Teresa Cervera

Análisis acústico de la voz: fiabilidad de un conjunto de parámetros multidimensionales

Resumen La fiabilidad del analisis acustico de la voz es una cuestion relevante poco estudiada todavia. Se presenta aqui un estudio correlacional sobre la fiabilidad de los parametros de la voz en una muestra de 148 adultos sanos. El analisis se llevo a cabo mediante el MDVP- Multi-Dimensional Voice Program instalado en una unidad de CSL-Computerized Speech Lab de Kay Elemetrics. Por cada sujeto se obtuvieron 29 parametros de voz a partir de dos registros de la vocal /a/ sostenida. Se ofrecen los resultados generales separados por generos y la fiabilidad testretest obtenida en cada par de medidas. Los datos muestran una alta estabilidad intra-sujeto en los parametros de Frecuencia Fundamental; estabilidad aceptable en los parametros de Perturbacion de Frecuencia y de Amplitud, Ruido, Subarmonicos e Irregularidad de la voz; y una consistencia muy baja en los parametros de Temblor. Los parametros relacionados con el shimmer son mas fiables que los relacionados con el jitter. De acuerdo con los resultados obtenidos se extraen conclusiones utiles para la practica clinica.

Speech recognition and working memory capacity in young-elderly listeners: Effects of hearing sensitivity.

Young normal-hearing listeners and young-elderly listeners between 55 and 65 years of age, ranging from near-normal hearing to moderate hearing loss, were compared using different speech recognition tasks (consonant recognition in quiet and in noise, and time-compressed sentences) and working memory tasks (serial word recall and digit ordering). The results showed that the group of young-elderly listeners performed worse on both the speech recognition and working memory tasks than the young listeners. However, when pure-tone audiometric thresholds were used as a covariate variable, the significant differences between groups disappeared. These results support the hypothesis that sensory decline in young-elderly listeners seems to be an important factor in explaining the decrease in speech processing and working memory capacity observed at these ages.

Acoustic Analysis of Pathological Voices Compressedwith MPEG System

The MPEG-1 Layer 3 compression schema of audio signal, commonly known as mp3, has caused a great impact in recent years as it has reached high compression rates while conserving a high sound quality. Music and speech samples compressed at high bitrates are perceptually indistinguishable from the original samples, but very little was known about how compression acoustically affects the voice signal. A previous work with normal voices showed a high fidelity at high-bitrate compressions both in voice parameters and the amplitude-frequency spectrum. In the present work, dysphonic voices were tested through two studies. In the first study, spectrograms, long-term average spectra (LTAS), and fast Fourier transform (FFT) spectra of compressed and original samples of running speech were compared. In the second study, intensities, formant frequencies, formant bandwidths, and a multidimensional set of voice parameters were tested in a set of sustained phonations. Results showed that compression at high bitrates (96 and 128 kbps) preserved the relevant acoustic properties of the pathological voices. With compressions at lower bitrates, fidelity decreases, introducing some important alterations. Results from both works, Gonzalez and Cervera and this paper, open up the possibility of using MPEG-compression at high bitrates to store or transmit high-quality speech recordings, without altering their acoustic properties.

The effect of MPEG audio compression on multidimensional set of voice parameters

The MPEG-1 Layer 3 compression schema of audio signal, or commonly known as mp3, has caused a great impact in recent years as it has reached high compression rates while also conserving a high sound quality. Previous listening tests have shown that music and speech samples compressed at high bitrates are virtually indistinguishable from the original samples, but very little is known about how compression acoustically affects the voice signal. In Experiment 1 the spectral composition of original and compressed speech signals were analyzed by means of the Long-Term Average Spectrum using the Computerized Speech Laboratory (Kay Elemetrics Corp. (Pine Brook, NJ, USA)). In Experiment 2 a set of 29 voice parameters extracted by using the Multidimensional Voice Program of Kay are compared between original and compressed voices at different bitrates. Results show a high fidelity at high-bitrate compressions (128 and 160 kbit per second (kbps)) both in voice parameters and the amplitude-frequency spectrum. Compressions at 64 kbps or lower bitrates introduces substantial modifications in the voice signal, seriously altering parameters related with tremor, amplitude perturbation, noise, subharmonics and voice irregularities, likewise the signal spectrum is altered in its high frequency region.

Test of Spanish sentences to measure speech intelligibility in noise conditions.

This article describes the development of a test for measuring the intelligibility of speech in noise for the Spanish language, similar to the test developed by Kalikow, Stevens, and Elliot (Journal of the Acoustical Society of America, 5, 1337–1360, 1977) for the English language. The test consists of six forms, each comprising 25 high-predictability (HP) sentences and 25 low-predictability (LP) sentences. The sentences were used in a perceptual task to assess their intelligibility in babble noise across three different signal-to-noise ratio (SNR) conditions in a sample of 474 normal-hearing listeners. The results showed that the listeners obtained higher scores of intelligibility for HP sentences than for LP sentences, and the scores were lower for the higher SNRs, as was expected. The final six forms were equivalent in intelligibility and phonetic content.

