Female Talkers Research Articles

Effect of talker sex on infants’ detection of spondee words in a two-talker or a speech-shaped noise masker

Speech recognition performance in the presence of competing speech is typically better for adults when the target and masker talkers are different sexes than when the target and masker talkers are the same sex. One explanation for this result is that the acoustic differences between male and female speech productions promote segregation of the two streams of speech, thus leading to a reduction in informational masking. In this study, an observer-based psychophysical procedure was used to compare infants’ (7–13 months) masked speech detection thresholds for spondee words produced by a male or a female talker in either a two-female-talker or a speech-shaped noise masker. Infants were assigned to a single testing condition. Maskers were presented continuously throughout testing at an overall level of 50 dB SPL, fixed throughout testing. Following training to an 80%-correct criterion, thresholds for the target word were measured adaptively using a 2-down, 1-up procedure. Infants’ thresholds in the two-female-talker masker were higher for the female compared to the male target word. In contrast, infants’ thresholds were similar for the female and male target words in the speech-shaped noise masker. These results suggest that introducing a different sex between the target and masker aids in the segregation of sounds for infants, as has previously been shown for adults. [Work supported by the NIH.]

Talker-specific perceptual adaptation during online speech perception

Despite the ubiquity of between-talker differences in accent and dialect, little is known about how listeners adjust to this source of variability as language is perceived in real time. In three experiments, we examined whether, and when, listeners can use specific knowledge of a particular talker's accent during on-line speech processing. Listeners were exposed to the speech of two talkers, a male who had an unfamiliar regional dialect of American English, in which the /æ/ vowel is raised to /ei/ only before /g/ (e.g., bag is pronounced /beig/), and a female talker without the dialect. In order to examine how knowledge of a particular talker's accent influenced language processing, we examined listeners' interpretation of unaccented words such as back and bake in contexts that included a competitor like bag. If interpretation processes are talker-specific, the pattern of competition from bag should vary depending on how that talker pronounces the competitor word. In all three experiments, listeners rapidly used their knowledge of how the talker would have pronounced bag to either rule out or include bag as a temporary competitor. Providing a cue to talker identity prior to the critical word strengthened these effects. These results are consistent with views of language processing in which multiple sources of information, including previous experience with the current talker and contextual cues, are rapidly integrated during lexical activation and selection processes.

Voice gender differences and separation of simultaneous talkers in cochlear implant users with residual hearing

Perception of a target voice in the presence of a competing talker, of same or different gender as the target, was investigated in cochlear implant users, in implant-alone and bimodal (acoustic hearing in the non-implanted ear) conditions. Recordings of two male and two female talkers acted as targets and maskers, to investigate whether bimodal benefit increased for different compared to same gender target/maskers due to increased ability to perceive and utilize fundamental frequency and spectral-shape differences. In both listening conditions participants showed benefit of target/masker gender difference. There was an overall bimodal benefit, which was independent of target/masker gender difference.

Comparison of frequency lowering algorithms on Mandarin speech recognition

This paper examined several frequency lowering algorithms for improving speech recognition in Chinese listeners with high-frequency sensorineural hearing loss, including both frequency compression and frequency transposition algorithms. The frequency lowering algorithms were evaluated by a subjective listening test. Monosyllabic words in Mandarin spoken by a female and a male talker were used as speech materials. Speech materials processed by frequency compression and frequency transposition were presented to normal-hearing listeners in the listening tests, as well as the control condition of unprocessed speech. More benefits in speech recognition were observed with speech spoken by female talker than by male talker. It was showed that frequency lowering made little difference for some words while words with dental consonant were most infected by frequency lowering. The results indicate that Mandarin recognition for high-frequency hearing loss may benefit from frequency lowering in some cases, while whether choosing frequency lowering or not and which algorithm to choose depends on individuals.

