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Current techniques for measuring normal incidence sound transmission loss with a modified impedance tube, or transmission tube, require setting up two different absorbing termination loads at the end of the downstream tube [ASTM E2611-09, Standard Test Method for Measurement of Normal Incidence Sound Transmission of Acoustical Materials Based on the Transfer Matrix Method (American Society for Testing and Materials, West Conshohocken, 2009)]. The process of physically handling the two required passive absorbing loads is a possible source of measurement errors, which are mainly due to changes in sample test position, or in test setup re-assembly, between measurements. In this paper, a modified transmission tube apparatus is proposed for non-intrusively changing the downstream acoustic load by means of a combined passive-active termination. It provides a controlled variable sound absorption which simplifies the setup of standard two-load techniques, without the need of physically handling the apparatus during the tests. This virtually eliminates the risk of errors associated with the physical manipulation of the two passive terminations. Transmission loss measurements in some representative test conditions are reported, showing improvements over current implementations, in reducing by approximately 50% the measurement variations associated with the setup of the two required absorbing terminations. Measurement results agree within 0.4 dB (maximum difference in high resolution broadband), and 0.04 dB (mean difference in 1/3-octave bands), with those obtained using standard passive two-load methods.

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OBJECTIVE: Dyslexia is the difficulty of children in learning to read and write as results of neurological deficiencies. The objective was to test the Phonological awareness (PA) and Sinusoidal amplitude modulation (SAM) threshold in children with Phonological dyslexia (PD). METHODS: We performed a case-control, analytic, cross sectional study. We studied 14 children with PD and 14 control children from 7 to 11 years of age, by means of PA measurement and by SAM test. The mean age of dyslexic children was 8.39 years and in the control group was 8.15. RESULTS: Children with PD exhibited inadequate skills in PA, and SAM. We found significant correlations between PA and SAM at 4 Hertz frequency, and calculated regression equations that predicts between one-fourth and one-third of variance of measurements. CONCLUSION: Alterations in PA and SAM found can help to explain basis of deficient language processing exhibited by children with PD.

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Abstract Background: Zapotec is a language used mainly in the state of Oaxaca in Mexico of tonal characteristic; homophone words with difference in fundamental frequency with different meanings. Our objective was to analyze changes in the electroencephalographic (EEG) theta rhythm during word discrimination of lexical tonal bi-syllabic homophone word samples of Zapotec. Methods: We employed electroencephalography analysis during lexical tonal discrimination in 12 healthy subjects 9-16 years of age. Results: We observed an increase in theta relative power between lexical discrimination and at rest eyes-open state in right temporal site. We also observed several significant intra- and inter-hemispheric correlations in several scalp sites, mainly in left fronto-temporal and right temporal areas when subjects were performing lexical discrimination. Conclusions: Our data suggest more engagement of neural networks of the right hemisphere are involved in Zapotec language discrimination.

Resumen Introducción: El zapoteco es un lenguaje hablado principalmente en el estado de Oaxaca, en México, que tiene la característica de ser tonal; es decir, las palabras homófonas que difieren en la altura del fundamental tienen diferente significado. El objetivo de este trabajo fue analizar los cambios del ritmo theta del electroencefalograma en el curso de la discriminación de palabras bisilábicas homófonas en zapoteco. Método: Se empleó el análisis espectral del electroencefalograma durante la discriminación tonal léxica del lenguaje zapoteco en 12 niños sanos de 9-16 años. Resultados: Se observó una mayor potencia relativa theta en la región temporal derecha durante la discriminación léxica en comparación con el registro de reposo-ojos abiertos. También se observaron varias correlaciones significativas intra e interhemisféricas con predominio entre la región frontotemporal izquierda y temporal derecha mientras se realizaba la discriminación tonal léxica. Conclusión: Estos resultados sugieren que hay un mayor compromiso de las redes neuronales en el hemisferio derecho que participan en la discriminación del lenguaje zapoteco.

