Walking and talking: an investigation of cognitive-motor dual tasking in multiple sclerosis

Reliability and Construct Validity of Three Self-report Questionnaires Assessing Dual-Task Difficulties in People With Multiple Sclerosis: An International Study

OBJECTIVE

To evaluate the reliability and validity of the dual-tasking questionnaire (DTQ), dual-task screening list (DTSL), and dual-task impact on daily life activities questionnaire (DIDA-Q).

DESIGN

Multicenter, cross-sectional study SETTING: Persons with multiple sclerosis (pwMS) were recruited from 7 multiple sclerosis centers across 6 countries (Belgium, Chile, Italy, Israel, Spain, and Turkey).

PARTICIPANTS

A total of 356 pwMS (mean age 47.5±11.5y, expanded disability status scale, 3.79±1.83) were enrolled.

INTERVENTIONS

Not applicable MAIN OUTCOME MEASURES: The reliability (internal consistency, test-retest, and measurement error) and construct validity (structural and convergent) were assessed.

RESULTS

The DTQ, DTSL, and DIDA-Q demonstrated excellent test-retest reliability (intraclass correlation coefficients [95% CI], 0.84 [0.80-0.87] to 0.90 [0.87-0.92]) and internal consistency (Cronbach α: 0.86-0.96). As hypothesized, the 3 questionnaires showed a strong correlation with each other, moderate-to-strong correlations with other self-report questionnaires (perceived walking difficulties, fatigue, and fear of falling), and low-to-moderate correlations with cognitive information processing speed, manual dexterity, and dual-task walking performance (walking with word list generation task), showing convergent validity. The DIDA-Q exhibited systematically superior properties. These results were also verified in subsets from 6 different countries. In the structural validity analysis, all questionnaires displayed 2 main factors, allocated as "motor-driven" and "cognitive-driven" subscales.

CONCLUSIONS

The DTQ, DTSL, and DIDA-Q have good-to-excellent measurement properties, with the highest properties observed in DIDA-Q. The use of these self-reported questionnaires can be used in research and clinical practice to assess the effect of dual-task difficulties on the daily life of ambulatory pwMS.

From "invisible" to "audible": Features extracted during simple speech tasks classify patient-reported fatigue in multiple sclerosis

BACKGROUND

Fatigue is a major "invisible" symptom in people with multiple sclerosis (PwMS), which may affect speech. Automated speech analysis is an objective, rapid tool to capture digital speech biomarkers linked to functional outcomes.

OBJECTIVE

To use automated speech analysis to assess multiple sclerosis (MS) fatigue metrics.

METHODS

Eighty-four PwMS completed scripted and spontaneous speech tasks; fatigue was assessed with Modified Fatigue Impact Scale (MFIS). Speech was processed using an automated speech analysis pipeline (ki elements: SIGMA speech processing library) to transcribe speech and extract features. Regression models assessed associations between speech features and fatigue and validated in a separate set of 30 participants.

RESULTS

Cohort characteristics were as follows: mean age 49.8 (standard deviation (SD) = 13.6), 71.4% female, 85% relapsing-onset, median Expanded Disability Status Scale (EDSS) 2.5 (range: 0-6.5), mean MFIS 27.6 (SD = 19.4), and 30% with MFIS > 38. MFIS moderately correlated with pitch (R = 0.32, p = 0.005), pause duration (R = 0.33, p = 0.007), and utterance duration (R = 0.31, p = 0.0111). A logistic model using speech features from multiple tasks accurately classified MFIS in training (area under the curve (AUC) = 0.95, R2 = 0.59, p < 0.001) and test sets (AUC = 0.93, R2 = 0.54, p = 0.0222). Adjusting for EDSS, processing speed, and depression in sensitivity analyses did not impact model accuracy.

CONCLUSION

Fatigue may be assessed using simple, low-burden speech tasks that correlate with gold-standard subjective fatigue measures.

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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Mapping cognitive dysfunction in relapsing multiple sclerosis with mild disability: A cross-sectional study from South India

Background

Cognitive dysfunction in multiple sclerosis (MS) occurs early. Locally adapted neuropsychological data from India in MS is scarce.

Objectives

We aimed to identify the pattern of cognitive impairment in relapsing MS (RMS) with mild disability using a regionally-adapted MS-specific cognitive battery.

Methodology

The study included 59 persons with MS (pwMS) with expanded disability status scale (EDSS)≤ 4 and 62 controls. The battery had 8 neuropsychological tests (Paced Auditory Serial Addition Test [PASAT], Symbol Digit Modalities Test [SDMT], Rey Auditory Verbal Learning Test [RAVLT], Brief Visuospatial Memory Test-Revised [BVMT-R], verbal fluency [VF], Judgement of Line Orientation Test [JOLOT], Wisconsin Card Sorting Test [WCST] and Trail Making Test-B [TMT-B]) with 11 measures. The scores were compared between the groups for pattern and associations of cognitive impairment.

Results

The pwMS cohort had 39 (66.1%) females; mean age of 32.56 (±8.17) years. Scores were significantly worse for pwMS in 10 of 11 tests (except JOLOT). Cohen's-d test showed the largest effect sizes for PASAT, SDMT, VF and TMT-B. Cognitive impairment (defined as ≥2 abnormal tests) were noted in 41 (69.5%) pwMS. Male sex was associated with cognitive impairment (p = 0.002).

Conclusions

In pwMS with mild disability, nearly two-thirds had cognitive abnormalities, predominantly involving processing speed, working memory, executive function, and VF.

Dual-task gait has prognostic value for cognitive decline in Parkinson's disease

INTRODUCTION

Cognitive decline frequently occurs in individuals with Parkinson's disease (PD), but the clinical methods to predict the onset of cognitive changes are limited. Given preliminary evidence of the link between gait and cognition, the purpose of this study was to determine if dual task (DT) gait was related to declines in cognition over two years in PD.

METHODS

A retrospective two-year longitudinal study of 48 individuals with PD using data from the Parkinson's Progression Markers Initiative of the Michael J. Fox Foundation. The following data were extracted at baseline: spatiotemporal gait (during single and DT), demographics (age, sex), PD disease duration (time since diagnosis), motor function (Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS)), and cognition (Montreal Cognitive Assessment (MoCA)), with MoCA scores also extracted after two years.

RESULTS

A binomial logistic regression was conducted, with all covariates (above) in block 1 and DT effect (DTE) of gait characteristics in block 2 entered in a stepwise fashion. The final model was statistically significant (χ2(6) = 23.20, p < 0.001) and correctly classified 78.7 % of participants by cognitive status after two years. Only DTE of arm swing asymmetry (ASA) (p = 0.030) was included in block 2 such that a 1 % decline in DTE resulted in 1.6 % increased odds of cognitive decline.

CONCLUSIONS

Individuals with greater change in arm swing asymmetry from single to DT gait may be more likely to experience a decline in cognition within two years. These results suggested that reduced automaticity or poor utilization of attentional resources may be indicative of subtle changes in cognition and indicate that DT paradigms may hold promise as a marker of future cognitive decline.

Effect of melatonin intake on postural balance, functional mobility and fall risk in persons with multiple sclerosis: a pilot study

AIM

To assess the safety and the effect of a nocturnal melatonin (MEL) ingestion on postural balance, functional mobility and fall risk the following morning in adults with multiple sclerosis (MS).

METHODS

Fourteen adults with relapsing-remitting MS (RR-MS) (28.36 ± 6.81 years) were evaluated before and after nocturnal ingestion of MEL (6 mg) or placebo (PLA). Evaluations included a posturographic test of static bipedal postural balance with dual-task in eyes open (EO) and eyes closed conditions, and a clinical test of unipedal balance. The physical performance tests were: Timed Up and Go test (TUGT) (mobility), Four Square Step Test (FSST) (fall risk), and Timed 25-foot walk test (T25FWT) (walking speed). Cognitive performance [Montreal Cognitive Assessment (MoCA) and Simple Reaction Time (SRT) tests] and sleep quality [Spiegel's sleep questionnaire (SSQ)] were also assessed.

