Evaluation of the Tobii EyeX Eye tracking controller and Matlab toolkit for research.

The Tobii Eyex Controller is a new low-cost binocular eye tracker marketed for integration in gaming and consumer applications. The manufacturers claim that the system was conceived for natural eye gaze interaction, does not require continuous recalibration, and allows moderate head movements. The Controller is provided with a SDK to foster the development of new eye tracking applications. We review the characteristics of the device for its possible use in scientific research. We develop and evaluate an open source Matlab Toolkit that can be employed to interface with the EyeX device for gaze recording in behavioral experiments. The Toolkit provides calibration procedures tailored to both binocular and monocular experiments, as well as procedures to evaluate other eye tracking devices. The observed performance of the EyeX (i.e. accuracy < 0.6°, precision < 0.25°, latency < 50 ms and sampling frequency ≈55 Hz), is sufficient for some classes of research application. The device can be successfully employed to measure fixation parameters, saccadic, smooth pursuit and vergence eye movements. However, the relatively low sampling rate and moderate precision limit the suitability of the EyeX for monitoring micro-saccadic eye movements or for real-time gaze-contingent stimulus control. For these applications, research grade, high-cost eye tracking technology may still be necessary. Therefore, despite its limitations with respect to high-end devices, the EyeX has the potential to further the dissemination of eye tracking technology to a broad audience, and could be a valuable asset in consumer and gaming applications as well as a subset of basic and clinical research settings.

Adaptive and predictive control of a simulated robot arm.

In this work, a basic cerebellar neural layer and a machine learning engine are embedded in a recurrent loop which avoids dealing with the motor error or distal error problem. The presented approach learns the motor control based on available sensor error estimates (position, velocity, and acceleration) without explicitly knowing the motor errors. The paper focuses on how to decompose the input into different components in order to facilitate the learning process using an automatic incremental learning model (locally weighted projection regression (LWPR) algorithm). LWPR incrementally learns the forward model of the robot arm and provides the cerebellar module with optimal pre-processed signals. We present a recurrent adaptive control architecture in which an adaptive feedback (AF) controller guarantees a precise, compliant, and stable control during the manipulation of objects. Therefore, this approach efficiently integrates a bio-inspired module (cerebellar circuitry) with a machine learning component (LWPR). The cerebellar-LWPR synergy makes the robot adaptable to changing conditions. We evaluate how this scheme scales for robot-arms of a high number of degrees of freedom (DOFs) using a simulated model of a robot arm of the new generation of light weight robots (LWRs).

Bio-inspired adaptive feedback error learning architecture for motor control.

This study proposes an adaptive control architecture based on an accurate regression method called Locally Weighted Projection Regression (LWPR) and on a bio-inspired module, such as a cerebellar-like engine. This hybrid architecture takes full advantage of the machine learning module (LWPR kernel) to abstract an optimized representation of the sensorimotor space while the cerebellar component integrates this to generate corrective terms in the framework of a control task. Furthermore, we illustrate how the use of a simple adaptive error feedback term allows to use the proposed architecture even in the absence of an accurate analytic reference model. The presented approach achieves an accurate control with low gain corrective terms (for compliant control schemes). We evaluate the contribution of the different components of the proposed scheme comparing the obtained performance with alternative approaches. Then, we show that the presented architecture can be used for accurate manipulation of different objects when their physical properties are not directly known by the controller. We evaluate how the scheme scales for simulated plants of high Degrees of Freedom (7-DOFs).

Percutaneous PFO closure using the Premere device occluder: initial experience.

INTRODUCTION: Most data on percutaneous closure of patent foramen ovale (PFO) relate to devices not specifically designed for this pathology. OBJECTIVE: Our aim in this article is to share our initial experience with the Premere PFO closure system. METHODS: In our hospital 14 consecutive patients presenting cryptogenic stroke underwent percutaneous closure using this device. The device was successfully implanted in 11 of the 14 patients (78.5%). Implantation was impossible in three patients because of a significant atrial septal aneurysm (ASA) or a multiperforated septum. RESULTS: Mean clinical and echocardiographical follow-up was 7 +/- 7 months. A residual shunt was seen in only one patient (9%) three months after device implantation. During follow-up, no device-related complications were observed, such as device thrombosis or fistula. None of the patients presented other significant clinical events such as strokes or arrhythmia. CONCLUSION: According to our experience the Premere is a secure and reliable device for PFO closure, but patients must be selected carefully for implantation to exclude those presenting significant ASA.

