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1.
Trends Hear ; 28: 23312165241229572, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38347733

RESUMO

Subjective reports indicate that hearing aids can disrupt sound externalization and/or reduce the perceived distance of sounds. Here we conducted an experiment to explore this phenomenon and to quantify how frequently it occurs for different hearing-aid styles. Of particular interest were the effects of microphone position (behind the ear vs. in the ear) and dome type (closed vs. open). Participants were young adults with normal hearing or with bilateral hearing loss, who were fitted with hearing aids that allowed variations in the microphone position and the dome type. They were seated in a large sound-treated booth and presented with monosyllabic words from loudspeakers at a distance of 1.5 m. Their task was to rate the perceived externalization of each word using a rating scale that ranged from 10 (at the loudspeaker in front) to 0 (in the head) to -10 (behind the listener). On average, compared to unaided listening, hearing aids tended to reduce perceived distance and lead to more in-the-head responses. This was especially true for closed domes in combination with behind-the-ear microphones. The behavioral data along with acoustical recordings made in the ear canals of a manikin suggest that increased low-frequency ear-canal levels (with closed domes) and ambiguous spatial cues (with behind-the-ear microphones) may both contribute to breakdowns of externalization.


Assuntos
Auxiliares de Audição , Perda Auditiva Neurossensorial , Localização de Som , Percepção da Fala , Adulto Jovem , Humanos , Fala , Perda Auditiva Bilateral , Ruído , Percepção da Fala/fisiologia
2.
J Acoust Soc Am ; 153(5): 2780, 2023 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-37140176

RESUMO

In speech-on-speech listening experiments, some means for designating which talker is the "target" must be provided for the listener to perform better than chance. However, the relative strength of the segregation variables designating the target could affect the results of the experiment. Here, we examine the interaction of two source segregation variables-spatial separation and talker gender differences-and demonstrate that the relative strengths of these cues may affect the interpretation of the results. Participants listened to sentence pairs spoken by different-gender target and masker talkers, presented naturally or vocoded (degrading gender cues), either colocated or spatially separated. Target and masker words were temporally interleaved to eliminate energetic masking in either an every-other-word or randomized order of presentation. Results showed that the order of interleaving had no effect on recall performance. For natural speech with strong talker gender cues, spatial separation of sources yielded no improvement in performance. For vocoded speech with degraded talker gender cues, performance improved significantly with spatial separation of sources. These findings reveal that listeners may shift among target source segregation cues contingent on cue viability. Finally, performance was poor when the target was designated after stimulus presentation, indicating strong reliance on the cues.


Assuntos
Percepção da Fala , Fala , Humanos , Sinais (Psicologia) , Mascaramento Perceptivo , Percepção Auditiva
3.
J Acoust Soc Am ; 150(4): 2327, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34717459

RESUMO

Previous studies of level discrimination reported that listeners with high-frequency sensorineural hearing loss (SNHL) place greater weight on high frequencies than normal-hearing (NH) listeners. It is not clear whether these results are influenced by stimulus factors (e.g., group differences in presentation levels, cross-frequency discriminability of level differences used to measure weights) and whether such weights generalize to other tasks. Here, NH and SNHL weights were measured for level, duration, and frequency discrimination of two-tone complexes after measuring discriminability just-noticeable differences for each frequency and stimulus dimension. Stimuli were presented at equal sensation level (SL) or equal sound pressure level (SPL). Results showed that weights could change depending on which frequency contained the more discriminable level difference with uncontrolled cross-frequency discriminability. When cross-frequency discriminability was controlled, weights were consistent for level and duration discrimination, but not for frequency discrimination. Comparing equal SL and equal SPL weights indicated greater weight on the higher-level tone for level and duration discrimination. Weights were unrelated to improvements in recognition of low-pass-filtered speech with increasing cutoff frequency. These results suggest that cross-frequency weights and NH and SNHL weighting differences are influenced by stimulus factors and may not generalize to the use of speech cues in specific frequency regions.


