RESUMEN
BACKGROUND AND OBJECTIVE: Tinnitus is a symptom experienced by millions of people around the world, generating psychological, physical and social consequences. There are different therapeutic options that seek to reduce the symptom and the related consequences. One of the newest alternatives is training with Neurofeedback, a neuromodulation technique that looks for modify brain activity. The objective of this research was to determine the efficacy of Neurofeedback treatment parameters in reducing the perception of tinnitus and in reducing the behavioral consequences triggered by the symptom, through a systematic review between 2010 and 2020. MATERIALS AND METHODS: The data search was carried out in Spanish and English on PubMed/MedLine, EBSCO Host, Embase, Scopus, CENTRAL, SpringerLink and OpenGrey databases. The systematic review was carried out according to the stages established by PRISMA and five studies were identified to be included in the qualitative analysis. RESULTS: All studies demonstrated that NFB training for tinnitus decreases symptom perception and related consequences. At the neural level, there was an increase in the activity of the alpha wave and a decrease in the activity of delta, gamma and beta. CONCLUSIONS: Neurofeedback has a modulating effect on brain activity patterns. However, although all the studies reported a decrease in the consequences related to the symptom at the behavioral level after treatment, due to the lack of development of this technique for the symptom and the characteristics of the studies reviewed, it cannot be certainty of efficacy on behavioral and neurophysiological consequences.
RESUMEN
Groundwater recharge in hyper arid areas often depends on surface water infiltration and diffuse recharge of highly evaporated precipitation only contribute under favorable conditions. This happens in the Calama basin two-aquifer system, in the Central Andean area of northern Chile. A conceptual model of the groundwater system and its relationship with the Loa River is defined. We focus on the confined aquifer of the Calama basin, combining hydrodynamic, hydrogeochemical and isotopic methods. Radiocarbon (14C) activity data of dissolved inorganic carbon (DIC), in conjunction with chemical data, are applied to evaluate groundwater residence time within the confined aquifer. The Loa River recharges the Calama basin aquifers in its northeastern part, with water that has chemical and isotopic characteristics inherited from the arid environment and volcanic rocks in its upper basin. In the central and northeastern part of the confined aquifer, minor variations in chloride concentration suggest that the deep aquifer is well confined. The δ18O and δ2H values in groundwater of the confined aquifer show an increasing isotopic fractionation from the recharge area (around -10 δ18O) to those in the discharge area (between -8.5 and -8) in the southwestern part of the aquifer. The 14C activity continuously decreases down flow from the recharge by the Loa River. Adjusted DIC radiocarbon ages indicate a groundwater travel time between 1500 and 4000â¯years in the confined aquifer of Calama. Despite the limitations and uncertainties of radiocarbon in DIC to estimate groundwater transit times for the confined aquifer and considering complementary chemical and isotopic constraints, the DIC 14C provides acceptable values. The approach may be applicable in other confined aquifers in hyper-arid climates in which the formation of aquifer systems linked to river damming by geological action took place. This information is needed for sound management of the scarce groundwater resources.
RESUMEN
Antecedentes y objetivo El tinnitus es un síntoma experimentado por millones de personas alrededor del mundo, genera consecuencias a nivel psicológico, físico y social. Existen diferentes opciones terapéuticas que buscan disminuir el síntoma y las consecuencias relacionadas. Una de las alternativas más novedosas es el entrenamiento con neurofeedback, una técnica de neuromodulación en la que se busca modificar la actividad cerebral. El objetivo de esta investigación fue determinar la eficacia de los parámetros del tratamiento con neurofeedback en la reducción de la percepción del tinnitus y en la disminución de las consecuencias conductuales desencadenadas por el síntoma, mediante una revisión sistemática comprendida entre los años 2010 y 2020. Materiales y métodos La búsqueda de datos fue realizada en español e inglés, y se llevó a cabo en las bases de datos PubMed/MedLine, EBSCO Host, Embase, Scopus, CENTRAL, SpringerLink y OpenGrey. La revisión sistemática fue realizada conforme las etapas establecidas por PRISMA y se identificaron 5 estudios para ser incluidos en el análisis cualitativo. Resultados La totalidad de los estudios reportaron que el entrenamiento con neurofeedback para el tinnitus disminuyó la percepción del síntoma y las consecuencias relacionadas. A nivel neural se dio un aumento de la actividad de la onda alfa y la disminución de la actividad de delta, gamma y beta. Conclusiones El neurofeedback posee un efecto modulador sobre los patrones de actividad cerebral. Sin embargo, aunque la totalidad de los estudios reportaron una disminución de las consecuencias relacionadas con el síntoma a nivel conductual después del tratamiento, debido a la falta de desarrollo de esta técnica para el síntoma y las características de los estudios revisados, no se puede tener certeza de la eficacia sobre las consecuencias conductuales y neurofisiológicas. (AU)
Background and objective Tinnitus is a symptom experienced by millions of people around the world, generating psychological, physical, and social consequences. There are different therapeutic options that seek to reduce the symptom and the related consequences. One of the newest alternatives is training with Neurofeedback, a neuromodulation technique that looks for modify brain activity. The objective of this research was to determine the efficacy of Neurofeedback treatment parameters in reducing the perception of tinnitus and in reducing the behavioral consequences triggered by the symptom, through a systematic review between 2010 and 2020. Materials and methods The data search was carried out in Spanish and English on PubMed/MedLine, EBSCO Host, Embase, Scopus, CENTRAL, SpringerLink and OpenGrey databases. The systematic review was carried out according to the stages established by PRISMA and five studies were identified to be included in the qualitative analysis. Results All studies demonstrated that NFB training for tinnitus decreases symptom perception and related consequences. At the neural level, there was an increase in the activity of the alpha wave and a decrease in the activity of delta, gamma, and beta. Conclusions Neurofeedback has a modulating effect on brain activity patterns. However, although all the studies reported a decrease in the consequences related to the symptom at the behavioral level after treatment, due to the lack of development of this technique for the symptom and the characteristics of the studies reviewed, it cannot be certainty of efficacy on behavioral and neurophysiological consequences. (AU)