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1.
Neuroimage ; 240: 118407, 2021 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-34280527

RESUMO

Spontaneous transient states were recently identified by functional magnetic resonance imaging and magnetoencephalography in healthy subjects. They organize and coordinate neural activity in brain networks. How spontaneous transient states are altered in abnormal brain conditions is unknown. Here, we conducted a transient state analysis on resting-state electroencephalography (EEG) source space and developed a state transfer analysis to patients with disorders of consciousness (DOC). They uncovered different neural coordination patterns, including spatial power patterns, temporal dynamics, spectral shifts, and connectivity construction varies at potentially very fast (millisecond) time scales, in groups with different consciousness levels: healthy subjects, patients in minimally conscious state (MCS), and patients with vegetative state/unresponsive wakefulness syndrome (VS/UWS). Machine learning based on transient state features reveal high classification accuracy between MCS and VS/UWS. This study developed methodology of transient states analysis on EEG source space and abnormal brain conditions. Findings correlate spontaneous transient states with human consciousness and suggest potential roles of transient states in brain disease assessment.


Assuntos
Transtornos da Consciência/diagnóstico por imagem , Eletroencefalografia/métodos , Adulto , Comportamento , Conectoma , Estado de Consciência/fisiologia , Transtornos da Consciência/fisiopatologia , Eletroencefalografia/instrumentação , Feminino , Humanos , Intenção , Aprendizado de Máquina , Imageamento por Ressonância Magnética/métodos , Masculino , Cadeias de Markov , Pessoa de Meia-Idade , Modelos Neurológicos , Atividade Motora , Estado Vegetativo Persistente/diagnóstico por imagem , Estado Vegetativo Persistente/fisiopatologia , Sensação , Vigília/fisiologia , Adulto Jovem
2.
Epilepsia Open ; 6(2): 331-338, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34033243

RESUMO

OBJECTIVE: To determine whether the portable Ceribell® electroencephalograph (EEG) (Mountain View, CA) used for suspected status epilepticus (SE) can reduce time to diagnosis and on-call workforce demands and whether it can be applied to patients in respiratory isolation. METHODS: A multidisciplinary team developed a protocol for the use of the Ceribell EEG. The staff deploying the device, the attending physician, and the interpreting neurologist completed evaluation tools for each patient. Data maintained for quality and resource planning of 18-channel electroencephalography ordered for suspected SE were used as controls. Times to diagnosis were compared by application of Welch-Satterthwaite tests and workforce call-in demands by Fisher's exact t test. We evaluated qualitative data related to the use of the EEG in COVID-19 isolation rooms and on its technical aspects and acceptance by staff members. RESULTS: The Ceribell EEG reduced diagnosis time (P = .0000006) and on-call workforce demand (P = .02). The device can be used at any time of day in any hospital care area and has advantages in respiratory isolation rooms. SIGNIFICANCE: Compared with a standard 18-channel EEG, the Ceribell device allowed earlier diagnosis of SE and non-SE conditions and reduced workforce demands. Due to the ease of its use and its simple components, which can be readily disinfected, it is advantageous for COVID-19 patients in isolation.


Assuntos
COVID-19 , Eletroencefalografia , Serviços Médicos de Emergência , Controle de Infecções , Estado Epiléptico/diagnóstico , Tempo para o Tratamento/normas , Serviços de Atendimento/instrumentação , COVID-19/epidemiologia , COVID-19/prevenção & controle , COVID-19/terapia , Diagnóstico Precoce , Eletroencefalografia/instrumentação , Eletroencefalografia/métodos , Serviços Médicos de Emergência/métodos , Serviços Médicos de Emergência/organização & administração , Serviços Médicos de Emergência/normas , Pesquisa sobre Serviços de Saúde , Mão de Obra em Saúde , Hospitalização , Humanos , Controle de Infecções/métodos , Controle de Infecções/organização & administração , Estudo de Prova de Conceito , Melhoria de Qualidade , SARS-CoV-2 , Gestão da Segurança , Estado Epiléptico/terapia
3.
Sci Rep ; 10(1): 15406, 2020 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-32958791