Assuntos
Perda Auditiva Neurossensorial , Percepção da Fala , Limiar Auditivo , Sinais (Psicologia) , Audição , Perda Auditiva Neurossensorial/diagnóstico , Humanos , Fala
4.
Trends Hear ; 24: 2331216520945516, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32853117

RESUMO

Many listeners with sensorineural hearing loss have uneven hearing sensitivity across frequencies. This study addressed whether this uneven hearing loss leads to a biasing of attention to different frequency regions. Normal-hearing (NH) and hearing-impaired (HI) listeners performed a pattern discrimination task at two distant center frequencies (CFs): 750 and 3500 Hz. The patterns were sequences of pure tones in which each successive tonal element was randomly selected from one of two possible frequencies surrounding a CF. The stimuli were presented at equal sensation levels to ensure equal audibility. In addition, the frequency separation of the tonal elements within a pattern was adjusted for each listener so that equal pattern discrimination performance was obtained for each CF in quiet. After these adjustments, the pattern discrimination task was performed under conditions in which independent patterns were presented at both CFs simultaneously. The listeners were instructed to attend to the low or high CF before the stimulus (assessing selective attention to frequency with instruction) or after the stimulus (divided attention, assessing inherent frequency biases). NH listeners demonstrated approximately equal performance decrements (re: quiet) between the two CFs. HI listeners demonstrated much larger performance decrements at the 3500 Hz CF than at the 750 Hz CF in combined-presentation conditions for both selective and divided attention conditions, indicating a low-frequency attentional bias that is apparently not under subject control. Surprisingly, the magnitude of this frequency bias was not related to the degree of asymmetry in thresholds at the two CFs.


Assuntos
Surdez , Perda Auditiva Neurossensorial , Atenção , Limiar Auditivo , Audição , Perda Auditiva Neurossensorial/diagnóstico , Humanos
5.
Appl Psycholinguist ; 41(2): 381-400, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34121781

RESUMO

Memory for speech benefits from linguistic structure. Recall is better for sentences than for random strings of words (the "sentence superiority effect"; SSE), and evidence suggests that ongoing speech may be organized advantageously as clauses in memory (recall by word position shows within-clause "U shape"). In this study, we examined the SSE and clause-based organization for closed-set speech materials with low semantic predictability and without typical prosody. An overall SSE was observed and accuracy by word position was enhanced at the clause boundaries for these materials. Next, we tested the effects of mental manipulation on the SSE and clause-based organization. Listeners heard word strings that were syntactic, were arranged syntactically then presented backwards, or were random draws. Participants responded to materials as presented or in reversed order, requiring mental manipulation. Clause-level organization was apparent only for materials presented in syntactic order regardless of response order. After accounting for benefits due to reductions in uncertainty for these close-set materials, an SSE was present for syntactic materials regardless of response order, and for the syntactic backwards condition with reverse-order response (yielding a syntactically correct sentence in the response). Thus, the SSE was both resistant to and could be obtained following mental manipulation.

6.
J Acoust Soc Am ; 146(5): 3215, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31795657

RESUMO

When a target talker speaks in the presence of competing talkers, the listener must not only segregate the voices but also understand the target message based on a limited set of spectrotemporal regions ("glimpses") in which the target voice dominates the acoustic mixture. Here, the hypothesis that a broad audible bandwidth is more critical for these sparse representations of speech than it is for intact speech is tested. Listeners with normal hearing were presented with sentences that were either intact, or progressively "glimpsed" according to a competing two-talker masker presented at various levels. This was achieved by using an ideal binary mask to exclude time-frequency units in the target that would be dominated by the masker in the natural mixture. In each glimpsed condition, speech intelligibility was measured for a range of low-pass conditions (cutoff frequencies from 500 to 8000 Hz). Intelligibility was poorer for sparser speech, and the bandwidth required for optimal intelligibility increased with the sparseness of the speech. The combined effects of glimpsing and bandwidth reduction were well captured by a simple metric based on the proportion of audible target glimpses retained. The findings may be relevant for understanding the impact of high-frequency hearing loss on everyday speech communication.

