Journal of NeuroEngineering and Rehabilitation最新文献

Background: Stroke survivors often experience impaired upper extremity motor function due to abnormal muscle synergies. This pilot study evaluated the feasibility and preliminary effectiveness of electromyography-guided human-machine interaction training designed to expand the repertoire of intermuscular coordination patterns and improve upper extremity motor function in chronic stroke survivors.

Methods: Four chronic stroke survivors with mild-to-moderate upper extremity motor impairment and three age-matched healthy controls participated in a six-week electromyography-guided training intervention. Participants practiced selectively activating one elbow flexor muscle while suppressing another (brachioradialis or biceps brachii). Throughout the course of the intervention, the effect of the training on intermuscular coordination, task performance, and motor function and impairment level of the stroke-affected upper extremity were assessed.

Results: Participants in both the control and stroke groups successfully learned to selectively activate targeted muscles, expanding their repertoire of habitual intermuscular coordination patterns. Stroke survivors demonstrated improvements in force generation, reaching ability, wrist rotation, and clinical measures of upper extremity motor function and spasticity. Participants also reported improved ease in performing daily activities.

Conclusions: This is, to our knowledge, the first study to demonstrate the feasibility of using electromyography-guided human-machine interaction training to expand the repertoire of habitual intermuscular coordination patterns and improve upper extremity motor function in chronic stroke survivors. These findings highlight the potential of electromyography-guided human-machine interaction training as a neurorehabilitation approach to address motor deficits associated with abnormal intermuscular coordination following stroke.

Trial registration: The study was registered at the Clinical Research Information Service of Korea National Institute of Health (KCT0005803).

Background: Accurate assessment of neuro-sacral function after spinal cord injury/lesion and cauda equina (SCI+) is essential for diagnosis, prognosis and early management. The current bedside standard, the digital rectal examination (DRE), is subjective, invasive, and examiner dependent. Surface electromyography (s-EMG) offers a quantitative alternative but has lacked point-of-care integration. We developed the ElectroSacroGram (ESG), a bedside digital s-EMG tool enabling real-time objective assessment of sacral somatic function after SCI+. This study aimed to (1) develop the ESG protocol based on clinical consensus; and (2) evaluate its diagnostic performance compared to radiological findings and expert-performed DRE.

Methods: In this prospective proof-of-concept diagnostic study at a specialized Level 1 trauma center, 52 adults with suspected SCI + and 21 healthy participants underwent ESG and DRE. ESG quantified sacral motor (resting external anal sphincter tone, maximal voluntary anal contraction (maxVAC), reflex (bulbospongious or bulbocavernosus reflex (BSR)), and sensory (electrical perceptual threshold (EPT)) function using low-intensity electrical stimulation. Clinically relevant DRE parameters were selected by an expert panel. Content validity was assessed using item/scale content validity indices (CVI), agreement with DRE (Cohen's κ) and diagnostic accuracy were calculated against imaging-confirmed spinal lesions.

Results: Normative ESG values were established in healthy participants. Neurologically impaired patients showed reduced maxVAC and BSR amplitudes and elevated EPT. ESG demonstrated excellent content validity (S-CVI = 1.00), strong agreement with DRE for VAC (κ = 0.876) and EPT (κ = 0.881), and high diagnostic accuracy (sensitivity 83.3%, specificity 100%, overall accuracy 86.5%).

Conclusions: ESG enables precise, reproducible evaluation of sacral motor, reflex, and sensory integrity in real-time at bedside. By complementing and objectifying the DRE, it offers a promising precision-medicine tool for early neuro-sacral assessment, enhancing clinical research and improving SCI + diagnosis, for the acute phase and in the context of spinal shock.

Background: Despite significant advances in biosignal extraction techniques for studying neuromotor disorders, there remains an unmet need for a method that effectively links muscle structure and dynamics to muscle activation. Addressing this gap could improve the quantification of neuromuscular impairments and pave the way for precision rehabilitation. In this study, we demonstrate the proof of concept of recording multimodal signals from the brain, muscles, and resulting limb kinematics. We also explore the use of ultrasound imaging to extract limb kinematics.

Methods: We collected data from three healthy volunteers and one individual with cerebral palsy during single degree-of-freedom ankle and wrist movements. Participants performed range of motion (ROM) tasks at approximately 1-second intervals, either volitionally or through functional electrical stimulation. We simultaneously recorded electroencephalography, surface electromyography (EMG), continuous ultrasound imaging, and motion capture data. Joint kinematics were computed from ultrasound imaging using a technique called sonomyography (SMG), and we evaluated the technical feasibility of estimating joint kinematics from both sonomyography and surface EMG signals.

