Dynamic Motor Tasks Research Articles

Dynamic Stability, Symmetry, and Smoothness of Gait in People with Neurological Health Conditions.

Neurological disorders such as stroke, Parkinson's disease (PD), and severe traumatic brain injury (sTBI) are leading global causes of disability and mortality. This study aimed to assess the ability to walk of patients with sTBI, stroke, and PD, identifying the differences in dynamic postural stability, symmetry, and smoothness during various dynamic motor tasks. Sixty people with neurological disorders and 20 healthy participants were recruited. Inertial measurement unit (IMU) sensors were employed to measure spatiotemporal parameters and gait quality indices during different motor tasks. The Mini-BESTest, Berg Balance Scale, and Dynamic Gait Index Scoring were also used to evaluate balance and gait. People with stroke exhibited the most compromised biomechanical patterns, with lower walking speed, increased stride duration, and decreased stride frequency. They also showed higher upper body instability and greater variability in gait stability indices, as well as less gait symmetry and smoothness. PD and sTBI patients displayed significantly different temporal parameters and differences in stability parameters only at the pelvis level and in the smoothness index during both linear and curved paths. This study provides a biomechanical characterization of dynamic stability, symmetry, and smoothness in people with stroke, sTBI, and PD using an IMU-based ecological assessment.

The impact of vestibular function on cognitive–motor interference: a case–control study on dual-tasking in persons with bilateral vestibulopathy and normal hearing

Bilateral vestibulopathy (BV) is a chronic vestibular disorder, characterized by bilaterally absent or significantly impaired vestibular function. Symptoms typically include, but are not limited to, unsteadiness and movement-induced blurred vision (oscillopsia). This prospective case–control study aimed to elucidate the impact of BV on cognitive and motor performance and on cognitive–motor interference. Cognitive and motor performance, as well as cognitive–motor interference were measured in persons with BV and normal hearing using the 2BALANCE dual-task protocol. The experimental group was matched to a healthy control group based on age, sex, and educational level. The 2BALANCE protocol comprises cognitive tests assessing visuospatial memory, mental rotation, visual and auditory response inhibition, visual and auditory working memory, and processing speed. The cognitive tests were performed in single-task condition (while seated), and in dual-task condition (during a static and a dynamic motor task). The static motor task consisted of balancing on a force platform with foam pad. The dynamic motor task consisted of walking at a self-selected speed. These motor tasks were also performed in single-task condition. A generalized estimating equations model was used to investigate group differences for all cognitive and motor outcome measures. The estimated marginal means, as well as the odds ratios (OR), and their 95% confidence intervals (CI) were calculated. For the backward digit recall test, a baseline measurement was performed and analyzed using a student-t test. A total of 22 patients with BV and normal hearing and 22 healthy control subjects were assessed [mean age (SD), BV = 53.66 (13.35) and HC = 53.21 (13.35), 68% male]. The BV group had poorer mental rotation skills in single-task condition, compared to the control group [odds ratio (OR) = 2.30, confidence interval (CI) = 1.12–4.73, P = 0.024]. Similarly, auditory and visual working memory were also poorer in the BV group in single-task condition (P = 0.028 and P = 0.003, respectively). The BV group also performed poorer on the mental rotation task and the visual response inhibition task in dual-task condition (OR = 2.96, CI = 1.57–5.59, P < 0.001 and OR = 1.08, CI = 1.01–1.16, P = 0.032, respectively). Additionally, an interaction effect, indicating increased cognitive–motor interference in the BV group, was observed for mental rotation, response inhibition, and auditory working memory (P = 0.003 to 0.028). All static motor outcome parameters indicated more postural sway in the BV group compared to the control group for all test conditions (P < 0.001 to 0.026). No group differences were noted for the dynamic motor task. These findings suggest a link between vestibular function and cognitive performance, as well as a greater interference between cognitive and motor performance in BV, compared to healthy controls.

