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1.
Neural Netw ; 118: 262-270, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31326660

RESUMO

Multi-channel EEG data are usually necessary for spatial pattern identification in motor imagery (MI)-based brain computer interfaces (BCIs). To some extent, signals from some channels containing redundant information and noise may degrade BCI performance. We assume that the channels related to MI should contain common information when participants are executing the MI tasks. Based on this hypothesis, a correlation-based channel selection (CCS) method is proposed to select the channels that contained more correlated information in this study. The aim is to improve the classification performance of MI-based BCIs. Furthermore, a novel regularized common spatial pattern (RCSP) method is used to extract effective features. Finally, a support vector machine (SVM) classifier with the Radial Basis Function (RBF) kernel is trained to accurately identify the MI tasks. An experimental study is implemented on three public EEG datasets (BCI competition IV dataset 1, BCI competition III dataset IVa and BCI competition III dataset IIIa) to validate the effectiveness of the proposed methods. The results show that the CCS algorithm obtained superior classification accuracy (78% versus 56.4% for dataset1, 86.6% versus 76.5% for dataset 2 and 91.3% versus 85.1% for dataset 3) compared to the algorithm using all channels (AC), when CSP is used to extract the features. Furthermore, RCSP could further improve the classification accuracy (81.6% for dataset1, 87.4% for dataset2 and 91.9% for dataset 3), when CCS is used to select the channels.


Assuntos
Interfaces Cérebro-Computador , Eletroencefalografia/métodos , Máquina de Vetores de Suporte , Eletroencefalografia/normas , Humanos
2.
Brain Lang ; 191: 9-16, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30731324

RESUMO

The left anterior negativity (LAN) is an ERP component that has been often associated with morphosyntactic processing, but recent reports have questioned whether the LAN effect, in fact, exists. The present project examined whether the LAN effect, observed in the grand average response to local agreement violations, is the result of the overlap between two different ERP effects (N400, P600) at the level of subjects (n = 80), items (n = 120), or trials (n = 6160). By-subject, by-item, and by-trial analyses of the ERP effect between 300 and 500 ms showed a LAN for 55% of the participants, 46% of the items, and 49% of the trials. Many examples of the biphasic LAN-P600 response were observed. Mixed-linear models showed that the LAN effect size was not reduced after accounting for subject variability. The present results suggest that there are cases where the grand average LAN effect represents the brain responses of individual participants, items, and trials.


Assuntos
Encéfalo/fisiologia , Eletroencefalografia/normas , Potenciais Evocados , Linguagem , Adulto , Artefatos , Variação Biológica Individual , Compreensão , Eletroencefalografia/métodos , Feminino , Humanos , Masculino
3.
Int J Neural Syst ; 29(2): 1850038, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30375254

RESUMO

Automatic identification of negative stress is an unresolved challenge that has received great attention in the last few years. Many studies have analyzed electroencephalographic (EEG) recordings to gain new insights about how the brain reacts to both short- and long-term stressful stimuli. Although most of them have only considered linear methods, the heterogeneity and complexity of the brain has recently motivated an increasing use of nonlinear metrics. Nonetheless, brain dynamics reflected in EEG recordings often exhibit a multiscale nature and no study dealing with this aspect has been developed yet. Hence, in this work two nonlinear indices for quantifying regularity and predictability of time series from several time scales are studied for the first time to discern between visually elicited emotional states of calmness and negative stress. The obtained results have revealed the maximum discriminant ability of 86.35% for the second time scale, thus suggesting that brain dynamics triggered by negative stress can be more clearly assessed after removal of some fast temporal oscillations. Moreover, both metrics have also been able to report complementary information for some brain areas.


Assuntos
Ondas Encefálicas/fisiologia , Córtex Cerebral/fisiopatologia , Eletroencefalografia/métodos , Emoções/fisiologia , Entropia , Reconhecimento Facial/fisiologia , Estresse Psicológico/fisiopatologia , Adulto , Eletroencefalografia/normas , Humanos , Sensibilidade e Especificidade , Percepção Social
4.
Curr Opin Anaesthesiol ; 32(1): 101-107, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30507680