7.
Trends Hear ; 23: 2331216519854597, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31172880

RESUMO

Speech perception in complex sound fields can greatly benefit from different unmasking cues to segregate the target from interfering voices. This study investigated the role of three unmasking cues (spatial separation, gender differences, and masker time reversal) on speech intelligibility and perceived listening effort in normal-hearing listeners. Speech intelligibility and categorically scaled listening effort were measured for a female target talker masked by two competing talkers with no unmasking cues or one to three unmasking cues. In addition to natural stimuli, all measurements were also conducted with glimpsed speech-which was created by removing the time-frequency tiles of the speech mixture in which the maskers dominated the mixture-to estimate the relative amounts of informational and energetic masking as well as the effort associated with source segregation. The results showed that all unmasking cues as well as glimpsing improved intelligibility and reduced listening effort and that providing more than one cue was beneficial in overcoming informational masking. The reduction in listening effort due to glimpsing corresponded to increases in signal-to-noise ratio of 8 to 18 dB, indicating that a significant amount of listening effort was devoted to segregating the target from the maskers. Furthermore, the benefit in listening effort for all unmasking cues extended well into the range of positive signal-to-noise ratios at which speech intelligibility was at ceiling, suggesting that listening effort is a useful tool for evaluating speech-on-speech masking conditions at typical conversational levels.


Assuntos
Mascaramento Perceptivo , Inteligibilidade da Fala , Percepção da Fala , Adulto , Percepção Auditiva , Sinais (Psicologia) , Feminino , Testes Auditivos , Humanos , Masculino , Razão Sinal-Ruído , Som , Adulto Jovem
8.
J Acoust Soc Am ; 145(1): 440, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30710924

RESUMO

The ability to identify the words spoken by one talker masked by two or four competing talkers was tested in young-adult listeners with sensorineural hearing loss (SNHL). In a reference/baseline condition, masking speech was colocated with target speech, target and masker talkers were female, and the masker was intelligible. Three comparison conditions included replacing female masker talkers with males, time-reversal of masker speech, and spatial separation of sources. All three variables produced significant release from masking. To emulate energetic masking (EM), stimuli were subjected to ideal time-frequency segregation retaining only the time-frequency units where target energy exceeded masker energy. Subjects were then tested with these resynthesized "glimpsed stimuli." For either two or four maskers, thresholds only varied about 3 dB across conditions suggesting that EM was roughly equal. Compared to normal-hearing listeners from an earlier study [Kidd, Mason, Swaminathan, Roverud, Clayton, and Best, J. Acoust. Soc. Am. 140, 132-144 (2016)], SNHL listeners demonstrated both greater energetic and informational masking as well as higher glimpsed thresholds. Individual differences were correlated across masking release conditions suggesting that listeners could be categorized according to their general ability to solve the task. Overall, both peripheral and central factors appear to contribute to the higher thresholds for SNHL listeners.


Assuntos
Perda Auditiva Neurossensorial/fisiopatologia , Percepção da Fala , Adolescente , Adulto , Limiar Auditivo , Feminino , Perda Auditiva Neurossensorial/psicologia , Humanos , Masculino , Mascaramento Perceptivo
9.
Trends Hear ; 22: 2331216518807519, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30353783

RESUMO

The perception of simple auditory mixtures is known to evolve over time. For instance, a common example of this is the "buildup" of stream segregation that is observed for sequences of tones alternating in pitch. Yet very little is known about how the perception of more complicated auditory scenes, such as multitalker mixtures, changes over time. Previous data are consistent with the idea that the ability to segregate a target talker from competing sounds improves rapidly when stable cues are available, which leads to improvements in speech intelligibility. This study examined the time course of this buildup in listeners with normal and impaired hearing. Five simultaneous sequences of digits, varying in length from three to six digits, were presented from five locations in the horizontal plane. A synchronized visual cue at one location indicated which sequence was the target on each trial. We observed a buildup in digit identification performance, driven primarily by reductions in confusions between the target and the maskers, that occurred over the course of three to four digits. Performance tended to be poorer in listeners with hearing loss; however, there was only weak evidence that the buildup was diminished or slowed in this group.