RESULTS

In EO condition, MEL decreased the posturographic parameters [center of pressure (CoP) sway area (CoPAr), CoP path length (CoPL) and CoPL in the mediolateral axis (CoPLX)] more than PLA by 15.82% (p = 0.0006), 12.48% (p  = 0.0004) and 14.25% (p = 0.0002), respectively. Durations of TUGT and FSST decreased following MEL session more than the PLA one by 14.52% (p = 0.017) and 19.85% (p = 0.0006), respectively. MEL increased the unipedal stance time, SSQ and MoCA scores more than PLA by 49.81% (p = 0.04), 32.21% (p = 0.004) and 11.87% (p = 0.008), respectively.

CONCLUSION

This pilot study showed that acute nocturnal MEL ingestion seems to be safe for enhancing postural balance, fun mobility and fall risk in RR-MS adults probably through improving sleep quality and cognitive function.

Cognitive function influences cognitive-motor interference during dual task walking in multiple sclerosis

BACKGROUND

Both physical and cognitive impairments are common in people with multiple sclerosis (PwMS). Performing a cognitive task while walking (i.e., dual-task walking) can introduce cognitive-motor interference (CMI), resulting in changes in walking performance. The association between the levels of cognitive impairment and of CMI in MS remains unclear.

OBJECTIVES

To examine the association between cognitive functioning and differences in walking performance arise between single- and dual-task walking.

METHODS

Ninety-five PwMS performed self-preferred pace walking and dual-task walking. The gait parameters recorded were used to compute dual task costs (DTC) as a metric of CMI. Cognitive functioning was assessed using Match, an unsupervised test developed based on the Symbol Digit Modalities Test. Participants were categorized as higher (HCF) and lower cognitive functioning (LCF) based on a Match z-score < -1.5.

RESULTS

LCF group had elevated DTC for stride velocity, relative to the HCF group. Higher DTC for stride velocity was associated with lower cognition, as assessed by Match test.

CONCLUSION

The findings support the hypothesis that CMI is associated with cognitive functioning in PwMS.

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.

Dual-task difficulties as a risk factor for unemployment in people with multiple sclerosis

BACKGROUND

No study has investigated the impact of dual-tasking difficulties as a risk factor for unemployment in people with multiple sclerosis (pwMS). The aim was to examine the influence of dual-task performance on employment status and work difficulties and to identify the predictors of employment status in pwMS.

METHODS

Eighty-four pwMS, including 42 employed and 42 unemployed, participated in the study. Dual-task difficulties were assessed using the Dual-task Impact on Daily-living Activities-Questionnaire (DIDA-Q), while dual-task performance was evaluated through the 30-second Walk Test and Nine-Hole Peg Test, incorporating a cognitive task. Walking and cognitive function were also measured.

RESULTS

Employed pwMS had better scores in walking, cognitive function, single and dual-task performance than unemployed pwMS (p < .05). Lower scores in walking (odds ratio [OR] = 1.81, p < .001) and upper extremity-related (OR = 1.44, p = .019) dual-task performance and higher scores in the cognitive subscale of the DIDA-Q questionnaire (OR = 1.20, p = .037) were significantly associated with higher odds of being unemployed. Among employed pwMS, DIDA-Q subscales showed moderate-to-strong correlations with MSWSDQ-23 scores. The other variables showed weak-to-moderate correlations with subscale and total scores of MSWSDQ-23.

CONCLUSION

Cognitive function, as opposed to motor function, has been found to be a significant predictor of unemployment in pwMS.

Executive functions in relapsing-remitting multiple sclerosis

Some studies suggest that patients with relapsing-remitting multiple sclerosis have problems in the functioning of working memory, and more specifically in executive functions, but the available results are still inconsistent. The aim of the present study was to examine executive functioning in multiple sclerosis using classical and representative tasks for divided attention, updating, attentional shifting, and inhibition. The sample was composed of 48 participants aged between 18 and 59 years (24 persons living with multiple sclerosis and 24 healthy participants matched in age and education level). The executive functions of divided attention, updating, attentional shifting, and inhibition were analyzed through the Dual-Task Paradigm, the N-Back task, the Trail Making Test (TMT), and the Stroop test, respectively. The analyses of the data showed that the functioning of working memory was impaired in multiple sclerosis in the executive functions of divided attention and updating when the group of persons living with MS and the control group were compared. In addition, the performance in the four executive functions analyzed did not show the same profile across the persons living with MS in the sample, as no deficit in attentional shifting or inhibition was observed. It can be concluded that the presence of deficits was observed only in the executive functions of divided attention and updating under the condition of greater cognitive demand. The clinical implications of these results are underlined due to their impact on daily life.

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.

The moderating roles of self-efficacy and depression in dual-task walking in multiple sclerosis: A test of self-awareness theory

OBJECTIVE

Multiple sclerosis (MS) is a debilitating neurological disease associated with a variety of psychological, cognitive, and motoric symptoms. Walking is among the most important functions compromised by MS. Dual-task walking (DTW), an everyday activity in which people walk and engage in a concurrent, discrete task, has been assessed in MS, but little is known about how it relates to other MS symptoms. Self-awareness theory suggests that DTW may be a function of the interactions among psychological, cognitive, and motor processes.

METHOD

Cognitive testing, self-report assessments for depression and falls self-efficacy (FSE), and walk evaluations [DTW and single-task walk (STW)] were assessed in seventy-three people with MS in a clinical care setting. Specifically, we assessed whether psychological factors (depression and FSE) that alter subjective evaluations regarding one's abilities would moderate the relationships between physical and cognitive abilities and DTW performance.

RESULTS

DTW speed is related to diverse physical and cognitive predictors. In support of self-awareness theory, FSE moderated the relationship between STW and DTW speeds such that lower FSE attenuated the strength of the relationship between them. DTW costs - the change in speed normalized by STW speed - did not relate to cognitive and motor predictors. DTW costs did relate to depressive symptoms, and depressive symptoms moderated the effect of information processing on DTW costs.

CONCLUSIONS

Findings indicate that an interplay of physical ability and psychological factors - like depression and FSE - may enhance understanding of walking performance under complex, real-world, DTW contexts.

Effects of multi-task training on motor and cognitive performances in multiple sclerosis patients without clinical disability: a single-blinded randomized controlled trial

OBJECTIVE

This study aimed to investigate the effects of multi-task training on motor and cognitive performance in People with Multiple Sclerosis (PwMS) without clinical disability compared to single-task training and a control group.

METHODS

A total of 42 patients were randomly assigned to three groups labeled as Multi-Task Training Group (MTTG, n:14), Single-Task Training Group (STTG, n:14), and Control Group (CG, n:14). The STTG performed only motor tasks based on the task-oriented training program twice a week for 6 weeks while the MTTG performed the same tasks concurrently with additional motor and cognitive tasks. The CG performed relaxation exercises at home. Postural stability by posturography, walking by Timed Up-and-Go, manual dexterity by Nine-Hole Peg Test, mental tracking by Counting Backward, and verbal fluency by Word List Generation were assessed before and after the intervention under single and dual-task conditions.

RESULTS

In the MTTG, both single cognitive and single motor task performances increased, and, moreover, the cognitive Dual-Task Costs (DTCs) decreased although the motor DTCs were not changed significantly. There were significant group-by-time interactions in favor of MTTG only on the mental tracking DTC during walking compared to the STTG. Moreover, the changes in postural and walking DTCs were associated with changes in single-motor task performance.

CONCLUSION

This study suggests that multi-task training is effective in reducing cognitive DTC rather than motor DTC under dual-task conditions in PwMS without clinical disability.

TRIAL REGISTRATION NUMBER

NCT03512886.

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.

Turning and multitask gait unmask gait disturbance in mild-to-moderate multiple sclerosis: Underlying specific cortical thinning and connecting fibers damage

Multiple sclerosis (MS) causes gait and cognitive impairments that are partially normalized by compensatory mechanisms. We aimed to identify the gait tasks that unmask gait disturbance and the underlying neural correlates in MS. We included 25 patients with MS (Expanded Disability Status Scale score: median 2.0, interquartile range 1.0-2.5) and 19 healthy controls. Fast-paced gait examinations with inertial measurement units were conducted, including straight or circular walking with or without cognitive/motor tasks, and the timed up and go test (TUG). Receiver operating characteristic curve analysis was performed to distinguish both groups by the gait parameters. The correlation between gait parameters and cortical thickness or fractional anisotropy values was examined by using three-dimensional T1-weighted imaging and diffusion tensor imaging, respectively (corrected p < .05). Total TUG duration (>6.0 s, sensitivity 88.0%, specificity 84.2%) and stride velocity during cognitive dual-task circular walking (<1.12 m/s, 84.0%, 84.2%) had the highest discriminative power of the two groups. Deterioration of these gait parameters was correlated with thinner cortical thickness in regional areas, including the left precuneus and left temporoparietal junction, overlapped with parts of the default mode network, ventral attention network, and frontoparietal network. Total TUG duration was negatively correlated with fractional anisotropy values in the deep cerebral white matter areas. Turning and multitask gait may be optimal to unveil partially compensated gait disturbance in patients with mild-to-moderate MS through dynamic balance control and multitask processing, based on the structural damage in functional networks.