Lists of Spanish sentences with equivalent predictability, phonetic content, length, and frequency of the last word.

This paper presents a pool of Spanish sentences designed for use in cognitive research and speech processing in circumstances in which the effects of context are relevant. These lists of sentences are divided into six lists of 25 equivalent high-predictability sentences and six lists of 25 low-predictability sentences according to the extent to which the last word can be predicted by the preceding context. These lists were also equivalent in phonetic content, length and frequency of the last word. These lists are intended for use in psycholinguistic research with Spanish-speaking listeners.

La adquisición de las relaciones anafóricas en castellano: clases de anáforas y el efecto de la distancia

ResumenSe ha estudiado la comprension de relaciones anaforicas escritas en 810 ninos de 8 anos y 10 meses a 10 anos y 10 meses de edad. A traves de 32 textos cortos en una tarea de lapiz y papel, se han considerado cinco clases de anaforas: pronombres personales atonos, pronombre relativo “que”, adverbio de lugar “donde”, pronombres demostrativos y el contraste “este/aquel” con valor anaforico. En cada una de ellas se ha manipulado la distancia entre el antecedentey elemento forico, obteniendo tres versiones de cada texto con el mismo significado (distancia corta, media y larga). Los resultados muestran: a) un incremento global de la comprension de las relaciones anaforicas en esas edades. b) una comprension mejor cuanto mas proximos se hallan los elementos de la anafora. c) una mejor comprension del pronombre relativo y el adverbio de lugar respecto a los pronombres personales atonos, y de estos sobre los pronombres demostrativos. d) El contraste “este/aquel” presenta un patron de respuestas cualitativam...

Influence of Articulation Rate on Two Memory Tasks in Young and Older Adults

This study investigated the relation between phonological loop functioning and age. Phonological loop is a time-based subsystem of the Working Memory Model of Baddeley and Wilson, which uses rehearsal of information as an active process to avoid phonological decay. Performance differences were examined between young and older adults in two speech-based memory tasks, such as the immediate serial recall of words and the Digit Ordering Task. Analysis showed that performance on both tasks was lower for the older group. Articulation rate was also measured to test the hypothesis that the impairment of some cognitive functions in adults can be associated to their slowness or the greater time needed by older adults for the rehearsal process. A significant negative correlation was found for articulation rate with age. When the effect of articulation rate on Serial Recall and Digit Ordering Tasks was partialled out, the difference between the two groups was eliminated.

The Effects of Linguistic Context on Word Recognition in Noise by Elderly Listeners Using Spanish Sentence Lists (SSL)

This study evaluated the effects of the linguistic context on the recognition of words in noise in older listeners using the Spanish Sentence Lists. These sentences were developed based on the approach of the SPIN test for the English language, which contains high and low predictability (HP and LP) sentences. In addition, the relative contribution of peripheral hearing sensitivity, measured by pure-tone hearing thresholds (PTA), to the performance on both types of sentences was assessed in a regression analysis. The results showed that older listeners obtained benefits on word recognition from the linguistic context. PTA contributed significantly to explaining the variance in performance on both HP and LP sentences.

Dificultades en la comprensión del habla rápida en oyentes mayores con pérdidas auditivas leves o moderadas

Objetivo En este trabajo se evaluan las dificultades de los adultos mayores, sin y con perdidas auditivas (presbiacusia y perdidas moderadas), en la comprension del habla rapida. El habla rapida es habitual en la comunicacion diaria. Sin embargo, no contamos con suficientes estudios que evaluen este problema en oyentes castellanoparlantes, tal como existen para oyentes angloparlantes. Material y metodo Se comparo el reconocimiento de frases presentadas a 3 tasas de aceleracion: normal, rapida y muy rapida, en los 3 grupos de oyentes. Estas medidas se correlacionaron con medidas audiologicas y con la puntuacion obtenida en un cuestionario de problemas de comunicacion. Resultados La ejecucion en la comprension del habla rapida fue peor en los dos grupos de oyentes con perdidas auditivas que en el grupo de audicion normal. Ademas, las correlaciones entre la comprension del habla rapida, la audiometria tonal y el cuestionario fueron significativas. Conclusiones Los resultados de este trabajo indican que las habilidades en el reconocimiento del habla rapida se deterioran cuando el sujeto tiene perdidas auditivas, sean las tipicas de la presbiacusia u otro tipo de perdidas moderadas en toda la gama de frecuencias.