Lower levels of in-stent late loss are not associated with the risk of stent thrombosis in patients receiving drug-eluting stents.

AIMS: The aim of this study was to evaluate whether there is any relationship between in-stent late loss (ISLL) and the risk of stent thrombosis (ST) in patients treated with drug eluting stents (DES). The benefit of DES in reducing binary angiographic restenosis and the need for new revascularisation procedures is due to a reduction on ISLL. It has been hypothesised, however, that neointimal hyperplasia could preclude ST, and thus a very low ISLL could increase the risk of ST. METHODS AND RESULTS: We selected 26 randomised clinical trials comparing bare metal stents and DES or different DES types, and including clinical and angiographic follow-up. In order to evaluate the association between risk of ST and ISLL, meta-regression analyses were conducted, weighting for the number of patients of each study. Twenty-six studies were included, retrieving 36 subgroups for analysis and 8,971 patients treated with DES. The incidence for ST and LST was 0.81% and 0.17%. Using meta-regression techniques, neither the risk of ST nor the risk of LST were found to be significantly associated with ISLL, accounting for -0.82 and -0.002 meta-regression estimates respectively (IC 95%: -1.92 to 0.28 for ST and -0.008 to 0.003 for LST). CONCLUSIONS: The risk of ST and LST after DES implantation is not related with ISLL values. A very low mean value of ISLL is nor associated with a higher risk of ST.

Revascularización coronaria en el paciente diabético / Coronary revascularization in diabetic patients

La enfermedad cardiovascular es la principal causa de morbilidad y mortalidad en los pacientes con diabetes mellitus. Se ha demostrado que los pacientes diabéticos presentan una mayor incidencia de enfermedad coronaria multivaso, con mayor frecuencia de lesiones complejas, pobres lechos distales y una progresión de la enfermedad más rápida que la población general no diabética. La revascularización coronaria percutánea (ICP) ha demostrado su utilidad en los pacientes diabéticos. Sin embargo, aunque los resultados angiográficos iniciales son buenos, hay una mayor incidencia de reestenosis, un riesgo más elevado de complicaciones y una menor supervivencia a largo plazo. Los stents farmacoactivos han reducido notablemente el riesgo de reestenosis y complicaciones tardías. En espera de los resultados de los estudios actualmente en marcha, en los pacientes diabéticos con enfermedad multivaso, la cirugía de derivación aortocoronaria sigue siendo el tratamiento de primera elección. Sin embargo, hay que destacar que, desde un punto de vista práctico, a la hora de indicar cirugía de derivación aortocoronaria o ICP deberemos basarnos en las características particulares del paciente (p. ej., comorbilidad asociada) y en la experiencia del propio centro, ya que hay notables diferencias en función de la experiencia del equipo quirúrgico y de cardiología intervencionista. Por último, es muy importante destacar que, en los pacientes diabéticos en los que se realiza revascularización coronaria, con independencia del método utilizado, es de trascendental importancia establecer un tratamiento médico enérgico que incluya modificaciones en el estilo de vida (tabaquismo, síndrome metabólico, etc.), antiagregación plaquetaria, tratamiento con estatinas en las dosis adecuadas (objetivo terapéutico con un valor de colesterol unido a lipoproteínas de baja densidad < 70 mg/dl), bloqueadores beta, inhibidores de la enzima de conversión de la angiotensina-inhibidores de los receptores de la angiotensina II, control glicérico-metabólico, etc., ya que en estos pacientes la progresión de la enfermedad es mucho más rápida que en la población no diabética y el riesgo de complicaciones, a pesar de la revascularización, sigue siendo elevado (AU)

