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1.
Nature ; 477(7365): 457-61, 2011 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-21881561

RESUMO

The discovery of antibiotics more than 70 years ago initiated a period of drug innovation and implementation in human and animal health and agriculture. These discoveries were tempered in all cases by the emergence of resistant microbes. This history has been interpreted to mean that antibiotic resistance in pathogenic bacteria is a modern phenomenon; this view is reinforced by the fact that collections of microbes that predate the antibiotic era are highly susceptible to antibiotics. Here we report targeted metagenomic analyses of rigorously authenticated ancient DNA from 30,000-year-old Beringian permafrost sediments and the identification of a highly diverse collection of genes encoding resistance to ß-lactam, tetracycline and glycopeptide antibiotics. Structure and function studies on the complete vancomycin resistance element VanA confirmed its similarity to modern variants. These results show conclusively that antibiotic resistance is a natural phenomenon that predates the modern selective pressure of clinical antibiotic use.


Assuntos
Genes Bacterianos/genética , Metagenômica , Resistência a Vancomicina/genética , Animais , Antibacterianos/farmacologia , Bactérias/classificação , Bactérias/enzimologia , Bactérias/genética , Teorema de Bayes , Cristalografia por Raios X , DNA de Cloroplastos/genética , Congelamento , Genes Mitocondriais/genética , Genes de Plantas/genética , Sedimentos Geológicos/microbiologia , História Antiga , Ligação de Hidrogênio , Modelos Moleculares , Dados de Sequência Molecular , Filogenia , Conformação Proteica , RNA Ribossômico/genética , RNA Ribossômico 16S/genética , Sibéria , Resistência a Vancomicina/efeitos dos fármacos , Vertebrados/genética , beta-Lactamases/genética
2.
Sensors (Basel) ; 17(8)2017 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-28771168

RESUMO

To address the need for asthma self-management in pediatrics, the authors present the feasibility of a mobile health (mHealth) platform built on their prior work in an asthmatic adult and child. Real-time asthma attack risk was assessed through physiological and environmental sensors. Data were sent to a cloud via a smartwatch application (app) using Health Insurance Portability and Accountability Act (HIPAA)-compliant cryptography and combined with online source data. A risk level (high, medium or low) was determined using a random forest classifier and then sent to the app to be visualized as animated dragon graphics for easy interpretation by children. The feasibility of the system was first tested on an adult with moderate asthma, then usability was examined on a child with mild asthma over several weeks. It was found during feasibility testing that the system is able to assess asthma risk with 80.10 ± 14.13% accuracy. During usability testing, it was able to continuously collect sensor data, and the child was able to wear, easily understand and enjoy the use of the system. If tested in more individuals, this system may lead to an effective self-management program that can reduce hospitalization in those who suffer from asthma.


Assuntos
Asma , Criança , Humanos , Autogestão , Telemedicina , Interface Usuário-Computador , Tecnologia sem Fio
3.
J Neuroeng Rehabil ; 12: 80, 2015 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-26400061

RESUMO

BACKGROUND: Direct brain control of overground walking in those with paraplegia due to spinal cord injury (SCI) has not been achieved. Invasive brain-computer interfaces (BCIs) may provide a permanent solution to this problem by directly linking the brain to lower extremity prostheses. To justify the pursuit of such invasive systems, the feasibility of BCI controlled overground walking should first be established in a noninvasive manner. To accomplish this goal, we developed an electroencephalogram (EEG)-based BCI to control a functional electrical stimulation (FES) system for overground walking and assessed its performance in an individual with paraplegia due to SCI. METHODS: An individual with SCI (T6 AIS B) was recruited for the study and was trained to operate an EEG-based BCI system using an attempted walking/idling control strategy. He also underwent muscle reconditioning to facilitate standing and overground walking with a commercial FES system. Subsequently, the BCI and FES systems were integrated and the participant engaged in several real-time walking tests using the BCI-FES system. This was done in both a suspended, off-the-ground condition, and an overground walking condition. BCI states, gyroscope, laser distance meter, and video recording data were used to assess the BCI performance. RESULTS: During the course of 19 weeks, the participant performed 30 real-time, BCI-FES controlled overground walking tests, and demonstrated the ability to purposefully operate the BCI-FES system by following verbal cues. Based on the comparison between the ground truth and decoded BCI states, he achieved information transfer rates >3 bit/s and correlations >0.9. No adverse events directly related to the study were observed. CONCLUSION: This proof-of-concept study demonstrates for the first time that restoring brain-controlled overground walking after paraplegia due to SCI is feasible. Further studies are warranted to establish the generalizability of these results in a population of individuals with paraplegia due to SCI. If this noninvasive system is successfully tested in population studies, the pursuit of permanent, invasive BCI walking prostheses may be justified. In addition, a simplified version of the current system may be explored as a noninvasive neurorehabilitative therapy in those with incomplete motor SCI.