Assuntos
Perda Auditiva Bilateral/psicologia , Perda Auditiva Neurossensorial/psicologia , Audição , Ruído/efeitos adversos , Mascaramento Perceptivo , Pessoas com Deficiência Auditiva/psicologia , Inteligibilidade da Fala , Percepção da Fala , Estimulação Acústica , Adolescente , Adulto , Audiometria de Tons Puros , Limiar Auditivo , Estudos de Casos e Controles , Sinais (Psicologia) , Feminino , Perda Auditiva Bilateral/diagnóstico , Perda Auditiva Bilateral/fisiopatologia , Perda Auditiva Neurossensorial/diagnóstico , Perda Auditiva Neurossensorial/fisiopatologia , Humanos , Masculino , Estimulação Luminosa , Fatores de Tempo , Percepção Visual , Adulto Jovem
10.
J Acoust Soc Am ; 143(2): 1085, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29495693

RESUMO

The ability to identify who is talking is an important aspect of communication in social situations and, while empirical data are limited, it is possible that a disruption to this ability contributes to the difficulties experienced by listeners with hearing loss. In this study, talker identification was examined under both quiet and masked conditions. Subjects were grouped by hearing status (normal hearing/sensorineural hearing loss) and age (younger/older adults). Listeners first learned to identify the voices of four same-sex talkers in quiet, and then talker identification was assessed (1) in quiet, (2) in speech-shaped, steady-state noise, and (3) in the presence of a single, unfamiliar same-sex talker. Both younger and older adults with hearing loss, as well as older adults with normal hearing, generally performed more poorly than younger adults with normal hearing, although large individual differences were observed in all conditions. Regression analyses indicated that both age and hearing loss were predictors of performance in quiet, and there was some evidence for an additional contribution of hearing loss in the presence of masking. These findings suggest that both hearing loss and age may affect the ability to identify talkers in "cocktail party" situations.


Assuntos
Envelhecimento/psicologia , Perda Auditiva/psicologia , Ruído/efeitos adversos , Mascaramento Perceptivo , Pessoas com Deficiência Auditiva/psicologia , Reconhecimento Psicológico , Acústica da Fala , Percepção da Fala , Qualidade da Voz , Estimulação Acústica , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Audiometria da Fala , Boston , Feminino , Audição , Perda Auditiva/diagnóstico , Perda Auditiva/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , South Carolina , Adulto Jovem
11.
Ear Hear ; 39(4): 756-769, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29252977

RESUMO

OBJECTIVES: The "visually guided hearing aid" (VGHA), consisting of a beamforming microphone array steered by eye gaze, is an experimental device being tested for effectiveness in laboratory settings. Previous studies have found that beamforming without visual steering can provide significant benefits (relative to natural binaural listening) for speech identification in spatialized speech or noise maskers when sound sources are fixed in location. The aim of the present study was to evaluate the performance of the VGHA in listening conditions in which target speech could switch locations unpredictably, requiring visual steering of the beamforming. To address this aim, the present study tested an experimental simulation of the VGHA in a newly designed dynamic auditory-visual word congruence task. DESIGN: Ten young normal-hearing (NH) and 11 young hearing-impaired (HI) adults participated. On each trial, three simultaneous spoken words were presented from three source positions (-30, 0, and 30 azimuth). An auditory-visual word congruence task was used in which participants indicated whether there was a match between the word printed on a screen at a location corresponding to the target source and the spoken target word presented acoustically from that location. Performance was compared for a natural binaural condition (stimuli presented using impulse responses measured on KEMAR), a simulated VGHA condition (BEAM), and a hybrid condition that combined lowpass-filtered KEMAR and highpass-filtered BEAM information (BEAMAR). In some blocks, the target remained fixed at one location across trials, and in other blocks, the target could transition in location between one trial and the next with a fixed but low probability. RESULTS: Large individual variability in performance was observed. There were significant benefits for the hybrid BEAMAR condition relative to the KEMAR condition on average for both NH and HI groups when the targets were fixed. Although not apparent in the averaged data, some individuals showed BEAM benefits relative to KEMAR. Under dynamic conditions, BEAM and BEAMAR performance dropped significantly immediately following a target location transition. However, performance recovered by the second word in the sequence and was sustained until the next transition. CONCLUSIONS: When performance was assessed using an auditory-visual word congruence task, the benefits of beamforming reported previously were generally preserved under dynamic conditions in which the target source could move unpredictably from one location to another (i.e., performance recovered rapidly following source transitions) while the observer steered the beamforming via eye gaze, for both young NH and young HI groups.