RESUMO

PURPOSE OF REVIEW: To summarize recent recommendations on intraoperative electroencephalogram (EEG) neuromonitoring in the elderly aimed at the prevention of postoperative delirium and long-term neurocognitive decline. We discuss recent perioperative EEG investigations relating to aging and cognitive dysfunction, and their implications on intraoperative EEG neuromonitoring in elderly patients. RECENT FINDINGS: The incidence of postoperative delirium in elderly can be reduced by monitoring depth of anesthesia, using an index number (0-100) derived from processed frontal EEG readings. The recently published European Society of Anaesthesiology guideline on postoperative delirium in elderly now recommends guiding general anesthesia with such indices (Level A). However, intraoperative EEG signatures are heavily influenced by age, cognitive function, and choice of anesthetic agents. Detailed spectral EEG analysis and research on EEG-based functional connectivity provide new insights into the pathophysiology of neuronal excitability, which is seen in elderly patients with postoperative delirium. SUMMARY: Anesthesiologists should become acquainted with intraoperative EEG signatures and their relation to age, anesthetic agents, and the risk of postoperative cognitive complications. A working knowledge would allow an optimized and individualized provision of general anesthesia for the elderly.


Assuntos
Anestesia Geral/efeitos adversos , Disfunção Cognitiva/prevenção & controle , Delírio do Despertar/prevenção & controle , Monitorização Neurofisiológica Intraoperatória/métodos , Procedimentos Cirúrgicos Operatórios/efeitos adversos , Fatores Etários , Idoso , Envelhecimento/fisiologia , Anestésicos/efeitos adversos , Cognição/efeitos dos fármacos , Cognição/fisiologia , Disfunção Cognitiva/diagnóstico , Disfunção Cognitiva/epidemiologia , Disfunção Cognitiva/etiologia , Monitores de Consciência , Eletroencefalografia/métodos , Eletroencefalografia/normas , Delírio do Despertar/diagnóstico , Delírio do Despertar/epidemiologia , Delírio do Despertar/etiologia , Humanos , Incidência , Monitorização Neurofisiológica Intraoperatória/instrumentação , Monitorização Neurofisiológica Intraoperatória/normas , Guias de Prática Clínica como Assunto
5.
Seizure ; 64: 45-49, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30554130

RESUMO

PURPOSE: To evaluate the clinical utility of the ambulatory electroencephalogram (AEEG) in children. METHOD: Data from 199 consecutive referrals for a paediatric AEEG were reviewed retrospectively. Information was gathered on various aspects of the referral process, the characteristics of the children referred and the reasons for referral. Clinical utility was calculated as the percentage of cases in which the investigation provided useful information with respect to the question asked of the test. RESULTS: The AEEG was useful in 64.8% cases overall. In 51.4% of cases the reason for referral was to capture events, however the test was only useful in 42.6% of these. The most common reason for an unsuccessful investigation was failure to capture events (55.6%). Suspected encephalopathy with status epilepticus during sleep (ESES) was the indication in a substantial number of cases (38.6%), and the investigation was useful in most of these (97.5%). Technical issues were only responsible for 7 (9.7%) of unsuccessful studies. CONCLUSION: The paediatric AEEG was useful in two thirds of patients. Failure to capture events appears to be the most significant limiting factor. The AEEG is very useful in investigating suspected ESES.


Assuntos
Eletroencefalografia/normas , Epilepsia/diagnóstico , Monitorização Ambulatorial/normas , Sono/fisiologia , Estado Epiléptico/diagnóstico , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Estudos Retrospectivos , Adulto Jovem
6.
Epilepsy Behav ; 90: 191-196, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30578096