Assuntos
Interfaces Cérebro-Computador , Terapia por Estimulação Elétrica/instrumentação , Terapia por Estimulação Elétrica/métodos , Paraplegia/reabilitação , Traumatismos da Medula Espinal/reabilitação , Encéfalo/fisiopatologia , Eletroencefalografia/métodos , Estudos de Viabilidade , Humanos , Masculino , Paraplegia/etiologia , Próteses e Implantes , Traumatismos da Medula Espinal/complicações , Caminhada/fisiologia
4.
J Neuroeng Rehabil ; 12: 57, 2015 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-26162751

RESUMO

BACKGROUND: Many stroke survivors have significant long-term gait impairment, often involving foot drop. Current physiotherapies provide limited recovery. Orthoses substitute for ankle strength, but they provide no lasting therapeutic effect. Brain-computer interface (BCI)-controlled functional electrical stimulation (FES) is a novel rehabilitative approach that may generate permanent neurological improvements. This study explores the safety and feasibility of a foot-drop-targeted BCI-FES physiotherapy in chronic stroke survivors. METHODS: Subjects (n = 9) operated an electroencephalogram-based BCI-FES system for foot dorsiflexion in 12 one-hour sessions over four weeks. Gait speed, dorsiflexion active range of motion (AROM), six-minute walk distance (6MWD), and Fugl-Meyer leg motor (FM-LM) scores were assessed before, during, and after therapy. The primary safety outcome measure was the proportion of subjects that deteriorated in gait speed by ≥0.16 m/s at one week or four weeks post-therapy. The secondary outcome measures were the proportion of subjects that experienced a clinically relevant decrease in dorsiflexion AROM (≥2.5°), 6MWD (≥20 %), and FM-LM score (≥10 %) at either post-therapy assessment. RESULTS: No subjects (0/9) experienced a clinically significant deterioration in gait speed, dorsiflexion AROM, 6MWT distance, or FM-LM score at either post-therapy assessment. Five subjects demonstrated a detectable increase (≥0.06 m/s) in gait speed, three subjects demonstrated a detectable increase (≥2.5°) in dorsiflexion AROM, five subjects demonstrated a detectable increase (≥10 %) in 6MWD, and three subjects demonstrated a detectable increase (≥10 %) in FM-LM. Five of the six subjects that exhibited a detectable increase in either post-therapy gait speed or 6MWD also exhibited significant (p < 0.01 using a Mann-Whitney U test) increases in electroencephalogram event-related synchronization/desynchronization. Additionally, two subjects experienced a clinically important increase (≥0.16 m/s) in gait speed, and four subjects experienced a clinically important increase (≥20 %) in 6MWD. Linear mixed models of gait speed, dorsiflexion AROM, 6MWD, and FM-LM scores suggest that BCI-FES therapy is associated with an increase in lower motor performance at a statistically, yet not clinically, significant level. CONCLUSION: BCI-FES therapy is safe. If it is shown to improve post-stroke gait function in future studies, it could provide a new gait rehabilitation option for severely impaired patients. Formal clinical trials are warranted.


Assuntos
Interfaces Cérebro-Computador , Terapia por Estimulação Elétrica/métodos , Transtornos Neurológicos da Marcha/etiologia , Transtornos Neurológicos da Marcha/reabilitação , Modalidades de Fisioterapia/efeitos adversos , Modalidades de Fisioterapia/instrumentação , Reabilitação do Acidente Vascular Cerebral , Acidente Vascular Cerebral/complicações , Adulto , Idoso , Idoso de 80 Anos ou mais , Doença Crônica , Terapia por Estimulação Elétrica/instrumentação , Eletroencefalografia , Estudos de Viabilidade , Feminino , Pé/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Segurança do Paciente , Amplitude de Movimento Articular , Reprodutibilidade dos Testes , Resultado do Tratamento , Caminhada
5.
Neuroimage ; 101: 695-703, 2014 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-25094020

