Upper-limb Movements Research Articles

Long-latency and Volitional Responses Modulate Upper Extremity Movements During a Novel Visuomotor Tracking Task

Precise upper limb movements are essential for daily tasks and motor function. These movements are governed by feedforward and feedback mechanisms. Feedforward responses enable anticipatory movement planning, while feedback responses utilize sensory information for real-time corrections. Long-latency reflexes (LLRs) represent crucial feedback responses during unexpected perturbations. LLRs are integral in maintaining motor control and can adapt based on various factors. However, the mechanisms governing LLRs, especially in the upper extremity, remain unclear. Methods: Forty healthy participants performed a visuomotor elbow flexion task with one arm while the opposite limb remained static. Muscle activity of the biceps and triceps muscles of both upper extremities was recorded during perturbations. Participants completed a task with varying speeds and resistance levels. Electromyography data was analyzed across pre-perturbation, short-latency reflex (SLR), long-latency reflex (LLR), and voluntary response (VR) phases. Results: In response to unexpected upper extremity perturbations, participants predominantly relied on two core strategies. Inhibitory long-latency reflexes within the biceps played a central role, with participants emphasizing inhibition to maintain movement stability in a window of 50-120 ms after the disturbance. Furthermore, volitional control, primarily executed through the triceps muscles, emerged as another dominant approach, allowing participants to actively regain precision and control after the perturbation in a volitional manner starting from 120 ms. Participants’ response to perturbations reflected the task context and perceived urgency. Over repeated trials, participants refined their response strategies, becoming more precise and effcient. Variations in movement speed and resistance influenced muscle activity. Preliminary evidence suggested the involvement of cross-transcortical communication in response to perturbations, with delayed responses observed in the non-participating upper extremity. Conclusion: This study reveals that participants use both long-latency and volitional responses to counteract perturbations during an upper extremity visuomotor task, adapting their response strategies over time. Biceps inhibitory LLRs and triceps voluntary activation characterize feedback control in this context. These findings shed light on the dynamic nature of upper extremity feedback responses during unpredictable perturbations and suggest the involvement of cross-transcortical communication. Understanding these mechanisms can inform rehabilitation strategies for individuals with neurological conditions affecting motor control. Research Support: This study was funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development: R01HD084645, R01HD082109. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Prefrontal cortex activity and functional organisation in dual-task ocular pursuit is affected by concurrent upper limb movement.

Tracking a moving object with the eyes seems like a simple task but involves areas of prefrontal cortex (PFC) associated with attention, working memory and prediction. Increasing the demand on these processes with secondary tasks can affect eye movements and/or perceptual judgments. This is particularly evident in chronic or acute neurological conditions such as Alzheimer's disease or mild traumatic brain injury. Here, we combined near infrared spectroscopy and video-oculography to examine the effects of concurrent upper limb movement, which provides additional afference and efference that facilitates tracking of a moving object, in a novel dual-task pursuit protocol. We confirmed the expected effects on judgement accuracy in the primary and secondary tasks, as well as a reduction in eye velocity when the moving object was occluded. Although there was limited evidence of oculo-manual facilitation on behavioural measures, performing concurrent upper limb movement did result in lower activity in left medial PFC, as well as a change in PFC network organisation, which was shown by Graph analysis to be locally and globally more efficient. These findings extend upon previous work by showing how PFC is functionally organised to support eye-hand coordination when task demands more closely replicate daily activities.

Examining the feasibility of immersive virtual reality to measure upper limb motor performance in typically developing children and adolescents

Over the last five years, virtual reality (VR) has become more popular in pediatric physiotherapy. In this study, we assessed the feasibility and acceptability of measuring upper-limb movements in typically-developing children and adolescents using an immersive virtual reality (iVR) headset. Thirty-six typically-developing children (age: 12 ± 2.1 y) were recruited and required to draw circles in a custom-built virtual environment using a Meta-Quest-2 headset. Outcomes were the System Usability Scale (SUS), Developmental Coordination Disorder-Questionnaire (DCD-Q), and three metrics of circle drawing performance (movement time, mean velocity and circle roundness). The mean score for the SUS was 74 ± 11, indicating good levels of acceptability and usability when the participants used the headset. No strong relationships were observed between the circle drawing metrics and DCD-Q scores (rho = < 0.3, p = > 0.05), but circle roundness ratios were positively and significantly correlated with SUS scores (rho = 0.5, p = 0.003). No adverse effects associated with iVR use were reported for any participants. This study showed that iVR is a viable method to measure upper-limb motor performance in children and adolescents, highlighting the potential value of this tool in pediatric physiotherapy practice.