The neural basis for energetic and informational masking effects in speech perception

Functional imaging studies of speech perception have revealed extensive involvement of the dorsolateral temporal lobes in aspects of speech and voice processing. In the current study, fMRI was used as a functional imaging method to address the perception of speech in different masking conditions. Throughout the scanning experiment, subjects were directed to listen to a female talker with whom they had been familiarized previously. In addition to the acoustic noise generated by the scanner, different kinds of masking sound were also presented diotically, at SPL levels determined by pilot testing. The masking sounds were signal correlated noise, spectrally rotated speech, and a second female talker. The results show a network of activation in the bilateral temporal lobes, prefrontal cortex and parietal lobes that were commonly activated across all masking conditions. Controlling for the effects of energetic masking, informational masking gave rise exclusively to clusters of activity in bilateral STG, with peak level activations in left anterior-mid STG and posterior STS/STG and right primary auditory cortex. Post-test intelligibility measures were used to reveal greater activation in the left temporal lobe, which was associated with higher performance scores.

The Impact of Listening Condition on Background Noise Acceptance for Young Adults With Normal Hearing

To evaluate the effect of different speech conditions on background noise acceptance. A total of 23 stimulus pairings, differing in primary talker gender (female, male, conventional), number of background talkers (1, 4, 12), and gender composition of the background noise (female, male, mixed) were used to evaluate background noise acceptance. A repeated measures research design was used. Participants were 15 female and 15 male young adults with normal hearing. Background noise acceptance was evaluated with the acceptable noise level (ANL). The results revealed main effects of primary talker gender, number of background talkers, and listener gender. ANL was lower for conditions of a female primary talker and for conditions with multitalker backgrounds. Male listeners had significantly lower ANLs than female listeners. An interaction occurred between primary talker and background noise composition. For female primary talker conditions, the male talker backgrounds produced the lowest ANLs. For male primary talker conditions, the lowest ANLs were obtained with the female and male background talker conditions. Background noise acceptance depends on the listener and the stimulus condition. Stimulus selection can influence the measurement of ANL. The results support the use of the commercially available ANL materials.

The Effect of Stimulus Bandwidth on Perception of Fricative /s/ among Individuals with Different Degrees of Sensorineural Hearing Loss

Most of the speech sounds that contribute to speech intelligibility are dominated by high-frequency components. The phoneme /s/ is the third or fourth most frequently occurring phoneme in the English language and second most frequently occurring consonantal phoneme in Hindi language. Given the importance of the phoneme /s/, it is ironic that, this sound contains the highest frequency acoustic elements of any speech sound in English and most of the non-English languages ranging from 4500 Hz to more than 8000 Hz. The most common type of hearing impairment affecting speech perception is high-frequency sensorineural loss (SN) and such individuals require good high frequency audibility in order to better perceive fricative cues, regardless of hearing status. While many studies appear to support the general notion that high-frequency amplification may not always be beneficial, the inter-subject variability in most studies precludes a clearly defined rule that would distinguish listeners who are likely to benefit from high-frequency amplification from those who are not. The current study is aimed to determine and compare the effective bandwidth required for the perception of fricative /s/ in individuals with normal hearing and hearing impairment as a function of degree of hearing loss. A total of 100 Hindi speaking subjects equally divided into four groups (Group I: Normal hearing, Group II: Moderate SN hearing loss, Group III: Moderately severe SN hearing loss, Group IV: Severe SN hearing loss) participated in the study. Nonsense syllables containing the phonemes /s/, /f/, /ṣ/ and /c/ in /i/ vowel context and low pass filtered at 1, 2, 3, 4, 5, 6, 7, 8 and 9 KHz produced by a female talker were used as stimulus. The results revealed that there was a statistically significant effect (p 0.05) was seen at 9 KHz between groups. In addition, individuals with normal hearing required lower bandwidth for accurate fricative perception and there was a statistically significant difference (p<0.05) in mean bandwidth between groups. Among the hearing impaired group, as the degree of hearing loss increased the subjects required higher bandwidth for accurate perception of fricative. This study has important implications in knowing the effective bandwidth required for the perception of high frequency speech sounds among individuals with hearing loss on individual basis which in turn helps in the selection of appropriate rehabilitative devices.