RESUMO

Brain machine interfaces (BMIs) have the potential to provide intuitive control of neuroprostheses to restore grasp to patients with paralyzed or amputated upper limbs. For these neuroprostheses to function, the ability to accurately control grasp force is critical. Grasp force can be decoded from neuronal spikes in monkeys, and hand kinematics can be decoded using electrocorticogram (ECoG) signals recorded from the surface of the human motor cortex. We hypothesized that kinetic information about grasping could also be extracted from ECoG, and sought to decode continuously-graded grasp force. In this study, we decoded isometric pinch force with high accuracy from ECoG in 10 human subjects. The predicted signals explained from 22% to 88% (60 ± 6%, mean ± SE) of the variance in the actual force generated. We also decoded muscle activity in the finger flexors, with similar accuracy to force decoding. We found that high gamma band and time domain features of the ECoG signal were most informative about kinetics, similar to our previous findings with intracortical LFPs. In addition, we found that peak cortical representations of force applied by the index and little fingers were separated by only about 4mm. Thus, ECoG can be used to decode not only kinematics, but also kinetics of movement. This is an important step toward restoring intuitively-controlled grasp to impaired patients.


Assuntos
Mapeamento Encefálico/métodos , Eletroencefalografia/métodos , Contração Isométrica/fisiologia , Córtex Motor/fisiologia , Músculo Esquelético/fisiologia , Adulto , Eletrodos Implantados , Eletromiografia , Feminino , Ritmo Gama/fisiologia , Mãos/fisiologia , Humanos , Cinética , Masculino , Pessoa de Meia-Idade , Adulto Jovem
6.
J Neuroeng Rehabil ; 10: 77, 2013 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-23866985

RESUMO

BACKGROUND: Spinal cord injury (SCI) can leave the affected individuals with paraparesis or paraplegia, thus rendering them unable to ambulate. Since there are currently no restorative treatments for this population, novel approaches such as brain-controlled prostheses have been sought. Our recent studies show that a brain-computer interface (BCI) can be used to control ambulation within a virtual reality environment (VRE), suggesting that a BCI-controlled lower extremity prosthesis for ambulation may be feasible. However, the operability of our BCI has not yet been tested in a SCI population. METHODS: Five participants with paraplegia or tetraplegia due to SCI underwent a 10-min training session in which they alternated between kinesthetic motor imagery (KMI) of idling and walking while their electroencephalogram (EEG) were recorded. Participants then performed a goal-oriented online task, where they utilized KMI to control the linear ambulation of an avatar while making 10 sequential stops at designated points within the VRE. Multiple online trials were performed in a single day, and this procedure was repeated across 5 experimental days. RESULTS: Classification accuracy of idling and walking was estimated offline and ranged from 60.5% (p = 0.0176) to 92.3% (p = 1.36×10-20) across participants and days. Offline analysis revealed that the activation of mid-frontal areas mostly in the µ and low ß bands was the most consistent feature for differentiating between idling and walking KMI. In the online task, participants achieved an average performance of 7.4±2.3 successful stops in 273±51 sec. These performances were purposeful, i.e. significantly different from the random walk Monte Carlo simulations (p<0.01), and all but one participant achieved purposeful control within the first day of the experiments. Finally, all participants were able to maintain purposeful control throughout the study, and their online performances improved over time. CONCLUSIONS: The results of this study demonstrate that SCI participants can purposefully operate a self-paced BCI walking simulator to complete a goal-oriented ambulation task. The operation of the proposed BCI system requires short training, is intuitive, and robust against participant-to-participant and day-to-day neurophysiological variations. These findings indicate that BCI-controlled lower extremity prostheses for gait rehabilitation or restoration after SCI may be feasible in the future.


Assuntos
Interfaces Cérebro-Computador , Neurorretroalimentação/métodos , Traumatismos da Medula Espinal/reabilitação , Terapia de Exposição à Realidade Virtual/métodos , Caminhada/fisiologia , Adulto , Eletroencefalografia , Humanos , Imagens, Psicoterapia/métodos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
7.
J Neuroeng Rehabil ; 10: 111, 2013 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-24321081