Compensation-corrective adaptive control strategy for upper-limb rehabilitation robots

Trunk compensation is a common behavior observed in stroke patients during rehabilitation, and it can hinder their recovery outcomes. To address this issue, we developed a new upper-limb rehabilitation robot that takes advantage of both end-effector and exoskeleton robots. Moreover, we propose a compensation-corrective adaptive control (CCAC) strategy, which employs an admittance model and incorporates two estimators. Specifically, the first estimator is designed to assess human intention, allowing for compliant human-robot interaction. The second estimator calculates dynamic assistance that adjusts for trunk compensation, utilizing two virtual forces applied to the hand and shoulder. Based on this novel CCAC strategy, the newly designed robot is capable of assisting upper limb movements and correcting compensatory postures simultaneously. Results indicate a significant reduction in trunk compensation across three types of reaching tasks when the robot provides assistance. Moreover, the CCAC strategy enhances upper-limb motor performance, resulting in reduced position errors and increased shoulder and elbow joint angles. These findings underscore the potential of the proposed CCAC strategy, combined with upper-limb exoskeleton robots, as a promising approach for correcting compensatory postures and optimizing the advantages of robotic stroke rehabilitation.

Using Virtual Reality in a Rehabilitation Program for Patients With Breast Cancer: Phenomenological Study.

Surgery is an essential treatment for early-stage breast cancer. However, various side effects of breast cancer surgery, such as arm dysfunction and lymphedema, remain causes for concern. Rehabilitation exercises to prevent such side effects should be initiated within 24 hours after surgery. Virtual reality (VR) can assist the process of rehabilitation; however, the feasibility of applying VR for rehabilitation must be explored, in addition to experiences of this application. This study explored patients' attitudes toward and experiences of using VR for their rehabilitation to determine the feasibility of such VR use and to identify potential barriers. A phenomenological qualitative study was conducted from September to December 2021. A total of 18 patients with breast cancer who had undergone surgical treatment were interviewed using open-ended questions. The Colaizzi 7-step procedure for phenomenological analysis was used for data analysis. To ensure high study reliability, this study followed previously reported quality criteria for trustworthiness. Three themes were identified: (1) VR was powerful in facilitating rehabilitation, (2) early and repetitive upper limb movements were an advantage of VR rehabilitation, and (3) extensive VR use had challenges to be overcome. Most of the interviewed patients reported positive experiences of using VR for rehabilitation. Specifically, VR helped these patients identify appropriate motion and angle limits while exercising; in other words, knowledge gained through VR can play a key role in the rehabilitation process. In addition, the patients reported that the use of VR provided them company, similar to when a physiotherapist is present. Finally, the gamified nature of the VR system seemed to make VR-based rehabilitation more engaging than traditional rehabilitation, particularly with respect to early rehabilitation; however, the high cost of VR equipment made VR-based rehabilitation difficult to implement at home. The interviewed patients with breast cancer had positive experiences in using VR for rehabilitation. The high cost of both VR equipment and software development presents a challenge for applying VR-based rehabilitation.

Scapular Motor Control and Upper Limb Movement Quality in Subjects with and without Chronic Shoulder Pain: A Cross-Sectional Study