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ABSTRACT Objective Dyslexia is the difficulty of children in learning to read and write as results of neurological deficiencies. The objective was to test the Phonological awareness (PA) and Sinusoidal amplitude modulation (SAM) threshold in children with Phonological dyslexia (PD). Methods We performed a case-control, analytic, cross sectional study. We studied 14 children with PD and 14 control children from 7 to 11 years of age, by means of PA measurement and by SAM test. The mean age of dyslexic children was 8.39 years and in the control group was 8.15. Results Children with PD exhibited inadequate skills in PA, and SAM. We found significant correlations between PA and SAM at 4 Hertz frequency, and calculated regression equations that predicts between one-fourth and one-third of variance of measurements. Conclusion Alterations in PA and SAM found can help to explain basis of deficient language processing exhibited by children with PD.

RESUMEN Objetivo La Dislexia es la dificultad en niños de aprender a leer y escribir como resultado de una deficiencia neurológica. Nuestro objetivo fue probar la Conciencia fonológica (CF) y la Modulación sinusoidal de la amplitud (MSA) en niños con Dislexia fonológica (DF). Métodos Realizamos un estudio analítico, transversal, de casos y controles. Estudiamos la CF y la MSA en 14 niños con DF y 14 controles de 7–11 años. La edad media de los niños con DF fue de 8.39 años y de los controles fue 8.15. Resultados Los niños con DF presentaron deficiencias en CF y en MSA. Encontramos correlaciones entre CF y MSA en la frecuencia de 4 Hertzios (Hz), calculamos ecuaciones de regresión que predijeron de un cuarto a un tercio de la varianza de las mediciones. Conclusión Las deficiencias en CF y en MSA pueden ayudar a comprender las alteraciones en el procesamiento del lenguaje presentadas por los niños con DF.

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BACKGROUND: Zapotec is a language used mainly in the state of Oaxaca in Mexico of tonal characteristic; homophone words with difference in fundamental frequency with different meanings. Our objective was to analyze changes in the electroencephalographic (EEG) theta rhythm during word discrimination of lexical tonal bi-syllabic homophone word samples of Zapotec. METHODS: We employed electroencephalography analysis during lexical tonal discrimination in 12 healthy subjects 9-16 years of age. RESULTS: We observed an increase in theta relative power between lexical discrimination and at rest eyes-open state in right temporal site. We also observed several significant intra- and inter-hemispheric correlations in several scalp sites, mainly in left fronto-temporal and right temporal areas when subjects were performing lexical discrimination. CONCLUSIONS: Our data suggest more engagement of neural networks of the right hemisphere are involved in Zapotec language discrimination.

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OBJECTIVE: Compare if localization of sounds and words discrimination in reverberant environment is different between children with dyslexia and controls. METHOD: We studied 30 children with dyslexia and 30 controls. Sound and word localization and discrimination was studied in five angles from left to right auditory fields (-90o, -45o, 0o, +45o, +90o), under reverberant and no-reverberant conditions; correct answers were compared. RESULTS: Spatial location of words in no-reverberant test was deficient in children with dyslexia at 0º and +90o. Spatial location for reverberant test was altered in children with dyslexia at all angles, except –-90o. Word discrimination in no-reverberant test in children with dyslexia had a poor performance at left angles. In reverberant test, children with dyslexia exhibited deficiencies at -45o, -90o, and +45o angles. CONCLUSION: Children with dyslexia could had problems when have to locate sound, and discriminate words in extreme locations of the horizontal plane in classrooms with reverberation.

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Objective Compare if localization of sounds and words discrimination in reverberant environment is different between children with dyslexia and controls. Method We studied 30 children with dyslexia and 30 controls. Sound and word localization and discrimination was studied in five angles from left to right auditory fields (-90o, -45o, 0o, +45o, +90o), under reverberant and no-reverberant conditions; correct answers were compared. Results Spatial location of words in no-reverberant test was deficient in children with dyslexia at 0º and +90o. Spatial location for reverberant test was altered in children with dyslexia at all angles, except –-90o. Word discrimination in no-reverberant test in children with dyslexia had a poor performance at left angles. In reverberant test, children with dyslexia exhibited deficiencies at -45o, -90o, and +45o angles. Conclusion Children with dyslexia could had problems when have to locate sound, and discriminate words in extreme locations of the horizontal plane in classrooms with reverberation. .