Entropy Measures with Three-axis Motion Time-series Data: Comparison of Dominant and Non-dominant Hand in Multi-directional Reach

Background: Motion variance differs among individuals, knowing as the differences in dominant and non-dominant hand functions provide beneficial information to clinicians or therapists regarding accurate diagnosis and rehabilitation purposes. However, due to subjective considerations, there are some limitations of the handedness questionnaires, which are one of the standard methods for evaluating interlimb function differences. Objective: This study aims to quantify the differences in upper limb motions between the dominant and non-dominant hands in the reaching task using approximate entropy (ApEn) and sample entropy (SampEn) measures. This study also provides proper combinations of parameter values m and r for the ApEn and SampEn measures in the hand movement data of the reaching task. Methods: Twenty volunteers performed a multi-directional reaching task. The acceleration data of hand motions were recorded by GENEActiv 3D acceleration sensor (Activinsights Ltd., UK) with a sampling frequency of 1000 Hz. In addition, the ApEn and SampEn values were analysed. Results: The ApEn values of the dominant hand were statistically significantly lower than those of the non-dominant hand for parameter combinations of m=2,3,4,5 with r=0.15,0.20,0.25 for the Y- and Z-axis (p&lt;0.05). The SampEn values of the dominant hand significantly demonstrated lower than those of the non-dominant hand for all axes when computing on combinations of parameter m=2,3,4,5 with r=0.15,0.20 (p&lt;0.05). Conclusion: The ApEn and SampEn measures could be used to predict the degree of regularity or complexity of the reaching hand motion time-series data. These entropy measures also reveal the differences between the dominant and non-dominant hand movements, quantifying movement differences in the dynamic motor tasks associated with hemispheric brain asymmetry.

Association of Bilateral Vestibulopathy With and Without Hearing Loss With Cognitive-Motor Interference

The past years, evidence suggested that the primary symptoms traditionally associated with bilateral vestibulopathy (BV) do not represent the full picture of this patient population. Recent literature also demonstrated cognitive impairment. However, although multitasking and dual-tasking are widely present in everyday activities, most of these studies assessed cognitive function only in single-task conditions. To uncover the association of BV with and without hearing loss with cognitive and motor performance and cognitive-motor interference. This prospective case-control study assessed persons with an isolated BV and persons with BV and a concomitant hearing loss compared with a healthy control group. Data were analyzed in December 2022. The study was conducted at Ghent University (Ghent, Belgium). Data collection took place between March 26, 2021, and November 29, 2022. All participants completed the 2BALANCE dual-task protocol, comprising a static and a dynamic motor task that was combined with 5 visual cognitive tasks. These cognitive tasks assessed mental rotation, visuospatial memory, working memory, response inhibition (executive function), and processing speed. All cognitive tasks were performed in a single-task condition (while seated) and in a dual-task condition (combined with a static and a dynamic motor task). The static task comprised balancing on a force platform with foam pad, and the dynamic task comprised walking at a self-selected speed on the GAITRite Walkway. Both motor tasks were performed in the single-task and dual-task condition. Nineteen persons with BV and hearing loss (mean [SD] age, 56.70 [10.12] years; 10 women [52.6%]), 22 persons with an isolated BV (mean [SD] age, 53.66 [13.35] years; 7 women [31.8%]), and 28 healthy control participants were included (mean [SD] age, 53.73 [12.77] years; 12 women [42.9%]). Both patient groups had mental rotation and working memory impairment in a single-task condition and slower processing speed when walking (ie, during the dynamic dual-task condition). Additionally, the patient group with hearing loss had impaired visuospatial memory and executive function deficits in single-task and dual-task conditions, while this could only be elicited when performing a motor task in persons with isolated BV (ie, when dual-tasking). The findings of this case-control study suggest an association between vestibular function and cognitive and motor performance, even greater in persons with a concomitant hearing loss than in persons with an isolated BV.

Limiting the Use of Electromyography and Ground Reaction Force Data Changes the Magnitude and Ranking of Modelled Anterior Cruciate Ligament Forces

Neuromusculoskeletal models often require three-dimensional (3D) body motions, ground reaction forces (GRF), and electromyography (EMG) as input data. Acquiring these data in real-world settings is challenging, with barriers such as the cost of instruments, setup time, and operator skills to correctly acquire and interpret data. This study investigated the consequences of limiting EMG and GRF data on modelled anterior cruciate ligament (ACL) forces during a drop-land-jump task in late-/post-pubertal females. We compared ACL forces generated by a reference model (i.e., EMG-informed neural mode combined with 3D GRF) to those generated by an EMG-informed with only vertical GRF, static optimisation with 3D GRF, and static optimisation with only vertical GRF. Results indicated ACL force magnitude during landing (when ACL injury typically occurs) was significantly overestimated if only vertical GRF were used for either EMG-informed or static optimisation neural modes. If 3D GRF were used in combination with static optimisation, ACL force was marginally overestimated compared to the reference model. None of the alternative models maintained rank order of ACL loading magnitudes generated by the reference model. Finally, we observed substantial variability across the study sample in response to limiting EMG and GRF data, indicating need for methods incorporating subject-specific measures of muscle activation patterns and external loading when modelling ACL loading during dynamic motor tasks.

