Los potenciales evocados auditivos de estado estable a múltiples frecuencias y su valor en la evaluación objetiva de la audición

One of the main objectives in conducting an electroaudiometric examination is to obtain a specific frequency evaluation of the audibility thresholds. In recent decades, multiple technical proposals have been made based on the recording of Auditory Evoked Potentials (AEP). They are not affected by sedation or sleep and can be detected at stimulation intensities very close to the threshold of audibility. The aforementioned advantages have made it a useful tool for objective hearing evaluation. However, this technique has certain limitations from the electroaudiometric point of view, mainly due to the lack of specified frequency of said response.Auditory Steady State  Responses (ASSR) by isolated tonal stimuli and at stimulation frequencies between 75 and 110 Hz have been proposed as a valid alternative for performing a specific frequency audiometry. This type of response represents the synchronous discharge of the brain stem neurons, which follow the modulation frequency of the stimulus that gives rise to them.There have been multiple authors who in recent years and using this type of response have obtained reliable estimates of the tonal audibility threshold, both in healthy children and adults and in hard of hearing subjects. This technique has multiple advantages over transient PEAs in determining specific thresholds in frequency: 1) Given the periodicity of the response, it can be represented in the frequency domain, thus minimizing the complexity of its measurement, 2) The acoustic stimulus used is more specific in frequency, 3) Due to the rectification properties of the cochlea, the response caused by an amplitude modulated tone is represented as a spectral peak at the modulation frequency, 4) These peaks Spectrals can be detected using different frequency domain statistics.Despite the advantages described above, obtaining a complete audiogram using PEAee triggered by isolated tonal stimuli can be time consuming. More recently, an optimized variant of the ASSR between 75 and 110 Hz has been proposed with the simultaneous use of multiple tones modulated in amplitude. Given the fact that each carrier tone is modulated with a different frequency, multiple tones can then be added together, forming a complex tone composed of multiple tones modulated in amplitude. Using then as a stimulus, a mix composed of tones of 500, 1000, 2000 and 4000 Hz we can simultaneously activate and evaluate these four frequency regions of the cochlea. On the other hand, these complex stimuli can be presented binaurally, evaluating both ears simultaneously.PEAee caused by multiple amplitude-modulated tones have been used with encouraging results in the objective determination of audibility thresholds in children and adults, hearing-impaired patients, and in the early detection of hearing defects. This article summarizes some basic concepts, as well as their clinical applications.Uno de los principales objetivos en la realización de un examen electroaudiométrico es la obtención de una evaluación frecuencia específico de los umbrales de audibilidad. En las últimas décadas han sido propuestas múltiples técnicas basadas en el registro de los Potenciales Evocados Auditivos (PEA). Los mismos no son afectados por la sedación ni el sueño y pueden ser detectados a intensidades de estimulación muy cercanas al umbral de audibilidad. Las ventajas antes mencionadas lo han convertido en una útil herramienta para la evaluación objetiva de la audición. No obstante, esta técnica tiene ciertas limitaciones desde el punto de vista electroaudiométrico, debido principalmente a la falta de frecuencia especificada de dicha respuesta.     Los Potenciales Evocados Auditivos de Estado Estable (PEAee) por estímulos tonales aislados y a frecuencias de estimulación entre 75 y 110 Hz han sido propuestos como una alternativa valida para la realización de una audiometría frecuencia especifica. Este tipo de respuesta representa la descarga sincrónica de las neuronas del tronco cerebral, las cuales siguen la frecuencia de modulación del estimulo que les da origen.     Múltiples han sido los autores que en los últimos años y usando este tipo de respuesta han obtenido estimaciones confiables del umbral de audibilidad tonal, tanto en niños y adultos sanos como en sujetos hipoacúsicos. Esta técnica tiene múltiples ventajas sobre los PEA transitorios en la determinación de umbrales específicos en frecuencia: 1) Dado la periodicidad de la respuesta esta puede ser representada en el dominio de la frecuencia, minimizando por ende la complejidad de su medición, 2) El estimulo acústico empleado es mas especifico en frecuencia, 3) Debido a las propiedades de rectificación de la coclea la respuesta provocada por un tono modulado en amplitud es representada como un pico espectral a la frecuencia de modulación, 4) Estos picos espectrales pueden ser detectados usando diferentes estadígrafos en el dominio de la frecuencia.     A pesar de las ventajas anteriormente descritas, la obtención de un audiograma completo mediante el uso de los PEAee provocados por estímulos tonales aislados puede requerir un gran consumo de tiempo. Más recientemente ha sido propuesta una variante optimizada de los PEAee entre 75 y 110 Hz con el empleo simultaneo de múltiples tonos modulados en amplitud. Dado el hecho que cada tono portador es modulado con una frecuencia diferente, múltiples tonos pueden ser entonces sumados, formando un tono complejo compuesto por múltiples tonos modulados en amplitud. Usando entonces como estimulo, una mezcla compuesta por tonos de 500, 1000, 2000 y 4000 Hz podemos activar y evaluar simultáneamente estas cuatro regiones de frecuencia de la cóclea. Por otra parte, estos estímulos complejos pueden ser presentados binauralmente, evaluando ambos oídos simultáneamente. Los PEAee provocados por múltiples tonos modulados en amplitud han sido empleados con alentadores resultados en la determinación objetiva de los umbrales de audibilidad en niños y adultos, pacientes hipoacúsicos y en la detección temprana de defectos auditivos. El presente artículo resume algunos conceptos básicos, así como sus aplicaciones clínicas