RESUMO

BACKGROUND: Excessive reliance on wheelchairs in individuals with tetraplegia or paraplegia due to spinal cord injury (SCI) leads to many medical co-morbidities, such as cardiovascular disease, metabolic derangements, osteoporosis, and pressure ulcers. Treatment of these conditions contributes to the majority of SCI health care costs. Restoring able-body-like ambulation in this patient population can potentially reduce the incidence of these medical co-morbidities, in addition to increasing independence and quality of life. However, no biomedical solution exists that can reverse this loss of neurological function, and hence novel methods are needed. Brain-computer interface (BCI) controlled lower extremity prostheses may constitute one such novel approach. METHODS: One able-bodied subject and one subject with paraplegia due to SCI underwent electroencephalogram (EEG) recordings while engaged in alternating epochs of idling and walking kinesthetic motor imagery (KMI). These data were analyzed to generate an EEG prediction model for online BCI operation. A commercial robotic gait orthosis (RoGO) system (suspended over a treadmill) was interfaced with the BCI computer to allow for computerized control. The subjects were then tasked to perform five, 5-min-long online sessions where they ambulated using the BCI-RoGO system as prompted by computerized cues. The performance of this system was assessed with cross-correlation analysis, and omission and false alarm rates. RESULTS: The offline accuracy of the EEG prediction model averaged 86.30% across both subjects (chance: 50%). The cross-correlation between instructional cues and the BCI-RoGO walking epochs averaged across all subjects and all sessions was 0.812 ± 0.048 (p-value <10(-4)). Also, there were on average 0.8 false alarms per session and no omissions. CONCLUSION: These results provide preliminary evidence that restoring brain-controlled ambulation after SCI is feasible. Future work will test the function of this system in a population of subjects with SCI. If successful, this may justify the future development of BCI-controlled lower extremity prostheses for free overground walking for those with complete motor SCI. Finally, this system can also be applied to incomplete motor SCI, where it could lead to improved neurological outcomes beyond those of standard physiotherapy.


Assuntos
Braquetes , Interfaces Cérebro-Computador , Marcha/fisiologia , Robótica/métodos , Traumatismos da Medula Espinal/reabilitação , Adulto , Eletroencefalografia , Humanos , Imaginação , Masculino , Paraplegia/etiologia , Paraplegia/reabilitação , Traumatismos da Medula Espinal/complicações , Caminhada/fisiologia
8.
Curr Biol ; 18(17): 1320-6, 2008 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-18771918

RESUMO

Although the iconic mammoth of the Late Pleistocene, the woolly mammoth (Mammuthus primigenius), has traditionally been regarded as the end point of a single anagenetically evolving lineage, recent paleontological and molecular studies have shown that successive allopatric speciation events must have occurred within Pleistocene Mammuthus in Asia, with subsequent expansion and hybridization between nominal taxa [1, 2]. However, the role of North American mammoth populations in these events has not been adequately explored from an ancient-DNA standpoint. To undertake this task, we analyzed mtDNA from a large data set consisting of mammoth samples from across Holarctica (n = 160) and representing most of radiocarbon time. Our evidence shows that, during the terminal Pleistocene, haplotypes originating in and characteristic of New World populations replaced or succeeded those endemic to Asia and western Beringia. Also, during the Last Glacial Maximum, mammoth populations do not appear to have suffered an overall decline in diversity, despite differing responses on either side of the Bering land bridge. In summary, the "Out-of-America" hypothesis holds that the dispersal of North American woolly mammoths into other parts of Holarctica created major phylogeographic structuring within Mammuthus primigenius populations, shaping the last phase of their evolutionary history before their demise.


Assuntos
DNA Mitocondrial/química , Fósseis , Mamíferos/genética , Filogenia , Animais , Ásia , Biodiversidade , Extinção Biológica , Geografia , Haplótipos , América do Norte , Dinâmica Populacional
9.
J Neuroeng Rehabil ; 8: 49, 2011 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-21867567