A Method for Accessing the Non-Slip Function of Socks in an Acute Maneuver.

The shoe upper hides the foot motion on the insole, so it has been challenging to measure the non-slip function of socks in a dynamic motor task. The study aimed to propose a method to estimate the non-slip function of socks in an acute maneuver. Participants performed a shuttle run task while wearing three types of socks with different frictional properties. The forces produced by foot movement on the upper during the task were measured by pressure sensors installed at the upper. A force platform was also used to measure the ground reaction force at the outsole and ground. Peak force and impulse values computed by using forces measured by the pressure sensors were significantly different between the sock conditions, while there were no such differences in those values computed by using ground reaction forces measured by a force platform. The results suggested that the non-slip function of socks could be quantified by measuring forces at the foot-upper interface. The method could be an affordable option to measure the non-slip function of socks with minimal effects from skin artifacts and shoe upper integrity.

2BALANCE: Test-retest reliability of a cognitive-motor dual-task protocol.

Aside from typical symptoms such as dizziness and vertigo, persons with vestibular disorders often have cognitive and motor problems. These symptoms have been assessed in single-task condition. However, dual-tasks assessing cognitive-motor interference might be an added value as they reflect daily life situations better. Therefore, the 2BALANCE protocol was developed. In the current study, the test-retest reliability of this protocol was assessed. The 2BALANCE protocol was performed twice in 20 healthy young adults with an in-between test interval of two weeks. Two motor tasks and five different cognitive tasks were performed in single and dual-task condition. Intraclass correlation coefficients (ICC), the standard error of measurement, and the minimal detectable difference were calculated. All cognitive tasks, with the exception of the mental rotation task, had favorable reliability results (0.26≤ICC≤0.91). The dynamic motor task indicated overall substantial reliability values in all conditions (0.67≤ICC≤0.98). Similar results were found for the static motor task during dual-tasking (0.50≤ICC≤0.92), but were slightly lower in single-task condition (-0.26≤ICC≤0.75). The 2BALANCE protocol was overall consistent across trials. However, the mental rotation task showed lowest reliability values.

Intermittent Visual Occlusions Increase Balance Training Effectiveness.

Improving dynamic balance can prevent falls in humans with neurological and mechanical deficits. Dynamic balance requires the neural integration of multisensory information to constantly assess the state of body mechanics. Prior research found that intermittent visual rotations improved balance training during walking on a narrow beam, but limitations from the immersive virtual reality headset hindered balance training effectiveness overall. We theorized that intermittent visual occlusions with electrically controlled liquid crystal glasses would overcome the previous limitations of the immersive virtual reality headset and provide a means to enhance dynamic balance training efficacy. Forty healthy young individuals walked on a treadmill-mounted balance beam for 30 min (20 subjects with intermittent visual occlusions and 20 subjects with unperturbed vision). Balance performance, in number of step-offs of the beam, improved by 78% for the visual occlusions group on the same day of the training, a near fourfold improvement compared to the 21% improvement for the unperturbed vision group (t(38) = –5.2, p < 0.001). The difference between groups was also apparent 2 weeks later testing for retention (60% improvement for the visual occlusions group, 5% for the unperturbed vision group; t(38) = –4.2, p < 0.001). Intermittent visual occlusions are likely a simple method for enhancing balance training in dynamic motor tasks.

Assessing the Tidal Volume through Wearables: A Scoping Review.

The assessment of respiratory activity based on wearable devices is becoming an area of growing interest due to the wide range of available sensors. Accordingly, this scoping review aims to identify research evidence supporting the use of wearable devices to monitor the tidal volume during both daily activities and clinical settings. A screening of the literature (Pubmed, Scopus, and Web of Science) was carried out in December 2020 to collect studies: i. comparing one or more methodological approaches for the assessment of tidal volume with the outcome of a state-of-the-art measurement device (i.e., spirometry or optoelectronic plethysmography); ii. dealing with technological solutions designed to be exploited in wearable devices. From the initial 1031 documents, only 36 citations met the eligibility criteria. These studies highlighted that the tidal volume can be estimated by using different technologies ranging from IMUs to strain sensors (e.g., resistive, capacitive, inductive, electromagnetic, and optical) or acoustic sensors. Noticeably, the relative volumetric error of these solutions during quasi-static tasks (e.g., resting and sitting) is typically ≥10% but it deteriorates during dynamic motor tasks (e.g., walking). As such, additional efforts are required to improve the performance of these devices and to identify possible applications based on their accuracy and reliability.