RESUMO

Cochlear-implant (CI) users rely on temporal envelope modulations (TEMs) to understand speech, and clinical outcomes depend on the accuracy with which these TEMs are encoded by the electrically-stimulated neural ensembles. Non-invasive EEG measures of this encoding could help clinicians identify and disable electrodes that evoke poor neural responses so as to improve CI outcomes. However, recording EEG during CI stimulation reveals huge stimulation artifacts that are up to orders of magnitude larger than the neural response. Here we used a custom-built EEG system having an exceptionally high sample rate to accurately measure the artefact, which we then removed using linear interpolation so as to reveal the neural response during continuous electrical stimulation. In ten adult CI users, we measured the 40-Hz electrically evoked auditory steady-state response (eASSR) and electrically evoked auditory change complex (eACC) to amplitude-modulated 900-pulses-per-second pulse trains, stimulated in monopolar mode (i.e. the clinical default), and at different modulation depths. We successfully measured artifact-free 40-Hz eASSRs and eACCs. Moreover, we found that the 40-Hz eASSR, in contrast to the eACC, showed substantial responses even at shallow modulation depths. We argue that the 40-Hz eASSR is a clinically feasible objective measure to assess TEM encoding in CI users.


Assuntos
Limiar Auditivo/fisiologia , Surdez/fisiopatologia , Potenciais Evocados Auditivos/fisiologia , Artefatos , Implante Coclear/métodos , Implantes Cocleares , Estimulação Elétrica , Eletroencefalografia/instrumentação , Eletroencefalografia/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pessoas com Deficiência Auditiva/reabilitação , Percepção do Tempo
4.
Rev Sci Instrum ; 91(6): 064101, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32611067

RESUMO

This paper describes a novel method to measure the temporal latency of electroencephalography (EEG) systems using a customized photosensitive phantom. The system was evaluated with three different EEG devices, a medical grade (g.Tec), a consumer grade (Emotiv), and a low-cost device (Arduino SpikerShield). The temporal latencies of the three EEG devices were measured. The proposed method can be easily adapted to assess other EEG devices. The measurements obtained in this experiment provided concrete data for future experiments where accurate timing data are critical.


Assuntos
Eletroencefalografia/instrumentação , Desenho de Equipamento , Luz , Imagens de Fantasmas , Calibragem , Custos e Análise de Custo , Eletroencefalografia/economia , Fatores de Tempo
5.
J Pak Med Assoc ; 70(3): 526-530, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32207440

RESUMO

Advancements in the Neuro-rehabilitation across Pakistan is warranted to effectively and efficiently deal with the disease burden of neurological conditions. Being a developing country, an in-expensive treatment approach is required to culminate the rise in the disease occurrence in Pakistan. Brain-Computer Interfaces (BCIs) have come up as a new channel for communication and control, eliminating the need of physical input, opening doors to a wide array of applications in terms of assistive and rehabilitative devices for paralyzed patients and those with neuromuscular disorders. Even with a promising prospect, BCIs and electroencephalograms (EEG) can be very expensive and therefore, they are not practically applicable. For this reason, the purpose of the current study was to come up with a possibility of an inexpensive BCI for rehabilitation of patients with neuro-muscular disorders in Pakistan by using a low-cost and readily available equipment like Emotiv EPOC+ EEG headset and electrical muscle stimulator.


Assuntos
Interfaces Cérebro-Computador , Eletroencefalografia , Reabilitação Neurológica , Doenças Neuromusculares/reabilitação , Interfaces Cérebro-Computador/economia , Interfaces Cérebro-Computador/provisão & distribuição , Equipamentos e Provisões Elétricas , Eletroencefalografia/instrumentação , Eletroencefalografia/métodos , Desenho de Equipamento , Humanos , Reabilitação Neurológica/instrumentação , Reabilitação Neurológica/métodos , Doenças Neuromusculares/diagnóstico , Doenças Neuromusculares/fisiopatologia
6.
IEEE J Biomed Health Inform ; 24(3): 735-746, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31180902

RESUMO

Wearable electroencephalogram (EEG) solutions allow portability and real-time measurements in uncontrolled conditions. For reliable and reproducible interpretation of the EEG data, it is essential to accurately identify EEG segments contaminated by artefacts. Two data quality indicator approaches are proposed: pragmatic and regression based. The former extracts statistical features and applies data-driven thresholding, while the latter uses a regression model on the same set of statistical features to predict data quality. The performance of the approaches is validated against EEG data recorded during uncontrolled laboratory and free-living conditions, and compared to a validated approach. The proposed approaches achieve average accuracy of over [Formula: see text] in detecting artefactual data, which is higher than the FORCe signal quality estimation method ([Formula: see text]). The main strength of the proposed algorithms is in the significant increase of specificity over the state-of-the-art. The two models perform equally across different databases. Training of the two approaches on free-living conditions data showed better generalization when tested on different types of databases, i.e., uncontrolled laboratory and free-living. Although the accuracy in determining artefact-contaminated data is highest when using a window size of 8 s, the accuracy drop is minor when using shorter window size, demonstrating another advantage over existing methods. Given low complexity of both pragmatic and regression approach, it facilitates a real-time implementation, which is demonstrated using a wearable EEG headset system available at IMEC.


