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This study examined the contribution of perceptual and cognitive factors to speech-perception abilities in cochlear-implant (CI) users. Thirty CI users were tested on word intelligibility in sentences with and without semantic context, presented in quiet and in noise. Performance was compared with measures of spectral-ripple detection and discrimination, thought to reflect peripheral processing, as well as with cognitive measures of working memory and non-verbal intelligence. Thirty age-matched and thirty younger normal-hearing (NH) adults also participated, listening via tone-excited vocoders, adjusted to produce mean performance for speech in noise comparable to that of the CI group. Results suggest that CI users may rely more heavily on semantic context than younger or older NH listeners, and that non-auditory working memory explains significant variance in the CI and age-matched NH groups. Between-subject variability in spectral-ripple detection thresholds was similar across groups, despite the spectral resolution for all NH listeners being limited by the same vocoder, whereas speech perception scores were more variable between CI users than between NH listeners. The results highlight the potential importance of central factors in explaining individual differences in CI users and question the extent to which standard measures of spectral resolution in CIs reflect purely peripheral processing. [ABSTRACT FROM AUTHOR]

When there are constraints on the resources-equipment, manpower and time-to conduct speech intelligibility tests, the most reliable or significant SI assessor for many different types of rooms is always sought for. The purpose of this study was to determine the most significant speech intelligibility assessor in four medium classrooms. The speech intelligibility assessors tested were RT60, C50, D50, and STIPA. The data were acquired by means of sound recorder that recorded six Malay words spoken by a trained male speaker, in four medium classrooms.The recorded speech signals were analyzed by DIRAC software. The data of four speech intelligibility assessors have to be normalized before it can be analyzed by AHP. In conclusion, C50 has shown the most consistent prediction of speech intelligibility in all sampled classrooms. On the other hand, as the room gets larger, RT60 becomes significant for determining speech intelligibility in these sampled classrooms. [ABSTRACT FROM AUTHOR]

Deep learning techniques have been paramount in the last years, mainly due to their outstanding results in a number of applications, that range from speech recognition to face-based user identification. Despite other techniques employed for such purposes, Deep Boltzmann Machines (DBMs) are among the most used ones, which are composed of layers of Restricted Boltzmann Machines stacked on top of each other. In this work, we evaluate the concept of temperature in DBMs, which play a key role in Boltzmann-related distributions, but it has never been considered in this context up to date. Therefore, the main contribution of this paper is to take into account this information, as well as the impact of replacing a standard Sigmoid function by another one and to evaluate their influence in DBMs considering the task of binary image reconstruction. We expect this work can foster future research considering the usage of different temperatures during learning in DBMs. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to investigate the effects of 2nd language proficiency and linguistic uncertainty on performance and listening effort in mixed language contexts. Method: Thirteen native speakers of Dutch with varying degrees of fluency in English listened to and repeated sentences produced in both Dutch and English and presented in the presence of single-talker competing speech in both Dutch and English. Target and masker language combinations were presented in both blocked and mixed (unpredictable) conditions. In the blocked condition, in each block of trials the target--masker language combination remained constant, and the listeners were informed of both prior to beginning the block. In the mixed condition, target and masker language varied randomly from trial to trial. All listeners participated in all conditions. Performance was assessed in terms of speech reception thresholds, whereas listening effort was quantified in terms of pupil dilation. Results: Performance (speech reception thresholds) and listening effort (pupil dilation) were both affected by 2nd language proficiency (English test score) and target and masker language: Performance was better in blocked as compared to mixed conditions, with Dutch as compared to English targets, and with English as compared to Dutch maskers. English proficiency was correlated with listening performance. Listeners also exhibited greater peak pupil dilation in mixed as compared to blocked conditions for trials with Dutch maskers, whereas pupil dilation during preparation for speaking was higher for English targets as compared to Dutch ones in almost all conditions. Conclusions: Both listener's proficiency in a 2nd language and uncertainty about the target language on a given trial play a significant role in how bilingual listeners attend to speech in the presence of competing speech in different languages, but precise effects also depend on which language is serving as target and which as masker. [ABSTRACT FROM AUTHOR]

This paper presents a system for improving the quality of pronunciation error detection and correction for Qur’an recitation by Non-Arabic speakers. Most of the classical speech recognition systems are built using the Hidden Markov Model (HMM) with a Mixture of Gaussian Model (GMM). This paper attempts to enhance the GMM-HMM model’s performance by using Deep Neural Networks (DNNs). The major part of the work done in this paper is involved in the collection and processing of speakers’ data, and building and evaluation of baseline GMM system and the proposed DNN acoustic models for the Qur’an recitation framework. With the aim of solving some pronunciation problems and enhancing the overall performance of such a speech recognition system, we replace the mixture of Gaussians with a DNN. The DNN-HMM model outperforms the GMM-HMM model by 1.02% based on HTK’s word accuracy equation. By calculating the insertion results for both models, DNN-HMM showed progress by 2.59%. In addition, in substitution results, DNN-HMM shows progress with the confusion phonemes DAA by 15.09% and DHA by 17.28%. All experiments and results are presented and discussed in detail. [ABSTRACT FROM AUTHOR]