RESUMO

BACKGROUND: Many neurological conditions, such as stroke, spinal cord injury, and traumatic brain injury, can cause chronic gait function impairment due to foot-drop. Current physiotherapy techniques provide only a limited degree of motor function recovery in these individuals, and therefore novel therapies are needed. Brain-computer interface (BCI) is a relatively novel technology with a potential to restore, substitute, or augment lost motor behaviors in patients with neurological injuries. Here, we describe the first successful integration of a noninvasive electroencephalogram (EEG)-based BCI with a noninvasive functional electrical stimulation (FES) system that enables the direct brain control of foot dorsiflexion in able-bodied individuals. METHODS: A noninvasive EEG-based BCI system was integrated with a noninvasive FES system for foot dorsiflexion. Subjects underwent computer-cued epochs of repetitive foot dorsiflexion and idling while their EEG signals were recorded and stored for offline analysis. The analysis generated a prediction model that allowed EEG data to be analyzed and classified in real time during online BCI operation. The real-time online performance of the integrated BCI-FES system was tested in a group of five able-bodied subjects who used repetitive foot dorsiflexion to elicit BCI-FES mediated dorsiflexion of the contralateral foot. RESULTS: Five able-bodied subjects performed 10 alternations of idling and repetitive foot dorsifiexion to trigger BCI-FES mediated dorsifiexion of the contralateral foot. The epochs of BCI-FES mediated foot dorsifiexion were highly correlated with the epochs of voluntary foot dorsifiexion (correlation coefficient ranged between 0.59 and 0.77) with latencies ranging from 1.4 sec to 3.1 sec. In addition, all subjects achieved a 100% BCI-FES response (no omissions), and one subject had a single false alarm. CONCLUSIONS: This study suggests that the integration of a noninvasive BCI with a lower-extremity FES system is feasible. With additional modifications, the proposed BCI-FES system may offer a novel and effective therapy in the neuro-rehabilitation of individuals with lower extremity paralysis due to neurological injuries.


Assuntos
Tornozelo/fisiologia , Encéfalo/fisiologia , Terapia por Estimulação Elétrica/métodos , Eletroencefalografia/métodos , Movimento/fisiologia , Interface Usuário-Computador , Adulto , Terapia por Estimulação Elétrica/instrumentação , Eletroencefalografia/instrumentação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Paralisia/reabilitação , Adulto Jovem
10.
Biomed Eng Educ ; 1(1): 201-208, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35178535

RESUMO

By early spring 2020, the COVID-19 pandemic caused mandatory campus closures of academic institutions nationwide, prompting the rapid transition to online instruction. While lectures and exams were more straightforwardly administered online using video-chatting software, many hands-on laboratory-based courses were forced to develop creative solutions. In response to online instructional requirements, instructors at the University of California Irvine developed an online electroencephalography (EEG) laboratory to simulate the laboratory experiment for students unable to perform the experiment on campus. The laboratory experiment was performed and video recorded by the instructional team under three different scenarios to provide students with multiple data sets acquired under various experimental conditions often enacted by students. Students were required to complete a pre-lab quiz, analyze the acquired EEG data offline, complete a post-lab quiz, and submit their laboratory report to communicate their findings prior to final exams. Student performances compared to prior student performances, and qualitative survey responses, were examined to assess the effectiveness of and response to the online laboratory format. Based on student feedback and lab report grades, the majority of students responded positively and demonstrated an understanding of the EEG experiment's learning outcomes. In summary, the online EEG laboratory enabled students to achieve the main learning objectives and become familiar with the laboratory experiment, indicating its success as an alternative laboratory experiment.

11.
J Healthc Inform Res ; 2(1-2): 1-24, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30035250

RESUMO

This systematic review classifies smartwatch-based healthcare applications in the literature according to their application and summarizes what has led to feasible systems. To this end, we conducted a systematic review of peer-reviewed smartwatch studies related to healthcare by searching PubMed, EBSCOHost, Springer, Elsevier, Pro-Quest, IEEE Xplore, and ACM Digital Library databases to find articles between 1998 and 2016. Inclusion criteria were: (1) a smartwatch was used, (2) the study was related to a healthcare application, (3) the study was a randomized controlled trial or pilot study, and (4) the study included human participant testing. Each article was evaluated in terms of its application, population type, setting, study size, study type, and features relevant to the smartwatch technology. After screening 1,119 articles, 27 articles were chosen that were directly related to healthcare. Classified applications included activity monitoring, chronic disease self-management, nursing or home-based care, and healthcare education. All studies were considered feasibility or usability studies, and had limited sample sizes. No randomized clinical trials were found. Also, most studies utilized Android-based smartwatches over Tizen, custom-built, or iOS- based smartwatches, and many relied on the use of the accelerometer and inertial sensors to elucidate physical activities. The results show that most research on smartwatches has been conducted only as feasibility studies for chronic disease self-management. Specifically, these applications targeted various disease conditions whose symptoms can easily be measured by inertial sensors, such as seizures or gait disturbances. In conclusion, although smartwatches show promise in healthcare, significant research on much larger populations is necessary to determine their acceptability and effectiveness in these applications.