Objetivo Comparar localización de sonidos y localización-discriminación de palabras bajo reverberación y sin reverberación en niños disléxicos y controles. Método Estudiamos 30 niños disléxicos y 30 controles, pareados por edad. La localización sonora y discriminación a palabras fue estudiada en cinco ángulos horizontales en los campos izquierdo y derecho (-90o, -45o, 0o, +45o, +90o), bajo reverberación y sin reverberación; las respuestas correctas fueron comparadas Resultados: La localización sonora sin reverberación fue deficiente en niños disléxicos a 0º y +90º. La localización bajo reverberación falló en niños disléxicos en todos los ángulos, excepto –-90o. Durante la discriminación a palabras, sin reverberación, los niños disléxicos fallaron en ángulos izquierdos. En la prueba reverberante, los niños disléxicos fallaron a -–45o, -90o y +45o. Conclusion Los niños con dislexia pueden tener problemas cuando tienen que localizar sonidos y discriminar palabras en las localizaciones extremas del plano horizontal en salones de clases típicos con reverberación. .

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Objetivo: El objetivo es evaluar la habilidad para distinguir palabras usando dos pruebas psicoacústicas verbales de procesos centrales de la audición (PCA) en español: la prueba de fusión binaural (PFB) y la prueba de palabra filtrada (PPF), en niños con dislexia y en niños controles. Métodos: Cuarenta niños con dislexia seleccionados de grupos de terapia y 40 niños seleccionados de 298 niños de una escuela pública como controles, pareados por sexo y edad. Resultados: Hubo predominio masculino 2/l en los niños disléxicos. Los promedios de acierto para la PFB fueron del 65 al 66% para los niños con dislexia y del 78 al 80% para los niños control. Para la PPF éstos fueron del 50 al 55% para los niños con dislexia y del 67 al 71% para los controles (t de Student <0,05). Conclusiones: Estos resultados contribuyen a evidenciar alteraciones de los PCA para estímulos psicoacústicos verbales en niños con dislexia. Se propone evaluar cada paciente con pruebas de PCA para definir el plan de rehabilitación (AU)

Objectives: The aim is to assess the ability to discriminate words, using two psychoacoustic verbal tests of Central auditory processes in Spanish: Binaural Fusion Test (BFT in its Spanish version) and Filtered Word Test (FWT in its Spanish version) in children with dyslexia and controls. Methods: One group of 40 dyslexic children was receiving therapy for dyslexia at the time of the tests. 40 children without dyslexia were selected as controls, out of 298 children who attended a public school. Results: The rate of males to females was 2/1 in the dyslexic group. The average correct answers for the BFT were 65–66% in dyslexic group and 75–80% in the control group. For the FWT they were 50–54% in the dyslexic group and 67–71% in the control group (student t <0.05). Conclusions: These results contribute to make evident disorders in central auditory processing in children with dyslexia. We suggest using the tests with each patient in order to elaborate a rehabilitation plan (AU)

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OBJECTIVES: The aim is to assess the ability to discriminate words, using two psychoacoustic verbal tests of central auditory processes in Spanish: Binaural Fusion Test (BFT in its Spanish version) and Filtered Word Test (FWT in its Spanish version) in children with dyslexia and controls. METHODS: One group of 40 dyslexic children was receiving therapy for dyslexia at the time of the tests. 40 children without dyslexia were selected as controls, out of 298 children who attended a public school. RESULTS: The rate of males to females was 2/1 in the dyslexic group. The average correct answers for the BFT were 65-66% in dyslexic group and 75-80% in the control group. For the FWT they were 50-54% in the dyslexic group and 67-71% in the control group (student t <0.05). CONCLUSIONS: These results contribute to make evident disorders in central auditory processing in children with dyslexia. We suggest using the tests with each patient in order to elaborate a rehabilitation plan.

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