Cardiovascular disease is the principle cause of morbidity and mortality in patients with diabetes mellitus. It has been observed that diabetic patients usually present with a higher incidence of coronary artery disease involving multiple vessels, complex lesions, poor distal vascular beds, and more rapid disease progression than does the general nondiabetic population. Percutaneous coronary revascularization has been shown to be useful in diabetic patients. However, although initial angiographic results are good, there is a high incidence of restenosis, a increased risk of complications, and a low long-term survival rate. Drugeluting stent have markedly reduced the risk of restenosis and late complications. While the results of ongoing studies are still awaited, bypass surgery remains the treatment of first choice in diabetic patients with multivessel disease. Nevertheless, it is important to remember that, from a practical point of view, the decision on when to carry out bypass surgery or percutaneous coronary intervention must be based on the individual patient’s characteristics (e.g., associated comorbid conditions) and on the experience of the center involved. The level of experience of surgical teams and interventional cardiologists varies widely. Finally, it should be emphasized that the administration of aggressive medical treatment is of paramount importance in diabetic patients who are undergoing coronary revascularization, irrespective of the technique used. Treatment should include lifestyle modification (e.g., for smoking and metabolic syndrome), and, for example, antiplatelet therapy, an adequate statin dose (with the aim of achieving a low-density lipoprotein cholesterol level < 70 mg/dL), beta-blockers, angiotensinconverting enzyme inhibitors, and angiotensin II receptor antagonists because disease progression is much more rapid in these patients than in the nondiabetic population and the risk of complications remains elevated, despite revascularization (AU)

Nutricion enteral temprana en el paciente gastrectomizado: experimento clinico controlado / Early enteral nutrition in major abdominal surgery

La nutrición enteral temprana (NET) disminuye la morbilidad posoperatoria en pacientes con trauma grave. El presente trabajo evaluó el efecto de la NET sobre el catabolismo posoperatorio, la morbilidad posoperatoria y la estancia hospitalaria en un grupo homogéneo de pacientes sometidos a resección gástrica electiva. Diseño: experimento clínico controlado aleatorizado estratificado. Intervención: el grupo estudio recibió NET con dieta inmunoenriquecida (Inmunaid ,) mediante una sonda nasoyeyunal colocada en cirugía. El grupo control recibió cristaloides IV y soporte nutricional después del quinto día posoperatorio,sólo en caso de complicaciones. Variables: variables dependientes: complicaciones infecciosas y no infecciosas, estancia hospitalaria, balance nitrogenado y dinamometria. Se controlaron las variables sociodemográfícas, patologías de base, estado nutricional y tipo de cirugía. Resultados: entre marzo de 1994 y marzo de 1999, se incluyeron 54 pacientes licuados a gastrectomia electiva. Fueron aleatorizados al grupo intervenido (30 pacientes) y al grupo control (24 pacientes). Se incluyeron 35 hombres (64.8 por ciento) y 19 mujeres (35.2 por ciento), con una mediana de edad de 56 anos (rango 23- 84 anos). Las patologías que indicaron el procedimiento quirúrgico fueron: cáncer gástrico 41 (75.9 por ciento), enfermedad ácido péptica 7 (13 por ciento). cáncer de esófago distal 3 (5.6 por ciento). displasia gástrica 2 (3.7 por ciento) y adenomas gástricos 1 (1.9 por ciento). Los pacientes que recibieron HET presentaron disminución significatiua del catabolismo posoperatorio y mejoría de la fuerza muscular. La frecuencia de complicaciones infecciosas y no infecciosas fue mayor en el grupo de NET ( p= 0.005). La estancia hospitalaria total fue mayor en el grupo de NET (9.4 vs. 7-2 dias p= 0,03). Conclusiones: la nutrición enteral temprana disminuye el catabolismo posoperatorio, pero puede aumentar la frecuencia de complicaciones y (a estancia hospitalaria en pacientes sometidos a resecciones gástricas electivas