Publications by authors named "Cesar Marquez-Chin"

25 Publications

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A Scoping Review of Registered Clinical Studies on Management of Individuals With Acute Spinal Cord Injury (2000-2020): Trends and Characteristics of the Research Initiatives.

Am J Phys Med Rehabil 2022 Feb;101(2):184-190

From the Lyndhurst Centre, Toronto Rehabilitation Institute, University Health Network, Toronto, Ontario, Canada (JCF); KITE-Research Institute, University Health Network, Toronto, Ontario, Canada (JCF, DTF, CM-C); Division of Physical Medicine and Rehabilitation, Department of Medicine, University of Toronto, Toronto, Ontario, Canada (JCF); Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada (JCF); Rehabilitation Sciences Institute, University of Toronto, Toronto, Ontario, Canada (JCF); Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada (JCF); and Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada (CM-C).

Abstract: This scoping review examined the current trends and characteristics of the clinical research initiatives on the management of acute spinal cord injury. This review included all clinical studies on the acute treatment of spinal cord injury that were registered in the ClinicalTrials.gov website from February 2000 to December 2020. The search strategy combined the terms "acute spinal cord injury" and "treatment." There has been a gradual increase in the number of registered clinical studies on acute treatment of spinal cord injury over the past two decades. Of the 116 studies, there were 103 interventional studies, 12 observational studies, and 1 registry. While 115 clinical studies recruited male and female participants, most of the registered clinical studies included only adults with an upper age limit after spinal cord injury. Most of the registered clinical studies were interventional studies led by single institutions in North America (n = 70), Europe (n = 29), and Asia (n = 15). Most of the research initiatives were interventional studies on new therapies for management of individuals with spinal cord injury (n = 91). In conclusion, the results of this scoping review suggest that although there has been an increase in the amount and diversity of the research initiatives on treatment of acute spinal cord injury over the past two decades, their generalizability remains relatively limited.
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http://dx.doi.org/10.1097/PHM.0000000000001811DOI Listing
February 2022

Evacuation solutions for individuals with functional limitations in the built environment: a scoping review protocol.

Syst Rev 2021 Dec 20;10(1):316. Epub 2021 Dec 20.

Department of Mechanical Engineering, University of Alberta, Donadeo Innovation Centre for Engineering, 9211 116 Street NW, Edmonton, Alberta, T6G 1H9, Canada.

Background: Whether due to aging, disability, injury, or other circumstances, an increasing number of Canadians experience functional limitations that reduce their ability to participate in activities of daily life. While the built environment has become increasingly accessible, existing Canadian evacuation guidelines lack comprehensive strategies for evacuating individuals with functional limitations from buildings during emergencies. To inform guideline revisions, a map of existing solutions for evacuating such individuals is required. Therefore, this scoping review aims to provide an account of solutions that have been reported to safely evacuate individuals with functional limitations from the built environment.

Methods: We will conduct a scoping review using the Arksey and O'Malley methodological framework. To identify potentially relevant studies, comprehensive searches (from January 2002 onwards) of the CINAHL, Ei Compendex, Inspec, Embase, MEDLINE, KCI, RSCI, SciELO CI, Web of Science Collection, and Scopus databases will be performed. Using a set of inclusion and exclusion criteria, two reviewers will independently (1) classify identified studies as relevant, irrelevant, or maybe relevant by evaluating their titles and abstracts and (2) classify the relevant and maybe relevant studies as included or excluded by evaluating their full-text. From each included study, data on publication information, study purpose, methodological details, evacuation information, and outcomes will be extracted using a set of data extraction items. We will present a numerical summary of the key characteristics of the included studies. For each evacuation activity, reported evacuation solutions will be summarized, and citations provided for functional limitations that are targeted by a given evacuation solution. To inform Canadian evacuation guideline revisions, we will tabulate evacuation activities common to different types of buildings and emergencies.

Discussion: To our knowledge, this will be the first scoping review to identify the state and use of solutions for evacuating individuals with functional limitations from the built environment. Identifying solutions that enable all individuals to safely evacuate from different types of buildings will allow us to inform recommendations for the revision of evacuation guidelines in Canada and other jurisdictions. The findings of this scoping review will be published in a peer-reviewed journal, presented at relevant conferences, and made publicly available on the internet.

