Characterization and classification of kinesthetic motor imagery levels.

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.

Biomechanical and functional effects of shoulder kinesio taping® on cerebral palsy children interacting with virtual objects.

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.

Characterization of NF1 frameshift mutations in pediatric patients with neurofibromatosis type I.

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.

BIK/NBK gene as potential marker of prognostic and therapeutic target in breast cancer patients

PURPOSE: The purpose of this study is to determine the association between the BIK/NBK gene expression and estrogen receptor alpha expression. MATERIALS AND METHODS: We determined the association of BIK/NBK gene expression by real time quantitative reverse transcription polymerase chain reaction and estrogen receptor alpha expression by immunohistochemistry in samples of breast cancer tissue. RESULTS: We found a statistically significant correlation of BIK/NBK gene expression with the estrogen receptor alpha expression (ρ = 0.751, p = 0.004). For verify differences of BIK/NBK gene expression among ERα+ and ERα- breast cancer tissues, Mann-Whitney U test was performed, obtaining significant differences. CONCLUSIONS: BIK/NBK gene expression may have important clinical implications and provide predictive, prognostic or therapeutic marker in breast cancer patients according to the estrogen receptor alpha expression (AU)

A High Performance Tactile Feedback Display and Its Integration in Teleoperation.

This paper presents the development of a compact tactile display and its integration in teleoperation. The system's operation is based on the display of surface shape to an area of the fingertip through a 4 × 4 array of tactors moving perpendicularly to the skin surface. The tactors are spring loaded and are actuated remotely by dc motors through a flexible tendon transmission. This novel implementation of conventional actuation principles achieves a compact design with superior performance compared to devices of a similar footprint, demonstrating an excellent combination of tactor spatiotemporal resolution, force, and amplitude. The display's ergonomic design and high performance make it suitable for integration on haptic devices for tactile feedback in VR and in Teleoperation. This paper presents the design, control, and performance of the tactile display and of the transmission system. It also demonstrates its integration on an Omega7 force feedback device for the teleoperation of an LWR KUKA manipulator. An experiment is presented where users teleoperated the stylus of the robot in a 3D contour following task with and without tactile feedback. In this experiment, force feedback from the slave is fused with model-based local tactile feedback. Subjects' performances indicate an improvement in teleoperation when both tactile and force feedback are present.

[The congenital long QT syndrome and its management with a permanent pacemaker]. / Síndrome de QT largo congénito y su manejo con marcapaso permanente.

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.

[Changes in variability of heart rate and sudden death detected during ambulatory electrocardiography]. / Alteraciones de la variabilidad de la frecuencia cardiaca y muerte súbita detectada durante electrocardiografía ambulatoria.

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.

[Total electrical alternans and changes in auricular repolarization in a newborn infant]. / Alternancia eléctrica total y cambios en la repolarización auricular en un recién nacido.

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.

[Ablation of the atrioventricular node using radiofrequency in a cirrhosis patient]. / Ablación del nodo aurículo-ventricular por radiofrecuencia en una paciente con cirrosis.

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.

[Mitral subvalvular aneurysm of probable chagasic etiology]. / Aneurisma subvalvular mitral de probable etiología chagásica.

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.

[Permanent pacemakers in children. The indications, complications and long-term follow-up]. / Marcapasos permanentes en niños. Indicaciones, complicaciones y seguimiento a largo plazo.

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.

[Idiopathic ventricular tachycardia]. / Taquicardia ventricular idiopática.

Idiopathic is a nonspecific term applied to cases of ventricular tachycardia occurring in patients without overt heart disease or obvious precipitating circumstances. This arrhythmia should always be considered a diagnosis of exclusion. Periodic re-evaluation of patients with idiopathic arrhythmias should be performed to be certain that abnormalities do not develop.

[Permanent auricular paralysis. Report of 2 cases with different response to auricular stimulation]. / Parálisis auricular permanente. Informe de dos casos con diferente respuesta a la estimulación auricular.

Two well documented cases of permanent atrial standstill are reported. Both fulfilled the diagnostic criteria of absence of electrical and mechanical atrial activity. The importance of response to electrical stimuli and escape rhythm is discussed within the context of a severe, irreversible and evolutive disease.

[2-directional ventricular tachycardia associated with mitral valve prolapse]. / Taquicardia ventricular bidireccional asociada a prolapso valvular mitral.

We describe the case of a 11 year old male who developed a bidirectional tachycardia associated to mitral valve prolapse as the only evident anatomical anomaly. Simultaneous recordings of surface ECG readings and intracavitary tracings showed left ventricular origin of such tachycardia. In the present study we confirm the site of origin of the arrhythmia and the association between bidirectional tachycardia and mitral valve prolapse.

[Sudden death caused by 2-directional tachycardia in an adolescent]. / Muerte súbita por taquicardia bidireccional en un adolescente.

The history of a 12 year old male, who developed a bidirectional tachycardia and sudden death without evidence of neurological or cardiac disease is described. The role of bidirectional tachycardia related to sudden death is discussed, as well as its possible origin and mechanisms, based on the case described.

[Sudden cardiac death recorded during ambulatory electrocardiography]. / Muerte cardíaca súbita registrada durante electrocardiografía ambulatoria.

Two patients who had sudden unexpected death while being monitored by a Holter electrocardiograph apparatus are reported. The first patient with heart disease of unknown etiology initially developed first degree A-V block, progressive left bundle branch block and finally asystole. The second patient with previous coronary artery disease and recent myocardial infarction revealed multifocal ventricular extrasystoles with frequent bigeminism and trigeminism which ended in ventricular tachycardia and fibrillation. Emphasis is made on the necessity of detecting those high risk patients and establishing preventive post-hospitalization care to modify the evolution and prognosis in this group of patients.

[Helicoidal ventricular tachycardia caused by amitriptyline. Presentation of a case]. / Taquicardia ventricular helicoidal inducida por amitriptilina. Presentacion de un caso.

We present a case of a psychiatric patient treated with Amitriptyline who developed Stokes-Adams attacks with EKG manifestations of prolonged Q-T and "torsade de pointes".