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

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

Cognitive-Motor Interference and Cortical Activation While Walking in Individuals With Multiple Sclerosis

The present study expands on current understanding of dual-task cognitive-motor interference, by including cortical activation measures to both traditional and ecologically valid dual-task paradigms. Fifteen individuals with multiple sclerosis and 14 control participants underwent mobility testing while wearing functional near-infrared spectroscopy. In the absence of increased prefrontal cortical activation, subjects with multiple sclerosis performed significantly worse on measures of cognition under both single- and dual-task conditions. These findings suggest that persons with multiple sclerosis may be unable to allocate additional cortical resources to cognition under dual-task conditions, leading to significant cognitive-motor interference and decrements in performance. This study is the first to investigate cortical activation across several commonly used and ecologically valid dual-task assessments.

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.

The reliability and validity of the Turkish version of the dual-task questionnaire in patients with multiple sclerosis

BACKGROUND

Activities of daily living often require performing dual-task (DT). People with Multiple Sclerosis (PwMS) may have difficulties during dual-task and these difficulties negatively affect their quality of life. However, the number of validated questionnaires to assess DT difficulties in Multiple Sclerosis (MS) is very few. Therefore, the study aimed to translate and adapt the Dual-Task Questionnaire (DTQ) into Turkish, thereafter analyzing the psychometric properties in PwMS.

METHODS

A total of 51 PwMS were recruited in the study. Cronbach's alpha coefficient was used to evaluate internal consistency. The test-retest reliability was determined using the intraclass correlation coefficient (ICC). Correlations of the DTQ with motor-dual task costs (DTCs) and cognitive-DTCs were used to assess construct validity.

RESULTS

The mean age was 36.84±10.47 years. The internal consistency of the DTQ was acceptable (α= 0.780). The test-retest reliability of all items and the total score of the DTQ were excellent (ICC>0.90). The relationships of DTQ-Total between some parameters of motor-DTCs (ρ=-0.409-(-0.495) for walking-DTCs, ρ=-0.313 for manual dexterity-DTC during mental tracking, and ρ=-0.353 for balance-DTC during mental tracking) and cognitive-DTCs (ρ=0.328 for mental tacking-DTC during balance, ρ=0.290-0.342 for all verbal fluency-DTCs) were low to moderately significant.

CONCLUSION

Turkish version of DTQ is a reliable and valid tool to measure DT difficulty in PwMS. Additionally, the questionnaire is a reliable and valid Patient Reported Outcomes Initiative for MS (PROMS) for Turkish-speaking PwMS.

Addition of a Cognitive Task During Walking Alters Lower Body Muscle Activity

This study compared electromyography of five leg muscles during a single walking task (WALK) to a dual task (walking + cognitive task; COG) in 40 individuals (20 M and 20 F) using a wavelet analysis technique. It was hypothesized that muscle activation during the dual task would differ significantly from the walking task with respect to both timing (H1) and frequency (H2). The mean overall intensity for the COG trials was 4.1% lower for the tibialis anterior and 5.5% higher for the gastrocnemius medialis than in the WALK trials. The changes between the WALK and COG trials were short 50 ms bursts that occurred within 100 ms of heel strike in the tibialis anterior, and longer activation periods during the stance phase in the gastrocnemius medialis. No changes in overall intensity were observed in the peroneus longus, gastrocnemius lateralis, or soleus. Furthermore, no clear frequency bands within the signal could further characterize the overall changes in muscle activity during the COG task. This advances our understanding of how the division of attentional resources affects muscle activity in a healthy population of adults.

Instrumented Assessment of Motor Performance Fatigability During the 6-Min Walk Test in Mildly Affected People With Multiple Sclerosis

There are conflicting results regarding the changes in spatio-temporal gait parameters during the 6-min walk test (6MWT) as indicators of gait-related motor performance fatigability (PF) in people with Multiple Sclerosis (pwMS). To further analyze if gait-related motor PF can be quantified using instrumented gait analysis during the 6MWT, we investigated: (i) whether gait parameters recorded during the first or second minute were more stable and thus the better baseline to assess motor PF and (ii) if the minimum toe clearance (MTC) together with “classical” spatio-temporal gait parameters can be used to quantify motor PF in pwMS. Nineteen mildly affected pwMS [12 women/7 men; 47.8 ± 9.0 years; the Expanded Disability Status Scale (EDSS): 2.7 ± 1.0] and 24 healthy controls (HC; 15 women/9 men; 48.8 ± 7.6 years) completed the 6MWT equipped with inertial measurement units. Data were analyzed using the attractor method to compare the stability of gait parameters and, besides “classical” spatio-temporal gait parameters, the MTC was calculated as a potential new marker for motor PF in pwMS as this was shown in healthy older adults. It was found that (i) gait parameters were more stable in the second than in the first minute and (ii) gait-related motor PF could not be detected based on spatio-temporal gait parameters, including the MTC. Descriptive analysis indicated a decrease in MTC variability, which is assumed to be indicative for motor PF, toward the end of the 6MWT in some pwMS. Future studies should investigate gait parameters for the assessment of motor PF in pwMS recorded during more intense and/or longer walking protocols, taking the level of disability into account. Furthermore, using gait parameters recorded in the first minute of the 6MWT as a baseline for the assessment of motor PF should be avoided.

Neural correlates of dual-task walking in people with central neurological disorders: a systematic review

BACKGROUND

People with central neurological disorders experience difficulties with dual-task walking due to disease-related impairments. The objective of this review was to provide a comprehensive examination of the neural correlates (structural/functional brain changes) of dual-task walking in people with Parkinson's disease (PD), multiple sclerosis (MS), stroke, and Alzheimer's disease (AD).

METHODS

A systematic review of the literature was conducted, following PRISMA guidelines, on Medline, Embase, and Scopus. Included studies examined the relationship between structural and functional brain imaging and dual-task walking performance in people with PD, MS, stroke, and AD. Articles that met the inclusion criteria had baseline characteristics, study design, and behavioral and brain outcomes extracted. Twenty-three studies were included in this review.

RESULTS

Most structural imaging studies (75%) found an association between decreased brain integrity and poor dual-task performance. Specific brain regions that showed this association include the striatum regions and hippocampus in PD and supplementary motor area in MS. Functional imaging studies reported an association between increased prefrontal activity and maintained (compensatory recruitment) or decreased dual-task walking performance in PD and stroke. A subset (n = 2) of the stroke papers found no significant correlations. Increased supplementary motor area activity was associated with decreased performance in MS and stroke. No studies on AD were identified.

CONCLUSION

In people with PD, MS, and stroke, several neural correlates of dual-task walking have been identified, however, the direction of the association between neural and performance outcomes varied across the studies. The type of cognitive task used and presentation modality (e.g., visual) may have contributed to these mixed findings.

The effects of cognitive versus motor concurrent task on gait in individuals with transtibial amputation, transfemoral amputation and in a healthy control group

BACKGROUND

Lower limb amputation causes difficulties in mobility together with motor and sensory loss. Challenging situations such as concurrent tasks cause gait parameters to deteriorate. Understanding the effect of concurrent tasks on gait is important for the rehabilitation of amputees.

RESEARCH QUESTION

Are the effects of concurrent cognitive and motor tasks on gait parameters at fixed speed different in individuals with transtibial amputation, or transfemoral amputation compared to healthy individuals?

METHODS

The gait parameters were evaluated of 20 individuals with transtibial amputation, 13 individuals with transfemoral amputation and 20 healthy individuals while walking on a motorized treadmill under single task (ST), cognitive dual task (CDT) and motor dual task (MDT) conditions. The self-selected comfortable velocity, which was determined in the single-task gait, was used in all three walking tests.

