RESUMO
Objective.Kinesthetic Motor Imagery (KMI) represents a robust brain paradigm intended for electroencephalography (EEG)-based commands in brain-computer interfaces (BCIs). However, ensuring high accuracy in multi-command execution remains challenging, with data from C3 and C4 electrodes reaching up to 92% accuracy. This paper aims to characterize and classify EEG-based KMI of multilevel muscle contraction without relying on primary motor cortex signals.Approach.A new method based on Hurst exponents is introduced to characterize EEG signals of multilevel KMI of muscle contraction from electrodes placed on the premotor, dorsolateral prefrontal, and inferior parietal cortices. EEG signals were recorded during a hand-grip task at four levels of muscle contraction (0%, 10%, 40%, and 70% of the maximal isometric voluntary contraction). The task was executed under two conditions: first, physically, to train subjects in achieving muscle contraction at each level, followed by mental imagery under the KMI paradigm for each contraction level. EMG signals were recorded in both conditions to correlate muscle contraction execution, whether correct or null accurately. Independent component analysis (ICA) maps EEG signals from the sensor to the source space for preprocessing. For characterization, three algorithms based on Hurst exponents were used: the original (HO), using partitions (HRS), and applying semivariogram (HV). Finally, seven classifiers were used: Bayes network (BN), naive Bayes (NB), support vector machine (SVM), random forest (RF), random tree (RT), multilayer perceptron (MP), and k-nearest neighbors (kNN).Main results.A combination of the three Hurst characterization algorithms produced the highest average accuracy of 96.42% from kNN, followed by MP (92.85%), SVM (92.85%), NB (91.07%), RF (91.07%), BN (91.07%), and RT (80.35%). of 96.42% for kNN.Significance.Results show the feasibility of KMI multilevel muscle contraction detection and, thus, the viability of non-binary EEG-based BCI applications without using signals from the motor cortex.
Assuntos
Interfaces Cérebro-Computador , Eletroencefalografia , Imaginação , Cinestesia , Humanos , Eletroencefalografia/métodos , Imaginação/fisiologia , Masculino , Adulto , Feminino , Cinestesia/fisiologia , Adulto Jovem , Contração Muscular/fisiologia , Córtex Motor/fisiologia , Eletromiografia/métodos , Algoritmos , Movimento/fisiologia , Reprodutibilidade dos Testes , Máquina de Vetores de SuporteRESUMO
The reaching of objects is usually practiced by CP children in conventional or Virtual Reality-based therapies to enhance motor skill performance. Recently, Kinesio Taping® method has been studied to increase mechanical stability and improve functional movement of the upper limb; however, its influence on CP children´s upper limb motion has been rarely quantified due to lack of sensory measurement. Therefore, in this paper, we evaluate the biomechanical and functional effects of applying shoulder Kinesio Taping® on CP children in the reaching-transporting of virtual objects, by using a low-cost tracking device, exact robust differentiation of data and a simple nonlinear biomechanical dynamic model of the trunk and arm.
Assuntos
Fita Atlética , Paralisia Cerebral/fisiopatologia , Ombro/fisiopatologia , Realidade Virtual , Adolescente , Fenômenos Biomecânicos , Criança , Feminino , Humanos , Masculino , Movimento , Amplitude de Movimento Articular , Processamento de Sinais Assistido por Computador , Extremidade Superior/fisiopatologiaRESUMO
Neurofibromatosis type I is an autosomal dominant disease with complete penetrance and variable age-dependent expressivity. It is caused by heterozygous mutations in neurofibromin 1 (NF1). These occur throughout the length of the gene, with no apparent hotspots. Even though some mutations have been found repeatedly, most have been observed only once. This, along with the variable expressivity, has made it difficult to establish genotype-phenotype correlations. Here, we report the clinical and molecular characteristics of four pediatric patients with neurofibromatosis type I. Patients were clinically examined and DNA was extracted from peripheral blood. The whole coding sequence of NF1, plus flanking intronic regions, was examined by Sanger sequencing, and four frameshift mutations were identified. The mutation c.3810_3820delCATGCAGACTC was observed in a familial case. This mutation occurred within a sequence comprising two 8-bp direct repeats (GCAGACTC) separated by a CAT trinucleotide, with the deletion leading to the loss of the trinucleotide and the 8-bp repeat following it. The deletion might have occurred due to misalignment of the direct repeats during cell division. In the mutation c.5194delG, the deleted G is nested between two separate mononucleotide tracts (AAAGTTT), which could have played a role in creating the deletion. The other two mutations reported here are c.4076_4077insG, and c.3193_3194insA. All four mutations create premature stop codons. In three mutations, the consequence is predicted to be loss of the GAP-related, Sec14 homology, and pleckstrin homology-like domains; while in the fourth, only the latter two domains would be lost.
Assuntos
Mutação da Fase de Leitura/genética , Neurofibromatose 1/genética , Neurofibromina 1/genética , Criança , Pré-Escolar , Análise Mutacional de DNA , Feminino , Humanos , Íntrons , Masculino , Neurofibromatose 1/fisiopatologia , Deleção de SequênciaRESUMO
Two patients with the congenital form of the long QT syndrome and polymorphous ventricular tachycardias unresponsive to adrenergic beta-blockade, were successfully treated with permanent pacemaker. We discuss the role of cardiac stimulation with pacemakers in the context of all the therapeutic modalities, taking into account the recent knowledge of chromosomal alterations and also in ionic channels.