Mechanism of Anterior Cruciate Ligament Loading during Dynamic Motor Tasks.

This study determined anterior cruciate ligament (ACL) force and its contributors during a standardized drop-land-lateral jump task using a validated computational model. Three-dimensional whole-body kinematics, ground reaction forces, and muscle activation patterns from eight knee-spanning muscles were collected during dynamic tasks performed by healthy recreationally active females (n = 24). These data were used in a combined neuromusculoskeletal and ACL force model to determine lower limb muscle and ACL forces. Peak ACL force (2.3 ± 0.5 bodyweight) was observed at ~14% of stance during the drop-land-lateral jump. The ACL force was primarily generated through the sagittal plane, and muscle was the dominant source of ACL loading. The main ACL antagonists (i.e., loaders) were the gastrocnemii and quadriceps, whereas the hamstrings were the main ACL agonists (i.e., supporters). Combining neuromusculoskeletal and ACL force models, the roles of muscle in ACL loading and support were determined during a challenging motor task. Results highlighted the importance of the gastrocnemius in ACL loading, which could be considered more prominently in ACL injury prevention and rehabilitation programs.

Robust and high fidelity real-time hybrid substructuring

In many engineering applications, mechanical contact leads to unwanted dynamic phenomena, such as excitation of high frequency modes. To investigate the induced dynamics, systems need to be tested already in the early development stage. Real-Time Hybrid Substructuring (RTHS) is a Hardware-in-the-Loop approach, that enables testing of critical components with realistic boundary impedance. In RTHS, the critical components are tested experimentally, while the remaining system is simulated numerically in a co-simulation. The dynamics of the transfer system, which couples the experimental part with the numerical simulation render the test outcome inaccurate or even make it unstable unless they are compensated for. The aim of this work is to tackle two major shortcomings of RTHS, namely stability and fidelity of RTHS tests. This is achieved by the combined use of Normalized Passivity Control and Iterative Learning Control. Normalized Passivity Control guarantees passivity of the transfer system and Iterative Learning Control improves the actuator tracking performance iteratively in order to increase the fidelity of the test outcome. Furthermore, a convergence condition is proposed for Iterative Learning Control in this setup such that an optimal tuning of the learning law can be achieved. We tested the proposed compensation scheme experimentally for an RTHS test, where contact occurs. A special focus is put on investigating unstable RTHS tests, as their stabilization and accurate testing is a particular challenge. The results show that the test fidelity, which is measured by the relative root-mean-square error, can be improved by a factor of about 6.5. In addition, it is shown that the combination of velocity feedforward, Iterative Learning Control and Normalized Passivity Control improves the tracking and thus the test fidelity even further. The results reveal that the proposed method has the potential not only to overcome the nonlinear effects of friction in the actuator, but also to improve the tracking accuracy in highly dynamic motion tasks. The main advantages over existing compensation techniques are that only little knowledge about the transfer dynamics of the actuator and experimental part is needed and that the implementation is simple. Hence, it is assumed that this method will be of interest for testing with RTHS in many engineering applications, with or without contact.

Targeted Achilles Tendon Training and Rehabilitation Using Personalized and Real-Time Multiscale Models of the Neuromusculoskeletal System.