Spectral contrast analyses of vowels processed through a multichannel simulated hearing aid

Hearing aids are designed to separate the audible frequency response into independent channels so that gain can be modulated correspondingly, based on the degree and configuration of the hearing loss. However, increasing the number of channels and employing fast-acting compression might lead to the spectral flattening of speech segments. In this study, we performed spectral contrast analyses on three vowels /i, oo, u/ spoken by two male and two female talkers in a /CVC/ context. The initial consonant consisted of /p, b, t, d, k, g, s, sh/ and the final consonant consisted of /t/. Each /CVC/ word was spoken in the phrase, “I said /CVC/, again” Each phrase was then processed by a simulated hearing aid having 2, 4, 8, and 16 independent channels according to an amplification scheme (linear, compression [fast-fast, slow-slow, fast-slow]). Findings revealed that spectral contrast decreased (1) as the number of channels increased, (2) when a fast attack time was employed, and (3) when the talker was a male. Further, significant spectral flattening and shifts in vowel formants occurred for /i, oo/ compared to /u/. We discuss these findings relative to the speech-intelligibility performance of impaired listeners.

Talker and gender effects in induced, simulated, and perceived stress in speech

Prior modeling on the speech correlates of psychological stress have typically reported averaged data in which the problem of quantifying degree of stress was not adequately addressed. Harnsberger, Kahan, and Hollien (2006) reported a speech database in which stress was quantified both with (two) physiological measures and (two) self-report scales. In this study, these materials were assessed in two stress perception experiments, involving ratings and classification, and the subsequent analysis was organized by gender and individual talker. Several observations were made. First, both induced and simulated stress samples were perceptibly different from baseline, unstressed samples. Second, up to one third of talkers in a given gender group differed from the overall trend, showing instead a propensity to be rated as less stressed during high degrees of physiological arousal (reflected also in self-report scales); essentially, sounding calmer under stress than the baseline condition. Third, female talkers showed the expected positive correlation between the degree of physiological shift under stress versus the shift in self-reported stress ratings while, in male subjects, higher degrees of physiological arousal were underreported in self-report (a “tough guy” response). Finally, acoustic modeling efforts were conducted by gender and stress response type, for induced, simulated, and perceived stress.

Determination of Preferred Parameters for Multichannel Compression Using Individually Fitted Simulated Hearing Aids and Paired Comparisons

To determine preferred parameters of multichannel compression using individually fitted simulated hearing aids and a method of paired comparisons. Fourteen participants with mild to moderate hearing loss listened via a simulated five-channel compression hearing aid fitted using the CAMEQ2-HF method to pairs of speech sounds (a male talker and a female talker) and musical sounds (a percussion instrument, orchestral classical music, and a jazz trio) presented sequentially and indicated which sound of the pair was preferred and by how much. The sounds in each pair were derived from the same token and differed along a single dimension in the type of processing applied. For the speech sounds, participants judged either pleasantness or clarity; in the latter case, the speech was presented in noise at a 2-dB signal-to-noise ratio. For musical sounds, they judged pleasantness. The parameters explored were time delay of the audio signal relative to the gain control signal (the alignment delay), compression speed (attack and release times), bandwidth (5, 7.5, or 10 kHz), and gain at high frequencies relative to that prescribed by CAMEQ2-HF. Pleasantness increased with increasing alignment delay only for the percussive musical sound. Clarity was not affected by alignment delay. There was a trend for pleasantness to decrease slightly with increasing bandwidth, but this was significant only for female speech with fast compression. Judged clarity was significantly higher for the 7.5- and 10-kHz bandwidths than for the 5-kHz bandwidth for both slow and fast compression and for both talker genders. Compression speed had little effect on pleasantness for 50- or 65-dB SPL input levels, but slow compression was generally judged as slightly more pleasant than fast compression for an 80-dB SPL input level. Clarity was higher for slow than for fast compression for input levels of 80 and 65 dB SPL but not for a level of 50 dB SPL. Preferences for pleasantness were approximately equal with CAMEQ2-HF gains and with gains slightly reduced at high frequencies and were lower when gains were slightly increased at high frequencies. Speech clarity was not affected by changing the gain at high frequencies. Effects of alignment delay were small except for the percussive sound. A wider bandwidth was slightly preferred for speech clarity. Speech clarity was slightly greater with slow compression, especially at high levels. Preferred high-frequency gains were close to or a little below those prescribed by CAMEQ2-HF.

