Neurofisiología y bruxismo / Neurophysiology and bruxism

El bruxis mo muestra una fi siopatología compleja, donde se involucran señales aferentes y eferentes reguladas por el SNC a través de la expresión de neurotransmisores que repercute en una hiperactividad muscular disfuncional y eventualmente dañina. Para intentar comprender bruxismo desde sus particularidades neurofi siológicas, fue realizada una revisión bibliográfi ca en las bases de Medline y PubMed con el objetivo de establecer la relación entre neurotransmisores y el sistema neuromasticatorio, señalando las posibles alteraciones en su liberación que desencadenen irregularidades en los movimientos rítmicos de la mandíbula (rhythmic jaw Mmovement [RJM]) durante el sueño, inducidos por desórdenes en el sistema nervioso central, por trastornos psicológicos y psiquiátricos, drogadicción y prescripciones médicas, y en alguna medida a una respuesta reactiva a situaciones locales y cambios adaptativos. El funcionamiento masticatorio depende de la integración del aporte sensorial (aferente) de componentes como lo son el ligamento periodontal, músculos masticatorios, dientes y articulación temporomandibular, que puede ser perturbado; cuando alguna de estas partes sufre alteraciones en su integridad, infl amación o sobrecarga funcional o por alteraciones morfológicas, observándose una variedad de respuestas adaptativas y compensatorias (eferentes). En bruxismo esta información local es de relevancia menor, ya que este se rige por cambios centrales observados durante el sueño o bien alteraciones de infl uencia psicológica durante el bruxismo diurno. Consiguientemente, el bruxismo trae apareados cambios biológicos, emocionales y de conducta que repercuten en músculos mayores, preferentemente localizados en cabeza y cuello, ocasionando de manera secundaria numerosas alteraciones; particularmente en la región estomatognática, se observan diversos deterioros como daño de las mucosas, dolor miofascial y articular y atrición dental. La comprensión de los complejos procesos neurofi siológicos que determinan la aparición y persistencia de bruxismo puede ayudar a establecer estrategias de control y tratamiento (AU)

Bruxism shows a complex pathophysiology, where afferent and aff erent signals regulated by the CNS, through the expression of neurotransmitters with repercussion in dysfunctional and eventually harmful muscular hyperactivity. To try to understand bruxism from its neurophysiological peculiarities, a bibliographic review was carried out on the bases of Medline and PubMed, with the aim of establishing the relationship between neurotransmitters and the neuromasticatory system, pointing out the possible alterations in their release that trigger irregularities in the rhythmic movements of the jaw (rhythmic jaw movement [RJM]) during sleep induced by disorders in the central nervous system, psychological and psychiatric alterations, drug addiction and medical prescriptions, and to some extent, a reactive response to local situations and adaptive changes. The masticatory functioning depends on the integration of the sensory input (aff erent) of components such as the periodontal ligament, masticatory muscles, teeth and temporomandibular joint, which can be disturbed when any of these parts suff er alterations in their integrity, infl ammation, functional overload or morphological alterations, observing a variety of adaptive and compensatory (efferent) responses. In bruxism, this local information is of minor relevance, since it is governed by central changes observed during sleep or changes in psychological infl uence during daytime bruxism. Consequently, bruxism brings with it biological, emotional and behavioral changes that aff ect major muscles, preferably located in the head and neck, causing in a secondary way many other alterations. Particularly in the stomatognathic region, several deteriorations are observed, such as mucosal damage, myofascial and joint pain and dental attrition. The understanding of the complex neurophysiological processes that determine the appearance and persistence of bruxism can help to establish control and treatment strategies (AU)

Hearing Profile of Brazilian Forestry Workers' Noise Exposure

Introduction Researchers studying the hearing health of forestry workers have revealed the presence of a noise-induced hearing loss (NIHL) in this population and have concluded that the vibration of the equipment, the carbon monoxide released by motors, and pesticides might also contribute to NIHL. Objective To analyze the noise exposure in the Brazilian forestry industry workers and the effects on hearing. Methods The study sample comprised 109 employees of a company that specialized in reforestation. Their participants' mean age was 35.5 years (21 to 54 years), mean tenure at the company was 3.9 years (1 to 13 years), and mean total duration of noise exposure was 12.3 years (1 to 30 years). The existing documentation reporting on the jobs risk analysis was examined, noise level was measured, and pure tone audiometry was performed in all participants. Participants were divided into three groups according to their noise exposure levels in their current job. Results Of the participants who were exposed to noise levels less than 85 dBA (decibels with A-weighting filter), 23.8% had hearing loss, and 5.5% of the participants who were exposed to noise ranging from 85 to 89.9 dBA and 11% of the participants who were exposed to noise greater than 90 dBA had audiogram results suggestive of NIHL. Conclusion The implementation of a hearing loss prevention program tailored to forestry workers is needed. .

Study on the control of dynamic artificial limb ankle based on central pattern generator / 生物医学工程学杂志

In order to obtain the normal gait for the prosthesis-carrier with the change of external environment and gait, we designed a model of dynamic ankle prosthesis and control system and introduced the strategy of central pattern generator (CPG) about the moving trail of dynamic ankle prosthesis. The dynamic parts, which are incorporated in the model of dynamic ankle prosthesis, provide power in order to have anthropic function and character. The tool of Matlab/simulink was used to simulate the strategy. The simulation results showed that the strategy of CPG learn- ing control in this study was effective and could track the reference trail rapidly and fit the moving trail of a person's normal limb. It can make the prosthetic timely regulation and action, enhance the prosthetic intelligence. It has im- portant practical value for intelligent prosthesis development based on this analysis of technology.

Spinal cord injury as a trigger to develop periodic leg movements during sleep: an evolutionary perspective / Lesão medular como gatilho para desenvolver movimentos periódicos das pernas durante o sono: uma perspectiva evolutiva

The primary trigger to periodic limb movement (PLM) during sleep is still unknown. Its association with the restless legs syndrome (RLS) is established in humans and was reported in spinal cord injury (SCI) patients classified by the American Spinal Injury Association (ASIA) as A. Its pathogenesis has not been completely unraveled, though recent advances might enhance our knowledge about those malfunctions. PLM association with central pattern generator (CPG) is one of the possible pathologic mechanisms involved. This article reviewed the advances in PLM and RLS genetics, the evolution of CPG functioning, and the neurotransmitters involved in CPG, PLM and RLS. We have proposed that SCI might be a trigger to develop PLM.

O gatilho principal para o desenvolvimento de movimentos periódicos dos membros (MPM) durante o sono ainda é desconhecido. A associação entre o MPM e a síndrome das pernas inquietas (SPI) em seres humanos já foi previamente estabelecida e relatada em pacientes com lesão medular (LM), classificados pela American Spinal Injury Association (ASIA) como A. A patogênese do MPM não foi completamente desvendada, apesar de avanços recentes poderem ampliar o conhecimento sobre essas disfunções. Um dos possíveis mecanismos patológicos envolvidos é o gerador de padrão central (GPC). Este artigo revisou os avanços na genética do MPM e da SPI, a evolução do funcionamento do GPC e os neurotransmissores relacionados ao GPC, ao MPM e à SPI. Foi proposta a hipótese de que a LM poderia ser um gatilho para deflagrar os MPM.