Dual-task Effects Research Articles

Investigation of postural control and spatiotemporal parameters of gait during dual tasks in ataxic individuals

Concurrent cognitive and motor tasks in ataxic individuals cause functional limitations and negatively affect the independence of patients in daily life. This study aimed to examine the effects of dual task on postural control and spatiotemporal parameters of gait in ataxic individuals. The study included 20 individuals with ataxia. Disease severity was evaluated using the International Cooperative Ataxia Rating Scale. A force platform was used to evaluate postural sway and limits of stability and a GAITRite electronic walkway to evaluate the spatiotemporal parameters of gait. Postural control and gait were evaluated without a simultaneous task (task-1) and with dual tasks consisting of counting the names starting with "a selected letter such as A" (task-2), counting backwards aloud in threes from 100 (task-3), carrying a glass of water with a tray (task-4), and speaking on a mobile phone (task-5). The effects of dual task on postural control and gait parameters were examined with multiple comparisons. The tasks requiring cognitive skills (tasks 2, 3, 5) were determined to have a greater effect on the increase of body sway, and gait was seen to be affected by motor and/or cognitive tasks (tasks 2, 4, 5). From the results of the present study, it is thought that evaluations of postural control and gait performance of ataxic individuals together with the dual tasks they may encounter in daily life are important in terms of their independence in activities of daily living.

Comparing the effects of cognitive dual tasking on balance and gait motor performance in people with mild multiple sclerosis and healthy individuals

Background/Aims People with multiple sclerosis show both cognitive and postural impairment, and various static and dynamic postural activities may be affected under conditions of cognitive distraction. The aim of this study was to determine the effects of cognitive dual tasking on the balance and gait motor performance of people with mild multiple sclerosis (Expanded Disability Status Scale score of 2.0 ± 1.3) and healthy people and to compare these two groups in terms of performing single and dual tasks. Methods People with mild multiple sclerosis (n=39) and healthy individuals (n=33) performed static balance tests (Romberg's Test, tandem stance test, single-legged stance test) and dynamic balance tests (Functional Reach Test, Four Square Step Test, Timed Up and Go Test, 10-Metre Walk Test), with and without a word list generation test (single and dual tasks). Independent t-tests were used to evaluate differences between the two groups, and paired t-tests were used for single or dual tasks for all static and dynamic tests. The magnitude of differences in tasks between measures was expressed as Cohen's d. Results Dual task effects were more evident during dynamic balance tests in participants with multiple sclerosis and healthy participants (specifically the Timed Up and Go Test and 10-Metre Walk Test) (P<0.001). There was a significant difference between both groups only in terms of static balance (P<0.001). Conclusions Dynamic balance and gait were shown to be more affected when performing the dual cognitive task than static balance in people with multiple sclerosis. Dual tasks should be included in diagnoses.

Dual task effect on upper and lower extremity skills in different stages of Parkinson's disease.

Loss of automaticity and deteriorated executive function give rise to dual task deficits in Parkinson's disease (PD). This study aimed to compare single task and dual task upper and lower extremity skills in people with PD (PwPD) at different stages of PD and to examine the dual task effect (DTE) on upper and lower extremity skills in PwPD at different stages of PD. The second aim was to investigate the relationship between the DTE and the quality of life in PwPD. 30 patients divided into 2 groups as mild PD group and moderate PD group according to the Modified Hoehn & Yahr Scale. 15 age matched healthy adults were recruited as the control group. The Unified Parkinson's Disease Rating Scale (UPDRS), the Purdue Pegboard Test (PPT), the Timed Up and Go Test (TUG), the 10 Meter Walk Test (10MWT), and the Parkinson's Disease Questionnaire (PDQ-8) were used for assessments. Single task and dual task scores of all assessments of all groups were significantly different. The DTE on PPT was greater in mild and moderate PD groups than control group and significantly lower in mild PD group than moderate PD group. However, DTE on the TUG and 10MWT was not different in mild PD group than control group and DTE significantly lower in both groups than moderate PD group. Significant correlations between the DTE on PPT, TUG and 10MWT and the PDQ-8 in PwPD were observed. Dual task has a worsening effect on upper and lower extremity skills in PwPD. This effect can be observed earlier in upper extremity skills than lower extremity skills. Also, the DTE and the QoL in PwPD are related.

