrapping mediation procedures. ResultsForty-three percent of participants had pain in 2 or more musculoskeletal sites. Pain distribution was related to slower gait speed and other gait characteristics for all gait conditions. Associations persisted after adjustment for age, sex, education, body mass index, medication, and vision. Decrements in gait measures related to pain were comparable with decrements in gait related to dual-task conditions. There were no differences in dual-task cost among the pain distribution groups. Adjusted for confounders, pain-gait relationships appear mediated by selective attention. ConclusionsThese findings suggest that chronic pain contributes to decrements in gait, including slower gait speed, and that it operates through a cognitively-mediated pathway. Further research is needed to understand the mechanisms via pain alters mobility and to develop interventions to improve mobility among older adults with chronic pain.

Minimal Detectable Change in Dual-Task Cost for Older Adults With and Without Cognitive Impairment.

Dual-task (DT) training has become a common intervention for older adults with balance and mobility limitations. Minimal detectable change (MDC) of an outcome measure is used to distinguish true change from measurement error. Few studies reporting on reliability of DT outcomes have reported MDCs. In addition, there has been limited methodological DT research on persons with cognitive impairment (CI), who have relatively more difficulty with DTs than persons without CI. The purpose of this study was to describe test-retest reliability and MDC for dual-task cost (DTC) in older adults with and without CI and for DTs of varying difficulty. Fifty participants 65 years and older attended 2 test sessions within 7 to 19 days. Participants were in a high cognitive group (n = 27) with a Montreal Cognitive Assessment (MoCA) score of 26 or more, or a low cognitive group (n = 23) with a MoCA score of less than 26. During both sessions, we used a pressure-sensing walkway to collect gait data from participants. We calculated motor DTC (the percent decline in motor performance under DT relative to single-task conditions) for 4 DTs: the Timed Up and Go (TUG) while counting forward by ones (TUG1) and counting backward by threes (TUG3); and self-selected walking speed (SSWS) with the same secondary tasks (SSWS1 and SSWS3). Intraclass correlation coefficients (ICCs) and MDCs were calculated for DTC for the time to complete the TUG and spatiotemporal gait variables during SSWS. A 3-way analysis of variance was used to compare differences in mean DTC between groups, tasks, and sessions. ICCs varied across groups and tasks, ranging from 0.02 to 0.76. MDCs were larger for individuals with low cognition and for DTs involving counting backward by threes. For example, the largest MDC was 503.1% for stride width during SSWS3 for individuals with low cognition, and the smallest MDC was 5.6% for cadence during SSWS1 for individuals with high cognition. Individuals with low cognition demonstrated greater DTC than individuals with high cognition. SSWS3 and TUG3 resulted in greater DTC than SSWS1 and TUG1. There were no differences in DTC between sessions for any variable. Our study provides MDCs for DTC that physical therapists may use to assess change in older adults who engage in DT training. Persons with low cognition who are receiving DT training must exhibit greater change in DTC before one can be confident the change is real. Also, greater change must be observed for more challenging DTs. Thus, cognitive level and task difficulty should be considered when measuring change with DT training.

Differences in Cognitive-Motor Interference in Older Adults While Walking and Performing a Visual-Verbal Stroop Task

Objectives: Studies using the dual-task (DT) paradigm to explain age-related performance decline due to cognitive-motor interference (CMI) which causes DT costs (DTCs) revealed contradictory results for performances under DT conditions. This cross-sectional study analyzed whether differences in demographics, physical functioning, concerns of falling (CoF), and other mental factors can explain positive and negative DTCs in older adults while walking in DT situations.Methodology: N = 222 participants (57–89 years) performed a single task (ST) and a DT walking condition (visual-verbal Stroop task) in randomized order on a treadmill. Gait parameters (step length, step width) were measured at a constant self-selected walking speed. Demographics [age, Mini Mental Status Examination (MMSE)], physical functioning (hand grip strength), CoF [Falls Efficacy Scale International (FES-I)], and mental factors [Short Form-12 (SF-12)] were assessed. An analysis of variance (ANOVA) was used to reveal subgroup differences. A four-step hierarchical regression analysis was conducted to identify which variables determine the DTC.Results: Three subgroups were identified: (1) participants (n = 53) with positive DTCs (improvements under DT conditions); (2) participants with negative DTCs (n = 60) in all gait parameters; and (3) participants (n = 109) who revealed non-uniform DTCs. Baseline characteristics between the subgroups showed differences in age (F(2,215) = 4.953; p = 0.008; η2 = 0.044). The regression analysis revealed that physical functioning was associated with positive DTC and CoF with negative DTC.Conclusion: The results confirmed a huge inter-individual variability in older adults. They lead us to suggest that factors causing performance differences in DTCs needs to be reassessed. Functional age seems to determine DTCs rather than calendric age. Psychological variables particularly seem to negatively influence DT performance.