Systematic Review Registration: Open Science Framework: osf.io/jefgy.
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http://dx.doi.org/10.1186/s13643-021-01844-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8691014PMC
December 2021

KITE-BCI: A brain-computer interface system for functional electrical stimulation therapy.

J Spinal Cord Med 2021 ;44(sup1):S203-S214

Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada.

Context/objective: Integrating brain-computer interface (BCI) technology with functional electrical stimulation therapy (FEST) is an emerging strategy for upper limb motor rehabilitation after spinal cord injury (SCI). Despite promising results, the combined use of these technologies (BCI-FEST) in clinical practice is minimal. To address this issue, we developed KITE-BCI, a BCI system specifically designed for clinical application and integration with dynamic FEST. In this paper, we report its technical features and performance. In addition, we discuss the differences in distributions of the BCI- and therapist-triggered stimulation latencies.

Design: Two single-arm 40-session interventional studies to test the feasibility of BCI-controlled FEST for upper limb motor rehabilitation in individuals with cervical SCI.

Setting: Rehabilitation programs within the University and Lyndhurst Centres of the Toronto Rehabilitation Institute - University Health Network, Toronto, Canada.

Participants: Five individuals with sub-acute (< 6 months post-injury) SCI at the C4-C5 level, AIS B-D, and three individuals with chronic (> 24 months post-injury) SCI at C4 level, AIS B-C.

Outcome Measures: We measured BCI setup duration, and to characterize the performance of KITE-BCI, we recorded BCI sensitivity, defined as the percentage of successful BCI activations out of the total number of cued movements.

Results: The overall BCI sensitivities were 74.46% and 79.08% for the sub-acute and chronic groups, respectively. The average KITE-BCI setup duration across the two studies was 11 min and 13 s.

Conclusion: KITE-BCI demonstrates a clinically viable single-channel BCI system for integration with FEST resulting in a versatile technology-enhanced upper limb motor rehabilitation strategy after SCI.
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http://dx.doi.org/10.1080/10790268.2021.1970895DOI Listing
December 2021

Preliminary evaluation of the reliability and validity of the 3D printed Toronto Rehabilitation Institute-Hand Function Test in individuals with spinal cord injury.

J Spinal Cord Med 2021 ;44(sup1):S225-S233

KITE, Toronto Rehabilitation Institute - University Health Network, Toronto, Canada.

Objective: The study objectives were to evaluate the inter-rater and intra-rater reliability; and criterion and construct validity of the 3D printed Toronto Rehabilitation Institute -Hand Function Test (3D TRI-HFT) in individuals with spinal cord injury (SCI).

Design: Observational study.

Setting: Inpatient Rehabilitation Hospital.

Participants: Four individuals with subacute and three individuals with chronic SCI.

Interventions: Reliability and validity of the 3D TRI-HFT was assessed within two interventional studies.

Outcome Measures: Participants performed the 3D TRI-HFT, Graded Redefined Assessment of Strength, Sensibility and Prehension (GRASSP), Functional Independence Measure (FIM) and the Spinal Cord Independence Measure (SCIM) at baseline, after 20 and 40 sessions of therapy and at six month follow-up from baseline. 3D TRI-HFT assessments were graded at the time of performance and re-graded from the video recordings for purpose of reliability testing. Validity testing was done by comparing the scores on 3D TRI-HFT with the scores on the GRASSP, and the FIM and SCIM self care sub-scores.

Results: The 3D TRI-HFT had high intra-rater and inter-rater reliability in sub-acute and chronic SCI with ICC values exceeding 0.99. Moderate to strong correlations were found between 3D TRI-HFT object manipulation scores and the FIM and SCIM self care sub-scores, with r values in the range of 0.7-0.8. Strong correlations were found between the various components of GRASSP and the 3D TRI-HFT, with r values exceeding 0.9.

Conclusions: The 3D TRI-HFT is a reliable and valid measure to assess unilateral hand gross motor function in individuals with SCI.
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http://dx.doi.org/10.1080/10790268.2021.1961055DOI Listing
December 2021

Feasibility and significance of stimulating interscapular muscles using transcutaneous functional electrical stimulation in able-bodied individuals.

J Spinal Cord Med 2021 ;44(sup1):S185-S192

KITE, Toronto Rehabilitation Institute - University Health Network, Toronto, Canada.