RESUMO

Questionnaires or symptom lists have proved effective for differentiating epileptic seizures (ES) from psychogenic nonepileptic seizures (PNES). However, monitoring the events, corroborated by medical history gathered by experts, remains the gold standard. We directly compared symptoms and characteristic of the events self-reported by patients/eyewitnesses (Questionnaire A/B) with the information contained in the clinical charts of 50 patients with undefined diagnosis undergoing long-term monitoring. Data extracted from medical records were reformatted to fit the questionnaires' templates (A1/B1) for comparison. Quantitatively, self-reported information was considerably greater and more complete. Calculating sensitivity (SE) and specificity (SP) of all variables in the group with confirmed diagnosis, we identified those above the preset thresholds with the potential to discriminate between ES and PNES. Eight predictive variables were common to both methods: head injury, physical/emotional abuse, chronic fatigue (A); talked out of seizures, eyes closed, apnea, and collapsing (B). Eleven predictive variables were specific to direct questioning: preictal headache, bright light, feeling overwhelmed, heart racing, tingling and numbness, postictal trouble speaking, physical pain, history of gastro-esophageal reflux disease (GERD), self-inflicted injuries (A); on/off shaking, and side-to-side head movements (B). Thirteen predictive variables were generated by chart review: sleep deprivation, strong emotions/anxiety, preictal headache (warning), nausea/vomiting, history of PNES, cholecystectomy, depression, medications for behavioral problems (A1), sudden start/sudden stop of shaking, both sides shaking, falling during the seizure, feeling confused and disoriented postictally (B1). CONCLUSION: Self-reporting and clinical scrutiny are complementary. Structured questionnaires increase the range of predictive variables and should be utilized routinely to facilitate clinicians' quest for the correct diagnosis.


Assuntos
Convulsões/diagnóstico , Convulsões/psicologia , Autorrelato/normas , Transtornos Somatoformes/diagnóstico , Transtornos Somatoformes/psicologia , Adulto , Diagnóstico Diferencial , Eletroencefalografia/métodos , Eletroencefalografia/normas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Convulsões/fisiopatologia , Transtornos Somatoformes/fisiopatologia , Inquéritos e Questionários/normas
7.
Clin Neurophysiol ; 130(1): 25-37, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30472579

RESUMO

OBJECTIVE: Automatic detection of epileptic seizures based on deep learning methods received much attention last year. However, the potential of deep neural networks in seizure detection has not been fully exploited in terms of the optimal design of the model architecture and the detection power of the time-series brain data. In this work, a deep neural network architecture is introduced to learn the temporal dependencies in Electroencephalogram (EEG) data for robust detection of epileptic seizures. METHODS: A deep Long Short-Term Memory (LSTM) network is first used to learn the high-level representations of different EEG patterns. Then, a Fully Connected (FC) layer is adopted to extract the most robust EEG features relevant to epileptic seizures. Finally, these features are supplied to a softmax layer to output predicted labels. RESULTS: The results on a benchmark clinical dataset reveal the prevalence of the proposed approach over the baseline techniques; achieving 100% classification accuracy, 100% sensitivity, and 100% specificity. Our approach is additionally shown to be robust in noisy and real-life conditions. It maintains high detection performance in the existence of common EEG artifacts (muscle activities and eye movement) as well as background noise. CONCLUSIONS: We demonstrate the clinical feasibility of our seizure detection approach achieving superior performance over the cutting-edge techniques in terms of seizure detection performance and robustness. SIGNIFICANCE: Our seizure detection approach can contribute to accurate and robust detection of epileptic seizures in ideal and real-life situations.


Assuntos
Aprendizado Profundo , Eletroencefalografia/métodos , Convulsões/diagnóstico , Convulsões/fisiopatologia , Processamento de Sinais Assistido por Computador , Aprendizado Profundo/normas , Eletroencefalografia/normas , Humanos
8.
Epilepsy Behav ; 90: 233-237, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30583857

RESUMO

PURPOSE: The frequent association between headache and epilepsy has been increasingly studied in recent years. Through this study, we attempted to study possible temporal associations between epileptic seizures and headaches. We also tried to describe clinical aspects of headache in our patients with epilepsy. PATIENTS AND METHODS: We included patients with epilepsy and patients without epilepsy who presented for a first neurologic episode suggestive of epileptic seizure or unusual headache. These patients were invited to answer a standardized questionnaire screening for headache characteristics. Patients with epilepsy were asked for further data about their epilepsy. Electroencephalogram (EEG) was performed in all patients. Brain Magnetic resonance imaging MRI was reserved for patients in whom we suspected a structural lesion. RESULTS: Overall, we included 47 patients with a mean age of about 39 ±â€¯15 years (19 to 68 years old) and a female predominance (Sex Ratio: SR = 1.47). Most frequently, our patients documented periictal headache (Peri-IH) (85.1%) including respectively ictal headache (IH: 31.9%); postictal headache (Post-IH: 21.3%), and preictal headache (Pre-IH: 4.3%). Less frequently, our patients noted interictal headache (Inter-IH: 31.9%). Interestingly, these subgroups exhibited different headache patterns with predominantly unclassified-type headache (U-TH) in patients with IH (72.7%), tension-type headache (T-TH) in patients with Post-IH (73.3%), and migraine-type headache (M-TH) in patients with Inter-IH (60%). CONCLUSIONS: Our results suggest that patients with epilepsy could exhibit different headache types. The clinical pattern of headache seemed to be linked to the time of seizure onset.