Results: The technical feasibility study evaluated joint angle prediction using EMG and SMG under volitional (FES-OFF) and electrically stimulated (FES-ON) conditions. Root mean squared error (RMSE) between predicted and measured joint angles was computed for multiple methods of extracting kinematics from EMG and SMG. EMG-based RMSE ranged from 0.34 to 0.57 (FES-OFF) and 0.43-0.51 (FES-ON). SMG-based RMSE ranged from 0.10 to 0.25 across all conditions and methods. Linear regression analysis produced $R^2$ values between 0.31 and 0.81 depending on joint, condition, and method. No significant RMSE difference was found between FES-ON and FES-OFF conditions within SMG. SMG RMSE values were also comparable to previously reported values (10-25%) in prior literature.

Conclusion: Our findings suggest that sonomyography can be used as a noninvasive method for estimating joint kinematics when the joint movement is driven either by volition or by functional electrical stimulation. This technique can potentially be be useful in evaluating altered muscle dynamics and driving assistive and rehabilitation devices in individuals with neuromotor disorders such as cerebral palsy.

Background: Impaired arm position sense is a common somatosensory impairment after stroke, which significantly impacts the performance of functional activities using the upper limb. However, few clinical interventions target loss of position sense after stroke. Our aim was to use interlimb force-coupling to augment position sense of the stroke-affected arm during a bilateral reaching task and investigate the impact of training with this feedback manipulation on measures of arm position matching ability and both bilateral and unilateral motor control.

Methods: Twenty-four participants with a history of stroke were randomized (N = 12/group) to perform mirrored bimanual aiming movements with either interlimb force-coupling (Augmented PF) or uncoupled symmetrical reaches with only visual feedback about movement position. Participants completed 11 sessions (295 bimanual reaches/session) using a Kinarm End-Point robot. Performance on measures of arm position sense (Arm Position Matching, APM), motor impairment (Fugl-Meyer Upper Limb, FM), motor function (Wolf Motor Function Test, WMFT), unilateral reach accuracy and speed (Visually Guided Reaching, VGR), and bilateral reach symmetry were collected before and after training to characterize changes in upper limb somatosensory and motor control performance.

Results: APM Task Scores improved for both groups. This improvement was specifically observed through reduced APM variability, but not accuracy. FM scores also improved for both groups. The group that did not practice with force-coupling between limbs improved on measures of bilateral movement symmetry on a mirrored reaching task and had faster VGR movement times in post-test.

Conclusion: Symmetrical reach training with or without augmented PF led to reduced motor impairment and benefited upper limb position matching ability by reducing APM variability. Augmenting position sense during reaching did not provide additional benefits for position matching accuracy. Advantages for unilateral movement speed and bilateral reach symmetry measures in the group that practiced without interlimb coupling may reflect specificity of practice effects due to similarity between test and training conditions for this group.

Background: Brain/neural hand exoskeletons (B/NHEs) can restore motor function after severe stroke, enabling bimanual tasks critical for various activities of daily living. Yet, reliable clinical tests for assessing bimanual function compatible with B/NHEs are lacking. Here, we introduce the Berlin Bimanual Test for Stroke (BeBiT-S), a 10-task assessment focused on everyday bimanual activities, and evaluate its psychometric properties as well as compatibility with assistive technologies such as B/NHEs.

Methods: BeBiT-S tasks were selected based on their relevance to daily activities, representation of various grasp types, and compatibility with current (neuro-)prosthetic devices. A scoring system was developed to assess key aspects of bimanual function-including reaching, grasping, stabilizing, manipulating, and lifting-based on video recordings of task performance. The BeBiT-S was administered without support of assistive technology (unassisted condition) to 24 stroke survivors (mean age = 56.5 years; 9 female) with upper-limb hemiparesis. We evaluated interrater reliability through the intraclass correlation coefficient (ICC) and construct validity through correlations with the Chedoke Arm and Hand Activity Inventory (CAHAI), and Stroke Impact Scale (SIS). A subgroup of 15 stroke survivors (mean age 50.3 years, 5 female) completed a second session supported by a B/NHE (B/NHE-assisted condition) to assess the BeBiT-S' sensitivity to change related to B/NHE-application.