RESULTS

ST, CDT and MDT gait parameters of individuals with transtibial amputation, transfemoral amputation and healthy individuals were significantly different (p < 0.01). Covariance of step length variability increased in amputees when walking under MDT (p < 0.05). The dual task cost (DTC) for all the gait parameters was similar in all three groups (p > 0.05). The motor DTC of covariance of step length was greater than cognitive DTC (p < 0.05).

SIGNIFICANCE

Individuals with lower limb amputation have the capacity to walk with cognitive and motor tasks without changing velocity on the treadmill, but concurrent motor tasks cause an increase in gait variability. The results of this study suggest that there is an increase in gait variability especially with motor tasks, which may cause a higher risk of falling. Trial number: NCT04392466 (clinicaltrials.gov).

Reliability and validity of the modified Walking and Remembering Test in persons with multiple sclerosis

Cognitive dysfunction can adversely impact the walking ability of people with multiple sclerosis. However, valid and reliable standardized clinical tools to measure cognitive-motor interference or dual-tasking in people with multiple sclerosis remain lacking. This study evaluated the validity and reliability of the modified Walking and Remembering Test (mWART) in people with multiple sclerosis. Eleven adults (mean ± SD age, 51.1 ± 13.4 years) with multiple sclerosis (Expanded Disability Status Score, 2.0-6.0) and six adults (mean ± SD age, 41.5 ± 17.2 years) without multiple sclerosis were administered the mWART twice over a 2-week period. Participants were tested on gait and digit span length under single-task and dual-task conditions according to the mWART procedures over a 10-m walkway. intraclass correlation coefficient2,k were 0.961 for single-task gait velocity (P < 0.001), 0.968 for dual-task gait velocity (P < 0.001), 0.829 for single-task digit span (P = 0.004), and 0.439 for dual-task digit span (P = 0.154). Single-task gait velocity (P = 0.001) and dual-task gait velocity (P = 0.002) were able to discriminate between groups but dual-task costs were similar between participants with and without multiple sclerosis. Those with severe disability demonstrated the greater dual-task cost of gait velocity (P = 0.030). This study provides preliminary evidence of the mWART's validity and reliability in measuring dual-task performance in patients with multiple sclerosis with mild to severe disability. More research is required in more heterogeneous samples of persons with multiple sclerosis.

Digital Biomarkers in Multiple Sclerosis

For incurable diseases, such as multiple sclerosis (MS), the prevention of progression and the preservation of quality of life play a crucial role over the entire therapy period. In MS, patients tend to become ill at a younger age and are so variable in terms of their disease course that there is no standard therapy. Therefore, it is necessary to enable a therapy that is as personalized as possible and to respond promptly to any changes, whether with noticeable symptoms or symptomless. Here, measurable parameters of biological processes can be used, which provide good information with regard to prognostic and diagnostic aspects, disease activity and response to therapy, so-called biomarkers Increasing digitalization and the availability of easy-to-use devices and technology also enable healthcare professionals to use a new class of digital biomarkers-digital health technologies-to explain, influence and/or predict health-related outcomes. The technology and devices from which these digital biomarkers stem are quite broad, and range from wearables that collect patients' activity during digitalized functional tests (e.g., the Multiple Sclerosis Performance Test, dual-tasking performance and speech) to digitalized diagnostic procedures (e.g., optical coherence tomography) and software-supported magnetic resonance imaging evaluation. These technologies offer a timesaving way to collect valuable data on a regular basis over a long period of time, not only once or twice a year during patients' routine visit at the clinic. Therefore, they lead to real-life data acquisition, closer patient monitoring and thus a patient dataset useful for precision medicine. Despite the great benefit of such increasing digitalization, for now, the path to implementing digital biomarkers is widely unknown or inconsistent. Challenges around validation, infrastructure, evidence generation, consistent data collection and analysis still persist. In this narrative review, we explore existing and future opportunities to capture clinical digital biomarkers in the care of people with MS, which may lead to a digital twin of the patient. To do this, we searched published papers for existing opportunities to capture clinical digital biomarkers for different functional systems in the context of MS, and also gathered perspectives on digital biomarkers under development or already existing as a research approach.

Measures of postural control and mobility during dual-tasking as candidate markers of instability in Huntington's disease

BACKGROUND

Individuals with Huntington's disease (HD) have impairments in performing dual-tasks, however, there is limited information about the effects of changing postural and cognitive demands as well as which measures are best suited as markers of underlying motor-cognitive interference.

METHODS

Forty-three individuals with HD and 15 healthy controls (HC) completed single tasks of walking (Timed Up & Go (TUG), 7 m walk), standing (feet together, feet apart and foam surface) and seated cognitive performance (Stroop, Symbol Digit Modalities Test (SDMT), Delis-Kaplan Executive Function System (DKEFS) Sorting test) and dual cognitive-motor tasks while standing (+ Stroop) and walking (+ DKEFS, TUG cognitive). APDM Opal sensors recorded measures of postural sway and time to complete motor tasks.

RESULTS

Individuals with HD had a greater increase in standing postural sway compared to HC from single to dual-tasks and with changes to support surface. Both groups demonstrated a decrease in gait performance during the TUG cognitive, however, this difference was greater in people with HD compared to HC. While those with HD showed a greater dual-task motor cost compared to HC, both groups behaved similarly as condition complexity increased.

CONCLUSIONS

Standing postural sway is a more sensitive marker of instability than change in standard gait speed, particularly under dual-task conditions. The more complex TUG cognitive is a sensitive measure of walking dual-task performance. The results of this study provide insights about the nature of motor-cognitive impairments in HD and provide support for a distinction between static and dynamic postural control mechanisms during performance of dual-tasks.

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.

Approach to Posture and Gait in Huntington's Disease

Disturbances of gait occur in all stages of Huntington’s disease (HD) including the premanifest and prodromal stages. Individuals with HD demonstrate the slower speed of gait, shorter stride length, and increased variability of gait parameters as compared to controls; cognitive disturbances in HD often compound these differences. Abnormalities of gait and recurrent falls lead to decreased quality of life for individuals with HD throughout the disease. This scoping review aims to outline the cross-disciplinary approach to gait evaluation in HD and will highlight the utility of objective measures in defining gait abnormalities in this patient population.

Acoustic Speech Analytics Are Predictive of Cerebellar Dysfunction in Multiple Sclerosis

Speech production relies on motor control and cognitive processing and is linked to cerebellar function. In diseases where the cerebellum is impaired, such as multiple sclerosis (MS), speech abnormalities are common and can be detected by instrumental assessments. However, the potential of speech assessments to be used to monitor cerebellar impairment in MS remains unexplored. The aim of this study is to build an objectively measured speech score that reflects cerebellar function, pathology and quality of life in MS. Eighty-five people with MS and 21 controls participated in the study. Speech was independently assessed through objective acoustic analysis and blind expert listener ratings. Cerebellar function and overall disease disability were measured through validated clinical scores; cerebellar pathology was assessed via magnetic resonance imaging, and validated questionnaires informed quality of life. Selected speech variables were entered in a regression model to predict cerebellar function. The resulting model was condensed into one composite speech score and tested for prediction of abnormal 9-hole peg test (9HPT), and for correlations with the remaining cerebellar scores, imaging measurements and self-assessed quality of life. Slow rate of syllable repetition and increased free speech pause percentage were the strongest predictors of cerebellar impairment, complemented by phonatory instability. Those variables formed the acoustic composite score that accounted for 54% of variation in cerebellar function, correlated with cerebellar white matter volume (r = 0.3, p = 0.017), quality of life (r = 0.5, p < 0.001) and predicted an abnormal 9HPT with 85% accuracy. An objective multi-feature speech metric was highly representative of motor cerebellar impairment in MS.

Validating the walking while talking test to measure motor, cognitive, and dual-task performance in ambulatory individuals with multiple sclerosis

INTRODUCTION

Multiple Sclerosis (MS) is associated with demyelination of the central nervous system that negatively impacts both motor and cognitive function, resulting in difficulty performing simultaneous motor and cognitive tasks, or dual-tasks. Declines in dual-tasking have been linked with falls in MS; thus, dual-task assessment with the Walking While Talking Test (WWTT) is commonly utilized in the clinical setting. However, the validity and minimal detectable change (MDC) of the WWTT has not been established for persons with MS. The primary objective of the study was to establish the WWTT as a valid measure of dual-task function by examining concurrent validity with other motor, cognitive and dual-task measures, and to establish the MDC for both the simple and complex conditions of the WWTT.

