Differential effects and discriminative validity of motor and cognitive tasks varying in difficulty on cognitive-motor interference in persons with multiple sclerosis

Effect of Explicit Prioritization on Dual Tasks During Standing and Walking in People With Neurologic and Neurocognitive Disorders: A Systematic Review and Meta-analysis

OBJECTIVES

To examine the effectiveness of explicit task (ie, equal, motor or cognitive) prioritization during dual tasking (DT) in adults with neurologic and neurocognitive disorders (stroke, Parkinson disease [PD], multiple sclerosis, dementia, Alzheimer disease, and mild cognitive impairment).

DATA SOURCE

A systematic search in 4 databases (PubMed, Web of Science, Embase, and Cochrane Central) yielded 1138 unique studies published up to 2023.

STUDY SELECTION

Forty-one experimental studies were selected that assessed the effect of explicit prioritization instructions on both motor and cognitive performance during dual-tasks related to standing and walking in selected populations. Primary outcome measures were walking speed and response accuracy. Availability of data allowed us to perform a meta-analysis on 27 of the 41 articles by using inverse variance with a random effects model.

DATA EXTRACTION

The data including design, subject characteristics, motor and cognitive tasks, prioritization, motor and cognitive outcomes, instructions, and key findings were extracted. Two assessors rated the selected studies for risk of bias and quality using the Quality Assessment Tools of the National Institutes of Health.

DATA SYNTHESIS

This study examined 1535 adults who were asked to perform motor-cognitive DT in standing or walking, including 381 adults with stroke, 526 with PD, 617 with multiple sclerosis, 10 with dementia, 9 with Alzheimer disease, and 8 with mild cognitive impairment. During all prioritization instructions, participants slowed down during DT (standardized mean difference (SMD)equal=0.43; SMDmotor=0.78; SMDcognitive=0.69, P<.03) while maintaining similar response accuracy (SMDequal=0.12; SMDmotor=0.23; SMDcognitive=-.01, P>.05). However, considerable between-group heterogeneity was observed resulting in different motor and cognitive responses between pathologies.

CONCLUSION

Motor prioritization was achieved in adults with PD and stroke, unlike adults with neurocognitive disorders who were negatively affected by any type DT prioritizing. The reported within-group heterogeneity revealed that effects of explicit task prioritization are dependent on motor and cognitive task complexity, and the type of instructions. Recommendations are provided to ensure accurate use of instructions during DT paradigms.

Effect of task difficulty on dual-task cost during dual-task walking in people with multiple sclerosis

BACKGROUND

Cognitive-motor dual-task walking results a decrease in walking performance of patients with multiple sclerosis (PwMS) and it is known as dual-task cost (DTC). However, there is a lack of evidence about the effects of dual-tasks with hierarchical difficulty on DTC in PwMS.

RESEARCH QUESTION

This study aimed to investigate the effect of task difficulty on DTC during cognitive-motor dual-task walking in people with multiple sclerosis (PwMS).

METHODS

32 PwMS and 32 healthy controls were included. The 6-meter walking test (6-Meter WT) with comfortable speed was used as single-task walking condition. For dual-task conditions, walking tasks and cognitive tasks at two difficulty levels (simple and difficult) were combined and DTC for four cognitive-motor dual-task walking conditions as simple motor-simple cognitive (SM-SC), simple motor-difficult cognitive (SM-DC), difficult motor-simple cognitive (DM-SC) and difficult motor-difficult cognitive (DM-DC) were calculated. The 6-Meter WT was used also for simple dual-task walking task. The 6-Meter WT was applied by walking in a narrow base condition for creating a difficult dual-task walking task. For cognitive task difficulty, participants were asked to count backwards by 3 as simple cognitive task and by 7 as difficult cognitive task.

RESULTS

DTC was higher in PwMS than control subjects. DTC in all conditions were different (SM-SC

CONCLUSION

The results suggest that task difficulty affects the magnitude of DTC during cognitive-motor dual-task walking in PwMS. Moreover, difficult walking tasks combined with simple cognitive tasks result greater DCT on walking than simple walking tasks combined with difficult cognitive tasks.