Effect of cochlear implant in children suffering genetic hypoacusis caused by Waardenburg Syndrome and 35delG mutation

Introduction: Sensorineural hypoacusia is the most common form of hearing impairment, it is estimated that over 80% of all congenital hearing losses are from genetic origin, being distinguished in syndromic and non-syndromic; 35delG mutation is the most common cause of the first and Waardenburg syndrome (WS) is one of the most frequent in the last one; in both of them cases are usually identified patients with severe to profound hearing losses (HSP). The cochlear implant is considered an effective solution when the HSP do not get enough benefit through hearing aids. Objective: To analyze the results achieved with the use of cochlear implant in patients with HSP due to WS and 35delGmutation. Material and Methods: A descriptive cross-sectional study. Were studied patients with HSP of genetic cause, 27 due to 35delGmutation and 15 by WS. Hearing and logophoniatrics tests were performed. Results: Inner ear lesions happening in the in the studied patients it seems not affect the benefits of cochlear implant if general proper conditions are given. Conclusions: Cochlear Implant is a worthful therapeutic alternative for the hearing impaired due to these two studied illness; however, those with 35delG mutation, achieved best hearing performance categories. Keywords: deafness, hearing loss, genetics, rehabilitation, hearing impairment correction.</p

The evolution of the ventilatory ratio is a prognostic factor in mechanically ventilated COVID-19 ARDS patients

Background: Mortality due to COVID-19 is high, especially in patients requiring mechanical ventilation. The purpose of the study is to investigate associations between mortality and variables measured during the first three days of mechanical ventilation in patients with COVID-19 intubated at ICU admission. Methods: Multicenter, observational, cohort study includes consecutive patients with COVID-19 admitted to 44 Spanish ICUs between February 25 and July 31, 2020, who required intubation at ICU admission and mechanical ventilation for more than three days. We collected demographic and clinical data prior to admission; information about clinical evolution at days 1 and 3 of mechanical ventilation; and outcomes. Results: Of the 2,095 patients with COVID-19 admitted to the ICU, 1,118 (53.3%) were intubated at day 1 and remained under mechanical ventilation at day three. From days 1 to 3, PaO2/FiO2 increased from 115.6 [80.0-171.2] to 180.0 [135.4-227.9] mmHg and the ventilatory ratio from 1.73 [1.33-2.25] to 1.96 [1.61-2.40]. In-hospital mortality was 38.7%. A higher increase between ICU admission and day 3 in the ventilatory ratio (OR 1.04 [CI 1.01-1.07], p = 0.030) and creatinine levels (OR 1.05 [CI 1.01-1.09], p = 0.005) and a lower increase in platelet counts (OR 0.96 [CI 0.93-1.00], p = 0.037) were independently associated with a higher risk of death. No association between mortality and the PaO2/FiO2 variation was observed (OR 0.99 [CI 0.95 to 1.02], p = 0.47). Conclusions: Higher ventilatory ratio and its increase at day 3 is associated with mortality in patients with COVID-19 receiving mechanical ventilation at ICU admission. No association was found in the PaO2/FiO2 variation

Potenciales evocados corticales y evaluación lingüística de pacientes con implante coclear

El objetivo de este trabajo fue examinar la utilidad del Potencial Evocado Auditivo Cortical (PEAC) como herramienta objetiva que nos permita cuantificar el proceso de rehabilitación en pacientes con implante coclear. Se conformó una muestra de 20 pacientes, 12 del sexo masculino y con edades entre 7 y 16 años. Todos portadores de un Implante Coclear (IC) modelo Clarion HiRes 90K. Todas las variables mostraron una correlación estadísticamente significativa con la etapa del proceso de rehabilitación en que se encontraba cada paciente. Los PEAC registrados en pacientes con IC muestran una morfología muy similar a la que se obtiene en sujetos normoyentes, registrándose los componentes que caracterizan esta respuesta (P1, N1, P2 y N2). Se evidenció una correlación estadísticamente significativa entre las etapas de rehabilitación y la latencia de los componentes P1 y N1. También hubo correlación estadísticamente significativa entre el por ciento de fonemas erróneos calculados tras la aplicación de la prueba del Registro Fonológico Inducido y la latencia del componente P1. Contar con herramientas objetivas como el PEAC nos garantizaría un mayor y mejor aprovechamiento de la rehabilitación lingüística, así como podría ayudar a perfeccionar las técnicas de rehabilitación de los pacientes con implante coclear.The goal of this study was to examine the usefulness of Cortical Auditory Evoked Potentials (CAEP) as an objective tool that allows us to quantify the process of rehabilitation in patients with cochlear implant. The sample was composed of 20 patients, 12 male and aged between 7 and 16. All cochlear implant users (CI), model Clarion HiRes 90K. All variables showed a statistically significant correlation with the stage of the rehabilitation process in which each patient was. The CAEP reported in patients with CI showed a similar morphology to that obtained in subjects with normal hearing, recording the four components that characterize this response (P1, N1, P2 and N2). It showed a statistically significant correlation between the stages of rehabilitation and the latency of P1 and N1 components. There was also significant correlation between the percentage of incorrect phonemes calculated after applying the Induced Phonological Assessment (IPA) test and latency P1 component. To have objective tools such as the CAEP would guarantee a higher and better use of language rehabilitation, and could help refine rehabilitation techniques for patients with cochlear implants