Assuntos
Desenho de Equipamento , Fixação Ocular , Auxiliares de Audição , Perda Auditiva/reabilitação , Adolescente , Adulto , Atenção , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Processamento Espacial , Percepção da Fala , Adulto Jovem
12.
J Acoust Soc Am ; 142(4): EL369, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-29092558

RESUMO

A hearing-aid strategy that combines a beamforming microphone array in the high frequencies with natural binaural signals in the low frequencies was examined. This strategy attempts to balance the benefits of beamforming (improved signal-to-noise ratio) with the benefits of binaural listening (spatial awareness and location-based segregation). The crossover frequency was varied from 200 to 1200 Hz, and performance was compared to full-spectrum binaural and beamformer conditions. Speech intelligibility in the presence of noise or competing speech was measured in listeners with and without hearing loss. Results showed that the optimal crossover frequency depended on the listener and the nature of the interference.


Assuntos
Correção de Deficiência Auditiva/instrumentação , Sinais (Psicologia) , Auxiliares de Audição , Perda Auditiva Bilateral/reabilitação , Perda Auditiva Neurossensorial/reabilitação , Pessoas com Deficiência Auditiva/reabilitação , Percepção da Fala , Estimulação Acústica , Adulto , Audiometria da Fala , Estudos de Casos e Controles , Compreensão , Desenho de Equipamento , Feminino , Audição , Perda Auditiva Bilateral/diagnóstico , Perda Auditiva Bilateral/fisiopatologia , Perda Auditiva Bilateral/psicologia , Perda Auditiva Neurossensorial/diagnóstico , Perda Auditiva Neurossensorial/fisiopatologia , Perda Auditiva Neurossensorial/psicologia , Humanos , Masculino , Ruído/efeitos adversos , Mascaramento Perceptivo , Pessoas com Deficiência Auditiva/psicologia , Processamento de Sinais Assistido por Computador , Localização de Som , Inteligibilidade da Fala
13.
Trends Hear ; 21: 2331216517722304, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28758567

RESUMO

The aim of this study was to evaluate the performance of a visually guided hearing aid (VGHA) under conditions designed to capture some aspects of "real-world" communication settings. The VGHA uses eye gaze to steer the acoustic look direction of a highly directional beamforming microphone array. Although the VGHA has been shown to enhance speech intelligibility for fixed-location, frontal targets, it is currently not known whether these benefits persist in the face of frequent changes in location of the target talker that are typical of conversational turn-taking. Participants were 14 young adults, 7 with normal hearing and 7 with bilateral sensorineural hearing impairment. Target stimuli were sequences of 12 question-answer pairs that were embedded in a mixture of competing conversations. The participant's task was to respond via a key press after each answer indicating whether it was correct or not. Spatialization of the stimuli and microphone array processing were done offline using recorded impulse responses, before presentation over headphones. The look direction of the array was steered according to the eye movements of the participant as they followed a visual cue presented on a widescreen monitor. Performance was compared for a "dynamic" condition in which the target stimulus moved between three locations, and a "fixed" condition with a single target location. The benefits of the VGHA over natural binaural listening observed in the fixed condition were reduced in the dynamic condition, largely because visual fixation was less accurate.