Towards a New Reference Impairment System in the Subjective Evaluation of Speech Codecs

For subjective assessment of speech quality in codecs, a reference impairment system is required to introduce controlled degradations to calibrate subjective evaluation. A reference system provides a convenient means for making meaningful comparisons between subjective test results across laboratories and can be viewed as a scale on which mean opinion scores are projected, this scale being supposed to cover the whole range of quality. Nowadays, standardized anchor systems do not fit any more the degradations brought by the present codecs. This paper aims at offering new reference signals simulating the defaults of codecs currently used on telecommunication networks. Twenty wideband codecs are compared through dissimilarity tests. A multidimensional scaling technique allows us to define a four-dimensional perceptive space that appears stable for male and female talkers. A verbalization task suggests qualifying the degradations perceived by the listeners with the following attributes: muffle, background noise, noise on speech, and hiss, each conveyed by one dimension. These dimensions are correlated with objective measures such as spectral centroid, energy in the silent part in the high frequency sub-band, ratio of brightness between deterministic part and residual part of the signal and spectral correlation coefficient. New reference signals are produced and a phase of validation suggests a perceptive space quite coherent with the original one.

Determining Perceived Sound Quality in a Simulated Hearing Aid Using the International Speech Test Signal

Based on speech segments from female talkers of different languages, the International Speech Test Signal (ISTS) has speech-like acoustic properties but is not intelligible. This study investigated whether sound quality ratings for the ISTS are similar to ratings obtained for linguistically meaningful speech. A simulated hearing aid was used to process the ISTS for a variety of noise, nonlinear, linear, and combined nonlinear and linear processing conditions. The sound quality of the test conditions was rated by both normal-hearing and hearing-impaired (HI) listeners. Listeners' ratings were then modeled using the Hearing Aid Sound Quality Index (HASQI). The HASQI predictions indicated how closely the ISTS sound quality ratings were to listener ratings of American English. In the normal-hearing group, correlations between HASQI predictions and listener ratings were 0.90 for nonlinear processing, 0.78 for linear processing, and 0.88 for combined processing. In the HI group, correlations between HASQI predictions and listener ratings were 0.96 for nonlinear processing, 0.94 for linear processing, and 0.96 for combined processing. Since the ISTS is intended for use with hearing aids, the accuracy of the HASQI predictions for the HI listeners reinforces the validity of using this signal for hearing aid sound quality ratings and predictions.

Sentence recognition in noise for English-, Chinese-, and Korean-native listeners.

The present study aims to investigate the effects of background noise on English sentence recognition for English-native (EN), Chinese-native (CN), and Korean-native (KN) listeners. The hearing in Noise Test (HINT) [Nilsson et al., (1994)] was used to measure the percent correct word identification in both quiet and noise conditions. Each sentence consists of uniform length with six syllables spoken by a female talker with general unaccented dialect-free American English. Two types of noise, multitalker babble and long-term speech shaped noise (LTSSN), were presented at various singal-to-noise ratios SNRs. Preliminary data demonstrated that first, the sentence recognition of non-native listeners was significantly lower than native listeners in both quiet and noise conditions; second, both native and non-native listeners showed significant amount of masking release at each SNR (−10, −5, and 0 dB SNRs); third, there was substantial individual variability in sentence recognition within each non-native group. This variability might be related with high variability in phoneme recognition in noise for the non-native individuals.

