Bioethics and medical/legal considerations on cochlear implants in children

Cochlear implants are the best treatment for congenital profound deafness. Pediatric candidates to implantation are seen as vulnerable citizens, and the decision of implanting cochlear devices is ultimately in the hands of their parents/guardians. The Brazilian Penal Code dictates that deaf people may enjoy diminished criminal capacity. Many are the bioethical controversies around cochlear implants, as representatives from the deaf community have seen in them a means of decimating their culture and intrinsic values. Objective: This paper aims to discuss, in bioethical terms, the validity of implanting cochlear hearing aids in children by analyzing their vulnerability and the social/cultural implications of the procedure itself, aside from looking into the medical/legal aspects connected to their criminal capacity. Materials and Methods: The topic was searched on databases Medline and Lilacs; ethical analysis was done based on principialist bioethics. Results: Cochlear implants are the best therapeutic option for people with profound deafness and are morally justified. The level of criminal capacity attributed to deaf people requires careful analysis of the subject's degree of understanding and determination when carrying out the acts for which he/she has been charged. Conclusion: Cochlear implants are morally valid. Implantations must be analyzed on an each case basis. ENT physicians bear the ethical responsibility for indicating cochlear implants and must properly inform the child's parents/guardians and get their written consent before performing the procedure.

Probabilistic crack growth analyses using a boundary element model: Applications in linear elastic fracture and fatigue problems

This paper addresses the numerical solution of random crack propagation problems using the coupling boundary element method (BEM) and reliability algorithms. Crack propagation phenomenon is efficiently modelled using BEM, due to its mesh reduction features. The BEM model is based on the dual BEM formulation, in which singular and hyper-singular integral equations are adopted to construct the system of algebraic equations. Two reliability algorithms are coupled with BEM model. The first is the well known response surface method, in which local, adaptive polynomial approximations of the mechanical response are constructed in search of the design point. Different experiment designs and adaptive schemes are considered. The alternative approach direct coupling, in which the limit state function remains implicit and its gradients are calculated directly from the numerical mechanical response, is also considered. The performance of both coupling methods is compared in application to some crack propagation problems. The investigation shows that direct coupling scheme converged for all problems studied, irrespective of the problem nonlinearity. The computational cost of direct coupling has shown to be a fraction of the cost of response surface solutions, regardless of experiment design or adaptive scheme considered. (C) 2012 Elsevier Ltd. All rights reserved.

Brain activity and medical diagnosis: an EEG study

Abstract Background Despite new brain imaging techniques that have improved the study of the underlying processes of human decision-making, to the best of our knowledge, there have been very few studies that have attempted to investigate brain activity during medical diagnostic processing. We investigated brain electroencephalography (EEG) activity associated with diagnostic decision-making in the realm of veterinary medicine using X-rays as a fundamental auxiliary test. EEG signals were analysed using Principal Components (PCA) and Logistic Regression Analysis Results The principal component analysis revealed three patterns that accounted for 85% of the total variance in the EEG activity recorded while veterinary doctors read a clinical history, examined an X-ray image pertinent to a medical case, and selected among alternative diagnostic hypotheses. Two of these patterns are proposed to be associated with visual processing and the executive control of the task. The other two patterns are proposed to be related to the reasoning process that occurs during diagnostic decision-making. Conclusions PCA analysis was successful in disclosing the different patterns of brain activity associated with hypothesis triggering and handling (pattern P1); identification uncertainty and prevalence assessment (pattern P3), and hypothesis plausibility calculation (pattern P2); Logistic regression analysis was successful in disclosing the brain activity associated with clinical reasoning success, and together with regression analysis showed that clinical practice reorganizes the neural circuits supporting clinical reasoning.

Are mental health problems and depression associated with bruxism in children?

Renner AC, da Silva AAM, Rodriguez JDM, Simoes VMF, Barbieri MA, Bettiol H, Thomaz EBAF, Saraiva MC. Are mental health problems and depression associated with bruxism in children? Community Dent Oral Epidemiol 2011. (C) 2011 John Wiley & Sons A/S Abstract Objectives: Previous studies have found an association between bruxism and emotional and behavioral problems in children, but reported data are inconsistent. The objective of this study was to estimate the prevalence of bruxism, and of its components clenching and grinding, and its associations with mental problems and depression. Methods: Data from two Brazilian birth cohorts were analyzed: one from 869 children in Ribeirao Preto RP (Sao Paulo), a more developed city, and the other from 805 children in Sao Luis SL (Maranhao). Current bruxism evaluated by means of a questionnaire applied to the parents/persons responsible for the children was defined when the habit of tooth clenching during daytime and/or tooth grinding at night still persisted until the time of the assessment. Additionally, the lifetime prevalence of clenching during daytime only and grinding at night only was also evaluated. Mental health problems were investigated using the Strength and Difficulties Questionnaire (SDQ) and depression using the Childrens Depression Inventory (CDI). Analyses were carried out for each city: with the SDQ subscales (emotional symptoms, conduct problems, peer problems, attention/hyperactivity disorder), with the total score (sum of the subscales), and with the CDI. These analyses were performed considering different response variables: bruxism, clenching only, and grinding only. The risks were estimated using a Poisson regression model. Statistical inferences were based on 95% confidence intervals (95% CI). Results: There was a high prevalence of current bruxism: 28.7% in RP and 30.0% in SL. The prevalence of clenching was 20.3% in RP and 18.8% in SL, and grinding was found in 35.7% of the children in RP and 39.1% in SL. Multivariable analysis showed a significant association of bruxism with emotional symptoms and total SDQ score in both cities. When analyzed separately, teeth clenching was associated with emotional symptoms, peer problems, and total SDQ score; grinding was significantly associated with emotional symptoms and total SDQ score in RP and SL. Female sex appeared as a protective factor for bruxism, and for clenching and grinding in RP. Furthermore, maternal employment outside the home and white skin color of children were associated with increased prevalence of teeth clenching in SL. Conclusions: Mental health problems were associated with bruxism, with teeth clenching only and grinding at night only. No association was detected between depression and bruxism, neither clenching nor grinding. But it is necessary to be cautious regarding the inferences from some of our results.

Influence of the dopaminergic system, CREB, and transcription factor-κB on cocaine neurotoxicity

Cocaine is a widely used drug and its abuse is associated with physical, psychiatric and social problems. Abnormalities in newborns have been demonstrated to be due to the toxic effects of cocaine during fetal development. The mechanism by which cocaine causes neurological damage is complex and involves interactions of the drug with several neurotransmitter systems, such as the increase of extracellular levels of dopamine and free radicals, and modulation of transcription factors. The aim of this review was to evaluate the importance of the dopaminergic system and the participation of inflammatory signaling in cocaine neurotoxicity. Our study showed that cocaine activates the transcription factors NF-κB and CREB, which regulate genes involved in cellular death. GBR 12909 (an inhibitor of dopamine reuptake), lidocaine (a local anesthetic), and dopamine did not activate NF-κB in the same way as cocaine. However, the attenuation of NF-κB activity after the pretreatment of the cells with SCH 23390, a D1 receptor antagonist, suggests that the activation of NF-κB by cocaine is, at least partially, due to activation of D1 receptors. NF-κB seems to have a protective role in these cells because its inhibition increased cellular death caused by cocaine. The increase in BDNF (brain-derived neurotrophic factor) mRNA can also be related to the protective role of both CREB and NF-κB transcription factors. An understanding of the mechanisms by which cocaine induces cell death in the brain will contribute to the development of new therapies for drug abusers, which can help to slow down the progress of degenerative processes.