Assuntos
Eletroencefalografia/métodos , Processamento de Sinais Assistido por Computador/instrumentação , Dispositivos Eletrônicos Vestíveis , Adulto , Algoritmos , Encéfalo/fisiologia , Bases de Dados Factuais , Eletroencefalografia/instrumentação , Desenho de Equipamento , Feminino , Humanos , Masculino , Análise de Regressão
7.
Eur J Sport Sci ; 20(6): 713-721, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31456506

RESUMO

Current sport-scientific studies mostly neglect the assessment of sleep architecture, although the distribution of different sleep stages is considered an essential component influencing an athlete's recovery and performance capabilities. A mobile, self-applied tool like the SOMNOwatch plus EEG might serve as an economical and time-friendly alternative to activity-based devices. However, self-application of SOMNOwatch plus EEG has not been validated against conventional polysomnography (PSG) yet. For evaluation purposes, 25 participants (15 female, 10 male; M age = 22.92 ± 2.03 years) slept in a sleep laboratory on two consecutive nights wearing both, conventional PSG and SOMNOwatch plus EEG electrodes. Sleep parameters and sleep stages were compared using paired t-tests and Bland-Altman plots. No significant differences were found between the recordings for Sleep Onset Latency, stages N1 to N3 as well as Rapid Eye Movement stage. Significant differences (Bias [95%-confidence interval]) were present between Total Sleep Time (9.95 min [-29.18, 49.08], d = 0.14), Total Wake Time (-13.12 min [-47.25, 23.85], d = -0.28), Wake after Sleep Onset (-11.70 min [-47.25, 23.85], d = -0.34) and Sleep Efficiency (2.18% [-7.98, 12.34], d = 0.02) with small effect sizes. Overall, SOMNOwatch plus EEG can be considered a valid and practical self-applied method for the examination of sleep. In sport-scientific research, it is a promising tool to assess sleep architecture in athletes; nonetheless, it cannot replace in-lab PSG for all clinical or scientific purposes.


Assuntos
Atletas , Eletroencefalografia/instrumentação , Polissonografia/instrumentação , Fases do Sono/fisiologia , Dispositivos Eletrônicos Vestíveis , Adulto , Intervalos de Confiança , Eletrodos , Feminino , Humanos , Masculino , Latência do Sono/fisiologia , Sono REM/fisiologia , Fatores de Tempo , Adulto Jovem
8.
J Neurosci Nurs ; 51(6): 308-312, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31688282

RESUMO

INTRODUCTION: Limited access to specialized technicians and trained neurologists results in delayed access to electroencephalography (EEG) and an accurate diagnosis of patients with critical neurological problems. This study evaluated the performance of Ceribell Rapid Response EEG System (RR-EEG), which promises fast EEG acquisition and interpretation without traditional technicians or EEG-trained specialists. METHODS: The new technology was tested in a community hospital intensive care unit in Northern California. Three physicians (without previous training in EEG) were trained by the manufacturer of the RR-EEG and acquired EEG without the help of any EEG technicians. Time needed from order to EEG acquisition was noted. Quality of EEG and diagnostic information obtained with the new EEG technology were evaluated and compared with the same information from conventional clinical EEG system. RESULTS: Ten patients were tested with this new EEG technology, and 6 of these patients went on to have conventional EEGs when the EEG technicians arrived at the site. In these cases, the conventional EEG was significantly delayed (11.2 ± 3.6 hours) compared with RR-EEG (5.0 ± 2.4 minutes; P < .005). Use of RR-EEG helped clinicians rule out status epilepticus and prevent overtreatment in 4 of 10 cases. RR-EEG and conventional EEG systems yielded similar diagnostic information. CONCLUSION: RR-EEG can be set up by nurses, and diagnostic information about the presence or absence of seizures can be appreciated by nurses. The RR-EEG system, compared with the conventional EEG, did not require EEG technologists and enabled significantly faster access to diagnostic EEG information. This report confirms the ease of use and speed of acquisition and interpretation of EEG information at a community hospital setting using an RR-EEG device. This new technology has the potential to improve emergent clinical decision making and prevent overtreatment of patients in the intensive care unit setting while empowering nursing staff with useful diagnostic information in real time and at the bedside.