A cross-sectional analysis on the effects of age on dual tasking in typically developing children.

Dual tasking is an integral part of everyday activities for children. Therefore, as with the other aspects of child development-motor, cognitive, perceptual, psychological, and behavioral-it is important to understand the maturation process of dual-tasking skills in children. Characterizing age-related changes in children's dual-task performance has been problematic, because differences in dual-tasking ability are confounded by age differences in abilities in the relevant single-task performances. The effect of age on dual-tasking ability was examined in 221 typically developing children aged 5-8years using two motor-cognitive dual-task paradigms: walking while performing an n-back cognitive task, and drawing a trail while performing an n-back cognitive task. The test-retest reliability of the dual-task paradigm was examined by re-assessing 50 participants after 1month. Individual differences in single-task performance were controlled for, so that any age differences in dual-task costs could not be attributed to differences in single-task performance. There were no age-related differences in dual-task cost of any task (p > 0.05). However, the dual-task cost of trail-making was significantly greater than the dual-task cost of walking when performed under similar cognitive loads (p < 0.0001). The intra-class correlation coefficient ranged from 0.71 to 0.92 for all dual-task performances. The results suggest that previously reported age differences in dual-task costs in young children may have been driven by developmental differences in single-task ability, and that general task coordination ability is comparable in children 5-8years of age.

Dual-task cost in people with multiple sclerosis: A case–control study

Introduction Limitations in fine motor functioning and cognitive performance are frequently reported in multiple sclerosis. Studies about dual-task costs in multiple sclerosis generally explore walking and postural performance. This study aims at exploring dual-task costs when simultaneously performing fine motor and cognitive tasks. Method Eighty people with multiple sclerosis and 80 matched controls performed the nine-hole peg test and the months backward test under single and dual-task conditions. Differences in performance over time were analysed with the paired t-test; differences in dual-task costs between groups were analysed with independent t-tests. Results People with multiple sclerosis and controls showed a significant decrease in fine motor and cognitive performance in dual-task conditions compared to single-task conditions ( P &lt; 0.01). People with multiple sclerosis with limited hand capacity showed larger dual-task costs for cognitive performance compared to other hand capacity groups ( P &lt; 0.05). Individuals with multiple sclerosis with lower cognitive capacity showed larger dual-task costs for fine motor performance ( P &lt; 0.01). Conclusion Both people with multiple sclerosis and controls experience dual-task costs. People with multiple sclerosis with limited hand function showed an increased dual-task cost of cognitive performance and individuals with limited cognitive capacity showed a higher dual-task cost for fine motor performance. Therefore, occupational therapists should focus on cognitive or fine motor aspects during dual-task training dependent on individuals' capacities.