Despite the existence of several studies about the scapula’s position and motion, in shoulder pain conditions, there are still conflicting findings regarding scapular adaptations and reduced research about the scapula’s role during functional tasks. The present study aimed to compare scapular-related kinematic and electromyographic outcomes during different shoulder movements (with and without load) and the drinking task, between symptomatic and asymptomatic subjects. Forty subjects (divided into two groups) participated in this cross-sectional observational study. Scapulothoracic motion, scapulohumeral rhythm, and movement quality (considering trunk compensation, time-to-peak acceleration, and smoothness), as well as the relative surface electromyographic activity and muscle ratio considering the trapezius, serratus anterior, and levator scapulae (LS), were assessed. The symptomatic group presented the following: (1) changes in scapular upward rotation (p = 0.008) and winging (p = 0.026 and p = 0.005) during backward transport and drink phases; (2) increased muscle activity level of the middle trapezius (MT) in all tasks (p &lt; 0.0001 to p = 0.039), of LS during shoulder elevation with load (p = 0.007), and of LS and LT during most of the drinking task phases (p = 0.007 to p = 0.043 and p &lt; 0.0001 to p = 0.014, respectively); (3) a decreased serratus anterior lower portion activity level (SAlow) during shoulder lowering with load (p = 0.030) and drink phase (p = 0.047); and (4) an increased muscular ratio between scapular abductors/adductors (p = 0.005 to p = 0.036) and elevators/depressors (p = 0.008 to p = 0.028). Compared to asymptomatic subjects, subjects with chronic shoulder pain presented scapular upward rotation and winging adaptations; increased activity levels of MT, LT, and LS; decreased activity levels of SAlow; and increased scapular muscle ratios.

The relationship between manual ability, dystonia and choreoathetosis severity and upper limb movement patterns during reaching and grasping in children and young adults with dyskinetic cerebral palsy

IntroductionImpaired upper limb movements are a key feature in dyskinetic cerebral palsy (CP). However, information on how specific movement patterns relate to manual ability, performance and underlying movement disorders is lacking. Insight in these associations may contribute to targeted upper limb management in dyskinetic CP. This study aimed to explore associations between deviant upper limb movement patterns and (1) manual ability, (2) severity of dystonia/choreoathetosis, and (3) movement time/trajectory deviation during reaching and grasping. Participants/methodsParticipants underwent three-dimensional upper limb analysis during reaching forwards (RF), reaching sideways (RS) and reach-and-grasp vertical (RGV) as well as clinical assessment. Canonical correlation and regression analysis with statistical parametric mapping were used to explore associations between clinical/performance parameters and movement patterns (mean and variability). ResultsThirty individuals with dyskinetic CP participated (mean age 16±5 y; 20 girls). Lower manual ability was related to higher variability in wrist flexion/extension during RF and RS early in the reaching cycle (p < 0.05). Higher dystonia severity was associated with higher mean wrist flexion (40–82 % of the reaching cycle; p = 0.004) and higher variability in wrist flexion/extension (31–75 %; p < 0.001) and deviation (2–14 %; p = 0.007/60–73 %; p = 0.006) during RF. Choreoathetosis severity was associated with higher elbow pro/supination variability (12–19 %; p = 0.009) during RGV. Trajectory deviation was associated with wrist and elbow movement variability (p < 0.05). ConclusionCurrent novel analysis of upper limb movement patterns and respective timings allows to detect joint angles and periods in the movement cycle wherein associations with clinical parameters occur. These associations are not present at each joint level, nor during the full movement cycle. This knowledge should be considered for individualized treatment strategies.

Multifeature quantitative motor assessment of upper limb ataxia including drawing and reaching.

Voluntary upper limb movements are an ecologically important yet insufficiently explored digital-motor outcome domain for trials in degenerative ataxia. We extended and validated the trial-ready quantitative motor assessment battery "Q-Motor" for upper limb movements with clinician-reported, patient-focused, and performance outcomes of ataxia. Exploratory single-center cross-sectional assessment in 94 subjects (46 cross-genotype ataxia patients; 48 matched controls), comprising five tasks measured by force transducer and/or position field: Finger Tapping, diadochokinesia, grip-lift, and-as novel implementations-Spiral Drawing, and Target Reaching. Digital-motor measures were selected if they discriminated from controls (AUC >0.7) and correlated-with at least one strong correlation (rho ≥0.6)-to the Scale for the Assessment and Rating of Ataxia (SARA), activities of daily living (FARS-ADL), and the Nine-Hole Peg Test (9HPT). Six movement features with 69 measures met selection criteria, including speed and variability in all tasks, stability in grip-lift, and efficiency in Target Reaching. The novel drawing/reaching tasks best captured impairment in dexterity (|rho9HPT| ≤0.81) and FARS-ADL upper limb items (|rhoADLul| ≤0.64), particularly by kinematic analysis of smoothness (SPARC). Target hit rate, a composite of speed and endpoint precision, almost perfectly discriminated ataxia and controls (AUC: 0.97). Selected measures in all tasks discriminated between mild, moderate, and severe impairment (SARA upper limb composite: 0-2/>2-4/>4-6) and correlated with severity in the trial-relevant mild ataxia stage (SARA ≤10, n = 20). Q-Motor assessment captures multiple features of impaired upper limb movements in degenerative ataxia. Validation with key clinical outcome domains provides the basis for evaluation in longitudinal studies and clinical trial settings.