Objective: The study objective was to assess the feasibility of stimulating the lower trapezius (LT), the upper trapezius (UT) and serratus anterior (SA) muscles along with anterior or middle deltoid, using surface functional electrical stimulation (FES). The secondary aim was to understand the effects of LT, UT, and SA stimulation on maximum arm reach achieved in shoulder flexion and abduction.

Design: Single arm interventional study.

Setting: Inpatient Rehabilitation Hospital.

Participants: Ten healthy volunteers.

Intervention: Participants completed 10 trials for each of the 3 conditions in flexion and abduction, . (1) Active voluntary flexion or abduction, (2) FES for anterior deltoid for flexion or middle deltoid for abduction, and (3) FES for LT, UT, and SA along with anterior deltoid for flexion or middle deltoid for abduction.

Outcome Measures: Maximum arm reach and percent angle relative to the voluntary movement were computed from motion capture data for each condition. Wilcoxon signed-rank test was used to compare the maximum reach between two FES conditions.

Results: The study results showed that all three interscapular muscles can be stimulated using surface FES. Maximum reach in abduction was greater for FES of middle deltoid along with the interscapular muscles (51.77° ± 17.54°) compared to FES for middle deltoid alone (43.76° ± 15.32°; Z = -2.701, P = 0.007). Maximum reach in flexion for FES of anterior deltoid, along with interscapular muscles, was similar to that during FES of anterior deltoid alone.

Conclusion: Interscapular muscles can be stimulated using surface FES devices and should be engaged during rehabilitation as appropriate.
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http://dx.doi.org/10.1080/10790268.2021.1956251DOI Listing
December 2021

Characterizing the stimulation interference in electroencephalographic signals during brain-computer interface-controlled functional electrical stimulation therapy.

Artif Organs 2021 Aug 30. Epub 2021 Aug 30.

Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada.

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, F , and the EEG sampling rate, F .
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http://dx.doi.org/10.1111/aor.14059DOI Listing
August 2021

Brain-computer interface-triggered functional electrical stimulation therapy for rehabilitation of reaching and grasping after spinal cord injury: a feasibility study.

Spinal Cord Ser Cases 2021 03 19;7(1):24. Epub 2021 Mar 19.

Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada.

Study Design: Feasibility and preliminary clinical efficacy analysis in a single-arm interventional study.

Objectives: 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).

Setting: Spinal cord injury rehabilitation hospital-Toronto Rehabilitation Institute-Lyndhurst Centre.

Methods: 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.

Results: 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.

Conclusions: The new BCI-FEST intervention is safe, feasible, and promising for the rehabilitation of reaching and grasping after SCI.
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http://dx.doi.org/10.1038/s41394-020-00380-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7979732PMC
March 2021

Operant conditioning reveals task-specific responses of single neurons in a brain-machine interface.

J Neural Eng 2021 Mar 30;18(4). Epub 2021 Mar 30.

Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada.

. Volitional modulation of single cortical neurons holds great potential for the implementation of brain-machine interfaces (BMIs) because it can induce a rapid acquisition of arbitrary associations between machines and neural activity. It can also be used as a framework to study the limits of single-neuron control in BMIs.. We tested the control of a one-dimensional actuator in two BMI tasks which differed only in the neural contingency that determined when a reward was dispensed. A thresholded activity task, commonly implemented in single-neuron BMI control, consisted of reaching or exceeding a neuron activity level, while the second task consisted of reaching and maintaining a narrow neuron activity level (i.e. windowed activity task).. Single neurons in layer V of the motor cortex of rats improved performance during both the thresholded activity and windowed activity BMI tasks. However, correct performance during the windowed activity task was accompanied by activation of neighboring neurons, not in direct control of the BMI. In contrast, only neurons in direct control of the BMI were active at the time of reward during the thresholded activity task.. These results suggest that thresholded activity single-neuron BMI implementations are more appropriate compared to windowed activity BMI tasks to capitalize on the adaptability of cortical circuits to acquire novel arbitrary skills.
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http://dx.doi.org/10.1088/1741-2552/abeeacDOI Listing
March 2021

LatLRR-FCNs: Latent Low-Rank Representation With Fully Convolutional Networks for Medical Image Fusion.

Front Neurosci 2020 13;14:615435. Epub 2021 Jan 13.

The Key Laboratory of Clinical and Medical Engineering, School of Biomedical Engineering and Informatics, Nanjing Medical University, Nanjing, China.