Poorer divided attention in children born very preterm can be explained by difficulty with each component task, not the executive requirement to dual-task

ABSTRACTChildren born very preterm (VP, ≤ 32 weeks) exhibit poor performance on tasks of executive functioning. However, it is largely unknown whether this reflects the cumulative impact of non-executive deficits or a separable impairment in executive-level abilities. A dual-task paradigm was used in the current study to differentiate the executive processes involved in performing two simple attention tasks simultaneously. The executive-level contribution to performance was indexed by the within-subject cost incurred to single-task performance under dual-task conditions, termed dual-task cost. The participants included 77 VP children (mean age: 7.17 years) and 74 peer controls (mean age: 7.16 years) who completed Sky Search (selective attention), Score (sustained attention) and Sky Search DT (divided attention) from the Test of Everyday Attention for Children. The divided-attention task requires the simultaneous performance of the selective- and sustained-attention tasks. The VP group exhibited poorer performance on the selective- and divided-attention tasks, and showed a strong trend toward poorer performance on the sustained-attention task. However, there were no significant group differences in dual-task cost. These results suggest a cumulative impact of vulnerable lower-level cognitive processes on dual-tasking or divided attention in VP children, and fail to support the hypothesis that VP children show a separable impairment in executive-level abilities.

No differences in dual-task costs between forced- and free-choice tasks.

Humans appear to act in response to environmental demands or to pursue self-chosen goals. In the laboratory, these situations are often investigated with forced- and free-choice tasks: in forced-choice tasks, a stimulus determines the one correct response, while in free-choice tasks the participants choose between response alternatives. We compared these two tasks regarding their susceptibility to dual-task interference when the concurrent task was always forced-choice. If, as was suggested in the literature, both tasks require different "action control systems," larger dual-task costs for free-choice tasks than for forced-choice tasks should emerge in our experiments, due to a time-costly switch between the systems. In addition, forced-choice tasks have been conceived as "prepared reflexes" for which all intentional processing is said to take place already prior to stimulus onset giving rise to automatic response initiation upon stimulus onset. We report three experiments with different implementations of the forced- vs. free-choice manipulation. In all experiments we replicated slower responses in the free- than in the forced-choice task and the typical dual-task costs. These latter costs, however, were equivalent for forced- and free-choice tasks. These results are easier to reconcile with the assumption of one unitary "action control system."

Effect of age on dual-task performance in children and adults

Age effects on dual-task costs were examined in healthy adults (Exp. 1) and in typically developing children (Exp. 2). In both experiments, individual differences in performance on the single-task components were titrated so that any age differences in dual-task costs could not be attributed to differences in single-task performance. Dual-task costs were found, but there were no age-related differences in these costs in older relative to younger adults, in 7-year-old relative to 9-year-old children, or across all four age groups. The results from these experiments suggest that previously reported age differences in dual-task costs, in both healthy ageing and child development, may be due to a failure to adequately equate single-task difficulty.

Posture and cognition interfere in later adulthood even without concurrent response production

We investigated adult age differences in dual-task costs in cognitive-sensorimotor settings without concurrent response production and with individually adjusted resource demands for the cognitive task. Twenty-four young adults ( M = 25.42 years, SD = 3.55) and 23 older adults ( M = 68 years, SD = 4.46) performed a cognitive task and two postural control tasks (standing on a stable and moving platform) both separately (single-task context) and concurrently (dual-task context). The cognitive task did not require response production during posture data collection and its difficulty was individually adjusted to 80% correct performance under single-task conditions. Results showed pronounced age differences in postural control in the moving platform condition, which increased further under dual-task conditions. Our findings support the assumption of increased cognitive resource demands for postural control in older adults. They extend existing work by taking two shortcomings of previous studies into account. We discuss cognitive and posture task constraints in this and previous studies as factors determining multi-tasking and its changes in later adulthood.

Walking While Memorizing: Age-Related Differences in Compensatory Behavior

This study investigated predictions of the life-span theory of selection, optimization, and compensation, focusing on different patterns of task priority during dual-task performance in younger and older adults. Cognitive (memorizing) and sensorimotor (walking a narrow track) performance were measured singly, concurrently, and when task difficulty was manipulated. Use of external aids was measured to provide another index of task priority. Before dual-task testing, participants received extensive training with each component task and external aid. Age differences in dual-task costs were greater in memory performance than walking, suggesting that older adults prioritized walking over memory. Further, when given a choice of compensatory external aids to use, older adults optimized walking, whereas younger adults optimized memory performance. The results have broad implications for systemic theories of cognitive and sensorimotor aging, and the costs and benefits of assistive devices and environmental support for older populations.