Assuntos
Auxiliares de Audição , Perda Auditiva Neurossensorial/reabilitação , Orientação Espacial , Desenho de Prótese , Inteligibilidade da Fala , Adulto , Correção de Deficiência Auditiva/instrumentação , Feminino , Humanos , Masculino , Psicometria , Percepção da Fala , Adulto Jovem
14.
J Acoust Soc Am ; 141(1): 81, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-28147587

RESUMO

In many situations, listeners with sensorineural hearing loss demonstrate reduced spatial release from masking compared to listeners with normal hearing. This deficit is particularly evident in the "symmetric masker" paradigm in which competing talkers are located to either side of a central target talker. However, there is some evidence that reduced target audibility (rather than a spatial deficit per se) under conditions of spatial separation may contribute to the observed deficit. In this study a simple "glimpsing" model (applied separately to each ear) was used to isolate the target information that is potentially available in binaural speech mixtures. Intelligibility of these glimpsed stimuli was then measured directly. Differences between normally hearing and hearing-impaired listeners observed in the natural binaural condition persisted for the glimpsed condition, despite the fact that the task no longer required segregation or spatial processing. This result is consistent with the idea that the performance of listeners with hearing loss in the spatialized mixture was limited by their ability to identify the target speech based on sparse glimpses, possibly as a result of some of those glimpses being inaudible.


Assuntos
Perda Auditiva Bilateral/psicologia , Perda Auditiva Neurossensorial/psicologia , Localização de Som , Inteligibilidade da Fala , Percepção da Fala , Estimulação Acústica , Adulto , Audiometria da Fala , Vias Auditivas/fisiopatologia , Estudos de Casos e Controles , Sinais (Psicologia) , Feminino , Audição , Perda Auditiva Bilateral/diagnóstico , Perda Auditiva Bilateral/fisiopatologia , Perda Auditiva Neurossensorial/diagnóstico , Perda Auditiva Neurossensorial/fisiopatologia , Humanos , Masculino , Mascaramento Perceptivo , Adulto Jovem
15.
Trends Hear ; 202016 11 24.
Artigo em Inglês | MEDLINE | ID: mdl-27888257

RESUMO

This report introduces a new speech task based on simple questions and answers. The task differs from a traditional sentence recall task in that it involves an element of comprehension and can be implemented in an ongoing fashion. It also contains two target items (the question and the answer) that may be associated with different voices and locations to create dynamic listening scenarios. A set of 227 questions was created, covering six broad categories (days of the week, months of the year, numbers, colors, opposites, and sizes). All questions and their one-word answers were spoken by 11 female and 11 male talkers. In this study, listeners were presented with question-answer pairs and asked to indicate whether the answer was true or false. Responses were given as simple button or key presses, which are quick to make and easy to score. Two preliminary experiments are presented that illustrate different ways of implementing the basic task. In the first experiment, question-answer pairs were presented in speech-shaped noise, and performance was compared across subjects, question categories, and time, to examine the different sources of variability. In the second experiment, sequences of question-answer pairs were presented amidst competing conversations in an ongoing, spatially dynamic listening scenario. Overall, the question-and-answer task appears to be feasible and could be implemented flexibly in a number of different ways.


Assuntos
Compreensão , Percepção da Fala , Fala , Feminino , Humanos , Masculino , Ruído
16.
J Acoust Soc Am ; 140(1): 132, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27475139

RESUMO

Identification of target speech was studied under masked conditions consisting of two or four independent speech maskers. In the reference conditions, the maskers were colocated with the target, the masker talkers were the same sex as the target, and the masker speech was intelligible. The comparison conditions, intended to provide release from masking, included different-sex target and masker talkers, time-reversal of the masker speech, and spatial separation of the maskers from the target. Significant release from masking was found for all comparison conditions. To determine whether these reductions in masking could be attributed to differences in energetic masking, ideal time-frequency segregation (ITFS) processing was applied so that the time-frequency units where the masker energy dominated the target energy were removed. The remaining target-dominated "glimpses" were reassembled as the stimulus. Speech reception thresholds measured using these resynthesized ITFS-processed stimuli were the same for the reference and comparison conditions supporting the conclusion that the amount of energetic masking across conditions was the same. These results indicated that the large release from masking found under all comparison conditions was due primarily to a reduction in informational masking. Furthermore, the large individual differences observed generally were correlated across the three masking release conditions.