Assuntos
Cuidados Críticos , Eletroencefalografia/instrumentação , Hospitais Comunitários , Invenções , Convulsões/diagnóstico , California , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Tempo
9.
Clin Neurophysiol ; 130(11): 2076-2087, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31541985

RESUMO

OBJECTIVES: The HOME project is intended to provide evidence of diagnostic and therapeutic yield of a patient-controlled EEG home-monitoring for neurological outpatients. METHODS: This study evaluated the technical and practical usability and efficacy of a new portable dry-electrode EEG recorder in comparison to conventional EEG devices based on technical assessments and inter-rater comparisons of EEG record examinations of office-based practitioners and two experienced neurologists. RESULTS: The technical assessment was based on channel-wise comparisons of band power values derived from power spectra as observed in two recording modalities. Slight yet significant differences were observed only in the Delta-frequency band (1.5-4 Hz). The fraction of automatically detected artifact segments was larger in the new portable recordings than in conventional recordings (20% vs. 11%, median). Overall, 93% of raters' stated diagnostic findings gathered from conventional devices were concordant with stated diagnostic findings gathered from the new portable device. CONCLUSION: The new EEG device was shown to have technical comparability to and a high concordance rate of diagnostic findings with conventional EEG devices. SIGNIFICANCE: The new portable dry-electrode EEG device is suitable to meet the HOME projects' goal of establishing a patient-controlled EEG home-monitoring in the routine care of neurological outpatients. TRIAL REGISTRATION: DRKS DRKS00012685. Registered 09 August 2017, retrospectively registered.


Assuntos
Encéfalo/fisiopatologia , Eletroencefalografia/instrumentação , Doenças do Sistema Nervoso/fisiopatologia , Autogestão , Eletroencefalografia/métodos , Humanos , Monitorização Fisiológica
10.
JMIR Mhealth Uhealth ; 7(9): e14474, 2019 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-31482852

RESUMO

BACKGROUND: Registration of brain activity has become increasingly popular and offers a way to identify the mental state of the user, prevent inappropriate workload, and control other devices by means of brain-computer interfaces. However, electroencephalography (EEG) is often related to user acceptance issues regarding the measuring technique. Meanwhile, emerging mobile EEG technology offers the possibility of gel-free signal acquisition and wireless signal transmission. Nonetheless, user experience research about the new devices is lacking. OBJECTIVE: This study aimed to evaluate user experience aspects of emerging mobile EEG devices and, in particular, to investigate wearing comfort and issues related to emotional design. METHODS: We considered 7 mobile EEG devices and compared them for their wearing comfort, type of electrodes, visual appearance, and subjects' preference for daily use. A total of 24 subjects participated in our study and tested every device independently of the others. The devices were selected in a randomized order and worn on consecutive day sessions of 60-min duration. At the end of each session, subjects rated the devices by means of questionnaires. RESULTS: Results indicated a highly significant change in maximal possible wearing duration among the EEG devices (χ26=40.2, n=24; P<.001). Regarding the visual perception of devices' headset design, results indicated a significant change in the subjects' ratings (χ26=78.7, n=24; P<.001). Results of the subjects' ratings regarding the practicability of the devices indicated highly significant differences among the EEG devices (χ26=83.2, n=24; P<.001). Ranking order and posthoc tests offered more insight and indicated that pin electrodes had the lowest wearing comfort, in particular, when coupled with a rigid, heavy headset. Finally, multiple linear regression for each device separately revealed that users were not willing to accept less comfort for a more attractive headset design. CONCLUSIONS: The study offers a differentiated look at emerging mobile and gel-free EEG technology and the relation between user experience aspects and device preference. Our research could be seen as a precondition for the development of usable applications with wearables and contributes to consumer health informatics and health-enabling technologies. Furthermore, our results provided guidance for the technological development direction of new EEG devices related to the aspects of emotional design.