Cochlear measures of selective auditory attention.

The possibility that selective auditory attention can affect the responses of the cochlea via the medial olivocochlear (MOC) pathway was investigated in human listeners using a nonlinear version of the stimulus-frequency otoacoustic emission (SFOAE), called the nSFOAE [Walsh et al. (2010)]. During nSFOAE recording, listeners attended to one of two competing speech streams, each composed of seven randomly-selected spoken digits that were interleaved with the nSFOAE stimuli. The talker was female in one ear and male in the other (randomized across trials). The task of the listener was to match a subset of the digits spoken by the female talker to one of two choices presented visually on a computer screen. The nSFOAE stimulus was a tone (4.0 kHz, 200 ms) presented simultaneously to the two ears, either in quiet (tone-alone) or in noise (tone-plus-noise). When nSFOAEs were measured during periods of selective attention, the tone-plus-noise responses exhibited larger maximum magnitudes, and larger changes from the tone-alone magnitudes, compared to the responses measured during a no-attention condition, in which the competing speech streams were presented, but with no digit-matching required. The differences in magnitudes across conditions were as much as 4–5 dB. [Work supported by the NIDCD.]

The development of psychometrically equivalent Cantonese speech audiometry materials

Objective: The aim of this study was to develop and psychometrically evaluate speech audiometry materials that can be used to measure word recognition (WR) and speech recognition testing (SRT) in quiet for native speakers of Cantonese. Study Sample: Commonly used bisyllabic and trisyllabic Cantonese words were digitally recorded by native male and female talkers and then evaluated by twenty normal-hearing Cantonese listeners. Design: The recorded bisyllabic words were psychometrically evaluated and arranged into four WR lists and eight half-lists that are relatively homogeneous in audibility. Using logistic regression, SRT materials were developed by selecting 28 trisyllabic words with relatively steep psychometric functions and digitally adjusting their intensity to match the listeners’ mean pure-tone average. Result: The mean psychometric slopes for the WR materials were 7.5%/dB for the male talker and 7.6%/dB for the female talker, with no statistically significant differences between the lists or half-lists. At intensity levels required for 50% intelligibility, the mean psychometric slopes of the male and female talker SRT materials were 14.5%/dB and 14.9 %/dB, respectively. Conclusion: High-quality digital recordings of Cantonese speech audiometric WR and SRT materials were developed and validated in this study. These materials are available on compact disc, indexed by talker gender.SumarioObjetivo: El propósito de este estudio fue desarrollar y evaluar psicométricamente materiales de lenguaje que puedan utilizarse en reconocimiento de palabras (WR) y en pruebas de reconocimiento del lenguaje (SRT) en silencio para hablantes nativos del cantonés. Muestra del estudio: Se grabaron digitalmente palabras bisilábicas y trisilábicas comúnmente usadas en cantonés, usando hablantes nativos, masculinos y femeninos, que luego fueron evaluadas por veinte sujetos de origen cantonés con audición normal. Diseño: Las palabras bisilábicas grabadas fueron evaluadas psicométricamente y dispuestas en cuatro listas para WR y en 8 medias listas que eran relativamente homogéneas en cuanto a audibilidad. Usando regresión logística, se desarrollaron materiales para SRT por medio de la selección de 28 palabras trisilábicas con funciones audiométricas relativamente empinadas y ajustando la intensidad digitalmente para equipararse con el promedio tonal puro de los evaluadores. Resultados: La pendiente psicométrica media de los materiales para WR fue de 7.5%/dB para hablantes masculinos y de 7.6%/dB para hablantes femeninas, sin ninguna diferencia estadísticamente significativa entre las listas y las medias listas. A la intensidad requerida para el 50% de inteligibilidad, las pendientes psicométricas medias de los materiales para SRT, con hablantes masculinos y femeninos, fueron de 14.5%/dB y 14.9 %/dB, respectivamente. Conclusión: Se desarrollaron grabaciones digitales de alta calidad para materiales audiométricos en cantonés para WR y SRT, y se validaron en este estudio. Estos materiales están disponibles en disco compacto, y clasificados por el género del hablante.