Assuntos
Mascaramento Perceptivo , Inteligibilidade da Fala/fisiologia , Percepção da Fala/fisiologia , Adulto , Limiar Auditivo/fisiologia , Feminino , Audição , Humanos , Masculino , Fatores Sexuais , Fala , Fatores de Tempo , Adulto Jovem
17.
J Neurosci ; 36(31): 8250-7, 2016 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-27488643

RESUMO

UNLABELLED: While conversing in a crowded social setting, a listener is often required to follow a target speech signal amid multiple competing speech signals (the so-called "cocktail party" problem). In such situations, separation of the target speech signal in azimuth from the interfering masker signals can lead to an improvement in target intelligibility, an effect known as spatial release from masking (SRM). This study assessed the contributions of two stimulus properties that vary with separation of sound sources, binaural envelope (ENV) and temporal fine structure (TFS), to SRM in normal-hearing (NH) human listeners. Target speech was presented from the front and speech maskers were either colocated with or symmetrically separated from the target in azimuth. The target and maskers were presented either as natural speech or as "noise-vocoded" speech in which the intelligibility was conveyed only by the speech ENVs from several frequency bands; the speech TFS within each band was replaced with noise carriers. The experiments were designed to preserve the spatial cues in the speech ENVs while retaining/eliminating them from the TFS. This was achieved by using the same/different noise carriers in the two ears. A phenomenological auditory-nerve model was used to verify that the interaural correlations in TFS differed across conditions, whereas the ENVs retained a high degree of correlation, as intended. Overall, the results from this study revealed that binaural TFS cues, especially for frequency regions below 1500 Hz, are critical for achieving SRM in NH listeners. Potential implications for studying SRM in hearing-impaired listeners are discussed. SIGNIFICANCE STATEMENT: Acoustic signals received by the auditory system pass first through an array of physiologically based band-pass filters. Conceptually, at the output of each filter, there are two principal forms of temporal information: slowly varying fluctuations in the envelope (ENV) and rapidly varying fluctuations in the temporal fine structure (TFS). The importance of these two types of information in everyday listening (e.g., conversing in a noisy social situation; the "cocktail-party" problem) has not been established. This study assessed the contributions of binaural ENV and TFS cues for understanding speech in multiple-talker situations. Results suggest that, whereas the ENV cues are important for speech intelligibility, binaural TFS cues are critical for perceptually segregating the different talkers and thus for solving the cocktail party problem.


Assuntos
Estimulação Acústica/métodos , Reconhecimento Fisiológico de Modelo/fisiologia , Recreação , Localização de Som/fisiologia , Percepção da Fala/fisiologia , Aglomeração , Sinais (Psicologia) , Feminino , Humanos , Masculino , Ruído , Análise e Desempenho de Tarefas , Adulto Jovem
18.
Trends Hear ; 202016 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-27059627

RESUMO

Individuals with sensorineural hearing loss (SNHL) often experience more difficulty with listening in multisource environments than do normal-hearing (NH) listeners. While the peripheral effects of sensorineural hearing loss certainly contribute to this difficulty, differences in central processing of auditory information may also contribute. To explore this issue, it is important to account for peripheral differences between NH and these hearing-impaired (HI) listeners so that central effects in multisource listening can be examined. In the present study, NH and HI listeners performed a tonal pattern identification task at two distant center frequencies (CFs), 850 and 3500 Hz. In an attempt to control for differences in the peripheral representations of the stimuli, the patterns were presented at the same sensation level (15 dB SL), and the frequency deviation of the tones comprising the patterns was adjusted to obtain equal quiet pattern identification performance across all listeners at both CFs. Tonal sequences were then presented at both CFs simultaneously (informational masking conditions), and listeners were asked either to selectively attend to a source (CF) or to divide attention between CFs and identify the pattern at a CF designated after each trial. There were large differences between groups in the frequency deviations necessary to perform the pattern identification task. After compensating for these differences, there were small differences between NH and HI listeners in the informational masking conditions. HI listeners showed slightly greater performance asymmetry between the low and high CFs than did NH listeners, possibly due to central differences in frequency weighting between groups.