Assuntos
Eletroencefalografia/normas , Pacientes/psicologia , Telemedicina/normas , Adulto , Idoso , Eletroencefalografia/instrumentação , Eletroencefalografia/estatística & dados numéricos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pacientes/estatística & dados numéricos , Avaliação da Tecnologia Biomédica/métodos , Telemedicina/instrumentação , Telemedicina/estatística & dados numéricos
11.
Sensors (Basel) ; 19(12)2019 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-31234599

RESUMO

The functional validity of the signal obtained with low-cost electroencephalography (EEG) devices is still under debate. Here, we have conducted an in-depth comparison of the EEG-recordings obtained with a medical-grade golden-cup electrodes ambulatory device, the SOMNOwatch + EEG-6, vs those obtained with a consumer-grade, single dry electrode low-cost device, the NeuroSky MindWave, one of the most affordable devices currently available. We recorded EEG signals at Fp1 using the two different devices simultaneously on 21 participants who underwent two experimental phases: a 12-minute resting state task (alternating two cycles of closed/open eyes periods), followed by 60-minute virtual-driving task. We evaluated the EEG recording quality by comparing the similarity between the temporal data series, their spectra, their signal-to-noise ratio, the reliability of EEG measurements (comparing the closed eyes periods), as well as their blink detection rate. We found substantial agreement between signals: whereas, qualitatively, the NeuroSky MindWave presented higher levels of noise and a biphasic shape of blinks, the similarity metric indicated that signals from both recording devices were significantly correlated. While the NeuroSky MindWave was less reliable, both devices had a similar blink detection rate. Overall, the NeuroSky MindWave is noise-limited, but provides stable recordings even through long periods of time. Furthermore, its data would be of adequate quality compared to that of conventional wet electrode EEG devices, except for a potential calibration error and spectral differences at low frequencies.


Assuntos
Encéfalo/fisiologia , Eletroencefalografia/instrumentação , Adulto , Eletrodos , Eletroencefalografia/economia , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes , Razão Sinal-Ruído , Adulto Jovem
12.
Sensors (Basel) ; 19(9)2019 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-31035399

RESUMO

Suffering from continuous stress can lead to serious psychological and even physical disorders. Objective stress assessment methods using noninvasive physiological responses such as heart rate variability (HRV) and electroencephalograms (EEG) have therefore been proposed for effective stress management. In this study, a novel wearable device that can measure electrocardiograms (ECG) and EEG simultaneously was designed to enable continuous stress monitoring in daily life. The developed system is easily worn by hanging from both ears, is lightweight (i.e., 42.5 g), and exhibits an excellent noise performance of 0.12 µVrms. Significant time and frequency features of HRV and EEG were found in two different stressors, namely the Stroop color word and mental arithmetic tests, using 14 young subjects. Stressor situations were classified using various HRV and EEG feature selections and a support vector machine technique. The five-fold cross-validation results obtained when using both EEG and HRV features showed the best performance with an accuracy of 87.5%, which demonstrated the requirement for simultaneous HRV and EEG measurements.


Assuntos
Eletrocardiografia/métodos , Eletroencefalografia/métodos , Estresse Psicológico , Dispositivos Eletrônicos Vestíveis , Adulto , Área Sob a Curva , Eletrocardiografia/instrumentação , Eletroencefalografia/instrumentação , Frequência Cardíaca , Humanos , Masculino , Curva ROC , Máquina de Vetores de Suporte
13.
Annu Int Conf IEEE Eng Med Biol Soc ; 2019: 3131-3134, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31946551

RESUMO

The study of conformity from a neurobiological point of view has interested many authors: among them, Shestakova and colleagues (2013) have showed how conformity can be assessed through the analysis of event related potentials (ERPs). More specifically, the P300 component of the ERP was shown to be sensitive to the behavioral adjustment that an individual makes when not agreeing with the majority of a group. Starting from these contributions, in the present study, the famous experiment of Solomon Asch [1] was replicated online. The experiment was conducted on a sample of university students, using an innovative and low-cost tool capable of recording the brain signal (a wireless headset equipped with fourteen electrodes, called Emotiv EPOC). The present research aims to demonstrate how cheap and little sensitive tools enable the detection of ERP components that characterize social conformity in an ecological context.