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.
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http://dx.doi.org/10.3389/fnins.2020.615435DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7838502PMC
January 2021

Operant conditioning of motor cortex neurons reveals neuron-subtype-specific responses in a brain-machine interface task.

Sci Rep 2020 11 17;10(1):19992. Epub 2020 Nov 17.

Institute of Biomedical Engineering, University of Toronto, Toronto, ON, M5S 3G9, Canada.

Operant conditioning is implemented in brain-machine interfaces (BMI) to induce rapid volitional modulation of single neuron activity to control arbitrary mappings with an external actuator. However, intrinsic factors of the volitional controller (i.e. the brain) or the output stage (i.e. individual neurons) might hinder performance of BMIs with more complex mappings between hundreds of neurons and actuators with multiple degrees of freedom. Improved performance might be achieved by studying these intrinsic factors in the context of BMI control. In this study, we investigated how neuron subtypes respond and adapt to a given BMI task. We conditioned single cortical neurons in a BMI task. Recorded neurons were classified into bursting and non-bursting subtypes based on their spike-train autocorrelation. Both neuron subtypes had similar improvement in performance and change in average firing rate. However, in bursting neurons, the activity leading up to a reward increased progressively throughout conditioning, while the response of non-bursting neurons did not change during conditioning. These results highlight the need to characterize neuron-subtype-specific responses in a variety of tasks, which might ultimately inform the design and implementation of BMIs.
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http://dx.doi.org/10.1038/s41598-020-77090-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7672061PMC
November 2020

Why brain-controlled neuroprosthetics matter: mechanisms underlying electrical stimulation of muscles and nerves in rehabilitation.

Biomed Eng Online 2020 Nov 4;19(1):81. Epub 2020 Nov 4.

Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo, 153-8902, Japan.

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.
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http://dx.doi.org/10.1186/s12938-020-00824-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7641791PMC
November 2020

Functional electrical stimulation therapy for restoration of motor function after spinal cord injury and stroke: a review.

Biomed Eng Online 2020 May 24;19(1):34. Epub 2020 May 24.

Kite Research Institute, Toronto Rehabilitation Institute-University Health Network, 550 University Avenue, Toronto, ON, M5G 2A2, Canada.

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.
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http://dx.doi.org/10.1186/s12938-020-00773-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7245767PMC
May 2020

Restoration of Upper Limb Function After Chronic Severe Hemiplegia: A Case Report on the Feasibility of a Brain-Computer Interface-Triggered Functional Electrical Stimulation Therapy.

Am J Phys Med Rehabil 2020 03;99(3):e35-e40

From the Toronto Rehabilitation Institute - University Health Network, Toronto, Ontario, Canada (LIJ, NK, LL, VZ, MRP, CM-C); Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada (LIJ, MRP); and Rehabilitation Sciences Institute, University of Toronto, Toronto, Ontario, Canada (NK, MRP).

Functional electrical stimulation therapy (FEST) is a state-of-the-art treatment for retraining motor function after neurological injuries. Recent literature suggests that FEST can be further improved with brain-computer interface (BCI) technology. In this case study, we assessed the feasibility of using BCI-triggered FEST (BCI-FEST) to restore upper limb function in a 57-yr-old man with severe left hemiplegia resulting from a stroke 6 yrs before enrollment in the study. The intervention consisted of two blocks of forty 1-hr BCI-FEST sessions, with three sessions delivered weekly. During therapy, a single-channel BCI was used to trigger the stimulation programmed to facilitate functional movements. The measure of the feasibility of the BCI-FEST included assessing the implementation and safety of the intervention. Clinical improvements were assessed using (a) Functional Independence Measure, (b) Action Research Arm Test, (c) Toronto Rehabilitation Institute - Hand Function Test, and (d) Fugl-Meyer Assessment Upper Extremity test. Upon completion of 80 therapy sessions, 14-, 17-, and 18-point changes were recorded on Action Research Arm Test, Fugl-Meyer Assessment Upper Extremity test, and Toronto Rehabilitation Institute - Hand Function Test, respectively. The participant also indicated improvement as demonstrated by his ability to perform various day-to-day tasks. The results suggest that BCI-FEST is safe and viable.
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http://dx.doi.org/10.1097/PHM.0000000000001163DOI Listing
March 2020

EEG-Controlled Functional Electrical Stimulation Therapy With Automated Grasp Selection: A Proof-of-Concept Study.