The EEG-Based Fusion Entropy-Featured Identification of Isometric Contraction Forces under the Same Action.

This study explores the important role of assessing force levels in accurately controlling upper limb movements in human-computer interfaces. It uses a new method that combines entropy to improve the recognition of force levels. This research aims to differentiate between different levels of isometric contraction forces using electroencephalogram (EEG) signal analysis. It integrates eight different entropy measures: power spectrum entropy (PSE), singular spectrum entropy (SSE), logarithmic energy entropy (LEE), approximation entropy (AE), sample entropy (SE), fuzzy entropy (FE), alignment entropy (PE), and envelope entropy (EE). The findings emphasize two important advances: first, including a wide range of entropy features significantly improves classification efficiency; second, the fusion entropy method shows exceptional accuracy in classifying isometric contraction forces. It achieves an accuracy rate of 91.73% in distinguishing between 15% and 60% maximum voluntary contraction (MVC) forces, along with 69.59% accuracy in identifying variations across 15%, 30%, 45%, and 60% MVC. These results illuminate the efficacy of employing fusion entropy in EEG signal analysis for isometric contraction detection, heralding new opportunities for advancing motor control and facilitating fine motor movements through sophisticated human-computer interface technologies.

An Unusual Case of Brachial Artery Thrombosis in a Neonate Following Humerus fracture at Birth

A female infant of a diabetic mother born through LSCS at 39 weeks of gestation with a birth weight of 2908 grams was noted to have a paucity of movement of the left upper limb soon after birth. The extremity was pale, had markedly deranged perfusion, and was cold to touch with absent brachial, radial, and ulnar arterial pulsations. There was a swelling noted over the middle of the left arm, which was tender and associated with crepitus suspicious of a fracture. The right upper limb and lower limbs were normal. An urgent X-ray of the left upper limb showed a displaced fracture of the left humerus fracture and the Doppler study revealed absent flow in the brachial artery distal to the fracture site without thrombus. Urgent close reduction of the fracture following which the doppler showed a thrombus in the brachial artery extending up to its bifurcation. The thrombosis was managed medically with low molecular weight heparin and aspirin. There was a gradual improvement of limb perfusion with normalcy achieved on day 3 of life with no residual complications even on follow-up. The workup of neonatal thrombosis, its immediate management and current evidence for the same have been discussed in detail.

Development of a Novel Robotic Rehabilitation System Using Electrical Stimulation for Upper Limb Motor Recovery

To improve the quality of life for people with neurological disorders or accidents, it is important to create therapy tools for upper limb movement recovery that work and are easy for everyone to use. This study suggests a new artificial therapy device that uses electrical stimulation to help people recover their upper limb movement skills. The technology uses both artificial help and electrical treatment at the same time to help the brain change and learn new skills. The robotic therapy system is made up of a suit that moves with the upper limbs and supports them mechanically. It has sensors that can figure out what the user wants and change the amount of help based on that. In addition, the system has electrical activation probes that are put to target specific muscles or groups of muscles that help move the upper limbs. A closed-loop control system makes the system work. The user's moves are constantly tracked, and the robotic help and electrical stimulation are changed in real time. This flexible method lets recovery plans be made just for each person, based on their wants and results. A pilot study with people who have trouble moving their upper limbs was used to test how well the planned method would work. When the method was used for six weeks, the data showed big gains in motor function, muscle strength, and range of motion. Participants were also very happy with how easy the method was to use and how well it helped them improve their movement skills.

Upper limb movement quality measures: comparing IMUs and optical motion capture in stroke patients performing a drinking task.