Assuntos
Interfaces Cérebro-Computador , Eletroencefalografia , Eletroencefalografia/instrumentação , Potenciais Evocados P300 , Potenciais Evocados , Humanos , Conformidade Social
14.
IEEE Trans Biomed Eng ; 66(4): 900-909, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30080140

RESUMO

This paper presents an open source framework called Creamino. It consists of an Arduino-based cost-effective quick-setup EEG platform built with off-the-shelf components and a set of software modules that easily allow users to connect this system to Simulink or BCI-oriented tools (such as BCI2000 or OpenViBE) and set up a wide number of neuroscientific experiments. Creamino is capable of processing multiple EEG channels in real-time and operates under Windows, Linux, and Mac OS X in real-time on a standard PC. Its objective is to provide a system that can be readily fabricated and used for neurophysiological experiments and, at the same time, can serve as the basis for development of novel BCI platforms by accessing and modifying its open source hardware and software libraries. Schematics, gerber files, bill of materials, source code, software modules, demonstration videos, and instructions on how to use these modules are available free of charge for research and educational purposes online at https://github.com/ArcesUnibo/creamino. Application cases show how the system can be used for neuroscientific or BCI experiments. Thanks to its low production cost and its compatibility with open-source BCI tools, the system presented is particularly suitable for use in BCI research and educational applications.


Assuntos
Interfaces Cérebro-Computador , Eletroencefalografia , Processamento de Sinais Assistido por Computador , Software , Adulto , Eletroencefalografia/economia , Eletroencefalografia/instrumentação , Eletroencefalografia/métodos , Desenho de Equipamento , Humanos , Masculino , Adulto Jovem
15.
Sensors (Basel) ; 18(10)2018 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-30314263

RESUMO

Electroencephalogram (EEG) neurofeedback improves cognitive capacity and behaviors by regulating brain activity, which can lead to cognitive enhancement in healthy people and better rehabilitation in patients. The increased use of EEG neurofeedback highlights the urgent need to reduce the discomfort and preparation time and increase the stability and simplicity of the system's operation. Based on brain-computer interface technology and a multithreading design, we describe a neurofeedback system with an integrated design that incorporates wearable, multichannel, dry electrode EEG acquisition equipment and cognitive function assessment. Then, we evaluated the effectiveness of the system in a single-blind control experiment in healthy people, who increased the alpha frequency band power in a neurofeedback protocol. We found that upregulation of the alpha power density improved working memory following short-term training (only five training sessions in a week), while the attention network regulation may be related to other frequency band activities, such as theta and beta. Our integrated system will be an effective neurofeedback training and cognitive function assessment system for personal and clinical use.


Assuntos
Cognição/fisiologia , Eletroencefalografia/métodos , Neurorretroalimentação/instrumentação , Atenção/fisiologia , Ondas Encefálicas/fisiologia , Eletrodos , Eletroencefalografia/instrumentação , Desenho de Equipamento , Feminino , Voluntários Saudáveis , Humanos , Masculino , Memória de Curto Prazo , Neurorretroalimentação/métodos , Método Simples-Cego , Adulto Jovem
16.
J Neural Eng ; 15(6): 066019, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30215605

RESUMO

OBJECTIVE: Understanding the coordinated activity underlying brain computations requires large-scale, simultaneous recordings from distributed neuronal structures at a cellular-level resolution. One major hurdle to design high-bandwidth, high-precision, large-scale neural interfaces lies in the formidable data streams (tens to hundreds of Gbps) that are generated by the recorder chip and need to be online transferred to a remote computer. The data rates can require hundreds to thousands of I/O pads on the recorder chip and power consumption on the order of Watts for data streaming alone. One of the solutions is to reduce the bandwidth of neural signals before transmission. APPROACH: We developed a deep learning-based compression model to reduce the data rate of multichannel action potentials. The proposed compression model is built upon a deep compressive autoencoder (CAE) with discrete latent embeddings. The encoder network of CAE is equipped with residual transformations to extract representative features from spikes, which are mapped into the latent embedding space and updated via vector quantization (VQ). The indexes of VQ codebook are further entropy coded as the compressed signals. The decoder network reconstructs spike waveforms with high quality from the quantized latent embeddings through stacked deconvolution. MAIN RESULTS: Extensive experimental results on both synthetic and in vivo datasets show that the proposed model consistently outperforms conventional methods that utilize hand-crafted features and/or signal-agnostic transformations and compressive sensing by achieving much higher compression ratios (20-500×) and better or comparable reconstruction accuracies. Testing results also indicate that CAE is robust against a diverse range of imperfections, such as waveform variation and spike misalignment, and has minor influence on spike sorting accuracy. Furthermore, we have estimated the hardware cost and real-time performance of CAE and shown that it could support thousands of recording channels simultaneously without excessive power/heat dissipation. SIGNIFICANCE: The proposed model can reduce the required data transmission bandwidth in large-scale recording experiments and maintain good signal qualities, which will be helpful to design power-efficient and lightweight wireless neural interfaces. We have open sourced the code implementation of the work at https://github.com/tong-wu-umn/spike-compression-autoencoder.