METHODS

In a single visit, 38 adults (34 female, mean (SD) age 49.8(±9.1), Patient Determined Disease Steps (PDDS) mean 3, range 1-6) completed the WWTT simple (walk while reciting the alphabet) and complex (walk while reciting every other letter of the alphabet) conditions as well as a battery of cognitive and motor tests. Spearman correlations were used to examine concurrent validity. The sample was divided into low and high disability groups to determine the impact of disability severity on relationships among WWTT and cognitive and motor function.

RESULTS

Excellent concurrent validity (r ≥ 0.79; p < 0.001) was observed for the WWTT simple and complex with both motor (Timed Up-and-Go, Timed 25-Foot Walk, forward and backward walking velocity, Six-Spot Step Test) and dual-task measures (Timed Up-and-Go Cognitive). The WWTT-simple demonstrated moderate concurrent validity with measures of processing speed (Symbol Digit Modalities Test, p = 0.041) and was related to all motor and dual-task measures across disability levels. The WWTT complex was only related to complex motor tasks in the low disability group. Within the low disability group, WWTT was associated with processing speed (p = 0.045) and working memory (California Verbal Learning Test, p = 0.012). The MDC values were established for WWTT simple (6.9 s) and complex (8 s) conditions.

DISCUSSION

The WWTT is a quick, easy-to-administer clinical measure that captures both motor and cognitive aspects of performance for persons with MS. Clinicians should consider adding the WWTT to the evaluation of persons with MS to examine dual-task performance.

Dual-Motor-Task of Catching and Throwing a Ball During Overground Walking in Virtual Reality

Virtual Reality is a versatile platform to study human behavior in simulated environments and to develop interventions for functional rehabilitation. In this work, we designed a dual-task paradigm in a virtual environment where both tasks demand motor skills. Twenty-one healthy adults (mean age: 24.1 years) participated in this study. The experiment involved three conditions - normal overground walking, catch and throw a ball while standing, and catch and throw a ball while walking overground -all in the virtual environment. We investigated the dual-task gait characteristics and their correlations with outcomes from cognitive assessments. Results show that subjects walk conservatively with smaller stride lengths, larger stride widths and stride time while catching and throwing. However, they are able to throw the balls more accurately at the target and achieve higher scores. During the dual-task throw, we observed that the participants threw more balls during the stance phase of the gait when the foot was in the terminal stance and pre-swing region. During this region, the body has forward momentum. In addition, the changes in gait characteristics during dual-task throw correlate well with outcome measures in standardized cognitive tests. This study provides a new and engaging paradigm to analyze dual-motor-task cost in a virtual reality environment and it can be used as a basis to compare strategies adopted by different population groups with healthy young adults to execute coordinated motor tasks.

Dual-Task Performance in Multiple Sclerosis' Patients: Cerebellum Matters?

OBJECTIVE

Gait, cognitive impairments, and their mutual influence in dual tasking (cognitive-motor dual tasking, CM-DT) are important to address therapeutic approaches in patients with multiple sclerosis (PMS). CM-DT correlates have been widely investigated with variable and dissimilar results, due to differences in methods. However, although the cerebellum has recently shown to be involved in both motor and cognitive functions, few studies have explored its role in the integration of the concurrent execution of gait and cognition. This case-control study aims to explore the effects of adding a cognitive task to walking in PMS and to investigate the role of the cerebellum in the interfering process.

METHODS

In total, 20 patients and 18 healthy controls (HC) underwent clinical assessments, dual task (DT), and 3 T magnetic resonance imaging (MRI). DT was composed by three 2-min trials requiring fast walking. In 2 of them 2 different cognitive tasks were added.

RESULTS

Both groups evidenced the presence of cognitive-motor interference (CMI) for both cognitive conditions with a greater effect of word list generation task in PMS. Analysis of variance between HC and patients with high or low performances showed a significantly increased volume in Vermis lobules VIIIa and IX of high performers compared with HC.

CONCLUSION

Our results show that CMI is also present in healthy individuals but is significantly more disabling in PMS. Furthermore, MRI data point to the existence of an initial mechanism of cerebellar reorganization in PMS with lower interference. Subsequently, the failure of this mechanism due to the progression of disability leads to a more evident expression of symptoms.

Design and Evaluation of User-Centered Exergames for Patients With Multiple Sclerosis: Multilevel Usability and Feasibility Studies

BACKGROUND

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system. Patients with MS experience a wide range of physical and cognitive dysfunctions that affect their quality of life. A promising training approach that concurrently trains physical and cognitive functions is video game-based physical exercising (ie, exergaming). Previous studies have indicated that exergames have positive effects on balance and cognitive functions in patients with MS. However, there is still a need for specific, user-centered exergames that function as a motivating and effective therapy tool for patients with MS and studies investigating their usability and feasibility.

OBJECTIVE

The aim of this interdisciplinary research project is to develop usable and feasible user-centered exergames for the pressure-sensitive plate Dividat Senso by incorporating theoretical backgrounds from movement sciences, neuropsychology, and game research as well as participatory design processes.

METHODS

Focus groups (patients and therapists) were set up to define the user-centered design process. This was followed by the field testing of newly developed exergame concepts. Two sequential usability and feasibility studies were conducted on patients with MS. The first study included a single exergaming session followed by measurements. Between the first and second studies, prototypes were iterated based on the findings. The second study ran for 4 weeks (1-2 trainings per week), and measurements were taken before and after the intervention. For each study, participants answered the System Usability Scale (SUS; 10 items; 5-point Likert Scale; score range 0-100) and interview questions. In the second study, participants answered game experience-related questionnaires (Flow Short Scale [FSS]: 13 items; 7-point Likert Scale; score range 1-7; Game Flow questionnaire: 17 items; 6-point Likert Scale; score range 1-6). Mixed methods were used to analyze the quantitative and qualitative data.

RESULTS

In the first study (N=16), usability was acceptable, with a median SUS score of 71.3 (IQR 58.8-80.0). In the second study (N=25), the median SUS scores were 89.7 (IQR 78.8-95.0; before) and 82.5 (IQR 77.5-90.0; after), and thus, a significant decrease was observed after training (z=-2.077; P=.04; r=0.42). Moreover, high values were observed for the overall FSS (pre: median 5.9, IQR 4.6-6.4; post: median 5.8, IQR 5.4-6.2) and overall Game Flow Questionnaire (pre: median 5.0, IQR 4.7-5.3; post: median 5.1, IQR 4.9-5.3). A significant decrease was observed in the item perceived importance (FSS: z=-2.118; P=.03; r=0.42). Interviews revealed that user-centered exergames were usable, well accepted, and enjoyable. Points of reference were identified for future research and development.

CONCLUSIONS

The project revealed that the newly developed, user-centered exergames were usable and feasible for patients with MS. Furthermore, exergame elements should be considered in the development phase of user-centered exergames (for patients with MS). Future studies are needed to provide indications about the efficacy of user-centered exergames for patients with MS.

Instrumentally assessed gait quality is more relevant than gait endurance and velocity to explain patient-reported walking ability in early-stage multiple sclerosis

BACKGROUND AND PURPOSE

People with multiple sclerosis (PwMS) often report walking limitations even when the gold standard Expanded Disability Status Scale (EDSS) indicates normal walking endurance/autonomy. The present multicenter study on early-stage PwMS aims at analyzing which aspects are associated with patient-reported walking limitations measured with the 12-item Multiple Sclerosis Walking Scale (MSWS-12).

METHODS

Eighty-two PwMS (EDSS ≤ 2.5) were assessed using the Fullerton Advanced Balance Scale-short (FAB-s), the Fatigue Severity Scale (FSS) and the 6-min Walk Test (6MWT), the latter administered also to 21 healthy subjects. Participants performed the 6MWT wearing three inertial sensors on ankles and trunk. Instrumented metrics describing gait velocity (stride length and frequency) and quality (regularity, symmetry, instability) were computed from sensor data. Fatigue (FSS), balance (FAB-s), walking endurance (6MWT) and instrumented metrics were entered in a multiple regression model with MSWS-12 as dependent variable.