Perceptual Adaptation of Voice Gender Discrimination With Spectrally Shifted Vowels

To determine whether perceptual adaptation improves voice gender discrimination of spectrally shifted vowels and, if so, which acoustic cues contribute to the improvement. Voice gender discrimination was measured for 10 normal-hearing subjects, during 5 days of adaptation to spectrally shifted vowels, produced by processing the speech of 5 male and 5 female talkers with 16-channel sine-wave vocoders. The subjects were randomly divided into 2 groups; one subjected to 50-Hz, and the other to 200-Hz, temporal envelope cutoff frequencies. No preview or feedback was provided. There was significant adaptation in voice gender discrimination with the 200-Hz cutoff frequency, but significant improvement was observed only for 3 female talkers with F(0) > 180 Hz and 3 male talkers with F(0) < 170 Hz. There was no significant adaptation with the 50-Hz cutoff frequency. Temporal envelope cues are important for voice gender discrimination under spectral shift conditions with perceptual adaptation, but spectral shift may limit the exclusive use of spectral information and/or the use of formant structure on voice gender discrimination. The results have implications for cochlear implant users and for understanding voice gender discrimination.

Development of a Mandarin tone identification test: Sensitivity index d' as a performance measure for individual tones

Objective: The aim of this study was to develop comprehensive test material for Mandarin tone identification in noise for a male and a female talker. Additionally, the sensitivity index d' as a measure for the listeners' performance to identify individual tones was evaluated. Design: The study followed a prospective design. Study sample: The complete material comprises 72 loudness-balanced syllables in all 4 Mandarin tones. For a selection of 20 syllables, i.e. 80 test words, performance-versus-intensity functions were measured in spectrally matched noise for 16 normal-hearing participants. Results: The average speech reception thresholds in noise were −12.9 dB for the male and −13.6 dB for the female talker recordings. The corresponding slopes were 8.6%/dB and 7.3%/dB. As a performance measure for individual tones, the proportion of correct responses to specific tones was substantially contaminated by response bias. The sensitivity index d', calculated according to detection theory, provided reasonable and unbiased performance versus intensity functions. Conclusions: The results firstly indicate that the material is homogenous enough for use as a speech test in clinical work and research. Secondly, to assess the discrimination performance for individual tones, d' values outperform the simple proportion of correct responses.SumarioObjetivo: El propósito de este estudio fue desarrollar material integral de prueba para la identificación de tonos en mandarín en medio de ruido, con locutores masculinos y femeninos. Adicionalmente, se evaluó el índice de sensibilidad d', como una medida del desempeño del oyente para identificar tonos individuales. Diseño: El estudio siguió un diseño prospectivo. Muestra Del Estudio: El material completo involucró 72 sílabas con balance de intensidad subjetiva en los cuatro tonos del mandarín. Para una selección de 20 sílabas, p.e., 80 palabras de prueba, se realizaron funciones de desempeño-versus-intensidad en ruido espectral pareado para 16 participantes con audición normal. Resultados: Los umbrales promedio para recepción del lenguaje en ruido fueron de −12.9 dB para las grabaciones de locutores masculinos y −13.6 dB para locutores femeninos. Las pendientes correspondientes fueron de 8.6%/dB y 7.3%/dB. Como medida de desempeño para los tonos individuales, la proporción de respuestas correctas para tonos específicos, fue contaminada sustancialmente por sesgos de respuesta. El índice de sensibilidad d', calculado de acuerdo con la teoría de la detección, proporcionó funciones de desempeño-versus-intensidad razonables y sin sesgos. Conclusiones: Los resultados indican, primero, que el material es lo suficientemente homogéneo para ser utilizado como una prueba de lenguaje en el trabajo clínico y de investigación. Segundo, que para evaluar el desempeño en la discriminación de tonos individuales, los valores d' superan la proporción simple de respuestas correctas.