Investigation of Dual Task Effect on the Severity of Stuttering in School-Age Children

Objective Stuttering is a speech disorder that occurs with frequent and abnormal disruptions in speech, such as sound repetition, sound prolongation, and sound or airflow blockage. Despite the many theories, the cause of stuttering has not been entirely determined, and various factors have been proposed for its etiology. According to the vicious circle hypothesis, increased speech disfluency results from hypervigilance to speech. This study aimed to measure the effect of reduced attention on speech through verbal and non-verbal dual tasks among school children with stuttering. Furthermore, the effect of dual tasks on the severity of stuttering was investigated among them. Materials & Methods In this cross-sectional study, the participants included 39 children (5 girls, 12.8%) and (34 boys, 87.2%) aged 8-12 years (10.25±1.35) with developmental stuttering selected via convenience sampling from primary schools in districts four and eight and speech therapy clinics in Tehran, Iran. Dual tasks were designed using the Visual Basic program. During the study, four speech samples were recorded for each participant. The second and third samples were designed as a dual task (addition of verbal or non-verbal tasks), while the first and fourth samples were designed as a single task. The participant’s severity of stuttering in each sample was calculated based on the number of stuttered syllables (SS%), and data were analyzed by SPSS 20 software. Given the non-normal distribution of data, the generalized linear model with the Generalized Estimating Equation (GEE) and Bonferroni test were used to determine the difference in stuttering severity among speech samples. Results The GEE results showed that the severity of stuttering was different among the four speech samples (P=0.015). The lowest and highest mean stuttering severity among the 39 participants pertained to the non-verbal dual task (14.85) and the single initial task (17.11), respectively. A pairwise comparison of stuttering severity showed that the mean severity in the final single task was significantly lower than in the single initial task (P<0.05). However, mean stuttering severity was not significantly different between verbal and non-verbal tasks (P>0.05). Conclusion The findings showed that stuttering severity reduces when children with stuttering perform dual tasks. In other words, focusing children’s attention on verbal and non-verbal tasks while talking reduced their dysfluency.

Effects of Cycling Dual-Task on Cognitive and Physical Function in Parkinson’s Disease: A Randomized Double-Blind Pilot Study

(1) Background: Those with Parkinson’s disease (PD) may present difficulties in performing dual tasks (DT). The use of DT during training can improve different abilities. Therefore, the objective of this study is to verify the influence of a cycling exercise program combined with a cognitive task on cognitive and physical PD aspects; (2) Methods: A double-blind, randomized pilot study was undertaken. Participants performed a DT intervention composed of cycling and a cognitive task. The cycling parameters, MDS-UPDRS, PDQ-39, TUG Test, 30 s Chair Sit to Stand test and Stroop were used to measure outcomes; (3) Results: DT generated impairment in performing the cycling task, with significant differences in cycling parameters, active and passive distance (m), total work (W) and active speed (rpm). At the cognitive level, there was a trend of improvement in the group that performed the training with DT, which improved by 211%; (4) Conclusions: Combining cycling with a cognitive task caused impairment in the performance of the physical task and an improvement at the cognitive level. Therefore, combining cycling with a cognitive task in a presumably safer environment for patients with PD can be a good way to train these patients for the dual-task challenges with practical applications.

Gait stability in ambulant children with cerebral palsy during dual tasks.