Assuntos
Potenciais de Ação/fisiologia , Encéfalo/fisiologia , Eletroencefalografia/instrumentação , Eletroencefalografia/métodos , Algoritmos , Compressão de Dados , Bases de Dados Factuais , Eletroencefalografia/economia , Entropia , Humanos , Aprendizado de Máquina , Modelos Neurológicos , Redes Neurais de Computação , Processamento de Sinais Assistido por Computador , Análise de Ondaletas
17.
Psychophysiology ; 55(6): e13059, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29424021

RESUMO

A novel ERP approach was proposed to index variations in mental workload, particularly in attentional reserve, which is complementary to EEG spectral content thought to reflect mental effort. To our knowledge, no study has assessed mental effort and attentional reserve simultaneously in EEG gel-based and, importantly, dry systems, which are particularly well suited for real-world settings. Therefore, by systematically considering ERP, EEG spectral, and importantly the combination of both, this study examined if a small set of dry EEG electrodes could detect changes in both spectral and ERP metrics to assess the mental workload under various challenges with a similar fidelity to their gel-based counterparts in a laboratory setting. By employing both EEG gel-based and dry systems, the ERP and spectral markers were computed while participants executed a visuomotor task under three levels of challenge. For both EEG systems, more challenging levels of difficulty were associated with concomitant changes in ERP amplitude, and spectral power reflected a reduction of the attentional reserve and an increase in cognitive-motor effort, respectively. Those variations in attentional reserve and cognitive-motor effort collectively indexed mental workload with nearly identical fidelity for both gel-based and dry EEG systems. These findings promise to assess the mental workload in situations where the use of dry EEG systems could be advantageously employed to examine human cognitive-motor performance.


Assuntos
Atenção/fisiologia , Córtex Cerebral/fisiologia , Eletroencefalografia/métodos , Potenciais Evocados/fisiologia , Desempenho Psicomotor/fisiologia , Adulto , Eletroencefalografia/instrumentação , Feminino , Humanos , Masculino , Adulto Jovem
18.
Anesth Analg ; 126(1): 111-117, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28786839

RESUMO

Commercial brain function monitors for depth of anesthesia have been available for more than 2 decades; there are currently more than 10 devices on the market. Advances in this field are evidenced by updated versions of existing monitors, development of new monitors, and increasing research unveiling the mechanisms of anesthesia on the brain. Electroencephalography signal processing forms an integral part of the technology supporting the brain function monitors for derivation of a depth-of-anesthesia index. This article aims to provide a better understanding of the technology and functionality behind these monitors. This review will highlight the general design principles of these devices and the crucial stages in electroencephalography signal processing and classification, with a focus on the key mathematical techniques used in algorithm development for final derivation of the index representing anesthetic state. We will briefly discuss the advantages and limitations of this technology in the clinical setting as a tool in our repertoire used for optimizing individualized patient care. Also included is a table describing 10 available commercial depth-of-anesthesia monitors.


Assuntos
Anestesia/métodos , Monitores de Consciência , Eletroencefalografia/métodos , Monitorização Intraoperatória/métodos , Eletroencefalografia/instrumentação , Potenciais Evocados Auditivos/fisiologia , Humanos , Monitorização Intraoperatória/instrumentação , Processamento de Sinais Assistido por Computador/instrumentação
19.
Epilepsia ; 58(11): 1870-1879, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28980315