Spectroscopic and thermal characterization of extra virgin olive oil adulterated with edible oils

he substitution of extra virgin olive oil with other edible oils is the primary method forfraud in the olive-oil industry. Developing inexpensive analytical methods for confirming the qualityand authenticity of olive oils is a major strategy towards combatting food fraud. Current methodsused to detect such adulterations require complicated time- and resource-intensive preparation steps.In this work, a comparative study incorporating Raman and infrared spectroscopies, photolumines-cence, and thermal-conductivity measurements of different sets of adulterated olive oils is presented.The potential of each characterization technique to detect traces of adulteration in extra virgin oliveoils is evaluated. Concentrations of adulterant on the order of 5% can be detected in the Raman,infrared, and photoluminescence spectra. Small changes in thermal conductivity were also foundfor varying amounts of adulterants. While each of these techniques may individually be unableto identify impurity adulterants, the combination of these techniques together provides a holisticapproach to validate the purity and authenticity of olive oils.ICN2 is supported by the Severo Ochoa program from the Spanish Research Agency (AEI, grant no. SEV-2017-0706) and by the CERCA Programme/Generalitat de Catalunya. ICN2 authors acknowledge the support from the Spanish MICINN project SIP (PGC2018-101743-B-I00). A.C.-A. acknowledges the support from Fondecyt Iniciacion 11200620. R.C.N. acknowledges funding from the EU-H2020 research and innovation program under the Marie Sklodowska Curie Fellowship (Grant No. 897148)

Implante coclear en niños con hipoacusia de causa genética por Síndrome Waardenburg y mutación 35delG

Introduction: Sensorineural hypoacusia is the most common form of hearing impairment, it is estimated that over 80% of all congenital hearing losses are from genetic origin, being distinguished in syndromic and non-syndromic; 35delG mutation is the most common cause of the first and Waardenburg syndrome (WS) is one of the most frequent in the last one; in both of them cases are usually identified patients with severe to profound hearing losses (HSP). The cochlear implant is considered an effective solution when the HSP do not get enough benefit through hearing aids. Objective: To analyze the results achieved with the use of cochlear implant in patients with HSP due to WS and 35delGmutation. Material and Methods: A descriptive cross-sectional study. Were studied patients with HSP of genetic cause, 27 due to 35delGmutation and 15 by WS. Hearing and logophoniatrics tests were performed. Results: Inner ear lesions happening in the in the studied patients it seems not affect the benefits of cochlear implant if general proper conditions are given. Conclusions: Cochlear Implant is a worthful therapeutic alternative for the hearing impaired due to these two studied illness; however, those with 35delG mutation, achieved best hearing performance categories. Keywords: deafness, hearing loss, genetics, rehabilitation, hearing impairment correction.Introducción: La hipoacusia neurosensorial es la forma más común de déficit auditivo, se calcula que más de 80% de todas las pérdidas auditivas congénitas son de origen genético, siendo estas distinguidas en sindrómicas y no sindrómicas; la mutación 35delG es la causa más frecuente de las primeras y el Síndrome  Waardenburg (SW) es uno de los más frecuentes en las últimas, en ambas suelen identificarse pacientes con hipoacusias de severas a profundas (HSP). El implante coclear se considera una solución eficaz cuando la HSP no obtiene suficiente beneficio mediante prótesis auditivas. Objetivo: Analizar el resultado alcanzado con el uso del implante coclear en pacientes con HSP por SW y mutación 35delG. Material y Métodos: Se realizó un estudio descriptivo transversal. Fueron estudiados pacientes con HSP de causa genética, 27 debido a la mutación 35delG y 15 por SW. Se realizaron pruebas audiológicas y logofoniátricas. Resultados: La lesión que ocurre en el oído interno en los pacientes estudiados no parece afectar los beneficios que ofrece el implante coclear, si se dan las condiciones generales adecuadas. Conclusiones: El implante coclear es una alternativa terapéutica válida para la discapacidad auditiva debido a estas dos afecciones estudiadas; sin embargo, los que presentaron la mutación 35delG, alcanzaron mejores categorías de rendimiento auditivo.Palabras claves: Sordera, pérdida auditiva, genética, rehabilitación, corrección de deficiencia auditiva