The aim of this cross-sectional study was to measure the effect of dual tasks on gait stability in ambulant children with cerebral palsy (CP) compared to typically developing (TD) children. The children of the CP (n = 20) and TD groups (n = 20) walked first without a dual task, then while counting forward and finally while alternatively naming fruits and animals (DTf/a). They then completed the same cognitive exercises while sitting comfortably. We calculated the distance between the foot placement estimator (FPE) and the real foot placement in the anterior direction (DFPEAP) and in the mediolateral direction (DFPEML) as a measure of gait stability, in a gait laboratory using an optoelectronic system. Cognitive scores were computed. Comparisons within and between groups were analysed with linear mixed models. The dual task had a significant effect on the CP group in DFPEAP and DFPEML. The CP group was more affected than the TD group during dual task in the DFPEML. Children in both groups showed significant changes in gait stability during dual tasks. The impact of dual task on gait stability is possibly due to the sharing of attention between gait and the cognitive task. All children favoured a 'posture second' strategy during the dual task of alternatively naming animals and fruits. Children with CP increased their mediolateral stability during dual task.

Efficacy of mechanisms of neuroplasticity after a stroke.

The sequelae of stoke, including the loss and recovery of function, are strongly linked to the mechanisms of neuroplasticity. Rehabilitation and non-invasive brain stimulation (NIBS) paradigms have shown promise in modulating corticomotor neuroplasticity to promote functional recovery in individuals post-stroke. However, an important limitation to these approaches is that while stroke recovery depends on the mechanisms of neuroplasticity, those mechanisms may themselves be altered by a stroke. Compare Transcranial Magnetic Stimulation (TMS)-based assessments of efficacy of mechanism of neuroplasticity between individuals post-stroke and age-matched controls. Thirty-two participants (16 post-stroke, 16 control) underwent an assessment of mechanisms of neuroplasticity, measured by the change in amplitude of motor evoked potentials elicited by single-pulse TMS 10-20 minutes following intermittent theta-burst stimulation (iTBS), and dual-task effect (DTE) reflecting cognitive-motor interference (CMI). In stroke participants, we further collected: time since stroke, stroke type, location, and Stroke Impact Scale 16 (SIS-16). Although there was no between-group difference in the efficacy of TMS-iTBS neuroplasticity mechanism (p = 0.61, η2 = 0.01), the stroke group did not exhibit the expected facilitation to TMS-iTBS (p = 0.60, η2 = 0.04) that was shown in the control group (p = 0.016, η2 = 0.18). Sub-cohort analysis showed a trend toward a difference between those in the late-stage post-stroke and the control group (p = 0.07, η2 = 0.12). Within the post-stroke group, we found significant relationships between TMS-iTBS neuroplasticity and time since stroke onset, physical function (SIS-16), and CMI (all rs > |0.53| and p-values < 0.05). In this proof-of-principle study, our findings suggested altered mechanisms of neuroplasticity in post-stroke patients which were dependent on time since stroke and related to motor function. TMS-iTBS neuroplasticity assessment and its relationship with clinical functional measures suggest that TMS may be a useful tool to study post-stroke recovery. Due to insufficient statistical power and high variability of the data, generalization of the findings will require replication of the results in a larger, better-characterized cohort.

Dual-Task Effects on Concurrent Speech Production in School-Age Children With and Without Stuttering Disorders.

Contemporary motor theories indicate that well-practiced movements are best performed automatically, without conscious attention or monitoring. We applied this perspective to speech production in school-age children and examined how dual-task conditions that engaged sustained attention affected speech fluency, speech rate, and language productivity in children with and without stuttering disorders. Participants included 47 children (19 children who stutter, 28 children who do not stutter) from 7 to 12 years of age. Children produced speech in two baseline conditions with no concurrent task and under a dual-task condition requiring sustained attention to on-screen stimuli. Measures of speech fluency, speech rate, and language productivity were obtained for each trial and compared across conditions and groups. Dual-task conditions resulted in a reduction in stutter-like disfluencies relative to the initial baseline speaking condition. Effects were similar for both groups of children and could not be attributed to decreases in language productivity or a simple order effect. Findings suggest that diverting attention during the process of speech production enhances speech fluency in children, possibly by increasing the automaticity of motor speech sequences. Further research is needed to clarify neurophysiological mechanisms underlying these changes and to evaluate potential clinical applications of such effects. https://doi.org/10.23641/asha.19945838.