12.
Artigo em Inglês | MEDLINE | ID: mdl-29457803

RESUMO

This paper introduces the design, calibration, and validation of a low-cost portable sensor for the real-time measurement of dust particles within the environment. The proposed design consists of low hardware cost and calibration based on temperature and humidity sensing to achieve accurate processing of airborne dust density. Using commercial particulate matter sensors, a highly accurate air quality monitoring sensor was designed and calibrated using real world variations in humidity and temperature for indoor and outdoor applications. Furthermore, to provide a low-cost secure solution for real-time data transfer and monitoring, an onboard Bluetooth module with AES data encryption protocol was implemented. The wireless sensor was tested against a Dylos DC1100 Pro Air Quality Monitor, as well as an Alphasense OPC-N2 optical air quality monitoring sensor for accuracy. The sensor was also tested for reliability by comparing the sensor to an exact copy of itself under indoor and outdoor conditions. It was found that accurate measurements under real-world humid and temperature varying and dynamically changing conditions were achievable using the proposed sensor when compared to the commercially available sensors. In addition to accurate and reliable sensing, this sensor was designed to be wearable and perform real-time data collection and transmission, making it easy to collect and analyze data for air quality monitoring and real-time feedback in remote health monitoring applications. Thus, the proposed device achieves high quality measurements at lower-cost solutions than commercially available wireless sensors for air quality.

13.
Artigo em Inglês | MEDLINE | ID: mdl-29445779

RESUMO

Pediatric asthma is a prevalent chronic disease condition that can benefit from wireless health systems through constant symptom management. In this paper, we propose a smart watch based wireless health system that incorporates wireless sensing and ecological momentary assessment (EMA) to determine an individual's asthma symptoms. Since asthma is a multifaceted disease, this approach provides individualized symptom assessments through various physiological and environmental wireless sensor based EMA triggers specific to common asthma exacerbations. Furthermore, the approach described here improves compliance to use of the system through insightful EMA scheduling related to sensor detected environmental and physiological changes, as well as the patient's own schedule. After testing under several real world conditions, it was found that the system is sensitive to both physiological and environmental conditions that would cause asthma symptoms. Furthermore, the EMA questionnaires that were triggered based on these changes were specific to the asthma trigger itself, allowing for invaluable context behind the data to be collected.

14.
Brain Struct Funct ; 222(8): 3705-3748, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28523425

RESUMO

The mechanism by which the human primary motor cortex (M1) encodes upper extremity movement kinematics is not fully understood. For example, human electrocorticogram (ECoG) signals have been shown to modulate with upper extremity movements; however, this relationship has not been explicitly characterized. To address this issue, we recorded high-density ECoG signals from patients undergoing epilepsy surgery evaluation as they performed elementary upper extremity movements while systematically varying movement speed and duration. Specifically, subjects performed intermittent pincer grasp/release, elbow flexion/extension, and shoulder flexion/extension at slow, moderate, and fast speeds. In all movements, bursts of power in the high-[Formula: see text] band (80-160 Hz) were observed in M1. In addition, the amplitude of these power bursts and the area of M1 with elevated high-[Formula: see text] activity were directly proportional to the movement speed. Likewise, the duration of elevated high-[Formula: see text] activity increased with movement duration. Based on linear regression, M1 high-[Formula: see text] power amplitude and duration covaried with movement speed and duration, respectively, with an average [Formula: see text] of [Formula: see text] and [Formula: see text]. These findings indicate that the encoding of upper extremity movement speed by M1 high-[Formula: see text] activity is primarily linear. Also, the fact that this activity remained elevated throughout a movement suggests that M1 does not merely generate transient instructions for a specific movement duration, but instead is responsible for the entirety of the movement. Finally, the spatial distribution of high-[Formula: see text] activity suggests the presence of a recruitment phenomenon in which higher speeds or increased muscle activity involve activation of larger M1 areas.