Clinical assessment of upper limb sensorimotor function post-stroke is often constrained by low sensitivity and limited information on movement quality. To address this gap, recent studies proposed a standardized instrumented drinking task, as a representative daily activity combining different components of functional arm use. Although kinematic movement quality measures for this task are well-established, and optical motion capture (OMC) has proven effective in their measurement, its clinical application remains limited. Inertial Measurement Units (IMUs) emerge as a promising low-cost and user-friendly alternative, yet their validity and clinical relevance compared to the gold standard OMC need investigation. In this study, we conducted a measurement system comparison between IMUs and OMC, analyzing 15 established movement quality measures in 15 mild and moderate stroke patients performing the drinking task, using five IMUs placed on each wrist, upper arm, and trunk. Our findings revealed strong agreement between the systems, with 12 out of 15 measures demonstrating clinical applicability, evidenced by Limits of Agreement (LoA) below the Minimum Clinically Important Differences (MCID) for each measure. These results are promising, suggesting the clinical applicability of IMUs in quantifying movement quality for mildly and moderately impaired stroke patients performing the drinking task.

Is the correlation of the core muscle performance with shoulder pain and function altered by scapular dyskinesis in subjects with shoulder pain?

BACKGROUND: Daily activities that involve upper limb movements require muscle activation from different body parts by transferring forces and energy along the functional kinetic chain. The scapulae connect and transfer forces between the trunk and the upper limbs, so scapular dyskinesis may compromise the performance of the kinetic chain. OBJECTIVE: To assess the relationship between core muscle performance and shoulder pain and function in individuals with shoulder pain, with and without scapular dyskinesis. METHODS: Data was collected from 77 non-athlete adults aged between 18 and 50 years with shoulder pain, 45 had scapular dyskinesis. Core muscle performance was measured using the prone bridging test (PBT). Shoulder pain and disability were measured by the Shoulder Pain and Disability Index (SPADI), and the upper limbs’ stability was assessed by the Closed Kinetic Chain Upper Extremity Stability Test (CKCUEST). The peak torque of shoulder external and internal rotators was measured using an isokinetic dynamometer. Multiple linear regression models evaluated the relationship between the PBT and CKCUEST, SPADI, and shoulder rotator strength. RESULTS: Significant correlations were found between the PBT and the SPADI total score (r = – 0.522), pain domain (r = – 0.513), and disability domain (r = – 0.501); normalized score (r = 0.593), and the power (r = 0.624) of the CKCUEST; and peak torque for external (r = 0.256) and internal (r = 0.292) rotations. Scapular dyskinesis did not influence the magnitude of the correlations and predictive values. CONCLUSION: The PBT was correlated with shoulder pain and function, but scapular dyskinesis did not affect the magnitude of these relationships.

A Scoping Review on Mobile Health Technology for Assessment and Intervention of Upper Limb Motor Function in Children with Motor Impairments.

Upper limb (UL) motor dysfunctions impact residual movement in hands/shoulders and limit participation in play, sports, and leisure activities. Clinical and laboratory assessments of UL movement can be time-intensive, subjective, and/or require specialized equipment and may not optimally capture a child's motor abilities. The restrictions to in-person research experienced during the COVID-19 pandemic have inspired investigators to design inclusive at-home studies with child participants and their families. Relying on the ubiquity of mobile devices, mobile health (mHealth) applications offer solutions for various clinical and research problems. This scoping review article aimed to aggregate and synthesize existing research that used health technology and mHealth approaches to evaluate and assess the hand function and UL movement in children with UL motor impairment. A scoping review based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) model was conducted in March 2023 yielding 25 articles (0.32% of 7891 studies). Assessment characteristics included game or task-based tests (13/25, 52%), primarily for neurological disorders (e.g., autism spectrum disorder [ASD], dystonia, dysgraphia) or children with cerebral palsy (CP). Although several mHealth studies were conducted in the clinical environment (10/25, 40%), studies conducted at home or in nonclinical settings (15/25, 60%) reported acceptable and highly satisfactory to the patients as minimizing the potential risks in participation. Moreover, the remaining barriers to clinical translation included object manipulation on a touch screen, offline data analysis, real-world usability, and age-appropriate application design for the wider population. However, the results emphasize the exploration of mHealth over traditional approaches, enabling user-centered study design, family-oriented methods, and large-scale sampling in future research.