Musculoskeletal tissues, including tendons, are sensitive to their mechanical environment, with both excessive and insufficient loading resulting in reduced tissue strength. Tendons appear to be particularly sensitive to mechanical strain magnitude, and there appears to be an optimal range of tendon strain that results in the greatest positive tendon adaptation. At present, there are no tools that allow localized tendon strain to be measured or estimated in training or a clinical environment. In this paper, we first review the current literature regarding Achilles tendon adaptation, providing an overview of the individual technologies that so far have been used in isolation to understand in vivo Achilles tendon mechanics, including 3D tendon imaging, motion capture, personalized neuromusculoskeletal rigid body models, and finite element models. We then describe how these technologies can be integrated in a novel framework to provide real-time feedback of localized Achilles tendon strain during dynamic motor tasks. In a proof of concept application, Achilles tendon localized strains were calculated in real-time for a single subject during walking, single leg hopping, and eccentric heel drop. Data was processed at 250 Hz and streamed on a smartphone for visualization. Achilles tendon peak localized strains ranged from ∼3 to ∼11% for walking, ∼5 to ∼15% during single leg hop, and ∼2 to ∼9% during single eccentric leg heel drop, overall showing large strain variation within the tendon. Our integrated framework connects, across size scales, knowledge from isolated tendons and whole-body biomechanics, and offers a new approach to Achilles tendon rehabilitation and training. A key feature is personalization of model components, such as tendon geometry, material properties, muscle geometry, muscle-tendon paths, moment arms, muscle activation, and movement patterns, all of which have the potential to affect tendon strain estimates. Model personalization is important because tendon strain can differ substantially between individuals performing the same exercise due to inter-individual differences in these model components.

Reasoning Dynamically About the Area of a Rectangle: The Case of Lora and Isaac

This article reports on an exploratory study that engaged students in dynamic experiences of generating the area of a rectangle as a sweep of a line segment over a distance. A case study from a design experiment with one pair of third-grade students is presented to initiate a discussion around the forms of reasoning that students may exhibit as a result of their engagement with these dynamic motion tasks and the characteristics of the design that supported these particular forms of reasoning. The findings of this study show that engaging students in dynamic experiences of area may help them develop a conceptual understanding of the area of a rectangle as a continuous structure that can dynamically change based on the two linear measures that generate it: the length of the line segment swept and the distance of the sweep. These experiences can also help students from an early age develop a flexible understanding of a unit and reason covariationally about the continuous change of the quantities in measurement.

Parkinson's Disease Exhibits Amplified Intermuscular Coherence During Dynamic Voluntary Action.

Parkinson's disease (PD) is typically diagnosed and evaluated on the basis of overt motor dysfunction, however, subtle changes in the frequency spectrum of neural drive to muscles have been reported as well. During dynamic actions, coactive muscles of healthy adults often share a common source of 6–15 Hz (alpha-band) neural drive, creating synchronous alpha-band activity in their EMG signals. Individuals with PD commonly exhibit kinetic action tremor at similar frequencies, but the potential relationship between the intermuscular alpha-band neural drive seen in healthy adults and the action tremor associated with PD is not well-understood. A close relationship is most tenable during voluntary dynamic tasks where alpha-band neural drive is strongest in healthy adults, and where neural circuits affected by PD are most engaged. In this study, we characterized the frequency spectrum of EMG synchronization (intermuscular coherence) in 16 participants with PD and 15 age-matched controls during two dynamic motor tasks: (1) rotation of a dial between the thumb and index finger, and (2) dynamic scaling of isometric precision pinch force. These tasks produce different profiles of coherence between the first dorsal interosseous and abductor pollicis brevis muscles. We sought to determine if alpha-band intermuscular coherence would be amplified in participants with PD relative to controls, if such differences would be task-specific, and if they would correlate with symptom severity. We found that relative to controls, the PD group displayed amplified, but similarly task-dependent, coherence in the alpha-band. The magnitude of coherence during the rotation task correlated with overall symptom severity as per the UPDRS rating scale. Finally, we explored the potential for our coherence measures, with no additional information, to discriminate individuals with PD from controls. The area under the Receiver Operating Characteristic curve (AUC) indicated a clear separation between groups (AUC = 0.96), even though participants with PD were on their typical medication and displayed only mild-moderate symptoms. We conclude that a task-dependent, intermuscular neural drive within the alpha-band is amplified in PD. Its quantification via intermuscular coherence analysis may provide a useful tool for detecting the presence of PD, or assessing its progression.