Assuntos
Ritmo Gama , Córtex Motor/fisiologia , Movimento , Extremidade Superior/fisiologia , Adulto , Eletrocorticografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Atividade Motora , Processamento de Sinais Assistido por Computador , Adulto Jovem
15.
Artigo em Inglês | MEDLINE | ID: mdl-29354688

RESUMO

Asthma is the most prevalent chronic disease among pediatrics, as it is the leading cause of student absenteeism and hospitalization for those under the age of 15. To address the significant need to manage this disease in children, the authors present a mobile health (mHealth) system that determines the risk of an asthma attack through physiological and environmental wireless sensors and representational state transfer application program interfaces (RESTful APIs). The data is sent from wireless sensors to a smartwatch application (app) via a Health Insurance Portability and Accountability Act (HIPAA) compliant cryptography framework, which then sends data to a cloud for real-time analytics. The asthma risk is then sent to the smartwatch and provided to the user via simple graphics for easy interpretation by children. After testing the safety and feasibility of the system in an adult with moderate asthma prior to testing in children, it was found that the analytics model is able to determine the overall asthma risk (high, medium, or low risk) with an accuracy of 80.10±14.13%. Furthermore, the features most important for assessing the risk of an asthma attack were multifaceted, highlighting the importance of continuously monitoring different wireless sensors and RESTful APIs. Future testing this asthma attack risk prediction system in pediatric asthma individuals may lead to an effective self-management asthma program.

16.
J Neural Eng ; 13(2): 026016, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26859341

RESUMO

OBJECTIVE: Electrocorticography (ECoG)-based brain-computer interface (BCI) is a promising platform for controlling arm prostheses. To restore functional independence, a BCI must be able to control arm prostheses along at least six degrees-of-freedoms (DOFs). Prior studies suggest that standard ECoG grids may be insufficient to decode multi-DOF arm movements. This study compared the ability of standard and high-density (HD) ECoG grids to decode the presence/absence of six elementary arm movements and the type of movement performed. APPROACH: Three subjects implanted with standard grids (4 mm diameter, 10 mm spacing) and three with HD grids (2 mm diameter, 4 mm spacing) had ECoG signals recorded while performing the following movements: (1) pincer grasp/release, (2) wrist flexion/extension, (3) pronation/supination, (4) elbow flexion/extension, (5) shoulder internal/external rotation, and (6) shoulder forward flexion/extension. Data from the primary motor cortex were used to train a state decoder to detect the presence/absence of movement, and a six-class decoder to distinguish between these movements. MAIN RESULTS: The average performances of the state decoders trained on HD ECoG data were superior (p = 3.05 × 10(-5)) to those of their standard grid counterparts across all combinations of the µ, ß, low-γ, and high-γ frequency bands. The average best decoding error for HD grids was 2.6%, compared to 8.5% of standard grids (chance 50%). The movement decoders trained on HD ECoG data were superior (p = 3.05 × 10(-5)) to those based on standard ECoG across all band combinations. The average best decoding errors of 11.9% and 33.1% were obtained for HD and standard grids, respectively (chance error 83.3%). These improvements can be attributed to higher electrode density and signal quality of HD grids. SIGNIFICANCE: Commonly used ECoG grids are inadequate for multi-DOF BCI arm prostheses. The performance gains by HD grids may eventually lead to independence-restoring BCI arm prosthesis.


Assuntos
Eletrocorticografia/métodos , Eletrocorticografia/normas , Eletrodos Implantados/normas , Córtex Motor/fisiologia , Adulto , Eletrocorticografia/instrumentação , Feminino , Humanos , Masculino , Adulto Jovem
17.
Ann Biomed Eng ; 42(10): 2095-105, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25012465

RESUMO

Stroke survivors are typically affected by hand motor impairment. Despite intensive rehabilitation and spontaneous recovery, improvements typically plateau a year after a stroke. Therefore, novel approaches capable of restoring or augmenting lost motor behaviors are needed. Brain-computer interfaces (BCIs) may offer one such approach by using neurophysiological activity underlying hand movements to control an upper extremity orthosis. To test the performance of such a system, we developed an electroencephalogram-based BCI controlled electrically actuated hand orthosis. Six able-bodied participants voluntarily grasped/relaxed one hand to elicit BCI-mediated closing/opening of the orthosis mounted on the opposite hand. Following a short training/calibration procedure, participants demonstrated real-time, online control of the orthosis by following computer cues. Their performances resulted in an average of 1.15 (standard deviation: 0.85) false alarms and 0.22 (0.36) omissions per minute. Analysis of signals from electrogoniometers mounted on both hands revealed an average correlation between voluntary and BCI-mediated movements of 0.58 (0.13), with all but one online performance being statistically significant. This suggests that a BCI driven hand orthosis is feasible, and therefore should be tested in stroke individuals with hand weakness. If proven viable, this technology may provide a novel approach to the neuro-rehabilitation of hand function after stroke.


