Digital noise reduction in hearing aids and its acoustic effect on consonants /s/ and /z/

@#Introduction: Modulation-based noise reduction (MBNR) is one of the common noise reduction methods used in hearing aids. Gain reduction in high frequency bands may occur for some implementations of MBNR and fricatives might be susceptible to alteration, given the high frequency components in fricative noise. The main objective of this study is to quantify the acoustic effect of MBNR on /s, z/. Methods: Speech-and-noise signals were presented to, and recorded from, six hearing aids mounted on a head and torso simulator. Test stimuli were nonsense words mixed with pink, cafeteria, or speech-modulated noise at 0 dB SNR. Fricatives /s, z/ were extracted from the recordings for analysis. Results: Analysis of the noise confirmed that MBNR in all hearing aids was activated for the recordings. More than 1.0 dB of acoustic change occurred to /s, z/ when MBNR was turned on in four out of the six hearing aids in the pink and cafeteria noise conditions. The acoustics of /s, z/ by female talkers were affected more than male talkers. Significant relationships between amount of noise reduction and acoustic change of /s, z/ were found. Amount of noise reduction accounts for 42.8% and 16.8% of the variability in acoustic change for /s/ and /z/ respectively. Conclusion: Some clinically-available implementations of MBNR have measurable effects on the acoustics of fricatives. Possible implications for speech perception are discussed.

The acoustic parameters of perceptually normal voice production in Filipinos: An exploratory study among selected adults in Metro Manila

BACKGROUND AND OBJECTIVES: Acoustic analysis is an objective instrumental method that makes more accurate and reliable assessments of vocal characteristics possible. The aim of the current study was to describe the vocal characteristics of Filipinos with perceptually normal voices in terms of (1) fundamental frequency, (2) intensity, (3) frequency and intensity perturbations, (4) speaking fundamental frequency range, and (5) nasalance.METHODOLOGY: A total of 142 healthy adults aged 18 - 53 years participated in this study. The group was composed of 73 men (26.9 ± 6.4 years old) and 69 women (26.1 ± 6.5 years old). Voice samples were collected using Computerized Speech Laboratory™ (CSL; Model 4300B) during sustained phonation of vowel /a/ and spontaneous speech. Nasometer™ (Model 6200-3) was used to assess nasality while participants read plosive- and sibilant-loaded sentences.RESULTS AND CONCLUSION: The average acoustic values for males were F0 = 125.8 ± 23.4 Hz, SF0 = 122.6 ± 15.6 Hz, SF0 range = 85.8-269 Hz, SPL (speech) = 58.6 ± 5.3 dB, SPL (vowel) = 66.6 ± 6.2 dB, jitter = 0.92 ± 0.48%, shimmer = 2.21 ± 0.73%, nasalance = 12.5-17.1%; for females, F0 = 196.3 ± 23.0 Hz, SF0 = 194.8 ± 19.0 Hz, SF0 range = 97.1- 309.6Hz, SPL (speech) = 57.6 ± 4.3 dB, SPL (vowel) = 65.3 ± 4.5 dB, jitter = 1.12 ± 0.34%, shimmer = 2.7 ± 0.64%, nasalance = 13.1-19.1%. Significant differences were found between male and female subjects for F0, SF0, perturbation measures, and SPL during sustained phonation (p

Normatização de medidas acústicas para vozes normais / Standardization of acoustic measures for normal voice patterns

Pesquisas têm estabelecido que cada serviço deve estabelecer seus padrões normativos para a análise acústica. O objetivo do presente estudo é normatizar as medidas de freqüência fundamental (fo), jitter, shimmer e proporção harmônico-ruído (PHR) para adultos jovens com voz normal. MÉTODO: Participaram deste estudo 20 homens e 20 mulheres, de 20 a 45 anos de idade, sem sinais e sintomas de problemas vocais, produzindo as vogais sustentadas /a/ e /é/, analisadas pelo programa CSL- 4300 Kay-Elemetrics. RESULTADOS: Para as mulheres, respectivamente para a vogal /a/ e /é/ os valores médios foram: fo de 205,82Hz e 206,56Hz; jitter de 0,62 por cento e 0,59 por cento; shimmer de 0,22dB e 0,19dB; PHR de 10,9 dB e 11,04 dB. Para os homens, respectivamente para a vogal /a/ e /é/, os valores médios foram: fo de 119,84Hz e 118,92Hz; jitter de 0,49 por cento e 0,5 por cento; shimmer de 0,22 dB e 0,21 dB; PHR de 9,56 dB e 9,63dB. As medidas de fo e PHR foram significativamente maiores para as mulheres em comparação aos homens. CONCLUSÃO: As diferenças entre os nossos resultados e os dos outros autores confirmam a necessidade de se realizar a normatização para cada programa a ser utilizado.

Studies have established that normative data is necessary for acoustic analysis. The aim of the present study is to standardize fundamental frequency measures (fo), jitter, shimmer and harmonic-noise ratio (HNR) for young adults with normal voice. METHOD: 20 males and 20 females, between 20 and 45 years, without signs and symptoms of vocal problems; CSL-4300 Kay-Elemetrics; vowels /a/ and /é/. RESULTS: for females, vowels /a/ and /é/ had average measures of: fo 205.82 Hz and 206.56 Hz; jitter of 0.62 percent and 0.59 percent; shimmer of 0.22 dB and 0.19 dB; PHR of 10.9 dB and 11.04 dB, respectively. For males, vowel /a/ and /é/ had average measures of: fo 119.84 Hz and 118.92 Hz; jitter of 0.49 percent and 0.5 percent; shimmer of 0.22 dB and 0.21 dB; HNR 9.56 dB and 9.63 dB, respectively. Both fo and NHR female measures were significantly higher than their male counterparts. CONCLUSION: our results differ from the literature; therefore, it is important to standardize the program in use.