Top Spinal Cord Inj Rehabil 2018 ;24(3):265-274

Toronto Rehabilitation Institute - University Health Network, Toronto, Canada.

Functional electrical stimulation therapy (FEST) is a promising intervention for the restoration of upper extremity function after cervical spinal cord injury (SCI). This study describes and evaluates a novel FEST system designed to incorporate voluntary movement attempts and massed practice of functional grasp through the use of brain-computer interface (BCI) and computer vision (CV) modules. An EEG-based BCI relying on a single electrode was used to detect movement initiation attempts. A CV system identified the target object and selected the appropriate grasp type. The required grasp type and trigger command were sent to an FES stimulator, which produced one of four multichannel muscle stimulation patterns (precision, lateral, palmar, or lumbrical grasp). The system was evaluated with five neurologically intact participants and one participant with complete cervical SCI. An integrated BCI-CV-FES system was demonstrated. The overall classification accuracy of the CV module was 90.8%, when selecting out of a set of eight objects. The average latency for the BCI module to trigger the movement across all participants was 5.9 ± 1.5 seconds. For the participant with SCI alone, the CV accuracy was 87.5% and the BCI latency was 5.3 ± 9.4 seconds. BCI and CV methods can be integrated into an FEST system without the need for costly resources or lengthy setup times. The result is a clinically relevant system designed to promote voluntary movement attempts and more repetitions of varied functional grasps during FEST.
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http://dx.doi.org/10.1310/sci2403-265DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6037320PMC
October 2018

Reconstruction of reaching movement trajectories using electrocorticographic signals in humans.

PLoS One 2017 20;12(9):e0182542. Epub 2017 Sep 20.

Department of Electrical and Computer Engineering, University of Toronto, Toronto, Canada.

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.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0182542PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5606933PMC
October 2017

Neuron-Type-Specific Utility in a Brain-Machine Interface: a Pilot Study.

J Spinal Cord Med 2017 11 12;40(6):715-722. Epub 2017 Sep 12.

a Institute of Biomaterials and Biomedical Engineering, University of Toronto , Canada.

Context: Firing rates of single cortical neurons can be volitionally modulated through biofeedback (i.e. operant conditioning), and this information can be transformed to control external devices (i.e. brain-machine interfaces; BMIs). However, not all neurons respond to operant conditioning in BMI implementation. Establishing criteria that predict neuron utility will assist translation of BMI research to clinical applications.

Findings: Single cortical neurons (n=7) were recorded extracellularly from primary motor cortex of a Long-Evans rat. Recordings were incorporated into a BMI involving up-regulation of firing rate to control the brightness of a light-emitting-diode and subsequent reward. Neurons were classified as 'fast-spiking', 'bursting' or 'regular-spiking' according to waveform-width and intrinsic firing patterns. Fast-spiking and bursting neurons were found to up-regulate firing rate by a factor of 2.43±1.16, demonstrating high utility, while regular-spiking neurons decreased firing rates on average by a factor of 0.73±0.23, demonstrating low utility.

Conclusion/clinical Relevance: The ability to select neurons with high utility will be important to minimize training times and maximize information yield in future clinical BMI applications. The highly contrasting utility observed between fast-spiking and bursting neurons versus regular-spiking neurons allows for the hypothesis to be advanced that intrinsic electrophysiological properties may be useful criteria that predict neuron utility in BMI implementation.
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http://dx.doi.org/10.1080/10790268.2017.1369214DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5778935PMC
November 2017

Prediction of specific hand movements using electroencephalographic signals.

J Spinal Cord Med 2017 11 7;40(6):696-705. Epub 2017 Sep 7.

a Rehabilitation Engineering Laboratory, Lyndhurst Centre , Toronto Rehabilitation Institute - University Health Network , Toronto , ON , Canada.

Objective: To identify specific hand movements from electroencephalographic activity.

Design: Proof of concept study.

Setting: Rehabilitation hospital in Toronto, Canada.

Participants: Fifteen healthy individuals with no neurological conditions.