Assuntos
Cefaleia/diagnóstico por imagem , Cefaleia/fisiopatologia , Convulsões/diagnóstico por imagem , Convulsões/fisiopatologia , Autorrelato , Adulto , Idoso , Eletroencefalografia/métodos , Eletroencefalografia/normas , Feminino , Cefaleia/epidemiologia , Humanos , Imagem por Ressonância Magnética/métodos , Imagem por Ressonância Magnética/normas , Masculino , Pessoa de Meia-Idade , Convulsões/epidemiologia , Autorrelato/normas , Adulto Jovem
9.
Epilepsy Behav ; 89: 84-88, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30388666

RESUMO

OBJECTIVE: There is a high cost associated with recording quality video and electroencephalography (EEG) data in National Association of Epilepsy Center (NAEC) level IV epilepsy monitoring units (EMU). This study considers potential quality measures in EMUs for generalized tonic-clonic (GTC) seizures: types of safety signals, response time, and visibility of patient's limbs for semiology. These quality measures have been summarized across 12 EMUs to estimate response times to GTC seizures and the quality of video data that is captured during admissions. METHODS: Video electroencephalographies (vEEGs) from two prospective regulatory studies for the Brain Sentinel device were reviewed. A total of 232 subjects with a history of GTC seizures underwent routine clinical EMU stays. Fifty-four of the study subjects had 96 GTC seizures. The vEEG of events were reviewed for safety signal used, response time, and visibility of patient's limbs. RESULTS: The average response time from members of the hospital team was 22 s from electrographic generalization (minimum -37 s, maximum 111 s, two no response). For caregivers, average response was 11 s (minimum -15 s, maximum 33 s, 45 not present/no response). In 73% of events, the patient visibility was limited at seizure onset. In 55% of events with limited limb visibility, the visibility was improved (by removing sheets or improving camera angle) >30 s after start of the event. The primary safety signals were as follows: an alert from outside the patient room (54%), button press (23%), hospital team present at seizure start (14%), caregiver vocal alert (6%), and no response (2%). SIGNIFICANCE: The average response time of caregivers was twice as fast as the hospital team, underscoring the importance of having a person in the room during onset of a GTC seizure. Diagnostic yield could be improved with more timely removal of patient coverings. It was observed that when patients experienced a GTC seizure, 40% were fully or partially obscured for more than 30 s during the event, compromising the ability of epileptologists to evaluate semiology during seizure onset. Automated seizure alarms may help staff get to patients more quickly and improve diagnostic characterization.


Assuntos
Cuidadores/estatística & dados numéricos , Eletroencefalografia/normas , Epilepsia Tônico-Clônica/diagnóstico , Unidades Hospitalares/estatística & dados numéricos , Monitorização Fisiológica/estatística & dados numéricos , Segurança do Paciente/normas , Convulsões/diagnóstico , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Eletroencefalografia/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Monitorização Fisiológica/normas , Estudos Prospectivos , Fatores de Tempo , Gravação em Vídeo , Adulto Jovem
10.
Acta Neurochir (Wien) ; 160(12): 2489-2500, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30413938

RESUMO

BACKGROUND: Stereoelectroencephalography (SEEG) is an effective technique to help to locate and to delimit the epileptogenic area and/or to define relationships with functional cortical areas. We intend to describe the surgical technique and verify the accuracy, safety, and effectiveness of robot-assisted SEEG in a newly created SEEG program in a pediatric center. We focus on the technical difficulties encountered at the early stages of this program. METHODS: We prospectively collected SEEG indication, intraoperative events, accuracy calculated by fusion of postoperative CT with preoperative planning, complications, and usefulness of SEEG in terms of answering preimplantation hypothesis. RESULTS: Fourteen patients between the ages of 5 and 18 years old (mean 10 years) with drug-resistant epilepsy were operated on between April 2016 and April 2018. One hundred sixty-four electrodes were implanted in total. The median entry point localization error (EPLE) was 1.57 mm (1-2.25 mm) and the median target point localization error (TPLE) was 1.77 mm (1.2-2.6 mm). We recorded seven intraoperative technical issues. Two patients suffered complications: meningitis without demonstrated germ in one patient and a right frontal hematoma in the other. In all cases, the SEEG was useful for the therapeutic decision-making. CONCLUSION: SEEG has been useful for decision-making in all our pediatric patients. The robotic arm is an accurate tool for the insertion of the deep electrodes. Nevertheless, it is an invasive technique not risk-free and many problems can appear at the beginning of a robotic arm-assisted SEEG program that must be taken into account beforehand.