Dual tasking reduces gait asymmetry of trajectory deviation during obstacle circumvention in people with Parkinson's disease.

Certain aspects of gait may depend on cognition, and the effects of dual-tasking (DT) on gait asymmetry (GA) during obstacle circumvention in people with Parkinson's disease (pwPD) may be walking phase-dependent. While the approaching phase requires allocating significant cognitive resources to perform the task, outweighing the available resources may increase GA. During the avoiding phase, the obstacle could be used as an external cue, enhancing the attention to the obstacle and, consequently, improving gait control and regulating GA. The study investigated the effects of obstacle circumvention during gait with DT on GA in pwPD, considering the circumvention phase. Thirty participants, 15 pwPD and 15 neurologically healthy individuals, circumvented an obstacle 20 times (in total) according to side (right and left side) and DT (presence and absence). Spatial-temporal stride parameters, medial-lateral and horizontal trajectory deviations from the original path, strategy to obstacle circumvention (lead limb away from or close to the obstacle during the crossing step), and gaze parameters were calculated during the approaching and avoiding phases. The parameters were grouped considering the side that the obstacle was circumvented during each task, and the symmetry index was calculated. The results showed greater asymmetry of time of fixations, width, duration, and velocity during the approaching phase (p<0.02), whereas the avoiding phase decreased asymmetry of medial-lateral and horizontal trajectory deviations parameters (p<0.001) during obstacle circumvention with DT, in both pwPD and control group. The findings offer a basis for considering that goal-directed movement control may regulate GA in pwPD.

Effects on intermittent postural control in people with Parkinson's due to a dual task.

The aim of the present study was to determine the effects of performing a dual task on the sway density plot parameters in Parkinson's disease and control subjects. A cross-sectional design was used to establish differences in the mean peak, mean time, and mean distance between a group with Parkinson's disease and a control group without Parkinson's disease. The subjects performed, in a unique measurement session, two trials under three different randomized conditions: i. eyes open, ii. eyes closed, and iii. Eyes open with foam base. One trial was performed as a single task (i.e., the subjects completed one of the balance test), while the other trial was performed as a dual task (i.e., the subjects performed a cognitive task at the same time that they maintained the static balance). There was a group x dual task x condition effect in mean peak (F1.5, 51.1=5.21; p=0.015; η2p=0.13) and mean time (F1.4, 47.3=4.43; p=0.03; η2p=0.11) variables. According dual-task cost analysis, there was a main effect of the condition (F6,134=2.44; p=0.05; η2p=0.34) on MD (F2,68=6.90; p<0.01; η2p=0.17). This result indicates differences in the dual task interference in the postural control mechanisms between the Parkinson's disease population and healthy pairs. For easy dual tasks, the Parkinson subjects used anticipatory control responses for longer periods of time, and for more difficult tasks, their control strategy did not change regarding single balance task.

Influence of Different Dual-Task Conditions During Straight or Curved Walking on Gait Performance of Physically Active Older Women With Cognitive Decline.

Real-world walking requires shifting attention from different cognitive demands to adapt gait. This study aims to evaluate the effect of dual tasking on spatiotemporal gait parameters of older adults. Participants were asked to perform a primary complex single-walking task, consisting of a fast-paced linear and a curved gait. Primary task was performed separately and simultaneously with different motor and cognitive secondary tasks. Spatiotemporal gait parameters, walk ratio, and walk stability ratio were measured. Apart from stride length, which stood relatively unchanged, gait speed and cadence were strongly affected by cognitive dual tasking. Cadence seems to be the most impacted by dual tasking during curved gait as it combines challenges of both primary and secondary tasks. Also, during curved phase, walking ratio was significantly lower and stability ratio was greater demonstrating that participants adopted a cautious gait where maintenance of stability took preference over efficiency.

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.