Regional dialect variation in standard Italian.

Italy is a linguistically diverse country where a standard language (standard Italian) is in contact with various regional languages. Within this setting, the regional languages have influenced the standard Italian spoken throughout Italy and regional dialects of Standard Italian have emerged. Previous studies on the regional dialects of Standard Italian have predominantly taken a descriptive approach to discussing the phonological differences between the dialects and a broad acoustic study of the dialects is lacking. The present study seeks to identify several acoustic characteristics of regional varieties of spoken standard Italian. In the study, an acoustic investigation of vowels produced by male and female talkers from Northern, Central, and Southern Italy was carried out. Acoustic measures obtained included vowel duration and first and second formant frequencies. These measures were used to examine possible dialectal differences in vowel quality, vowel duration, and the overall acoustic vowel space. From these measures, several dialect‐specific phonetic features were identified. These dialect‐specific acoustic properties will be discussed. The results of the acoustic analysis will serve as a basis for future studies investigating the acoustic properties of the regional varieties of standard Italian and for identifying the types of cues listeners might use to distinguish the dialects.

Individual differences and age effects in a dichotic informational masking paradigm

Sixty normally-hearing listeners, ages 5 to 61 years, participated in a monaural speech understanding task designed to assess the impact of a single-talker speech masker presented to the opposite ear. The speech targets were masked by ipsilateral speech-spectrum noise. Masker level was fixed and target level was varied to estimate psychometric functions. The target/masker ratio that led to 51% correct performance in this task was taken as the baseline threshold. The impact of a modulated speech-spectrum noise, a male talker, or a female talker presented at a fixed level to the contralateral ear was quantified by the change in the baseline threshold and was assumed to reflect informational masking. The modulated-noise masker produced no informational masking across the entire age range. Speech maskers produced as much as 20 dB of informational masking for children aged 5-8 years and only 4 dB for adults. In contrast with previous studies using ipsilateral speech maskers, the male and female contralateral speech maskers produced comparable informational masking. Analyses of the developmental rate of change for informational masking and of the patterns of individual differences suggest that the informational masking produced by contralateral and ipsilateral maskers may be mediated by different mechanisms or processes.

Effects of Word Recognition Score as a Function of Consonant-to-Vowel Ratio (CVR) in Korean Non-sense Syllables

Non-linear amplification may increase intensity of consonants through improvement of consonants-to-vowel ratio (CVR). In this study, we evaluated the effects of word recognition scores for nonsense consonant-vowel (CV) syllables as a function of CVR. Twenty adults (32 ears) with sensorineural hearing loss participated and five consonants (/s/, /tɕh/, /kh/, /th/, /ph/) and three vowels (/u/, /a/, /i/) were used in this study. CV syllables were recorded by male and female talkers and combined with speech noise at 5 different CVR (0, 3, 6, 9, 12 dB). Randomized list of 150 nonsense CV syllables was presented to the participants at the most comfortable level. As a results, no significant differences were observed between the male and the female talkers in nonsense syllables recognition at all CVR. However, results indicated that audibility of consonants improved when CVR increased up to 6 dB or more. Error analysis demonstrated that substitution errors were the most frequently made in word-initial position and vowels. These findings provide meaningful information about auditory rehabilitation for the Korean hearing impaired and also help audiologists to make an effective decision on the compression threshold, compression ratio, and attack and release time of non-linear hearing aids. KEY WORDS：Consonant·Consonant-to-vowel ratio (CVR)·Non-sense syllable·Vowel.