Assuntos
Epilepsia Resistente a Medicamentos/cirurgia , Eletroencefalografia/métodos , Complicações Pós-Operatórias/epidemiologia , Robótica/métodos , Técnicas Estereotáxicas/efeitos adversos , Adolescente , Criança , Pré-Escolar , Tomada de Decisão Clínica , Epilepsia Resistente a Medicamentos/diagnóstico , Eletrodos Implantados/efeitos adversos , Eletrodos Implantados/normas , Eletroencefalografia/efeitos adversos , Eletroencefalografia/instrumentação , Eletroencefalografia/normas , Feminino , Humanos , Masculino , Robótica/instrumentação , Robótica/normas , Técnicas Estereotáxicas/instrumentação , Técnicas Estereotáxicas/normas
11.
Dis Markers ; 2018: 5174815, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30405860

RESUMO

Alzheimer's disease (AD) is a neurodegenerative disorder that accounts for nearly 70% of the more than 46 million dementia cases estimated worldwide. Although there is no cure for AD, early diagnosis and an accurate characterization of the disease progression can improve the quality of life of AD patients and their caregivers. Currently, AD diagnosis is carried out using standardized mental status examinations, which are commonly assisted by expensive neuroimaging scans and invasive laboratory tests, thus rendering the diagnosis time consuming and costly. Notwithstanding, over the last decade, electroencephalography (EEG) has emerged as a noninvasive alternative technique for the study of AD, competing with more expensive neuroimaging tools, such as MRI and PET. This paper reports on the results of a systematic review on the utilization of resting-state EEG signals for AD diagnosis and progression assessment. Recent journal articles obtained from four major bibliographic databases were analyzed. A total of 112 journal articles published from January 2010 to February 2018 were meticulously reviewed, and relevant aspects of these papers were compared across articles to provide a general overview of the research on this noninvasive AD diagnosis technique. Finally, recommendations for future studies with resting-state EEG were presented to improve and facilitate the knowledge transfer among research groups.


Assuntos
Doença de Alzheimer/diagnóstico , Eletroencefalografia/métodos , Doença de Alzheimer/fisiopatologia , Encéfalo/fisiopatologia , Eletroencefalografia/normas , Humanos
12.
Stereotact Funct Neurosurg ; 96(5): 311-319, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30326475

RESUMO

BACKGROUND: Invasive electrode monitoring provides more precise localization of epileptogenic foci in patients with medically refractory epilepsy. The use of hybrid depth electrodes that include microwires for simultaneous single-neuron monitoring is becoming more widespread. OBJECTIVE: To determine the safety and utility of hybrid depth electrodes for intracranial monitoring of medically refractory epilepsy. METHODS: We reviewed the medical charts of 53 cases of medically refractory epilepsy operated on from 2006 to 2017, where both non-hybrid and hybrid microwire depth electrodes were used for intracranial monitoring. We assessed the localization accuracy and complications that arose to assess the relative safety and utility of hybrid depth electrodes compared with standard electrodes. RESULTS: A total of 555 electrodes were implanted in 52 patients. The overall per-electrode complication rate was 2.3%, with a per-case complication rate of 20.8%. There were no infections or deaths. Serious or hemorrhagic complications occurred in 2 patients (0.4% per-electrode risk). Complications did not correlate with the use of any particular electrode type, and hybrids were equally as reliable as standard electrodes in localizing seizure onset zones. CONCLUSIONS: Hybrid depth electrodes appear to be as safe and effective as standard depth electrodes for intracranial monitoring and provide unique opportunities to study the human brain at single-neuron resolution.