RESULTS

Gait symmetry, gait instability, fatigue and balance were significantly associated with self-rated walking ability, whilst walking endurance and velocity were not. Fatigue, balance, gait symmetry and instability were more impaired in participants reporting mild-to-moderate (MS_MM-PWL , 25 ≤ MSWS-12 < 75) compared to those reporting none-to-minimal (MS_nm-PWL , 0 ≤ MSWS-12 ≤ 25) perceived walking limitations. Compared to healthy subjects, gait symmetry and stability were reduced in MS_nm-PWL and MS_MM-PWL , even in those participants with EDSS ≤ 1.5.

CONCLUSION

Instrumentally assessed gait quality aspects (symmetry and instability) are associated with patient-reported walking ability in early-stage PwMS and seem sensitive biomarkers to detect subtle impairments even in the earliest stages of the disease (EDSS ≤ 1.5). Future studies should assess their ability to follow walking change due to MS progression or pharmacological/rehabilitation interventions.

Non-invasive brain stimulation to assess neurophysiologic underpinnings of lower limb motor impairment in multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is a neuroinflammatory disease resulting in axonal demyelination and an amalgamation of symptoms which commonly result in decreased quality of life due to mobility dysfunction and limited participation in meaningful activities.

NEW METHOD

The use of non-invasive brain stimulation (NIBS) techniques, specifically transcranial magnetic and transcranial direct current stimulation, have been essential in understanding the pathophysiological decrements related to disease progression, particularly with regard to motor impairments. Although the research in this area has primarily focused on the upper extremities, new interest has arisen in understanding the neurophysiological underpinnings of lower limb impairment. Therefore, the purpose of this review is to: first, provide an overview of common NIBS techniques used to explore sensorimotor neurophysiology; second, summarize lower limb neuromuscular and mobility impairments typically observed in PwMS; third, review the current knowledge regarding interactions between TMS-assessed neurophysiology and lower limb impairments in PwMS; and fourth, provide recommendations for future NIBS studies based on current gaps in the literature.

RESULTS

PwMS exhibit reduced excitability and increased inhibitory neurophysiologic function which has been related to disease severity and lower limb motor impairments. Comparison with existing methods: Moreover, promising results indicate that the use of repetitive stimulation and transcranial direct current stimulation may prime neural adaptability and prove useful as a therapeutic tool in ameliorating lower limb impairments.

CONCLUSIONS

While these studies are both informative and promising, additional studies are necessary to be conclusive. As such, studies assessing objective measures of lower limb impairments associated with neurophysiological adaptations need further evaluation.

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

BACKGROUND

Cognitive-motor interference (CMI) has been well recognized in persons with multiple sclerosis (pwMS); however, there are limited data on effects of task difficulty.

OBJECTIVE

Examine (1) the effects of motor and cognitive tasks varying in difficulty on the magnitude of CMI and (2) the discriminative validity of CMI between pwMS and healthy controls (HC).

METHODS

Nine cognitive-motor dual-task (DT) conditions (combinations of three cognitive and three walking tasks) were examined. Outcome measures were DT-performance and dual-task cost (DTC) of gait parameters and correct answers. Task differences and overall group-effects were analysed by mixed model analysis, plus the Wilcoxon signed-rank tests or multivariate analysis of variances (MANOVAs), respectively.

RESULTS

Task effects were examined in 82 pwMS (Expanded Disability Status Scale (EDSS): 3.3 ± 1.0) and discriminative validity in a subsample (35 pwMS and 33 HC). Motor-DTC and DT-performance were affected by difficulty of both the cognitive task (p < 0.001) and the walking condition (p ⩽ 0.002), while cognitive-DTC only varied between cognitive tasks with a large difference in difficulty (p ⩽ 0.005) and not between walking conditions (p ⩾ 0.125). None of the DTCs differed between groups.

CONCLUSION

CMI, and especially motor performance, is affected by difficulty of the DT. Although pwMS performed worse on the tasks than HC, none of the DT-conditions showed a discriminative DTC.

Effect of robot-assisted gait training on gait automaticity in Parkinson disease: A prospective, open-label, single-arm, pilot study

ABSTRACT

Gait automaticity is reduced in patients with Parkinson disease (PD) due to impaired habitual control. The aim of this study was to investigate the effect of robot-assisted gait training (RAGT) on gait automaticity as well as gait speed and balance in patients with PD.This study was a prospective, open-label, single-arm, pilot study. We planned to recruit 12 patients with idiopathic PD. Participants received 12 sessions of RAGT using exoskeleton-type robotic device. Sessions were 45-minute each, 3 days a week, for 4 consecutive weeks using an exoskeleton-type gait robot. The primary outcome was the percentage of dual-task interference measured by the 10-Meter Walk Test (10MWT) under single and dual-task (cognitive and physical) conditions. Secondary outcomes were the Berg Balance Scale and Korean version of the Falls Efficacy Scale-International. All measures were evaluated before treatment (T0), after treatment (T1), and 1-month post-treatment (T2).Twelve patients were enrolled and 1 dropped out. Finally, 11 patients with idiopathic PD were analyzed. The mean age of 11 patients (5 males) was 66.46 ± 5.66 years, and disease duration was 112.91 ± 50.19 months. The Hoehn and Yahr stages were 2.5 in 8 patients and 3 in 3 patients. Linear mixed-effect model analysis showed a significant change over time only in single-task gait speed of the 10MWT (P = .007), but not in dual-task gait speed, dual-task interferences, and Korean version of the Falls Efficacy Scale-International. Cognitive dual-task interference significantly increased (P = .026) at T1, but not at T2 (P = .203). No significant changes were observed for physical dual-task interference at T1 and T2. Single-task gait speed of the 10MWT was significantly increased at T1 (P = .041), but not at T2 (P = .445). There were no significant changes in the dual-task gait speed of 10MWT. A significant improvement was observed in Berg Balance Scale score at T1 and T2 (P = .004 and P = .024, respectively).In this pilot study, despite improvement in walking speed and balance, gait automaticity in patients with PD was not improved by RAGT using an exoskeleton-type robot. Additional therapeutic components may be needed to improve gait automaticity using RAGT in patients with PD.

Dual-Task Cost and Related Clinical Features in Patients With Multiple Sclerosis

This study aimed to investigate the dual-task cost of both motor and cognitive performances in patients with multiple sclerosis (PwMS) and in healthy controls and to determine their relationships with clinical features in PwMS. The participants performed motor tasks (postural stability, walking, and manual dexterity) and cognitive tasks (mental tracking and verbal fluency) under single- and dual-task conditions. The results showed that postural stability under dual-task conditions did not change, whereas walking and manual dexterity deteriorated, regardless of the concurrent cognitive task, in PwMS (median Expanded Disability Status Scale score: 1) and the healthy controls. Verbal fluency decreased during postural stability, whereas it increased during walking, and it was maintained during manual dexterity in both groups. Mental tracking did not change during walking; it declined during manual dexterity in both groups. Mental tracking during postural stability deteriorated in PwMS, while it did not change in the healthy controls. In general, dual-task costs were associated with baseline performances of tasks rather than clinical features. Therefore, baseline performances of both tasks should be increased for improving dual-task performance in PwMS.

Qualitative Evaluation Informs Understanding of Motor Cognition and Therapies in Older Adults with Mild Cognitive Impairment

BACKGROUND

10%to 20%of Americans aged 65 and older have mild cognitive impairment (MCI) with 10%progressing to Alzheimer's disease (AD) each year. Underserved groups, including African Americans (AAs), are among the most vulnerable to MCI and AD. Although evidence continues to amass, the benefits of exercise and movement for AD is still understudied in AD.

OBJECTIVE

Understanding the attitudes, perceptions, and beliefs about motor-cognitive integration and examining the physical activity of a sample of predominantly Black women community members with self-reported memory problems will allow improved recruitment and refinement of multimodal interventions designed to improve motor-cognitive and cognitive function.

METHODS

We conducted focus groups with older adults who reported subjective memory complaints (n = 15; Black: n = 12, White: n = 3, mean age 71.7±5.8).