Intervention: Each individual performed six different hand movements, including four grasps commonly targeted during rehabilitation. All of them used their dominant hand and four of them repeated the experiment with their non-dominant hand. EEG was acquired from 8 different locations (C1, C2, C3, C4, CZ, F3, F4 and Fz). Time-frequency distributions (spectrogram) of the pre-movement EEG activity for each electrode were generated and each of the time-resolved spectral components (1 Hz to 50 Hz) was correlated with a hyperbolic tangent function to detect power decreases. The spectral components and time ranges with the largest correlation values were identified using a threshold. The resulting features were then used to implement a distance-based classifier.

Outcome Measures: Accuracy of classification.

Results: A minimum of three different dominant hand movements were classified correctly with average accuracies between 65-75% across all 15 participants. Average accuracies between 67-85% for the same three movements were achieved across four of the 15 participants who were tested with their non-dominant hand.

Conclusion: The results suggest that it may be possible to predict specific hand movements from a small number of electroencephalographic electrodes. Further studies including members of the spinal cord injury community are necessary to verify the suitability of the proposed process.
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http://dx.doi.org/10.1080/10790268.2017.1369215DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5778933PMC
November 2017

Functional electrical stimulation therapy for severe hemiplegia: Randomized control trial revisited.

Can J Occup Ther 2017 Apr 17;84(2):87-97. Epub 2017 Jan 17.

Background: 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.

Purpose: This study aims to assess the efficacy of functional electrical stimulation therapy in improving voluntary reaching and grasping after severe hemiplegia.

Method: 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.

Findings: 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.

Implications: The results may represent the largest upper-limb function improvements in any stroke population to date, especially in those with severe upper-limb deficit.
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http://dx.doi.org/10.1177/0008417416668370DOI Listing
April 2017

BCI-Triggered Functional Electrical Stimulation Therapy for Upper Limb.

Eur J Transl Myol 2016 Jun 5;26(3):6222. Epub 2016 Aug 5.

Toronto Rehabilitation Institute - University Health Network, Toronto, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada.

We present here the integration of brain-computer interfacing (BCI) technology with functional electrical stimulation therapy to restore voluntary function. The system was tested with a single man with chronic (6 years) severe left hemiplegia resulting from a stroke. The BCI, implemented as a simple "brain-switch" activated by power decreases in the 18 Hz - 28 Hz frequency range of the participant's electroencephalograpic signals, triggered a neuroprosthesis designed to facilitate forward reaching, reaching to the mouth, and lateral reaching movements. After 40 90-minute sessions in which the participant attempted the reaching tasks repeatedly, with the movements assisted by the BCI-triggered neuroprosthesis, the participant's arm function showed a clinically significant six point increase in the Fugl-Meyer Asessment Upper Extermity Sub-Score. These initial results suggest that the combined use of BCI and functional electrical stimulation therapy may restore voluntary reaching function in individuals with chronic severe hemiplegia for whom the rehabilitation alternatives are very limited.
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http://dx.doi.org/10.4081/ejtm.2016.6222DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5128980PMC
June 2016

EEG-Triggered Functional Electrical Stimulation Therapy for Restoring Upper Limb Function in Chronic Stroke with Severe Hemiplegia.

Case Rep Neurol Med 2016 2;2016:9146213. Epub 2016 Nov 2.

Rehabilitation Engineering Laboratory, The Lyndhurst Centre, Toronto Rehabilitation Institute-University Health Network, 520 Sutherland Drive, Toronto, ON, Canada M4G 3V9; Rehabilitation Engineering Laboratory, Institute of Biomaterials and Biomedical Engineering, University of Toronto, Mining Building, 164 College Street, Room 407, Toronto, ON, Canada M5S 3E3.

We report the therapeutic effects of integrating brain-computer interfacing technology and functional electrical stimulation therapy to restore upper limb reaching movements in a 64-year-old man with severe left hemiplegia following a hemorrhagic stroke he sustained six years prior to this study. He completed 40 90-minute sessions of functional electrical stimulation therapy using a custom-made neuroprosthesis that facilitated 5 different reaching movements. During each session, the participant attempted to reach with his paralyzed arm repeatedly. Stimulation for each of the movement phases (e.g., extending and retrieving the arm) was triggered when the power in the 18 Hz-28 Hz range (beta frequency range) of the participant's EEG activity, recorded with a single electrode, decreased below a predefined threshold. The function of the participant's arm showed a clinically significant improvement in the Fugl-Meyer Assessment Upper Extremity (FMA-UE) subscore (6 points) as well as moderate improvement in Functional Independence Measure Self-Care subscore (7 points). The changes in arm's function suggest that the combination of BCI technology and functional electrical stimulation therapy may restore voluntary motor function in individuals with chronic hemiplegia which results in severe upper limb deficit (FMA-UE ≤ 15), a population that does not benefit from current best-practice rehabilitation interventions.
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http://dx.doi.org/10.1155/2016/9146213DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5110888PMC
November 2016

Real-time two-dimensional asynchronous control of a computer cursor with a single subdural electrode.