Assuntos
Epilepsia Resistente a Medicamentos/diagnóstico por imagem , Eletrodos Implantados , Monitorização Neurofisiológica Intraoperatória/métodos , Neurônios/fisiologia , Convulsões/diagnóstico por imagem , Adulto , Epilepsia Resistente a Medicamentos/fisiopatologia , Epilepsia Resistente a Medicamentos/cirurgia , Eletrodos Implantados/normas , Eletroencefalografia/métodos , Eletroencefalografia/normas , Feminino , Humanos , Monitorização Neurofisiológica Intraoperatória/normas , Masculino , Pessoa de Meia-Idade , Convulsões/fisiopatologia , Convulsões/cirurgia
13.
Clin Neurophysiol ; 129(11): 2403-2410, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30278389

RESUMO

OBJECTIVE: To evaluate the accuracy of automated EEG source imaging (ESI) in localizing epileptogenic zone. METHODS: Long-term EEG, recorded with the standard 25-electrode array of the IFCN, from 41 consecutive patients with focal epilepsy who underwent resective surgery, were analyzed blinded to the surgical outcome. The automated analysis comprised spike-detection, clustering and source imaging at the half-rising time and at the peak of each spike-cluster, using individual head-models with six tissue-layers and a distributed source model (sLORETA). The fully automated approach presented ESI of the cluster with the highest number of spikes, at the half-rising time. In addition, a physician involved in the presurgical evaluation of the patients, evaluated the automated ESI results (up to four clusters per patient) in clinical context and selected the dominant cluster and the analysis time-point (semi-automated approach). The reference standard was location of the resected area and outcome one year after operation. RESULTS: Accuracy was 61% (95% CI: 45-76%) for the fully automated approach and 78% (95% CI: 62-89%) for the semi-automated approach. CONCLUSION: Automated ESI has an accuracy similar to previously reported neuroimaging methods. SIGNIFICANCE: Automated ESI will contribute to increased utilization of source imaging in the presurgical evaluation of patients with epilepsy.


Assuntos
Automação/métodos , Eletroencefalografia/métodos , Epilepsia/diagnóstico , Adolescente , Adulto , Automação/normas , Criança , Eletroencefalografia/normas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Sensibilidade e Especificidade
15.
Int J Psychophysiol ; 134: 30-43, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30253197

RESUMO

In this study we present the test-retest reliability of pre-intervention EEG/ERP (electroencephalogram/event-related potentials) data across four recording intervals separated by a washout period (18-22 days). POz-recording-reference EEG/ERP (28 sites, average reference) were recorded from thirty-two healthy male participants. Participants were randomly allocated into different intervention sequences, each with four intervention regimens: 10 mg vortioxetine, 20 mg vortioxetine, 15 mg escitalopram and Placebo. We report classical EEG spectra: δ (1-4 Hz), θ (4-8 Hz), α (8-12 Hz), ß (12-30 Hz), γ1 (30-45 Hz) and γ2 (45-80 Hz) of resting state and vigilance-controlled, and of auditory steady state response, as well as ERP components N100, P200 and P300 in auditory oddball task and error related negativity (ERN) and error positivity (Pe) in hybrid flanker task. Reliability was quantified using intra-class correlation coefficient (ICC). We found that θ, α and ß of continuous EEG were highly reliable (ICCs ≥ 0.84). Evoked power of other tasks demonstrated larger variability and less reliability compared to the absolute power of continuous EEG. Furthermore, reliabilities of ERP measures were lower compared to those of the EEG spectra. We saw fair to excellent reliability of the amplitude of the components such as Pe (0.60-0.82) and P300 (0.55-0.80). Moreover, blood tests confirmed that there was no measurable drug carry-over from the previous intervention. The results support that EEG/ERP is reliable across four recording intervals, thus it can be used to assess the effect of different doses and types of drugs with CNS effects.