Assuntos
Síndrome do QT Longo/congênito , Síndrome do QT Longo/terapia , Marca-Passo Artificial , Adulto , Criança , Eletrocardiografia , Feminino , Seguimentos , Humanos , Síndrome do QT Longo/diagnóstico , MasculinoRESUMO
Two patients with ischemic heart disease had sudden death detected by means of ambulatory electrocardiography; the first patient had ventricular tachycardia-asystole and the second bradycardia-asystole without mediating a ventricular tachyarrhythmia. In both cases the autonomic function of the heart was determined, by means of the heart rate variability for spectral analysis and for time domain analysis. An important decrease in heart rate variability in the patient with tachyarrhythmia was appreciated, more pronounced in the hour previous to his death. On the other hand, in the patient with bradycardia-asystole there was increased heart rate variability. This suggests different neural influences in both patients for the development of sudden death: an alteration in the autonomic function of the heart in the patient with ventricular tachyarrhythmias, related to a depressed parasympathetic tone. In the patient with bradycardia-asystole, the parasympathetic tone was accentuated.
Assuntos
Morte Súbita , Eletrocardiografia Ambulatorial , Frequência Cardíaca , Adulto , Idoso , Idoso de 80 Anos ou mais , Humanos , MasculinoRESUMO
A premature 3 days-old female with AV block Möbitz type II and structurally normal heart is presented. Progressive atrial abnormal repolarization was observed. Besides, transient total electrical alternans that included P wave, QRS complex, ST segment and T wave was evident. Retrospective analysis on ECG findings showed multiple metabolic and electrolytic disturbances related with this phenomenon. Hypoxia, hypothermia and long QT interval around an immature heart are particularly discussed as triggering factors.
Assuntos
Doenças em Gêmeos , Eletrocardiografia , Bloqueio Cardíaco/fisiopatologia , Bradicardia/fisiopatologia , Feminino , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Potenciais da Membrana/fisiologiaRESUMO
The ablation of cardiac arrhythmias by radiofrequency has changed radically the treatment of arrhythmias. We present the case of a woman with cirrhosis and no structural heart disease, who was severely limited in her activities because of drug-refractory paroxysmal supraventricular tachyarrhythmias. She underwent an atrio-ventricular node ablation by radiofrequency. She was discharged with no antiarrhythmic drugs and on a permanent cardiac pacing. She showed obvious improvement in her quality of life.
Assuntos
Nó Atrioventricular/cirurgia , Ablação por Cateter , Cirrose Hepática/complicações , Taquicardia Paroxística/cirurgia , Taquicardia Supraventricular/cirurgia , Bloqueio de Ramo/complicações , Estimulação Cardíaca Artificial , Eletrocardiografia , Feminino , Bloqueio Cardíaco/complicações , Hepatite C/complicações , Humanos , Pessoa de Meia-IdadeRESUMO
The case report is a woman 45 years old from a rural zone of the Federal District (Mexico City) with subvalvular mitral aneurysm of probable chagasic origin. Its main clinic manifestation was caused by the presence of recurrent ventricular arrhythmias refractory to medical treatment. The diagnosis was made by means of the serology, echocardiography, cineangiography and endocardial biopsy. The treatment consisted in the surgical resection of the aneurysm with successful evolution.
Assuntos
Cardiomiopatia Chagásica/complicações , Aneurisma Cardíaco/etiologia , Valva Mitral , Biópsia , Cateterismo Cardíaco , Cardiomiopatia Chagásica/diagnóstico , Cardiomiopatia Chagásica/cirurgia , Ecocardiografia , Eletrocardiografia Ambulatorial , Endocárdio/patologia , Feminino , Aneurisma Cardíaco/diagnóstico , Aneurisma Cardíaco/cirurgia , Doenças das Valvas Cardíacas/diagnóstico , Doenças das Valvas Cardíacas/etiologia , Doenças das Valvas Cardíacas/cirurgia , Humanos , Pessoa de Meia-Idade , Valva Mitral/diagnóstico por imagem , Valva Mitral/cirurgiaRESUMO
Definitive pacemakers were placed in 27 children from June 1970 to October 1988. The indication for the pacemakers was congenital auriculoventricular block in 12 patients who were symptomatic; 8 were children with postoperative auriculoventricular block; 4 had developed complete auriculoventricular block from myocardiopathies and 3 from idiopathic sick-sinus syndrome. Two patients died: one 4 months after placement of the pacemaker due to unrelated causes, and the other 14 years later due to fracture of the electrode. There were 23 who were reoperated for different reasons but the most frequent was battery failure in 8 patients and pacemaker malfunction in 4 patients. The electrode was implanted in the epicardium in 21 patients and via subclavian vein into the endocardium in 6 cases. The growth and development physically and mentally were normal during the follow-up of these children. The average follow-up period was 55.6 months.