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Key Words

• Dual-task
• Motor-cognitive tasks
• Multiple sclerosis
• Task difficulty
• Walking

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MESH Headings

• Humans
• Male
• Female
• Multiple Sclerosis/physiopathology
• Walking/physiology
• Adult
• Middle Aged
• Cognition/physiology
• Psychomotor Performance/physiology
• Task Performance and Analysis
• Case-Control Studies

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Affiliation(s)

Çağrı Gülşen Faculty of Health Sciences, Department of Physiotherapy and Rehabilitation, Eskişehir Osmangazi University, Eskişehir, Turkey.
Fatih Söke Gulhane Faculty of Physiotherapy and Rehabilitation, University of Health Sciences, Ankara, Turkey
Fatma Aydin Diskapi Yildirim Beyazit Teaching and Research Hospital, Department of Neurology, University of Health Sciences, Ankara, Turkey
Elvan Özcan Gülşen Yunus Emre Vocational School, Department of Health Care Services, Program in Geriatric Care, Anadolu University, Eskişehir, Turkey
Öznur Yilmaz Faculty of Physical Therapy and Rehabilitation, Hacettepe University, Ankara, Turkey
Bilge Koçer Diskapi Yildirim Beyazit Teaching and Research Hospital, Department of Neurology, University of Health Sciences, Ankara, Turkey
Etem Çürük Faculty of Health Sciences, Department of Physiotherapy and Rehabilitation, Korkut Ata University, Osmaniye, Turkey
Şeref Demirkaya Gulhane Faculty of Medicine, Department of Neurology, University of Health Sciences, Ankara, Turkey
Canan Yücesan Faculty of Medicine, Department of Neurology, Ankara University, Ankara, Turkey

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Cognitive-motor dual task to reveal gait impairments in multiple sclerosis patients at an early stage: A systematic review

BACKGROUND

Multiple sclerosis can cause locomotor and cognitive impairments even at lower levels of disability, which can impact daily life. The cognitive-motor dual task is commonly used to assess everyday locomotion. Thus, this study aimed to examine the effect of cognitive-motor dual tasks on gait parameters among patients with multiple sclerosis in the early disease stages and to determine whether dual tasks could be used as a clinical test to detect locomotion impairments.

METHODS

A systematic search of five databases was conducted in May 2024. The population of interest was patients with multiple sclerosis with an Expanded Disability Status Scale score of 4 or less. The following outcome measures were examined: spatiotemporal and kinematic parameters. The Newcastle-Ottawa Scale was used to assess the quality of the studies.

FINDINGS

Eleven studies including 270 patients with multiple sclerosis and 221 healthy controls. Three spatiotemporal parameters were modified both in patients with multiple sclerosis and healthy controls during dual-task performance: gait speed, stride length and the double support phase. No spatiotemporal parameter was affected during dual-task performance in patients with multiple sclerosis alone.

INTERPRETATION

Dual-task performance could be useful for assessing gait impairments in patients with multiple sclerosis provided that assessments and protocols are standardized. Nevertheless, the spatiotemporal parameters did not allow discrimination between patients with multiple sclerosis at an early stage and healthy controls. Three-dimensional gait analysis during dual-task performance could be a useful approach for detecting early gait impairments in patients with multiple sclerosis, assessing their progression and adjusting rehabilitation programs.

Evaluating Cognitive-Motor Interference in Multiple Sclerosis: A Technology-Based Approach

BACKGROUND

People with multiple sclerosis (PwMS) frequently present both cognitive and motor impairments, so it is reasonable to assume they may have difficulties in executing dual-tasks (DT). The aim of the present study is to identify novel technology-based parameters to assess cognitive-motor interference (CMI) in PwMS. In particular, we focused on the definition of dual-task cost (DTC) measures using wearable and portable tools such as insoles and mobile apps.

