Functional electrical stimulation is a technique to produce functional movements after paralysis. Electrical discharges are applied to a person's muscles making them contract in a sequence that ...allows performing tasks such as grasping a key, holding a toothbrush, standing, and walking. The technology was developed in the sixties, during which initial clinical use started, emphasizing its potential as an assistive device. Since then, functional electrical stimulation has evolved into an important therapeutic intervention that clinicians can use to help individuals who have had a stroke or a spinal cord injury regain their ability to stand, walk, reach, and grasp. With an expected growth in the aging population, it is likely that this technology will undergo important changes to increase its efficacy as well as its widespread adoption. We present here a series of functional electrical stimulation systems to illustrate the fundamentals of the technology and its applications. Most of the concepts continue to be in use today by modern day devices. A brief description of the potential future of the technology is presented, including its integration with brain-computer interfaces and wearable (garment) technology.
Introduction
The integration of brain–computer interface (BCI) and functional electrical stimulation (FES) has brought about a new rehabilitation strategy: BCI‐controlled FES therapy or BCI‐FEST. ...During BCI‐FEST, the stimulation is triggered by the patient’s brain activity, often monitored using electroencephalography (EEG). Several studies have demonstrated that BCI‐FEST can improve voluntary arm and hand function after an injury, but few studies have investigated the FES interference in EEG signals during BCI‐FEST. In this study, we evaluated the effectiveness of band‐pass filters, used to extract the BCI‐relevant EEG components, in simultaneously reducing stimulation interference.
Methods
We used EEG data from eight participants recorded during BCI‐FEST. Additionally, we separately recorded the FES signal generated by the stimulator to estimate the spectral components of the FES interference, and extract the noise in time domain. Finally, we calculated signal‐to‐noise ratio (SNR) values before and after band‐pass filtering, for two types of movements practiced during BCI‐FEST: reaching and grasping.
Results
The SNR values were greater after filtering across all participants for both movement types. For reaching movements, mean SNR values increased between 1.31 dB and 36.3 dB. Similarly, for grasping movements, mean SNR values increased between 2.82 dB and 40.16 dB, after filtering.
Conclusions
Band‐pass filters, used to isolate EEG frequency bands for BCI application, were also effective in reducing stimulation interference. In addition, we provide a general algorithm that can be used in future studies to estimate the frequencies of FES interference as a function of the selected stimulation pulse frequency, FSTIM, and the EEG sampling rate, FS.
The report suggests that the functional electrical stimulation (FES) interference in the electroencephalographic (EEG) signals recorded during brain–computer interface (BCI) controlled FES therapy is a function of the selected stimulation pulse frequency and the EEG sampling rate. After identifying the frequency components of the FES interference, we conducted a signal‐to‐noise ratio analysis and found that band‐pass filters, used for the purpose of isolating the BCI‐relevant EEG bands, were effective in reducing the stimulation interference.
Delivering short trains of electric pulses to the muscles and nerves can elicit action potentials resulting in muscle contractions. When the stimulations are sequenced to generate functional ...movements, such as grasping or walking, the application is referred to as functional electrical stimulation (FES). Implications of the motor and sensory recruitment of muscles using FES go beyond simple contraction of muscles. Evidence suggests that FES can induce short- and long-term neurophysiological changes in the central nervous system by varying the stimulation parameters and delivery methods. By taking advantage of this, FES has been used to restore voluntary movement in individuals with neurological injuries with a technique called FES therapy (FEST). However, long-lasting cortical re-organization (neuroplasticity) depends on the ability to synchronize the descending (voluntary) commands and the successful execution of the intended task using a FES. Brain-computer interface (BCI) technologies offer a way to synchronize cortical commands and movements generated by FES, which can be advantageous for inducing neuroplasticity. Therefore, the aim of this review paper is to discuss the neurophysiological mechanisms of electrical stimulation of muscles and nerves and how BCI-controlled FES can be used in rehabilitation to improve motor function.
Brain computer interface-triggered functional electrical stimulation therapy (BCI-FEST) has shown promise as a therapy to improve upper extremity function for individuals who have had a stroke or ...spinal cord injury. The next step is to determine whether BCI-FEST could be used clinically as part of broader therapy practice. To do this, we need to understand therapists' opinions on using the BCI-FEST and what limitations potentially exist. Therefore, we conducted a qualitative exploratory study to understand the perspectives of therapists on their experiences delivering BCI-FEST and the feasibility of large-scale clinical implementation.
Semi-structured interviews were conducted with physical therapists (PTs) and occupational therapists (OTs) who have delivered BCI-FEST. Interview questions were developed using the COM-B (Capability, Opportunity, Motivation-Behaviour) model of behaviour change. COM-B components were used to inform deductive content analysis while other subthemes were detected using an inductive approach.
We interviewed PTs (n = 3) and OTs (n = 3), with 360 combined hours of experience delivering BCI-FEST. Components and subcomponents of the COM-B determined deductively included: (1) Capability (physical, psychological), (2) Opportunity (physical, social), and (3) Motivation (automatic, reflective). Under each deductive subcomponent, one to two inductive subthemes were identified (n = 8). Capability and Motivation were perceived as strengths, and therefore supported therapists' decisions to use BCI-FEST. Under Opportunity, for both subcomponents (physical, social), therapists recognized the need for more support to clinically implement BCI-FEST.
We identified facilitating and limiting factors to BCI-FEST delivery in a clinical setting according to clinicians. These factors implied that education, training, a support network or mentors, and restructuring the physical environment (e.g., scheduling) should be targeted as interventions. The results of this study may help to inform future development of new technologies and interventions.