RESUMO

OBJECTIVE: New devices are needed for monitoring seizures, especially those associated with sudden unexpected death in epilepsy (SUDEP). They must be unobtrusive and automated, and provide false alarm rates (FARs) bearable in everyday life. This study quantifies the performance of new multimodal wrist-worn convulsive seizure detectors. METHODS: Hand-annotated video-electroencephalographic seizure events were collected from 69 patients at six clinical sites. Three different wristbands were used to record electrodermal activity (EDA) and accelerometer (ACM) signals, obtaining 5,928 h of data, including 55 convulsive epileptic seizures (six focal tonic-clonic seizures and 49 focal to bilateral tonic-clonic seizures) from 22 patients. Recordings were analyzed offline to train and test two new machine learning classifiers and a published classifier based on EDA and ACM. Moreover, wristband data were analyzed to estimate seizure-motion duration and autonomic responses. RESULTS: The two novel classifiers consistently outperformed the previous detector. The most efficient (Classifier III) yielded sensitivity of 94.55%, and an FAR of 0.2 events/day. No nocturnal seizures were missed. Most patients had <1 false alarm every 4 days, with an FAR below their seizure frequency. When increasing the sensitivity to 100% (no missed seizures), the FAR is up to 13 times lower than with the previous detector. Furthermore, all detections occurred before the seizure ended, providing reasonable latency (median = 29.3 s, range = 14.8-151 s). Automatically estimated seizure durations were correlated with true durations, enabling reliable annotations. Finally, EDA measurements confirmed the presence of postictal autonomic dysfunction, exhibiting a significant rise in 73% of the convulsive seizures. SIGNIFICANCE: The proposed multimodal wrist-worn convulsive seizure detectors provide seizure counts that are more accurate than previous automated detectors and typical patient self-reports, while maintaining a tolerable FAR for ambulatory monitoring. Furthermore, the multimodal system provides an objective description of motor behavior and autonomic dysfunction, aimed at enriching seizure characterization, with potential utility for SUDEP warning.


Assuntos
Eletroencefalografia/métodos , Monitorização Ambulatorial/métodos , Convulsões/diagnóstico , Convulsões/fisiopatologia , Adolescente , Adulto , Criança , Pré-Escolar , Eletroencefalografia/instrumentação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Monitorização Ambulatorial/instrumentação , Estudos Retrospectivos , Punho , Adulto Jovem
20.
Am J Physiol Heart Circ Physiol ; 313(6): H1190-H1198, 2017 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-28939646

RESUMO

With the sudden increase in affordable manufacturing technologies, the relationship between experimentalists and the designing process for laboratory equipment is rapidly changing. While experimentalists are still dependent on engineers and manufacturers for precision electrical, mechanical, and optical equipment, it has become a realistic option for in house manufacturing of other laboratory equipment with less precise design requirements. This is possible due to decreasing costs and increasing functionality of desktop three-dimensional (3-D) printers and 3-D design software. With traditional manufacturing methods, iterative design processes are expensive and time consuming, and making more than one copy of a custom piece of equipment is prohibitive. Here, we provide an overview to design a tissue bath and stabilizer for a customizable, suspended, whole heart optical mapping apparatus that can be produced significantly faster and less expensive than conventional manufacturing techniques. This was accomplished through a series of design steps to prevent fluid leakage in the areas where the optical imaging glass was attached to the 3-D printed bath. A combination of an acetone dip along with adhesive was found to create a water tight bath. Optical mapping was used to quantify cardiac conduction velocity and action potential duration to compare 3-D printed baths to a bath that was designed and manufactured in a machine shop. Importantly, the manufacturing method did not significantly affect conduction, action potential duration, or contraction, suggesting that 3-D printed baths are equally effective for optical mapping experiments.NEW & NOTEWORTHY This article details three-dimensional printable equipment for use in suspended whole heart optical mapping experiments. This equipment is less expensive than conventional manufactured equipment as well as easily customizable to the experimentalist. The baths can be waterproofed using only a three-dimensional printer, acetone, a glass microscope slide, c-clamps, and adhesive.


Assuntos
Potenciais de Ação , Coração/fisiologia , Preparação de Coração Isolado/instrumentação , Poliésteres/química , Impressão Tridimensional , Imagens com Corantes Sensíveis à Voltagem/instrumentação , Animais , Estimulação Cardíaca Artificial , Desenho Assistido por Computador , Análise Custo-Benefício , Eletroencefalografia/instrumentação , Desenho de Equipamento , Cobaias , Preparação de Coração Isolado/economia , Masculino , Teste de Materiais , Marca-Passo Artificial , Impressão Tridimensional/economia , Reprodutibilidade dos Testes , Fatores de Tempo , Imagens com Corantes Sensíveis à Voltagem/economia
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