METHODS

All participants underwent a verbal fluency task (cognitive single-task, ST), a motor ST of walking, and a combination of these tasks (DT). Number of words uttered in the cognitive ST and steps recorded by insoles were used to calculate the motor and cognitive DTC.

RESULTS

The number of steps strongly correlated with the walked meters for both single- (r = 0.88, p < 0.05) and dual- (r = 0.91, p < 0.05) tasks. Motor but not cognitive performances significantly worsened during DT. Over the cognitive ST and DT, the number of pronounced words progressively decreased, probably due to the activation of different cognitive processes. Cognitive efforts could be the cause of cognitive task prioritization.

CONCLUSIONS

Our findings promote the use of low-cost devices to assess CMI easily in the clinical context and to detect ecologically valid DT impairments.

Profiling cognitive-motor interference in a large sample of persons with progressive multiple sclerosis and impaired processing speed: results from the CogEx study

BACKGROUND

Performing cognitive-motor dual tasks (DTs) may result in reduced walking speed and cognitive performance. The effect in persons with progressive multiple sclerosis (pwPMS) having cognitive dysfunction is unknown.

OBJECTIVE

To profile DT-performance during walking in cognitively impaired pwPMS and examine DT-performance by disability level.

METHODS

Secondary analyses were conducted on baseline data from the CogEx-study. Participants, enrolled with Symbol Digit Modalities Test 1.282 standard deviations below normative value, performed a cognitive single task ([ST], alternating alphabet), motor ST (walking) and DT (both). Outcomes were number of correct answers on the alternating alphabet task, walking speed, and DT-cost (DTC: decline in performance relative to the ST). Outcomes were compared between EDSS subgroups (≤ 4, 4.5-5.5, ≥ 6). Spearman correlations were conducted between the DTCmotor with clinical measures. Adjusted significance level was 0.01.

RESULTS

Overall, participants (n = 307) walked slower and had fewer correct answers on the DT versus ST (both p < 0.001), with a DTCmotor of 15.8% and DTCcognitive of 2.7%. All three subgroups walked slower during the DT versus ST, with DTCmotor different from zero (p's < 0.001). Only the EDSS ≥ 6 group had fewer correct answers on the DT versus ST (p < 0.001), but the DTCcognitive did not differ from zero for any of the groups (p ≥ 0.039).

CONCLUSION

Dual tasking substantially affects walking performance in cognitively impaired pwPMS, to a similar degree for EDSS subgroups.

Motor Cognitive Dual-Task Testing to Predict Future Falls in Multiple Sclerosis: A Systematic Review

BACKGROUND

Mobility and cognitive impairments are often associated with increased fall risk among people with multiple sclerosis (PwMS). However, evidence on the concurrent assessment of gait or balance and cognitive tasks (dual-task) to predict falls appears to be inconsistent.

OBJECTIVE

To summarize the ability of gait or balance dual-task testing to predict future falls among PwMS.

METHODS

Seven databases including PubMed, Embase, Web of Science, Scopus, CINHAL, SPORTDiscuss, and PsycINFO were searched from inception to May 2022. Two independent reviewers identified studies that performed a dual-task testing among adults with multiple sclerosis and monitored falls prospectively for at least 3 months. Both reviewers also evaluated the quality assessment of the included studies.

RESULTS

Eight studies with 484 participants were included in the review. Most studies (75%) indicated that dual-task testing and dual-task cost did not discriminate prospective fallers (⩾1 fall) and non-fallers (0 fall) and were not found as predictors of future falls. However, dual-task cost of walking velocity (OR = 1.23, 95% CI 0.98-4.45, P = .05) and dual-task of correct response rate of serial 7 subtraction (OR = 1.34, 95% CI 1.04-3.74, P = .02) were significantly associated with increased risk of recurrent falls (≥2 falls). Pattern of cognitive-motor interference was also associated with an increased risk of falling. All studies presented with strong quality.