The feasibility of using virtual reality to induce mobility-related anxiety during turning

To determine the efficacy of using virtual reality (VR) to manipulate illusions of height and consequently, elevated mobility-related anxiety when turning. Moreover, we examined if mobility-related anxiety effects decline across time in VR environments as participants habituate. Altogether, 10 healthy participants (five women, mean (standard deviation) age = 28.5 (8.5) years) turned at self-selected and fast speeds on a 2.2 m walkway under two simulated environments: (1) ground elevation; and (2) high elevation (15 m above ground). Peak turning velocity was recorded using inertial sensors and participants rated their cognitive (i.e., worry) and somatic (i.e., tension) anxiety, confidence, and mental effort. A significant Height × Speed × Trial interaction (p = 0.013) was detected for peak turning velocity. On average, the virtual height illusion decreased peak turning velocity, especially at fast speeds. At low elevation, participants decreased speed across trials, but not significantly (p = 0.381), but at high elevation, they significantly increased speed across trials (p = 0.001). At self-selected speeds, no effects were revealed (all p > 0.188) and only effects for Height were observed for fast speeds (p < 0.001). After turning at high elevation, participants reported greater cognitive (p = 0.008) and somatic anxiety (p = 0.007), reduced confidence (p = 0.021), and greater mental effort (p < 0.001) compared to the low elevation. VR can safely induce mobility-related anxiety during dynamic motor tasks, and habituation effects from repeated exposure should be carefully considered in experimental designs and analysis.

Psychometric Properties of Cognitive-Motor Dual-Task Studies With the Aim of Developing a Test Protocol for Persons With Vestibular Disorders: A Systematic Review.

Patients suffering from vestibular disorders (VD) often present with impairments in cognitive domains such as visuospatial ability, memory, executive function, attention, and processing speed. These symptoms can be attributed to extensive vestibular projections throughout the cerebral cortex and subcortex on the one hand, and to increased cognitive-motor interference (CMI) on the other hand. CMI can be assessed by performing cognitive-motor dual-tasks (DTs). The existing literature on this topic is scarce and varies greatly when it comes to test protocol, type and degree of vestibular impairment, and outcome. To develop a reliable and sensitive test protocol for VD patients, an overview of the existing reliability and validity studies on DT paradigms will be given in a variety of populations, such as dementia, multiple sclerosis, Parkinson's disease, stroke, and elderly. The systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. An extensive literature search on psychometric properties of cognitive-motor DTs was run on MEDLINE, Embase, and Cochrane Databases. The studies were assessed for eligibility by two independent researchers, and their methodological quality was subsequently evaluated using the Consensus-based Standards for the selection of health Measurement Instruments (COSMIN). Thirty-three studies were included in the current review. Based on the reliability and validity calculations, including a static as well as dynamic motor task seems valuable in a DT protocol for VD patients. To evoke CMI maximally in this population, both motor tasks should be performed while challenging the vestibular cognitive domains. Out of the large amount of cognitive tasks employed in DT studies, a clear selection for each of these domains, except for visuospatial abilities, could be made based on this review. The use of the suggested DTs will give a more accurate and daily life representation of cognitive and motor deficiencies and their interaction in the VD population.

Distinct Coordination Strategies Associated with the Drop Vertical Jump Task.

Coordination of multiple degrees of freedom in the performance of dynamic and complex motor tasks presents a challenging neuromuscular control problem. Experiments have inferred that humans exhibit self-organized, preferred coordination patterns, which emerge due to actor and task constraints on performance. The purpose of this study was to determine if the set of effective coordination strategies that exist for a task centers on a small number of robust, invariant patterns of behavior. Kinetic movement patterns computed from a cohort of 780 primarily female adolescent athletes performing a drop vertical jump (DVJ) task were analyzed to discover distinct groups into which individuals could be classified based on the similarity of movement coordination solutions. Clustering of reduced-dimension joint moment of force time series revealed three very distinct, precisely delineated movement profiles that persisted across trials, and which exhibited different functional performance outcomes, despite no other apparent group differences. The same analysis was also performed on a different task-a single-leg drop landing-which also produced distinct movement profiles; however, the three DVJ profiles did not translate to this task as group assignment was inconsistent between these two tasks. The task demands of the DVJ and single-leg drop-successful landing, reversal of downward momentum, and, in the case of the DVJ, vertical propulsion toward a maximally positioned target-constrain movement performance such that only a few successful outcomes emerge. Discovery of the observed strategies in the context of associated task constraints may help our understanding of how injury risk movement patterns emerge during specific tasks, as well as how the natural dynamics of the system may be exploited to improve these patterns.