RESULTS

Findings from thematic analysis showed most participants knew of benefits of exercise. However, most participants reported not getting adequate exercise due to factors such as pain, increased responsibilities, and fear of injury. Despite barriers, participants expressed enthusiasm for multimodal interventions designed to target body and brain health and provided several suggestions to improve or enhance the proposed interventions.

CONCLUSION

Results provide useful insights regarding improving participation among historically under-represented groups in clinical movement-based research. Participants' discussion focused primarily on the way motor-cognitive integration prevents falls, maintains memory, and provides a social benefit. The reported perceived benefits and limitations of exercise, as this population understands it, can help researchers and physicians better engage the community for lifestyle changes that will support greater motor-cognitive health.

The patients' perspective on the perceived difficulties of dual-tasking: development and validation of the Dual-task Impact on Daily-living Activities Questionnaire (DIDA-Q)

BACKGROUND

Everyday-life activities often require performing dual tasks (DT), with consequent possible occurrence of motor-cognitive or motor-motor interference. This could reduce quality of life, in particular in people with neurological diseases. However, there is lack of validated tools to assess the patients' perspective on DT difficulties in this population. Therefore, we developed the Dual-task Impact on Daily-living Activities-Questionnaire (DIDA-Q) and tested its psychometric properties in people with multiple sclerosis (PwMS).

METHODS

Items were generated based on existing scales, DT paradigms used in previous studies and the opinion of a multi-stakeholder group, including both experts and PwMS. Twenty DT constituted the preliminary version of the DIDA-Q which was administered to 230 PwMS. The psychometric properties of the scale were evaluated including internal consistency, validity and reliability.

RESULTS

Nineteen items survived after exploratory factor analysis, showing a three-factor solution which identifies the components mostly contributing to DT perceived difficulty (i.e., balance and mobility, cognition and upper-limb ability). The DIDA-Q appropriately fits the graded response model, with first evaluations supporting internal consistency (Cronbach's alpha=0.95), validity (70% of the hypotheses for convergent and discriminant constructs confirmed) and reliability (intraclass correlation coefficients=0.95) of this tool.

CONCLUSION

The DIDA-Q could be used in research and clinical settings to discriminate individuals with low vs. high cognitive-motor or motor-motor interference, and to develop and evaluate the efficacy of personalized DT rehabilitative treatments in PwMS.

Effects of aerobic fitness on cognitive motor interference during self-paced treadmill walking in older adults

BACKGROUND

Older adults experience greater cognitive motor interference (CMI) due to declines in cognitive and physical function. Although aerobic fitness has beneficial effects on cognition, its association with CMI is not clear.

AIMS

This study aims to investigate the effects of aerobic fitness on CMI during self-paced treadmill walking in older adults.

METHODS

Thirty participants (67.6 ± 10.34 years, 21 females) were included in a 2-day cross-sectional design study. Aerobic fitness was assessed with the Rockport 1-mile test. The dual-task paradigm consisted of walking only, and dual-task standing and dual-task walking (i.e., standing/walking while performing the Modified Stroop color word test) on a treadmill. To assess CMI, gait speed and accuracy rate were measured to later calculate the dual-task cost for each parameter.

RESULTS

Individuals with low aerobic fitness exhibited significantly greater gait speed dual-task cost than individuals with high aerobic fitness (p < 0.05). There were no significant findings for accuracy rate dual-task cost.

DISCUSSION

These study findings are the first to demonstrate increases in CMI in relation to low aerobic fitness. Results can be attributed to the relationship between aerobic fitness and cognition as well as theories related to attentional capacity.

CONCLUSION

Older adults with low aerobic fitness possess greater CMI when compared to older adults with high aerobic fitness. This provides a foundation of knowledge on how aerobic fitness in older adults may affect CMI which can lead researchers to examine the causal relationships between an aerobic exercise intervention program and CMI in older adults.

The Effects of Dual Task Cognitive Interference and Fast-Paced Walking on Gait, Turns, and Falls in Men and Women with FXTAS

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a genetic neurodegenerative disorder characterized by cerebellar ataxia, tremor, and cognitive dysfunction. We examined the impact of dual-task (DT) cognitive-motor interference and fast-paced (FP) gait on gait and turning in FXTAS. Thirty participants with FXTAS and 35 age-matched controls underwent gait analysis using an inertial sensor-based 2-min walk test under three conditions: (1) self-selected pace (ST), (2) FP, and (3) DT with a concurrent verbal fluency task. Linear regression analyses were performed to assess the association between FXTAS diagnosis and gait and turn outcomes. Correlations between gait variables and fall frequency were also calculated. FXTAS participants had reduced stride length and velocity, swing time, and peak turn velocity and greater double limb support time and number of steps to turn compared to controls under all three conditions. There was greater dual task cost of the verbal fluency task on peak turn velocity in men with FXTAS compared to controls. Additionally, stride length variability was increased and cadence was reduced in FXTAS participants in the FP condition. Stride velocity variability under FP gait was significantly associated with the number of self-reported falls in the last year. Greater motor control requirements for turning likely made men with FXTAS more susceptible to the negative effects of DT cognitive interference. FP gait exacerbated gait deficits in the domains of rhythm and variability, and increased gait variability with FP was associated with increased falls. These data may inform the design of rehabilitation strategies in FXTAS.

On the Reliability of Examining Dual-Tasking Abilities Using a Novel E-Health Device—A Proof of Concept Study in Multiple Sclerosis

The assessment of neuropsychological functions and especially dual-tasking abilities is considered to be increasingly relevant in the assessment of neurological disease, and Multiple Sclerosis (MS) in particular. However, the assessment of dual-tasking abilities is hindered by specific software requirements and extensive testing times. We designed a novel e-health (progressive web application-based) device for the assessment of dual-tasking abilities usable in “bedside” and outpatient clinic settings and examined its reliability in a sample of N = 184 MS patients in an outpatient setting. Moreover, we examined the relevance of dual-tasking assessment using this device with respect to clinically relevant parameters in MS. We show that a meaningful assessment of dual-tasking is possible within 6 min and that the behavioral readouts overall show good reliability depending on dual-tasking difficulty. We show that dual-tasking readouts were correlated with clinically relevant parameters (e.g., EDSS, disease duration, processing speed) and were not affected by fatigue levels. We consider the tested dual-tasking assessment device suitable for routine clinical neuropsychological assessments of dual-tasking abilities. Future studies may further evaluate this test regarding its suitability in the long-term follow up assessments and to assess dual-tasking abilities in other neurological and psychiatric disorders.

Comparing 16 Different Dual-Tasking Paradigms in Individuals With Multiple Sclerosis and Healthy Controls: Working Memory Tasks Indicate Cognitive-Motor Interference

Background: Cognitive–motor interference (CMI) is measured by dual-tasking (DT), which involves motor and cognitive tasks. There is no consensus as to whether CMI is present in multiple sclerosis (MS).

Objectives: We investigated the effects of 16 DT conditions by measuring motor complexity, cognitive domain, and task difficulty.

Method: In total, 40 persons with MS (pwMSs) with Expanded Disease Status Scale (EDSS) 3.2 ± 1.7 and 31 age- and sex-matched healthy controls (HCs) completed 2 single walking, 8 single cognitive, and 2 complex walking tasks and 16 cognitive–motor DT. The main outcomes were mean values of gait velocity and the percentage change from single to DT (motor DT costs, mDTCs) and mean values of cognitive task accuracy and the percentage changes (cognitive DTC, cDTC).

Results: Two-way analyses of variance showed the main effect of cognitive task yielded an F ratio of F_{(4, 268)} = 72.35, p < 0.01, for mean gait velocity, and an F ratio of F_{(4, 304)} = 17.12, p < 0.001, for mDTC, indicating that the mean velocity was significantly lower and the mDTC significantly higher for DS_B (mean = 1.27, SD = 0.03, and mean = 13.52, SD = 1.28, respectively). The main effect of cognitive task yielded an F ratio of F_{(4, 116)} = 84.32, p < 0.001, with the lowest average accuracy for DS_B (mean = 43.95, SD = 3.33); no effect was found for cDTC. In pwMSs, the EDSS accounted for 28% (F = 13.65, p = 0.001) of variance in a model predicting the highest mDTC.

Conclusions: Overall, among different cognitive tasks added, the Digit Span backward was the most interfering cognitive task over gait velocity and accuracy. The effect was similar independently from the motor complexity and the group. PwMSs and HCs behaved in a similar manner at all motor complexity levels and during all cognitive task.