CONCLUSION

The scarce evidence indicates that dual-task testing is not able to predict future falls among PwMS. Further research with more complex motor and cognitive tasks and longer-term fall monitoring is required before dual-task testing can be recommended as a predictor of future falls in this population.

Multimodal Agility-Based Exercise Training for Persons With Multiple Sclerosis: A New Framework

INTRODUCTION

Multimodal agility-based exercise training (MAT) has been described as a framework for fall prevention in the elderly but might also be a valuable concept for exercise training in persons with Multiple Sclerosis (pwMS).

THE PROBLEM

Current recommendations advise pwMS to perform a multitude of different exercise training activities, as each of these has its separate evidence. However, pwMS struggle even more than the general population to be physically active. Additionally, Multiple Sclerosis often leads to co-occurring mobility and cognitive dysfunctions, for which simultaneous, time-efficient, and engaging training approaches are still limited in clinical practice and healthcare.

THE SOLUTION

The MAT framework has been developed to integratively improve cardiovascular, neuromuscular, and cognitive function by combining aspects of perception and orientation, change of direction, as well as stop-and-go patterns (ie, agility), in a group-training format. For pwMS, the MAT framework is conceptualized to include 3 Components: standing balance, dynamic balance (including functional leg strength), and agility-based exercises. Within these Components sensory, cognitive, and cardiovascular challenges can be adapted to individual needs.

RECOMMENDATIONS

We recommend investigating multimodal exercise interventions that go beyond easily standardized, unimodal types of exercise (eg, aerobic or resistance exercise), which could allow for time-efficient training, targeting multiple frequent symptoms of persons with mild disability at once. MAT should be compared to unimodal approaches, regarding sensor-based gait outcomes, fatigue-related outcomes, cognition, as well as neuroprotective, and (supportive) disease-modifying effects.

Patient-Reported Outcome Measures for Assessing Dual-Task Performance in Daily Life: A Review of Current Instruments, Use, and Measurement Properties

The patient perspective of dual-task (DT) impairment in real life is unclear. This review aimed (i) to identify patient-reported outcome measures (PROMs) on DT and evaluate their measurement properties and (ii) to investigate the usage of PROMs for the evaluation of DT difficulties. A systematic literature search was conducted using PubMed and Web of Science from inception to March 2022. Methodological quality was evaluated using the COSMIN checklist. Six studies examined the measurement properties of DT PROMs. Nine studies used DT PROMs as the outcome measure. Five PROMs were identified, including the Divided Attention Questionnaire (DAQ), Dual-Task-Impact on Daily-life Activities Questionnaire (DIDA-Q), a Questionnaire by Cock et al. (QOC), Dual-Tasking Questionnaire (DTQ), and Dual-Task Screening-List (DTSL). Fourteen measurement properties were documented: five (35.7%) rated quality as "sufficient", six (42.8%) "insufficient", and three (21.4%) "indeterminate". The quality of evidence for each measurement property ranged from very low to high. While DT performance is investigated in many populations, the use of PROMs is still limited, although five instruments are available. Currently, due to insufficient data, it is not possible to recommend a specific DT PROM in a specific population. An exception is DIDA-Q, which has the highest quality of measurement properties in people with multiple sclerosis.

Cognitive-motor interference in people with mild to moderate multiple sclerosis, in comparison with healthy controls

BACKGROUND

Reduced motor and cognitive dual-task capacity is found to be more common among people with multiple sclerosis (MS), than among healthy populations. However, studies in larger samples of MS conducted using a more stringent methodology, which includes comparisons to healthy controls, are needed. Thus, the primary aim of this study was to explore the effects on motor and cognitive dual-tasking in people with mild to moderate overall MS-disability, in comparison to healthy controls. A second aim was to explore the differences in dual-task performance on a cognitive task between two motor tasks in people with mild to moderate MS and healthy controls.