Assuntos
Interfaces Cérebro-Computador , Mãos/fisiologia , Aparelhos Ortopédicos , Adulto , Calibragem , Eletrodos , Eletroencefalografia/instrumentação , Feminino , Humanos , Masculino , Adulto Jovem
18.
Artigo em Inglês | MEDLINE | ID: mdl-25570189

RESUMO

The current treatment for ambulation after spinal cord injury (SCI) is to substitute the lost behavior with a wheelchair; however, this can result in many co-morbidities. Thus, novel solutions for the restoration of walking, such as brain-computer interfaces (BCI) and functional electrical stimulation (FES) devices, have been sought. This study reports on the first electroencephalogram (EEG) based BCI-FES system for overground walking, and its performance assessment in an individual with paraplegia due to SCI. The results revealed that the participant was able to purposefully operate the system continuously in real time. If tested in a larger population of SCI individuals, this system may pave the way for the restoration of overground walking after SCI.


Assuntos
Interfaces Cérebro-Computador , Estimulação Elétrica , Traumatismos da Medula Espinal/fisiopatologia , Caminhada/fisiologia , Adulto , Eletroencefalografia , Humanos , Masculino , Paraplegia
19.
Artigo em Inglês | MEDLINE | ID: mdl-25570191

RESUMO

Despite the prevalence of stroke-induced gait impairment due to foot drop, current rehabilitative practices to improve gait function are limited, and orthoses can be uncomfortable and do not provide long-lasting benefits. Therefore, novel modalities that may facilitate lasting neurological and functional improvements, such as brain-computer interfaces (BCIs), have been explored. In this article, we assess the feasibility of BCI-controlled functional electrical stimulation (FES) as a novel physiotherapy for post-stroke foot drop. Three chronic stroke survivors with foot drop received three, 1-hour sessions of therapy during 1 week. All subjects were able to purposefully operate the BCI-FES system in real time. Furthermore, the salient electroencephalographic (EEG) features used for classification by the data-driven methodology were determined to be physiologically relevant. Over the course of this short therapy, the subjects' dorsiflexion active range of motion (AROM) improved by 3°, 4°, and 8°, respectively. These results indicate that chronic stroke survivors can operate the BCI-FES system, and that BCI-FES intervention may promote functional improvements.


Assuntos
Interfaces Cérebro-Computador , Encéfalo/fisiologia , Estimulação Elétrica , Perna (Membro)/fisiologia , Acidente Vascular Cerebral/fisiopatologia , Análise Discriminante , Eletroencefalografia , Marcha/fisiologia , Humanos , Modalidades de Fisioterapia , Amplitude de Movimento Articular , Razão Sinal-Ruído
20.
Artigo em Inglês | MEDLINE | ID: mdl-25570190

RESUMO

Electrocorticogram (ECoG) is a promising long-term signal acquisition platform for brain-computer interface (BCI) systems such as upper extremity prostheses. Several studies have demonstrated decoding of arm and finger trajectories from ECoG high-gamma band (80-160 Hz) signals. In this study, we systematically vary the velocity of three elementary movement types (pincer grasp, elbow and shoulder flexion/extension) to test whether the high-gamma band encodes for the entirety of the movements, or merely the movement onset. To this end, linear regression models were created for the durations and amplitudes of high-gamma power bursts and velocity deflections. One subject with 8×8 high-density ECoG grid (4 mm center-to-center electrode spacing) participated in the experiment. The results of the regression models indicated that the power burst durations varied directly with the movement durations (e.g. R(2)=0.71 and slope=1.0 s/s for elbow). The persistence of power bursts for the duration of the movement suggests that the primary motor cortex (M1) is likely active for the entire duration of a movement, instead of providing a marker for the movement onset. On the other hand, the amplitudes were less co-varied. Furthermore, the electrodes of maximum R(2) conformed to somatotopic arrangement of the brain. Also, electrodes responsible for flexion and extension movements could be resolved on the high-density grid. In summary, these findings suggest that M1 may be directly responsible for activating the individual muscle motor units, and future BCI may be able to utilize them for better control of prostheses.


Assuntos
Interfaces Cérebro-Computador , Eletroencefalografia , Movimento/fisiologia , Adulto , Cotovelo/fisiologia , Eletrocorticografia , Eletrodos Implantados , Força da Mão/fisiologia , Humanos , Modelos Lineares , Masculino , Córtex Motor/fisiologia , Ombro/fisiologia
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