Yaşlı bireylerde tek-görev, çift-görev ve ardışık fiziksel-bilişsel eğitimin düşme riski ve denge performansı üzerine etkileri: randomize çalışma

Purpose: This study aimed to examine the effects of single-task, dual-task and successive physical-cognitive training on fall risk, balance, and gait performances in elderly.Methods: A total of 45 healthy older adults (73.0±4.6 years; 6 male and 39 female) underwent one of three interventions 3 times a week for 4 weeks. Group-1 performed single-task balance and gait exercises. Group-2 performed cognitive activity, balance, and gait exercises simultaneously. Group-3 performed successive cognitive activities and balance and gait exercises. Gait speed under single-task and dual-task conditions, Berg Balance Scale, Timed up and Go test, and Tinetti's Falls Efficacy Scale scores were evaluated before and after 4 weeks of interventions.Results: Gait speed under single-task condition, Timed up and Go Test, and Berg Balance Scale scores were improved in all groups (p&amp;lt;0.05). Gait speed under dual-task condition was improved in Groups-2 and 3 (p&amp;lt;0.05). Group-3 had greater improvement in Berg Balance Scale and Timed up and Go test scores than Group-2. Tinetti's Falls Efficacy Scale was improved in Group-1 and 3 after training while the improvement was greater in Group-3 (p=0.001).Conclusion: The present study suggests that an intervention involving cognitive and physical activities results in greater improvement in gait speed than interventions involving physical activities alone. However, successive physical-cognitive training may be more effective in reducing fear of fall and improving balance skills in elderly.

The effect of different dual tasks conditions on gait kinematics and spatio-temporal walking parameters in older adults

BackgroundDual-task (DT) walking has increasingly been investigated over the last decade because of its valuable role as a clinical marker of both cognitive impairment and fall risk in older adults based on cognitive and motor performance (DTEcog, DTEmotor). However, there is still a lack of information on what type of dual task to choose and which is the most adapted to the population of interest. Research questionTo evaluate the effect of different dual-tasks (DT3, DT7, FLU, STROOP) on the spatiotemporal and kinematic parameters of hip, knee, and ankle joints. MethodsThirty-eight older adults were recruited (9 men, 29 women, mean age = 77.5 +/- 6.5 years, mean height = 163.6 +/- 8.6 cm, mean weight = 67.5 +/- 15.3 kg). They performed a single and dual-task walk with the 4 types of tasks during 1 min, equipped with an inertial system. Dual-task effect (DTE) on spatiotemporal and kinematic variables as well as cognitive score and speed were calculated. ResultsAn alteration in most of the spatiotemporal parameters was observed in each DT condition (p < 0.05), especially in arithmetic tasks (DT3, DT7), while no DT effect was noticed on kinematic parameters (RMSE<3°) except on hip and knee angular velocities (RMSE>15°). Arithmetic tasks seemed to alter more spatiotemporal and kinematic parameters than the verbal fluency or STROOP test. However, DT7 appeared to be too difficult for the population of interest. SignificanceArithmetic tasks seemed to be very pertinent as a clinical dual-task protocol for older adults. The use of an inertial system to retrieve kinematic variables is an improvement in these dual-task protocols.

Additional cognitive load decreases performance but not adaptation to a visuomotor transformation

Dual-task paradigms are procedures for investigating interference with two tasks performed simultaneously. Studies that previously addressed dual-task paradigms within a visuomotor reaching task yielded mixed results. While some of the studies found evidence of cognitive interference, called dual-task costs, other studies did not. We assume that dual-task costs only manifest themselves within the explicit component of adaptation, as it involves cognitive resources for processing. We suspect the divergent findings to be due to the lack of differentiation between the explicit and implicit component. In this study, we aimed to investigate how a cognitive secondary task affects visuomotor adaptation overall and its different components, both during and after adaptation. In a series of posttests, we examined the explicit and implicit components separately. Eighty participants performed a center-outward reaching movement with a 30° cursor perturbation. Participants were either assigned to a single task group (ST) or a dual-task group (DT) with an additional auditory 1-back task. To further enhance our predicted effect of dual-task interference on the explicit component, we added a visual feedback delay condition to both groups (ST/DTDEL). In the other condition, participants received visual feedback immediately after movement termination (ST/DTNoDEL).While there were clear dual-task costs during the practice phase, there were no dual-task effects on any of the posttest measures. On one hand, our findings suggest that dual-task costs in visuomotor adaptation tasks can occur with sufficient cognitive demand, and on the other hand, that cognitive constraints may affect motor performance but not necessarily motor adaptation.