Results: The BeBiT-S demonstrated high interrater reliability in both the unassisted (ICC = 0.985, P < .001) and B/NHE-assisted (ICC = 0.862, P < .001) conditions. Unassisted BeBiT-S scores correlated with the CAHAI-8 (r(22) = 0.95, P < .001) and the SIS subscales "strength" (r(20) = 0.53, P = .012) and "hand function" (r(20) = 0.50, P = .018), indicating construct validity. BeBiT-S scores improved significantly with B/NHE assistance (Mdn = 60, P < .05), compared to when no assistance was provided (Mdn = 38, P < .05), demonstrating the test's sensitivity to change following the application of a B/NHE.

Conclusions: The findings support that the BeBiT-S is a reliable and valid tool for evaluating bimanual task performance in stroke survivors and is compatible with the use of assistive technology such as B/NHEs. Trial registration NCT04440709, submitted June 18th, 2020.

Background: EMG-based hand-gesture recognition can enable home-based post-stroke rehabilitation, yet one-size-fits-all feature sets overlook differences across recovery stage METHODS: Thirteen post-stroke participants performed seven gestures while EMG was recorded from six forearm sensors. From 38 time- and frequency-domain features, we derived stage-specific subsets for Low (Brunnstrom 1-2, minimal movement), Medium (3-4, partial movement), and High (5-6, near-normal movement) using a wrapper approach Sequential Forward Selection (SFS). For reference, we included a filter comparison using minimum Redundancy-Maximum Relevance (mRMR). To provide fair baselines, we reproduced two literature feature sets within an identical Light Gradient Boosting Machine (LightGBM) pipeline: (i) a healthy-cohort feature set and (ii) a patient-cohort feature set that was not stage-stratified and did not focus on feature selection (we adopted the features as reported). Multiple classifiers-Linear Discriminant Analysis, Support Vector Machines, Random Forest, LightGBM, Logistic Regression, and K-Nearest Neighbors-were evaluated via group-wise cross-validation. Within-stage variability was quantified using pairwise Jaccard overlap of selected features.

Results: Stage-tailored subsets achieved compact yet accurate models: High = 81.5% (14 features, LightGBM), Medium = 80.2% (9 features, LightGBM), Low = 65.0% (7 features, Random Forest). SFS exceeded the mRMR filter comparison and outperformed both literature baselines under the same LightGBM pipeline (paired tests across CV folds, [Formula: see text]). Relative to the healthy-cohort baseline, gains were +6.5% (High), +6.2% (Medium), and +12.0% (Low); relative to the non-stage-stratified patient baseline, gains were +9.5%, +10.2%, and +21.0%, respectively. Time-domain metrics-particularly Difference Absolute Standard Deviation Value and Sample Entropy were most frequently selected. Jaccard analyses indicated within-stage heterogeneity alongside convergence on a small set of core discriminative features.

Conclusions: Brunnstrom stage-specific feature engineering substantially improves EMG gesture-classification accuracy over both healthy-derived and non-stage-stratified patient baselines while reducing computational load. These findings support adaptive, stage-aware designs for wearable rehabilitation systems and motivate larger Low-stage cohorts and models robust to sparse or low-SNR signals.

Background: Gait instability is a common and disabling symptom of Parkinson's disease (PD), contributing to frequent falls and reduced quality of life. While clinical balance tests and spatiotemporal gait measures can predict fall risk, they do not fully explain the underlying control mechanisms. In healthy individuals, foot placement is actively adjusted based on an estimate of the Center of Mass (CoM) state to maintain gait stability, known as foot placement control. This estimation relies on the integration of multisensory information, which has been shown to be impaired in PD, potentially disrupting the control of gait stability through foot placement. This study aimed to investigate whether foot placement coordination during overground walking is impaired in people with PD.

Methods: Fifty people with PD and 51 healthy older adults walked overground for 10 min at self-selected walking speed. Foot placement errors were quantified as the deviation between the actual foot placement and the predicted placement derived from the CoM kinematic state during the preceding swing phase.

Results: Foot placement errors were significantly higher in people with PD than in healthy older adults in both mediolateral (p < 0.05) and anteroposterior directions (p < 0.0001), at both mid-swing and terminal swing. Relative explained variance in mediolateral direction was significantly higher in people with PD compared to healthy older adults (p < 0.005).

Conclusion: We provide first evidence of impaired coordination between the CoM and foot placement in PD. Future work should investigate a causal relationship between impaired foot placement control, sensorimotor integration and gait instability.