The evaluation of dual-task conditions on static postural control in the older adults: a systematic review and meta-analysis protocol

BackgroundIn postural stability evaluation, the dual-task concept is often adopted in order to create a more challenging situation. The dual-task consists of performing simultaneously two tasks, a primary static or dynamic motor task and an additional secondary cognitive task. Usually, a multitask condition leads to a reduction in the postural control performance, especially in older adults. Considering the wide spectrum of secondary task conditions existing in scientific literature, the present manuscript aims to write a peer-reviewed protocol that will be used in a systematic review and meta-analysis performed to identify the effects of different secondary tasks conditions in a population of older adults during static postural stability.MethodsThe study will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and for this manuscript, the PRISMA Protocol. PICOS criteria (population, intervention, comparison, outcomes, study design) will be also followed. The population examined will be healthy older adults over 60 years of age and all quantitative, qualitative, and mixed methods study design will be included. Original articles will be also included if written in English, while no restriction criteria will be applied to the country of origin. Instead, reviews, meta-analysis, abstracts, citations, scientific conferences, opinion pieces, books, books reviews, statements, letters, editorials, non-peer reviewed journals articles, and commentaries will be excluded. The research of literature will be performed using PubMed, Web of Science, and Scopus with words related to the topic. From each included study, information previously agreed will be extracted and inserted into a spreadsheet and a narrative synthesis containing summary tables and graphs will describe the articles taken in examination. Furthermore, a meta-analysis will be performed to establish which DT condition has a greater effect following the Hedges and Olkin approach, extension of Glass’ method and Cohen’s d will be calculated.DiscussionThe present manuscript wants to provide the protocol that will be used in the systematic review and meta-analysis with the intent to inform the researchers and professionals about the dual-task condition effects. Such will lead future investigations in using the most appropriate dual-task condition.Systematic review registrationPROSPERO CRD42018116597.

Validity of the Nintendo Wii Balance Board for the Assessment of Balance Measures in the Functional Reach Test.

The functional reach test (FRT) is widely used for assessing dynamic balance stability in elderly and pathological subjects. Force platforms (FPs) represent a fundamental part of the instrumented FRT experimental setup due to the central role of center-of-pressure (COP) displacement in FRT analysis. Recently, the nintendo wii balance board (NBB) has been suggested as a low-cost and reliable device for ground reaction force and COP measurement in poorly dynamic motor tasks. Therefore, this paper aimed to compare NBB-COP data with those obtained from a laboratory-grade platform during FRT. Data from 48 healthy subjects were simultaneously acquired from both devices. FP-COP and NBB-COP trajectories showed a remarkable correlation in both directions ( ) and low root-mean-square error values (1.14 ± 0.88 mm and 0.55 ± 0.28 mm for anterior-posterior and medial-lateral direction). Fixed biases between COP-based parameters did not exceed 2% of the FP outcomes with high consistency throughout the present measurement range (ICC consistency always >0.950). Only the COP mean velocity exhibited a tendency toward proportional errors, which can be adjusted by a calibration of NBB data. Findings of this paper confirmed the NBB validity for COP measurement in a widely used motor task as the functional reach, supporting the feasibility of NBB in research scenarios.

Improvements in event-related desynchronization and classification performance of motor imagery using instructive dynamic guidance and complex tasks

Background and objectiveThe motor-imagery based brain-computer interface supplies a potential approach for motor-impaired patients, not only to control rehabilitation facilities but also to promote recovery from motor dysfunctions. To improve event-related desynchronization during motor imagery and obtain improved brain-computer interface classification accuracy, we introduce dynamic video guidance and complex motor tasks to the motor imagery paradigm. MethodsEleven participants were included in the experiment; 64-channel electroencephalographic data were collected and analyzed during four motor imagery tasks with different guidance. Time-frequency analysis, spectral-time variation analysis, topographical distribution maps, and statistical analysis were utilized to analyze the event-related desynchronization patterns. Common spatial patterns were used to extract spatial pattern features and support vector machines were used to discriminate the offline classification accuracies in three bands (the alpha band, beta band, alpha and beta band) for comparison. ResultsThe experimental outcomes showed that complex motor imagery tasks coupled with dynamic video guidance induced significantly stronger event-related desynchronization than other paradigms, which use simple motor imagery tasks or static guidance. Similar results were obtained during analysis of the motor imagery brain-computer interface classification performance; namely, the highest average classification accuracy in complex and dynamic guidance was improved by approximately 14%, compared with static guidance. For individually specified paradigms, all participants obtained a classification accuracy that exceeded or was equal to 87.5%. ConclusionsThis study provides an optional route to enhance the event-related desynchronization activities and classification accuracy of a motor imagery brain-computer interface through optimization of motor imagery tasks and instructive guidance.