Stereotypy and Parkinsonism in tubercular meningitis: Expanding the spectrum

Abstract Movement disorders associated with tubercular meningitis have been reported, ranging from tremors to chorea. Stereotypy is a rare manifestation following tubercular meningitis. Here we report a rare case of a 29-year-old man who developed stereotypy and parkinsonism following tubercular meningitis. The stereotypy was in the form of rotatory movements of the right upper limb, which were repetitive, purposeless, non-goal directed, present for most of the day, and partially suppressible. In addition, it was associated with severe generalized parkinsonism. This report expands the spectrum of movement disorders seen in tubercular meningitis.

Immunohistochemical properties of motoneurons supplying the porcine trapezius muscle.

The trapezius muscle (TRAP) belongs to the scapulothoracic group of muscles, which play a crucial role in the integrity and strength of the upper limb, trunk, head, and neck movements and, thus, in maintaining balance. Combined retrograde tracing (using fluorescent tracer Fast Blue, FB) and double-labelling immunohistochemistry were applied to investigate the chemical coding of motoneurons projecting to the porcine TRAP. FB-positive (FB+) motoneurons supplying the cervical (c-TRAP) and thoracic part (th-TRAP) of the right (injected with the tracer) TRAP were located within the IX-th Rexed lamina in the ipsilateral ventral horn of the grey matter of the spinal medulla. Immunohistochemistry revealed that nearly all the neurons were cholinergic in nature [choline acetyltransferase (CHAT)- or vesicular acetylcholine transporter (VACHT)-positive]. Many retrogradelly labelled neurons displayed also immunoreactivity to calcitonin gene-related peptide (CGRP; approximately 68% of FB+ neurons). The smaller number of nerve cells (5%, 3%, 2% or 1%, respectively) stained for nitric oxide synthase (n-NOS), vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY) and substance P (SP). The retrogradely labelled neurons were closely apposed by nerve fibres expressing immunoreactivity to CHAT, VACHT, CGRP, SP, DβH, VIP, n-NOS, NPY, GAL, Leu-Enk and Met-Enk. Taking into account the clinical relevance of TRAP, the present results may be useful in designing further research aimed at the management of various dysfunctions of the muscle.

Extended reality to assess post-stroke manual dexterity: contrasts between the classic box and block test, immersive virtual reality with controllers, with hand-tracking, and mixed-reality tests

BackgroundRecent technological advancements present promising opportunities to enhance the frequency and objectivity of functional assessments, aligning with recent stroke rehabilitation guidelines. Within this framework, we designed and adapted different manual dexterity tests in extended reality (XR), using immersive virtual reality (VR) with controllers (BBT-VR-C), immersive VR with hand-tracking (BBT-VR-HT), and mixed-reality (MD-MR).ObjectiveThis study primarily aimed to assess and compare the validity of the BBT-VR-C, BBT-VR-HT and MD-MR to assess post-stroke manual dexterity. Secondary objectives were to evaluate reliability, usability and to define arm kinematics measures.MethodsA sample of 21 healthy control participants (HCP) and 21 stroke individuals with hemiparesis (IHP) completed three trials of the traditional BBT, the BBT-VR-C, BBT-VR-HT and MD-MR. Content validity of the different tests were evaluated by asking five healthcare professionals to rate the difficulty of performing each test in comparison to the traditional BBT. Convergent validity was evaluated through correlations between the scores of the traditional BBT and the XR tests. Test-retest reliability was assessed through correlations between the second and third trial and usability was assessed using the System Usability Scale (SUS). Lastly, upper limb movement smoothness (SPARC) was compared between IHP and HCP for both BBT-VR test versions.ResultsFor content validity, healthcare professionals rated the BBT-VR-HT (0[0–1]) and BBT-MR (0[0–1]) as equally difficult to the traditional BBT, whereas they rated BBT-VR-C as more difficult than the traditional BBT (1[0–2]). For IHP convergent validity, the Pearson tests demonstrated larger correlations between the scores of BBT and BBT-VR-HT (r = 0.94;p < 0.001), and BBT and MD-MR (r = 0.95;p < 0.001) than BBT and BBT-VR-C (r = 0.65;p = 0.001). BBT-VR-HT and MD-MR usability were both rated as excellent, with median SUS scores of 83[57.5–91.3] and 83[53.8–92.5] respectively. Excellent reliability was found for the BBT-VR-C (ICC = 0.96;p < 0.001), BBT-VR-HT (ICC = 0.96;p < 0.001) and BBT-MR (ICC = 0.99;p < 0.001). The usability of the BBT-VR-C was rated as good with a median SUS of 70[43.8–83.8]. Upper limb movements of HCP were significantly smoother than for IHP when completing either the BBT-VR-C (t = 2.05;p = 0.043) and the BBT-VR-HT (t = 5.21;p < 0.001).ConclusionThe different XR manual tests are valid, short-term reliable and usable tools to assess post-stroke manual dexterity.Trial registrationhttps://clinicaltrials.gov/ct2/show/NCT04694833; Unique identifier: NCT04694833, Date of registration: 11/24/2020.