Backward Walking and Dual-Task Assessment Improve Identification of Gait Impairments and Fall Risk in Individuals with MS

Background

Individuals with multiple sclerosis (MS) experience deficits in motor and cognitive domains, resulting in impairment in dual-task walking ability. The goal of this study was to compare performance of forward walking and backward walking in single- and dual-task conditions in persons with MS to age- and sex-matched healthy controls. We also examined relationships between forward and backward walking to cognitive function, balance, and retrospective fall reports.

Methods

All measures were collected in a single session. A 2 × 2 × 2 mixed model ANOVA was used to compare differences in forward and backward walking in single- and dual-task conditions between MS and healthy controls. Spearman correlations were used to examine relationships between gait and cognitive function, falls, and balance.

Results

Eighteen individuals with relapsing-remitting MS and 14 age- and sex-matched healthy controls participated. Backward walking velocity revealed significant differences between groups for both single-task (p = 0.015) and dual-task (p = 0.014) conditions. Persons with MS demonstrated significant differences between single- and dual-task forward and backward walking velocities (p = 0.023; p = 0.004), whereas this difference was only apparent in the backward walking condition for healthy controls (p = 0.004). In persons with MS, there were significant differences in double support time between single- and dual-task conditions in both backward (p < 0.001) and forward (p = 0.001) directions. More falls at six months were significantly associated with shorter backward dual-task stride length (r = −0.490; p = 0.046) and slower velocity (r = −0.483; p = 0.050).

Conclusion

Differences in MS and age- and sex-matched healthy controls are more pronounced during backward compared to forward walking under single- and dual-task conditions. Future work with a larger sample size is needed to validate the clinical utility of backward walking and dual-task assessments and mitigate the limited sensitivity of the current dual-task assessments that primarily rely upon forward walking.

Correlates of dual-task performance in people with multiple sclerosis: A systematic review

BACKGROUND

Gait, balance, and cognitive disorders are common in people with Multiple Sclerosis (MS). In addition, people with MS have impaired ability to concurrently perform gait/balance and cognitive tasks due to cognitive-motor interference (CMI). Clinical features of MS may affect CMI; however, the relationship between CMI and clinical features of MS remains unclear.

RESEARCH QUESTION

Are clinical features of MS associated with CMI?

METHODS

A systematic review was conducted, and four databases (CINAHL, MEDLINE, ProQuest, and Web of Science Core Collections) were searched up to March 2019 using a combination of keywords related to MS and dual-tasking/CMI. Cross-sectional or longitudinal studies that reported the association between CMI and clinical features of MS were included in the review. The correlation coefficient for the relationship between CMI and clinical features of MS were extracted and the results were categorized according to the clinical feature measured.

RESULTS

13 studies were included in this review, of which nine investigated the association between CMI and disability and cognition, and four investigated the association between CMI and other clinical features of MS. While some studies reported that disability and cognition were negatively associated with CMI, the evidence was inconsistent regarding the magnitude and presence of these relationships. In addition, the relationship between CMI and other clinical features of MS (balance, falls risk, fatigue, anxiety, depression, pain, spasticity) remains unclear.

SIGNIFICANCE

This review presents evidence from a small number of studies that suggests disability and cognition are negatively associated with CMI in people with MS, indicating that greater disability and cognitive dysfunction may be associated with lower dual-task performance. These findings highlight the potential importance of disability and cognition in the measurement and rehabilitation of people with dual-task impairments. However, further research is required to confirm these findings and determine the relationship between CMI and other clinical features of MS included in this review.

Reliability of gait and dual-task measures in multiple sclerosis

BACKGROUND

Single-task (ST) and dual-task (DT) assessments are commonly used to evaluate motor and cognitive impairment in people with multiple sclerosis (MS). Although variability can influence repeated DT testing measures, the reliability of several DT variables over time has not been adequately explored. For instance, a third testing session has never been included to observe whether DT has a learning effect. DT cognition rate reliability has not yet been examined and dual-task cost (DTC), a widely used calculation for DT interpretation, has not been proven reliable.

RESEARCH QUESTION

To evaluate the reliability of ST and DT measures of gait and cognition over three test sessions.

METHODS

This was a cross-sectional study involving 18 people with MS and 12 controls. Participants attended three test sessions, each one week apart. ST and DT (serial seven subtraction) gait variables, DTC, coefficient of variability (CV), and cognition rate were extracted and calculated using an instrumented walkway. Reliability was assessed using intraclass correlation coefficients (ICC) or Kendall's coefficient of concordance (KCC; nonparametric test) and minimum detectable change (MDC); between-session learning effect was assessed using repeated measures ANOVA.

RESULTS

ICC/KCC values for ST and DT gait variables ranged from moderate to excellent (0.50-0.99). However, reliability for DT stride width and cognition rate was lower in controls. In general, DTC and CV variables had poor ICCs and high MDC values (49.19-1478.67 %), although some DTC variables had moderate or higher reliability in controls. Cognition rate was reliable in both MS (ICC 0.91) and controls (ICC 0.84). A learning effect between sessions was observed for DT velocity in both groups and for DTC cadence in people with MS.

SIGNIFICANCE

ST and DT gait measures as well as DT cognition rate are reliable outcomes for repeated testing, while DTC and CV variables may not be suitable for long-term monitoring.

Design, Development, and Testing of an App for Dual-Task Assessment and Training Regarding Cognitive-Motor Interference (CMI-APP) in People With Multiple Sclerosis: Multicenter Pilot Study

Background

Dual tasking constitutes a large portion of most activities of daily living; in real-life situations, people need to not only maintain balance and mobility skills, but also perform other cognitive or motor tasks at the same time. Interest toward dual-task training (DTT) is increasing as traditional interventions may not prepare patients to adequately face the challenges of most activities of daily living. These usually involve simultaneous cognitive and motor tasks, and they often show a decline in performance. Cognitive-motor interference (CMI) has been investigated in different neurological populations, but limited evidence is present for people with multiple sclerosis (MS). The use of computerized tools is mandatory to allow the application of more standardized assessment and rehabilitation intervention protocols and easier implementation of multicenter and multilanguage studies.

Objective

To describe the design and development of CMI-APP, an adaptive and interactive technology tablet-based app, and to present the preliminary results of a multicenter pilot study involving people with MS performed in several European centers for evaluating the feasibility of and adherence to a rehabilitation program based on CMI-APP.

Methods

CMI-APP includes user-friendly interfaces for personal data input and management, assessment of CMI, and DTT. A dedicated team developed CMI-APP for Android tablets above API level 14 (version 4.0), using C# as the programming language and Unity and Visual Studio as development tools. Three cognitive assessment tests for working memory, information processing speed, and sustained attention and four motor assessment tests for walking at different difficulty levels were implemented. Dual cognitive-motor tasks were performed by combining single cognitive and motor tasks. CMI-APP implements exercises for DTT involving the following 12 cognitive functions: sustained attention, text comprehension, verbal fluency, auditory discrimination, visual discrimination, working memory, information processing speed, auditory memory, visual memory, verbal analog reasoning, visual analog reasoning, and visual spatial planning, which can be performed during walking or stepping on the spot. Fifteen people with MS (mean age 52.6, SD 8.6 years; mean disease duration 9.4, SD 8.4 years; mean Expanded Disability Status Scale score 3.6, SD 1.1) underwent DTT (20 sessions). Adherence to the rehabilitation program was evaluated according to the percentage of performed sessions, perceived exertion during the training (Borg 15-point Ratings of Perceived Exertion [RPE] Scale), and subjective experience of the training (Intrinsic Motivation Inventory [IMI]).

Results

The adherence rate was 91%. DTT was perceived as “somewhat difficult” (mean RPE Scale score 12.6, SD 1.9). IMI revealed that participants enjoyed the training and felt that it was valuable and, to some extent, important, without feelings of pressure. They felt competent, although they did not always feel they could choose the exercises, probably because the therapist chose the exercises and many exercises had few difficulty levels.

Conclusions

CMI-APP is safe, highly usable, motivating, and well accepted for DTT by people with MS. The findings are fundamental for the preparation of future large-sample studies examining CMI and the effectiveness of DTT interventions with CMI-APP in people with MS.