Assuntos
Transtornos da Audição/diagnóstico , Reconhecimento Fisiológico de Modelo , Mascaramento Perceptivo , Pessoas com Deficiência Auditiva/psicologia , Percepção da Fala , Inquéritos e Questionários , Estimulação Acústica , Adulto , Idoso , Idoso de 80 Anos ou mais , Audiometria , Estudos de Casos e Controles , Avaliação da Deficiência , Feminino , Auxiliares de Audição , Transtornos da Audição/psicologia , Transtornos da Audição/terapia , Humanos , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Pessoas com Deficiência Auditiva/reabilitação , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Adulto Jovem
19.
J Acoust Soc Am ; 138(5): 3245-61, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26627798

RESUMO

Previous psychoacoustical and physiological studies indicate that the medial olivocochlear reflex (MOCR), a bilateral, sound-evoked reflex, may lead to improved sound intensity discrimination in background noise. The MOCR can decrease the range of basilar-membrane compression and can counteract effects of neural adaptation from background noise. However, the contribution of these processes to intensity discrimination is not well understood. This study examined the effect of ipsilateral, contralateral, and bilateral noise on the "mid-level hump." The mid-level hump refers to intensity discrimination Weber fractions (WFs) measured for short-duration, high-frequency tones which are poorer at mid levels than at lower or higher levels. The mid-level hump WFs may reflect a limitation due to basilar-membrane compression, and thus may be decreased by the MOCR. The noise was either short (50 ms) or long (150 ms), with the long noise intended to elicit the sluggish MOCR. For a tone in quiet, mid-level hump WFs improved with ipsilateral noise for most listeners, but not with contralateral noise. For a tone in ipsilateral noise, WFs improved with contralateral noise for most listeners, but only when both noises were long. These results are consistent with MOCR-induced WF improvements, possibly via decreases in effects of compression and neural adaptation.


Assuntos
Limiar Auditivo/fisiologia , Membrana Basilar/fisiologia , Cóclea/fisiologia , Limiar Diferencial/fisiologia , Ruído , Núcleo Olivar/fisiologia , Detecção de Sinal Psicológico/fisiologia , Estimulação Acústica , Adolescente , Adulto , Dominância Cerebral , Feminino , Humanos , Masculino , Psicoacústica , Reflexo/fisiologia , Adulto Jovem
20.
J Acoust Soc Am ; 137(3): 1318-35, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25786945

RESUMO

Intensity discrimination Weber fractions (WFs) measured for short, high-frequency tones in quiet are larger at mid levels than at lower or higher levels. The source of this "mid-level hump" is a matter of debate. One theory is that the mid-level hump reflects basilar-membrane compression, and that WFs decrease at higher levels due to spread-of-excitation cues. To test this theory, Experiment 1 measured the mid-level hump and growth-of-masking functions to estimate the basilar membrane input/output (I/O) function in the same listeners. Results showed the initial rise in WFs could be accounted for by the change in I/O function slope, but there was additional unexplained variability in WFs. Previously, Plack [(1998). J. Acoust. Soc. Am. 103(5), 2530-2538] showed that long-duration notched noise (NN) presented with the tone reduced the mid-level hump even with a temporal gap in the NN. Plack concluded the results were consistent with central profile analysis. However, simultaneous, forward, and backward NN were not examined separately, which may independently test peripheral and central mechanisms of the NN. Experiment 2 measured WFs at the mid-level hump in the presence of NN and narrowband noise of different durations and temporal positions relative to the tone. Results varied across subjects, but were consistent with more peripheral mechanisms.


Assuntos
Vias Auditivas/fisiologia , Discriminação Psicológica , Percepção Sonora , Ruído/efeitos adversos , Mascaramento Perceptivo , Estimulação Acústica , Adolescente , Adulto , Audiometria de Tons Puros , Sinais (Psicologia) , Feminino , Humanos , Masculino , Adulto Jovem
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