Unilateral movement decoding of upper and lower limbs using magnetoencephalography

Problem: The effectiveness of distinguishing unilateral lower limb motor execution (ME) or imagery (MI) based on electroencephalogram (EEG) is limited by its low spatial resolution, since the somatotopies of bilateral lower limbs are close to each other. Aim: This research focused on differentiating unilateral lower limb tasks using magnetoencephalography (MEG) signals. Methods: MEG signals were recorded during unilateral upper and lower limb movements. Channel selection and extraction of band power features were performed at both the conventional sensor level and the proposed source level, reconstructed using beamforming. The classification performance at both levels was compared. Results: The theta band changes exhibited the most significant differences and lateralization across tasks. Task-related features were more prominent at the source than at the sensor level. The classification results indicate that all methods achieved an average accuracy of over 98.33% in classifying the upper limb task. For the classification of lower limb tasks, the average accuracies achieved at the source level (96.97% and 95.86%) were significantly higher than those obtained at the sensor level (90.00% and 92.57%). Conclusion and Significance: Our results demonstrated the feasibility of MEG in classifying unilateral lower limb movements, providing a potentially effective method for brain-computer interfaces (BCIs) to enhance control commands. Furthermore, signal processing at the source level can effectively enhance inter-task differences to achieve higher classification performance. Meanwhile, the theta band is highly effective in movement classification and may play an important role in motor function.

A small-sample time-series signal augmentation and analysis method for quantitative assessment of bradykinesia in Parkinson's disease

Patients with Parkinson's disease (PD) usually have varying degrees of bradykinesia, and the current clinical assessment is mainly based on the Movement Disorder Society Unified PD Rating Scale, which can hardly meet the needs of objectivity and accuracy. Therefore, this paper proposed a small-sample time series classification method (DTW-TapNet) based on dynamic time warping (DTW) data augmentation and attentional prototype network. Firstly, for the problem of small sample sizes of clinical data, a DTW-based data merge method is used to achieve data augmentation. Then, the time series are dimensionally reorganized using random grouping, and convolutional operations are performed to learn features from multivariate time series. Further, attention mechanism and prototype learning are introduced to optimize the distance of the class prototype to which each time series belongs to train a low-dimensional feature representation of the time series, thus reducing the dependency on data volume. Clinical experiments were conducted to collect motion capture data of upper and lower limb movements from 36 patients with PD and eight healthy controls. For the upper limb movement data, the proposed method improved the classification accuracy, weighted precision, and kappa coefficient by 8.89%-15.56%, 9.22%-16.37%, and 0.13-0.23, respectively, compared with support vector machines, long short-term memory, and convolutional prototype network. For the lower limb movement data, the proposed method improved the classification accuracy, weighted precision, and kappa coefficient by 8.16%-20.41%, 10.01%-23.73%, and 0.12-0.28, respectively. The experiments and results show that the proposed method can objectively and accurately assess upper and lower limb bradykinesia in PD.

A case of dystonic spasms in an adolescent: A neurologist’s enigma!

A 15-year-old boy presented with episodic abnormal movements of the right upper limb, neck, and jaw for 10 days associated with pain and spasms, following a penetrating injury to his right hand 2 months ago. He was successfully managed for tetanus with antitoxin, antibiotics, wound debridement, and supportive care. He was found to have protective tetanus antibody levels (1.1 IU/mL). To encounter tetanus in a vaccinated individual with an atypical focal presentation is a cause for concern and requires awareness to avoid delay in diagnosis and management.