Assuntos
Citalopram/farmacologia , Eletroencefalografia/normas , Potenciais Evocados/fisiologia , Inibidores de Captação de Serotonina/farmacologia , Vortioxetina/farmacologia , Adulto , Ondas Encefálicas/efeitos dos fármacos , Ondas Encefálicas/fisiologia , Citalopram/administração & dosagem , Estudos Cross-Over , Método Duplo-Cego , Eletroencefalografia/efeitos dos fármacos , Potencial Evocado P300/efeitos dos fármacos , Potencial Evocado P300/fisiologia , Potenciais Evocados/efeitos dos fármacos , Potenciais Evocados Auditivos/efeitos dos fármacos , Potenciais Evocados Auditivos/fisiologia , Humanos , Masculino , Reprodutibilidade dos Testes , Inibidores de Captação de Serotonina/administração & dosagem , Fatores de Tempo , Vortioxetina/administração & dosagem , Adulto Jovem
16.
Crit Care Med ; 46(12): e1105-e1111, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30188384

RESUMO

OBJECTIVES: To compare the performance of critical care providers with that of electroencephalography experts in identifying seizures using quantitative electroencephalography display tools. DESIGN: Diagnostic accuracy comparison among healthcare provider groups. SETTING: Multispecialty quaternary children's hospital in Canada. SUBJECTS: ICU fellows, ICU nurses, neurophysiologists, and electroencephalography technologists. INTERVENTION: Two-hour standardized one-on-one training, followed by a supervised individual review of 27 continuous electroencephalography recordings with the task of identifying individual seizures on eight-channel amplitude-integrated electroencephalography and color density spectral array displays. MEASUREMENTS AND MAIN RESULTS: Each participant reviewed 27 continuous electroencephalograms comprising 487 hours of recording containing a total of 553 seizures. Performance for seizure identification was compared among groups using a nested model analysis with adjustment for interparticipant variability within groups and collinearity among recordings. Using amplitude-integrated electroencephalography, sensitivity for seizure identification was comparable among ICU fellows (83.8%), ICU nurses (73.1%), and neurophysiologists (81.5%) but lower among electroencephalographic technologists (66.7%) (p = 0.003). Using color density spectral array, sensitivity was comparable among ICU fellows (82.4%), ICU nurses (88.2%), neurophysiologists (83.3%), and electroencephalographic technologists (73.3%) (p = 0.09). Daily false-positive rates were also comparable among ICU fellows (2.8 for amplitude-integrated electroencephalography, 7.7 for color density spectral array), ICU nurses (4.2, 7.1), neurophysiologists (1.2, 1.5), and electroencephalographic technologists (0, 0) (p = 0.41 for amplitude-integrated electroencephalography; p = 0.13 for color density spectral array). However, performance varied greatly across individual electroencephalogram recordings. Professional background generally played a greater role in determining performance than individual skill or electroencephalogram recording characteristics. CONCLUSIONS: Following standardized training, critical care providers and electroencephalography experts displayed similar performance for identifying individual seizures using both amplitude-integrated electroencephalography and color density spectral array displays. Although these quantitative electroencephalographic trends show promise as a tool for bedside seizure screening by critical care providers, these findings require confirmation in a real-world ICU environment and in daily clinical use.


Assuntos
Cuidados Críticos/normas , Eletroencefalografia/normas , Pessoal de Saúde/normas , Convulsões/diagnóstico , Canadá , Competência Clínica , Erros de Diagnóstico , Pessoal de Saúde/classificação , Humanos , Capacitação em Serviço/normas , Sensibilidade e Especificidade
17.
Clin Neurophysiol ; 129(11): 2296-2305, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30240976

RESUMO

OBJECTIVE: We devise a data-driven framework to assess the level of consciousness in etiologically heterogeneous comatose patients using intrinsic dynamical changes of resting-state Electroencephalogram (EEG) signals. METHODS: EEG signals were collected from 54 comatose patients (GCS ⩽ 8) and 20 control patients (GCS > 8). We analyzed the EEG signals using a new technique, termed Intrinsic Network Reactivity Index (INRI), that aims to assess the overall lability of brain dynamics without the use of extrinsic stimulation. The proposed technique uses three sigma EEG events as a trigger for ensuing changes to the directional derivative of signals across the EEG montage. RESULTS: The INRI had a positive relationship with GCS and was significantly different between various levels of consciousness. In comparison, classical band-limited power analysis did not show any specific patterns correlated to GCS. CONCLUSIONS: These findings suggest that reaching low variance EEG activation patterns becomes progressively harder as the level of consciousness of patients deteriorate, and provide a quantitative index based on passive measurements that characterize this change. SIGNIFICANCE: Our results emphasize the role of intrinsic brain dynamics in assessing the level of consciousness in coma patients and the possibility of employing simple electrophysiological measures to recognize the severity of disorders of consciousness (DOC).