A Novel Way of Measuring Dual-Task Interference: The Reliability and Construct Validity of the Dual-Task Effect Battery in Neurodegenerative Disease

Background. Decreased automaticity is common among individuals with neurodegenerative disease and is often assessed using dual-task (DT) paradigms. However, the best methods for assessing performance changes related to DT demands remain inconclusive. Objective. To investigate the reliability and validity of a novel battery of DT measures (DT Effect—Battery (DTE-B)) encompassing three domains: task-specific interference, task prioritization, and automaticity. Methods. Data for this retrospective cross-sectional study included 125 participants with Parkinson’s disease (PD), 127 participants with Alzheimer’s disease (AD), and 84 healthy older adults. Reliability analyses were conducted using a subset of each population. DTE-B measures were calculated from single and DT performance on the Timed Up and Go test and a serial subtraction task. Construct validity was evaluated via associations within the DTE-B and with theoretically supported measures as well as known-groups validity analyses. Results. Good to excellent reliability was found for DTE-B measures of task interference (motor and cognitive DT effects) (ICCs≥.658) and automaticity (combined DT effect (cDTE)) (ICCs≥.938). Evidence for convergent validity was found with associations within the hypothesized constructs. Known-groups validity analyses revealed differences in the DTE-B among the healthy group and PD and AD groups (ps≤.001), excepting task prioritization (ps≥.061). Conclusions. This study provides evidence to support the DTE-B as a reliable measure of multiple constructs pertinent to DT performance. The cDTE demonstrated evidence to support its validity as a measure of automaticity. Further investigation of the utility of the DTE-B in both PD and AD, as well as other populations, is warranted.

Does dual task merged in a mixed physical exercise protocol impact the mobility under dual task conditions in mild impaired stroke survivors? A feasibility, safety, randomized, and controlled pilot trial

Purpose To investigate the feasibility, safety, and effects of dual task (DT) in a mixed physical exercise protocol on mobility under DT in stroke survivors. Materials and methods Twenty-six chronic mild-impaired stroke survivors (age 51.57 ± 12.55; men= 13, women= 13) were randomly assigned into Experimental Group participating in a 15-week mixed (aerobic and resistance exercises performing a cognitive DT condition simultaneously) physical exercise protocol (30 sessions, 2x/week, duration of 60–90 min), and Control Group engaged in the same protocol without DT. Feasibility and outcome measures were assessed before and after the intervention and in a 5-week follow-up. Results DT physical exercise protocol was viable and safe. This protocol also improved mobility and gait when performed under DT, which was not found in the control group. DT does not influence aerobic resistance, strength, and balance responsiveness. It does not present any improvement in cognition, self-efficacy for falls, and quality of life. Conclusion The results indicate that mixed physical exercise under DT is feasible and safe for mild-impaired stroke survivors. Stroke survivors demonstrate more significant improvement in the mobility performance under DT when submitted to a DT mixed physical exercise protocol than the standard physical exercise intervention. Trial registration Brazilian clinical trials registry (RBR-4mvzz6); WHO trial record (U1111-1198-7173) IMPLICATIONS FOR REHABILITATION DT training can be prescribed by using clear and precise parameters for stroke survivors. Physical Exercise without DT requirements did not improve mobility performing and cognitive tasks simultaneously in stroke survivors. Clinicians are encouraged to incorporate DT requirements into the exercise routines to enhance mobility under DT to mild-moderate stroke survivors.

Association Between Turning Mobility and Cognitive Function in Chronic Poststroke.