Medical image fusion, which aims to derive complementary information from multi-modality medical images, plays an important role in many clinical applications, such as medical diagnostics and ...treatment. We propose the LatLRR-FCNs, which is a hybrid medical image fusion framework consisting of the latent low-rank representation (LatLRR) and the fully convolutional networks (FCNs). Specifically, the LatLRR module is used to decompose the multi-modality medical images into low-rank and saliency components, which can provide fine-grained details and preserve energies, respectively. The FCN module aims to preserve both global and local information by generating the weighting maps for each modality image. The final weighting map is obtained using the weighted local energy and the weighted sum of the eight-neighborhood-based modified Laplacian method. The fused low-rank component is generated by combining the low-rank components of each modality image according to the guidance provided by the final weighting map within pyramid-based fusion. A simple sum strategy is used for the saliency components. The usefulness and efficiency of the proposed framework are thoroughly evaluated on four medical image fusion tasks, including computed tomography (CT) and magnetic resonance (MR), T1- and T2-weighted MR, positron emission tomography and MR, and single-photon emission CT and MR. The results demonstrate that by leveraging the LatLRR for image detail extraction and the FCNs for global and local information description, we can achieve performance superior to the state-of-the-art methods in terms of both objective assessment and visual quality in some cases. Furthermore, our method has a competitive performance in terms of computational costs compared to other baselines.
In this study, we used electrocorticographic (ECoG) signals to extract the onset of arm movement as well as the velocity of the hand as a function of time. ECoG recordings were obtained from three ...individuals while they performed reaching tasks in the left, right and forward directions. The ECoG electrodes were placed over the motor cortex contralateral to the moving arm. Movement onset was detected from gamma activity with near perfect accuracy (> 98%), and a multiple linear regression model was used to predict the trajectory of the reaching task in three-dimensional space with an accuracy exceeding 85%. An adaptive selection of frequency bands was used for movement classification and prediction. This demonstrates the efficacy of developing a real-time brain-machine interface for arm movements with as few as eight ECoG electrodes.
Stroke is the leading cause of long-term disability. Stroke survivors seldom improve their upper-limb function when their deficit is severe, despite recently developed therapies.
This study aims to ...assess the efficacy of functional electrical stimulation therapy in improving voluntary reaching and grasping after severe hemiplegia.
A post hoc analysis of a previously completed randomized control trial ( clinicaltrials.gov , No. NCT00221078) was carried out involving 21 participants with severe upper-limb hemiplegia (i.e., Fugl-Meyer Assessment-Upper Extremity FMA-UE ≤ 15) resulting from stroke.
Functional Independence Measure Self-Care subscores increased 22.8 (±6.7) points in the intervention group and 9 (±6.5) in the control group, following 40 hr of equal-intensity therapy. FMA-UE score changes were 27.2 (±13.5) and 5.3 (±11.0) for the intervention and control groups, respectively.
The results may represent the largest upper-limb function improvements in any stroke population to date, especially in those with severe upper-limb deficit.
Feasibility and preliminary clinical efficacy analysis in a single-arm interventional study.
We developed a brain-computer interface-triggered functional electrical stimulation therapy (BCI-FEST) ...system for clinical application and conducted an interventional study to (1) assess its feasibility and (2) understand its potential clinical efficacy for the rehabilitation of reaching and grasping in individuals with sub-acute spinal cord injury (SCI).
Spinal cord injury rehabilitation hospital-Toronto Rehabilitation Institute-Lyndhurst Centre.
Five participants with sub-acute SCI completed between 12 and 40 1-hour sessions using BCI-FEST, with up to 5 sessions a week. We assessed feasibility by measuring participants' compliance with treatment, the occurrence of adverse events, BCI sensitivity, and BCI setup duration. Clinical efficacy was assessed using Functional Independence Measure (FIM) and Spinal Cord Independence Measure (SCIM), as primary outcomes. In addition, we used two upper-limb function tests as secondary outcomes.
On average, participants completed 29.8 sessions with no adverse events. Only one of the 149 sessions was affected by technical challenges. The BCI sensitivity ranged between 69.5 and 80.2%, and the mean BCI setup duration was ~11 min. In the primary outcomes, three out of five participants showed changes greater than the minimal clinically important differences (MCIDs). Additionally, the mean change in secondary outcome measures met the threshold for detecting MCID as well; four out of five participants achieved MCID.
The new BCI-FEST intervention is safe, feasible, and promising for the rehabilitation of reaching and grasping after SCI.
The built environment continues to become increasingly accessible to people with disabilities, yet there remains a lack of focus on how these individuals are evacuated in emergencies. The objective ...of this scoping review was to survey the academic literature to identify solutions for safely evacuating individuals with functional limitations from the indoor built environment (i.e., buildings). Journal articles and conference proceedings published in the year 2002 onwards were included. Two pairs of reviewers independently evaluated 3562 articles from ten databases and identified 99 articles. The results were categorized into six main evacuation solution types: notification, wayfinding, egress, building design, strategy, and training programs. Our findings highlight the importance of tailoring solutions to the needs of individuals with different functional limitations. Future work should focus on expanding the number of solutions available for (1) emergencies beyond fires (e.g., natural disasters); (2) unique building types that may require specialized engineering considerations; and (3) a greater variety of impairments (e.g., seeing, hearing, cognitive). We also emphasize the need for more interdisciplinary work and the importance of including rescuers and rescuees in emergency preparedness discussions. These collaborations will ensure that building designs, organizational procedures, and evacuation aids complement each other to maximize safety. To our knowledge, this is the first scoping review to identify solutions for evacuating individuals with functional limitations from buildings. These findings may help inform future recommendations for new evacuation guidelines around the world.
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