METHODS

This case-control study evaluated dual-task performance of the motor tasks standing with eyes closed (hereafter standing) and walking and a cognitive task assessing selective executive functions (auditory-Stroop test). Fifty-five people with MS (mild MS, n = 28; moderate MS, n = 27), and 30 healthy controls participated. Standing and walking were assessed using wireless inertial measurement unit sensors (APDM). Standing (three 30 s trials) was measured using sway area and root mean square sway, while walking (2 min) was measured using speed, stride length, and step time. Auditory-Stroop was measured using accuracy and response time. During dual-task assessments, each subject was instructed to pay equal attention to both tasks. Statistical significance was considered if p < .05.

RESULTS

Instanding no significant within-group differences in the standing measures were found between single-task and dual-task performance. However, dual-task performance differed significantly between all groups (moderate MS > mild MS > healthy controls), except between mild and moderate MS in sway area. Inwalking, all groups slowed down speed and shortened stride length during dual-task condition compared to single-task condition. Moderate MS performed significantly poorer than mild MS and healthy controls in dual-task walking, but mild MS did not differ from healthy controls. In thecognitivetask only mild MS increased significantly in auditory-Stroop response time during walking. In healthy controls, the performance of auditory-Stroop was not affected by dual-tasking. Moderate MS had significantly longer response time in dual-task auditory-Stroop compared to the other groups, but no differences were observed between mild MS and healthy controls. Only mild MS had significantly longer response time during walking than during standing.

CONCLUSION

This study showed that cognitive-motor interference in people with MS is present also in the early phases of the disease. This was shown during dual-tasking with slower walking and a longer response time in the cognitive task compared to healthy controls. Moderate MS performed poorer in almost every aspect of the motor and cognitive assessments in dual-task condition, compared to mild MS and healthy controls. Furthermore, during standing, people with MS performed poorer in standing measures compared to healthy controls. Additionally, healthy controls showed no cognitive interference during motor tasks. The results suggest that standardized regular assessment of dual-tasking in MS care might increase the individual's knowledge of dual-task capacity and contribute to understanding of possible related consequences. However, feasible assessment equipment and specific motor-cognitive dual-task training interventions for people with MS need to be developed.

Associations between clinical characteristics and dual task performance in Multiple Sclerosis depend on the cognitive and motor dual tasks used

BACKGROUND

In persons with Multiple Sclerosis (pwMS) performing a simultaneous cognitive task while walking often results in slower gait. Clinical characteristics associated with reduced dual task (DT) performance are not yet entirely clear. This multi-centre study aimed to determine the relationship between clinical and demographical characteristics with dual task (DT) walking performance in pwMS during multiple DT conditions.

METHODS

Nine DT conditions were analysed, consisting of combinations of three types of cognitive ('digit span', 'subtraction', 'vigilance') and three types of walking ('walk', 'walk with cup', 'walk over obstacles') conditions. Primary outcomes were DT gait speed (m/s) and motor DT cost of gait speed (DTCmotor, %). Secondary outcomes were clinical tests of physical and cognitive functioning and patient-reported and demographical outcomes. Firstly, univariate analyses and, subsequently, multivariate analyses with backward modelling, were conducted for each type of walking DT condition separately. Cognitive DT conditions were included in the models as main and as interaction effect with the secondary outcomes.

RESULTS

Analysis were performed in 81 pwMS (EDSS 3.3 ± 1.0). In the final models of DTCmotor, the significant main effects were in 'walk' DT-conditions the Symbol Digit Modalities Test (SDMT), in 'cup' conditions the SDMT and Dynamic Gait Index and in 'obstacles' conditions age. For DT gait speed, main effects were found for the 2-Minute Walking Test (2MWT) and the Multiple Sclerosis Walking Scale for all walking conditions. Additionally, interactions between cognitive DT-conditions and SDMT, age and 2MWT were found.

CONCLUSION

Clinical characteristics related to DT walking performance differed according to cognitive-motor DT-condition used. Still, in general, pwMS with a better mobility demonstrated higher DT gait speed, while a faster information processing speed was related to a lower DTCmotor.