Turning difficulties are common in patients with stroke. The detrimental effects of dual tasks on turning indicate a correlation between turning and cognition. Cognitive impairment is prevalent after stroke, and stroke patients with mild cognitive impairment had a poorer turning performance than did stroke patients with intact cognitive abilities. Therefore, we investigated the association between turning mobility and cognitive function in patients with chronic poststroke. Ninety patients with chronic stroke (>6 months post-stroke) were recruited. Angular velocity was assessed using wearable sensors during 180° walking turns and 360° turning on the spot from both sides. Global cognition and distinct cognitive domains were assessed using the Mini-Mental State Examination. In patients with stroke, turning mobility was significantly associated with global cognitive function and distinct cognitive domains, such as visuospatial ability and language. The balance function and lower limbs strength were mediators of the association between cognition and turning. The association highlights the complexity of the turning movement and dynamic motor and cognitive coordination necessary to safely complete a turn. However, our findings should be regarded as preliminary, and a thorough neuropsychological assessment to provide a valid description of distinct cognitive domains is required.

The Impact of Visual and Cognitive Dual-Task Demands on Traffic Perception During Road Crossing of Older and Younger Pedestrians.

With the help of the current experiment, we wanted to learn more about the impact of visually demanding vs. cognitively demanding secondary tasks on the attention allocation of older pedestrians during the phase of traffic perception within the process of road crossing. For this purpose, we used two different road crossing tasks as well as two different secondary tasks. The road crossing “stop task” was a signal detection task, where an approaching car had to be detected. The road crossing “go task” was a dynamic visual search task, where the resolution of a busy road situation had to be identified. The visual secondary task was a static visual search task and the cognitive secondary task was a 1-back (memory) task. One younger group (≤ 30 years) and one older group (≥ 65 years) of participants completed the tasks as single vs. dual-tasks in all possible combinations. Performance was measured through errors and response time; in addition, the subjective workload was assessed via NASA-TLX. Analyses show that the visual secondary task reduces performance in the road crossing more strongly than the cognitive task, while the visual task itself is less impaired by the road crossing tasks than is the cognitive task. Overall, performance diminishes from single to dual-task completion. Results further indicate age effects in terms of increased errors and response time for older compared to younger participants. In addition to these age effects, age-specific dual-task effects emerge for response time in the go task along with the visual task as well as for response time in the cognitive task along with the go task. Subjective workload is higher in the dual-task conditions than in the single tasks. Findings are discussed with regard to theoretical and practical implications.

Unimpaired performance during cognitive and visual manipulations in persons with anterior cruciate ligament reconstruction compared to healthy adults

Emerging research has proposed an increased reliance on visual processing and cognitive faculties in persons following anterior cruciate ligament reconstruction (ACLR). ACLR individuals display increased activation of visual and cognitive processing brain areas during task execution and exhibit dramatic performance decrements when vision is removed or cognitive difficulty is increased. Despite these intriguing findings, no previous studies have comprehensively assessed performance-related outcomes during tasks that challenge the cognitive and visual systems in ACLR individuals. The following hypotheses were proposed: 1) ACLR individuals will perform better on cognitive tests that required visual scanning; 2) ACLR individuals will utilize visual biofeedback when available during a proprioceptive task but experience decrements in performance when visual biofeedback is removed; and 3) during a cognitive-motor dual-task, the motor task will be more attentionally demanding for ACLR individuals compared to controls, whereas cognitive dual-task effects will be similar between groups. Twenty-one individuals with ACLR and 21 matched healthy adults performed a series of cognitive tests (Stroop, Trail Making Test, and NIH EXAMINER Battery), as well as a single-task angle-matching paradigm with and without visual biofeedback and a dual-task angle-matching paradigm with varying levels of visual and cognitive difficulty. ACLR individuals performed similarly on cognitive tasks, regardless of visual scanning requirements, demonstrated similar proprioceptive performance, evident via similar drift during the single-task conditions, and exhibited similar dual-task effects when the angle-matching paradigm was performed concurrently with a cognitive test compared to healthy adults. Despite a growing literature suggesting alterations to visual and cognitive system utilization in ACLR individuals, the current investigation found a subset of ACLR individuals do not exhibit this performance.