Journal of NeuroEngineering and Rehabilitation最新文献

Background: Stroke is a leading cause of disability, with up to 80% of survivors experiencing motor impairments. These impairments are attributed to various factors, including reduced neural drive and altered motor unit firing patterns. Rehabilitation aims to restore motor function by enhancing motor unit recruitment and synchronization. High-density electromyography (HD-EMG) is a valuable tool for evaluating these changes in motor unit activity.

Methods: We tested a wearable HD-EMG forearm sleeve to investigate the relationship between motor function and motor unit properties including firing rate, motor unit module activation, and coherence. Seven individuals with chronic stroke and seven able-bodied individuals attempted 12 cued hand and wrist movements while EMG was recorded. Motor units were decomposed across all movements using convolutive blind source separation.

Results: Fewer motor units were detectable in individuals with stroke compared to able-bodied participants. There was a significant reduction in motor unit firing rate during specific movements such as wrist flexion and hand open. Motor unit coupling and activation were altered following stroke, with reduced module activation in 8 of the 12 attempted movements. Furthermore, a reduction in coherence for gross movements and an increase in coherence for more dexterous thumb movements suggest altered neural drive to motor units after stroke that is differentially tuned to the complexity of movement. A combined neural control signature, consisting of multiple motor unit features, demonstrated strong correlation ([Formula: see text]) with clinical motor function scores.

Conclusions: This study demonstrates that HD-EMG can capture detailed motor unit activity and neural control characteristics across multiple forearm muscles in individuals with chronic stroke. By integrating multiple HD-EMG features, this approach provides new insights into neuromuscular alterations linked to hand motor function after stroke. These findings support the use of HD-EMG for monitoring recovery, predicting outcomes, and guiding more targeted rehabilitation, thus advancing both stroke research and patient care.

Background: The amputation of a limb constitutes one of the most severe disruptions of body integrity. Nevertheless, many individuals with limb amputation report a restored sense of integrity when wearing a prosthesis. The rubber limb illusion (RLI) has been proposed as an experimental model to study such experiences. In this paradigm, correlated visuo-tactile stimulation of the residual limb and an artificial limb can induce amputated individuals to experience ownership of the latter one which is then perceived as a counterpart of the missing limb. However, due to methodical limitations in previous setups, the neural processes underlying alterations in the sense of body integrity remain insufficiently understood.

Methods: In this cross-sectional study, we developed a novel RLI setup to systematically manipulate the sense of body integrity in a sample of N = 34 individuals with unilateral lower limb amputation. Participants completed six randomized trials across two experiments. In Experiment 1, we varied artificial limb appearance (intact vs. impaired) and visuo-tactile stimulation (synchronous vs. asynchronous) on the residual limb. In Experiment 2, we manipulated artificial limb appearance and induced the RLI on both the residual and the non-amputated limb. Neural activity was assessed using functional magnetic resonance imaging.

Results: Synchronous visuo-tactile stimulation of the residual limb and an intact artificial counterpart induced artificial limb ownership and was associated with improvements in perceived body integrity. Neuroimaging revealed specific activation in the left superior parietal lobule associated with dynamic changes in the sense of body integrity. Neural activity underlying RLI processing did not significantly differ between the residual limb and the non-amputated limb.

Conclusion: Appropriate multimodal sensory stimulation can strengthen the sense of body integrity in most individuals with lower limb amputation. This effect appears to be mediated by the brain's capacity for sensory integration within the body representation network. These insights advance our understanding of prosthesis-related experiences and may inform the development of improved prosthetic devices that employ non-invasive somatosensory feedback, thereby promoting positive rehabilitative outcomes through enhanced prosthesis embodiment.

Background: Walking while performing a concurrent cognitive task leads to cognitive-motor interference, resulting in slower and more variable gait. This is particularly the case in Parkinson's disease (PD), where dual-task situations exacerbate walking impairments, increasing fall risk and reducing quality of life. Cognitive-motor impairment has been linked to excessive attentional demands due to reduced locomotor automaticity. Neuroimaging studies suggest over-reliance on prefrontal resources potentially reflecting compensatory mechanisms. However, few studies link automaticity, performance, and cognitive capacity to prefrontal activity, particularly in PD. In older adults (OA) and people with PD, this study aims to: (1) describe dual-task effects and prefrontal cortical activity during walking with and without a dual-task, (2) determine the connection between prefrontal cortical activity and step time variability as a measure of gait automaticity, (3) explore associations between prefrontal cortical activity and other measures of gait automaticity and prioritization and (4) investigate executive function as a potential moderator in the compensatory relationship.

Methods: Data from 44 OA and 37 people with PD walking with and without an auditory Stroop task were analyzed. Gait variables were measured using inertial measurement units, and prefrontal activity was assessed with functional near-infrared spectroscopy (fNIRS). Executive function was determined with a trail making test. Data analysis involved linear regression models to explore relationships between prefrontal activity, gait automaticity, and executive function.

Results: Most participants had a cognitive priority trade-off when dual-tasking, and the OA group had more prefrontal activity compared to the PD group during single-task and dual-task walking. For PD there was a significant positive relationship between step time variability and prefrontal activity (β = 0.38, T = 6.26, p < 0.01), while OA had a relationship between age and prefrontal activity (β = 0.53, T = 2.33, p = 0.04). Secondary analyses showed relationships between prefrontal activity and dual-task cost of gait speed (β = 0.25, T = 2.90, p = 0.02) and Stroop response time (β = 0.27, T = 3.10, p = 0.01) in PD, but not in OA. No moderation effects were detected in the relationship between gait automaticity and prefrontal activity.

Conclusions: In PD, loss of gait automaticity is linked to increased prefrontal activity, suggesting compensatory mechanisms. In OA, prefrontal activity during walking seems to be primarily age-related.