J Spinal Cord Med 2012 Sep;35(5):382-91

iDAPT Technology R&D Team, Toronto Rehabilitation Institute University Centre, University Health Network, Toronto, Ontario, Canada.

Objective: To test the feasibility of controlling a computer cursor asynchronously in two dimensions using one subdural electrode.

Design: Proof of concept study.

Setting: Acute care hospital in Toronto, Canada.

Participant: A 68-year-old woman with a subdural electrode implanted for the treatment of essential tremor (ET) using direct brain stimulation of the primary motor cortex (MI).

Interventions: Power changes in the electrocorticography signals were used to implement a "brain switch". To activate the switch the subject had to decrease the power in the 7-13 Hz frequency range using motor imagery of the left hand. The brain switch was connected to a system for asynchronous control of movement in two dimensions. Each time the user reduced the amplitude in the 7-13 Hz frequency band below an experimentally defined threshold the direction of cursor changed randomly. The new direction was always different from those previously rejected ensuring the convergence of the system on the desired direction.

Outcome Measures: Training time, time and number of switch activations required to reach specific targets, information transfer rate.

Results: The user was able to control the cursor to specific targets on the screen after only 15 minutes of training. Each target was reached in 51.7 ± 40.2 seconds (mean ± SD) and after 9.4 ± 6.8 switch activations. Information transfer rate of the system was estimated to be 0.11 bit/second.

Conclusion: A novel brain-machine interface for asynchronous two-dimensional control using one subdural electrode was developed.
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http://dx.doi.org/10.1179/2045772312Y.0000000043DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3459567PMC
September 2012

Advanced technologies to curb healthcare-associated infections.

Healthc Pap 2009 ;9(3):51-5 discussion 60-2

Technology Research and Development (R & D) Team, Toronto Rehabilitation Institute, L. Bloomberg Faculty of Nursing, University of Toronto.

The commentary was prepared in response to the manuscript "Healthcare-Associated Infections as Patient Safety Indicators," by Gardam, Lemieux, Reason, van Dijk and Goel. Healthcare-associated infections are a severe patient safety hazard. Current patient safety initiatives targeting increased healthcare worker hand hygiene to prevent some of these infections have had limited effect. This commentary describes recent advances in electronic sensing and computational power that have provided new options to increase hand hygiene compliance as a step toward reducing healthcare-associated infections. Smart electronics can provide reasoning about a healthcare worker's circumstance and prompt the worker to perform hand hygiene when necessary. These novel approaches in technology development have tremendous potential to enhance the hand hygiene of healthcare workers and can support the prevention of this significant problem for patients in our hospitals.
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December 2009

Identification of arm movements using correlation of electrocorticographic spectral components and kinematic recordings.

J Neural Eng 2007 Jun 4;4(2):146-58. Epub 2007 Apr 4.

Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario M5S 3G9, Canada.

The purpose of this study was to explore the possibility of using electrocorticographic (ECoG) recordings from subdural electrodes placed over the motor cortex to identify the upper limb motion performed by a human subject. More specifically, we were trying to identify features in the ECoG signals that could help us determine the type of movement performed by an individual. Two subjects who had subdural electrodes implanted over the motor cortex were asked to perform various motor tasks with the upper limb contralateral to the site of electrode implantation. ECoG signals and upper limb kinematics were recorded while the participants were performing the movements. ECoG frequency components were identified that correlated well with the performed movements measured along 6D coordinates (X, Y, Z, roll, yaw and pitch). These frequencies were grouped using histograms. The resulting histograms had consistent and unique shapes that were representative of individual upper limb movements performed by the participants. Thus, it was possible to identify which movement was performed by the participant without prior knowledge of the arm and hand kinematics. To confirm these findings, a nearest neighbour classifier was applied to identify the specific movement that each participant had performed. The achieved classification accuracy was 89%.
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http://dx.doi.org/10.1088/1741-2560/4/2/014DOI Listing
June 2007
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