Assuntos
Coma/diagnóstico , Estado de Consciência , Eletroencefalografia/métodos , Adulto , Idoso , Algoritmos , Encéfalo/fisiopatologia , Coma/classificação , Eletroencefalografia/normas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Sensibilidade e Especificidade
18.
Psychophysiology ; 55(11): e13215, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30094856

RESUMO

Saccades constitute a major source of artifacts and confounds in brain imaging studies. Whereas some artifacts can be removed by omitting segments of data, saccadic artifacts cannot be typically eliminated by this method because of their high occurrence rate even during fixation (1-3 per second). Some saccadic artifacts can be alleviated by offline-correction algorithms, but these methods leave nonnegligible residuals and cannot mitigate the saccade-related visual activity. Here, we propose a novel yet simple approach for diminishing saccadic artifacts and confounds through experimental design. We suggest that specific tasks can lead to substantially less saccade occurrences around the time of stimulus presentation, starting from slightly before its onset and lasting for a few hundred milliseconds. In three experiments, we compared the frequency and size of saccades in a variety of tasks. Results of Experiment 1 showed that a foveal change-detection task reduced the number and sizes of saccades, relative to a parafoveal orientation-discrimination task. Experiment 2 replicated this finding with a parafoveal object recognition task. Experiment 3 showed that both foveal and parafoveal continuous change detection tasks induced fewer and smaller saccades than a discrete orientation-discrimination task. We conclude that adding a foveal or a parafoveal continuous task reduces saccades' number and size. This would lead to better artifact correction and enable the omission of contaminated data segments. This study may be the first step toward developing saccade-free experimental designs.


Assuntos
Artefatos , Eletroencefalografia/normas , Medições dos Movimentos Oculares/normas , Fóvea Central/fisiologia , Neuroimagem/normas , Projetos de Pesquisa/normas , Movimentos Sacádicos/fisiologia , Percepção Visual/fisiologia , Adulto , Feminino , Humanos , Masculino , Adulto Jovem
20.
Neuroimage Clin ; 20: 398-406, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30128278

RESUMO

Background: Electrode contact locations are important when planning tailored brain surgeries to identify pathological tissue targeted for resection and conversely avoid eloquent tissue. Current methods employ trained experts to use neuroimaging scans that are manually co-registered and localize contacts within ~2 mm. Yet, the state of the art is limited by either the expertise needed for each type of intracranial electrode or the inter-modality co-registration which increases error, reducing accuracy. Patients often have a variety of strips, grids and depths implanted; therefore, it is cumbersome and time-consuming to apply separate localization methods for each type of electrode, requiring expertise across different approaches. New method: To overcome these limitations, a computational method was developed by separately registering an implant magnetic resonance image (MRI) and implant computed tomography image (CT) to the pre-implant MRI, then calculating an iterative closest point transformation using the contact locations extracted from the signal voids as ground truth. Results: The implant MRI is robustly co-registered to the pre-implant MRI with a boundary-based registration algorithm. By extracting and utilizing 'signal voids' (the metal induced artifacts from the implant MRI) as electrode fiducials, the novel method is an all-in-one approach for all types of intracranial electrodes while eliminating inter-modality co-registration errors. Comparison with existing methods: The distance between each electrode centroid and the brain's surface was measured, for the proposed method as well as the state of the art method using two available software packages, SPM 12 and FSL 4.1. The method presented here achieves the smallest distances to the brain's surface for all strip and grid type electrodes, i.e. contacts designed to rest directly on the brain surface. Conclusion: We use one of the largest reported sample sizes in localization studies to validate this novel method for localizing different kinds of intracranial electrodes including grids, strips and depth electrodes.


Assuntos
Epilepsia Resistente a Medicamentos/diagnóstico por imagem , Eletrodos Implantados , Eletroencefalografia/métodos , Imagem por Ressonância Magnética/métodos , Tomografia Computadorizada por Raios X/métodos , Adolescente , Adulto , Epilepsia Resistente a Medicamentos/fisiopatologia , Eletrodos Implantados/normas , Eletroencefalografia/instrumentação , Eletroencefalografia/normas , Feminino , Humanos , Imagem por Ressonância Magnética/instrumentação , Imagem por Ressonância Magnética/normas , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/instrumentação , Tomografia Computadorizada por Raios X/normas , Adulto Jovem
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