Previous research on speech perception has found an effect of ethnicity, such that the same audio clip may be rated more accented when presented with an Asian face (Rubin, Donald L. 1992. Nonlanguage factors affecting undergraduates’ judgments of nonnative English-speaking teaching assistants. Research in Higher Education 33(4). 511–531. doi: 10.1007/bf00973770). However, most previous work has concentrated on Asian non-native English speakers, and Caucasian speakers remain under-explored. In this study, listeners carried out an accentedness rating task using stimuli from first language Korean, German, and English speakers in 3 conditions: audio only, video only, and audiovisual. Korean speakers received similar accentedness ratings regardless of condition, but German speakers were rated significantly less accented in the video condition and more accented in the audiovisual condition than the audio one. This result is explained as an expectation mismatch effect, whereby, when the listeners saw a Caucasian speaker they did not expect to hear a foreign accent, but if they actually heard one it was made more salient by their expectation to the contrary. [ABSTRACT FROM AUTHOR]

Current evidence demonstrates that even though some non-native listeners can achieve native-like performance for speech perception tasks in quiet, the presence of a background noise is much more detrimental to speech intelligibility for non-native compared to native listeners. Even when performance is equated across groups, it is likely that greater listening effort is required for non-native listeners. Importantly, the added listening effort might result in increased fatigue and a reduced ability to successfully perform multiple tasks simultaneously. Task-evoked pupil responses have been demonstrated to be a reliable measure of cognitive effort and can be useful in clarifying those aspects. In this study we compared the pupil response for 23 native English speakers and 27 Italian speakers of English as a second language. Speech intelligibility was tested for sentences presented in quiet and in background noise at two performance levels that were matched across groups. Signal-to-noise levels corresponding to these sentence intelligibility levels were pre-determined using an adaptive intelligibility task. Pupil response was significantly greater in non-native compared to native participants across both intelligibility levels. Therefore, for a given intelligibility level, a greater listening effort is required when listening in a second language in order to understand speech in noise. Results also confirmed that pupil response is sensitive to speech intelligibility during language comprehension, in line with previous research. However, contrary to our predictions, pupil response was not differentially modulated by intelligibility levels for native and non-native listeners. The present study corroborates that pupillometry can be deemed as a valid measure to be used in speech perception investigation, because it is sensitive to differences both across participants, such as listener type, and across conditions, such as variations in the level of speech intelligibility. Importantly, pupillometry offers us the possibility to uncover differences in listening effort even when those do not emerge in the performance level of individuals. [ABSTRACT FROM AUTHOR]

We investigated how struggling adult readers make use of sentence context to facilitate word processing when comprehending spoken language, conditions under which print decoding is not a barrier to comprehension. Stimuli were strongly and weakly constraining sentences (as measured by cloze probability), which ended with the most expected word based on those constraints or an unexpected but plausible word. Community-dwelling adults with varying literacy skills listened to continuous speech while their EEG was recorded. Participants, regardless of literacy level, showed N400 effects yoked to the cloze probability of the targets, with larger N400 amplitudes for less expected than more expected words. However, literacy-related differences emerged in an earlier time window of 170–300 ms: higher literacy adults produced a reduced negativity for strongly predictable targets over anterior channels, similar to previously reported effects on the Phonological Mapping Negativity (PMN), whereas low-literacy adults did not. Collectively, these findings suggest that in auditory sentence processing literacy may not notably affect the incremental activation of semantic features, but that comprehenders with underdeveloped literacy skills may be less likely to engage predictive processing. Thus, basic mechanisms of comprehension may be recruited differently as a function of literacy development—even in spoken language. [ABSTRACT FROM AUTHOR]

The difference in fundamental frequency (F0) between talkers is an important cue for speaker segregation. To understand how this cue varies across sound level, Chintanpalli, Ahlstrom, and Dubno [(2014). J. Assoc. Res. Otolaryngol. 15, 823–837] collected level-dependent changes in concurrent-vowel identification scores for same- and different-F0 conditions in younger adults with normal hearing. Modeling suggested that level-dependent changes in phase locking of auditory-nerve (AN) fibers to formants and F0s may contribute to concurrent-vowel identification scores; however, identification scores were not predicted to test this suggestion directly. The current study predicts these identification scores using the temporal responses of a computational AN model and a modified version of Meddis and Hewitt's [(1992). J. Acoust. Soc. Am. 91, 233–245] F0-based segregation algorithm. The model successfully captured the level-dependent changes in identification scores of both vowels with and without F0 difference, as well as identification scores for one vowel correct. The model's F0-based vowel segregation was controlled using the actual F0-benefit across levels such that the predicted F0-benefit matched qualitatively with the actual F0-benefit as a function of level. The quantitative predictions from this F0-based segregation algorithm demonstrate that temporal responses of AN fibers to vowel formants and F0s can account for variations in identification scores across sound level and F0-difference conditions in a concurrent-vowel task. [ABSTRACT FROM AUTHOR]

Background: The voice carries various information produced by vibrations of the vocal cords and the vocal tract. Though many studies have reported a relationship between vocal acoustic features and depression, including mel-frequency cepstrum coefficients (MFCCs) which applied to speech recognition, there have been few studies in which acoustic features allowed discrimination of patients with depressive disorder. Vocal acoustic features as biomarker of depression could make differential diagnosis of patients with depressive state. In order to achieve differential diagnosis of depression, in this preliminary study, we examined whether vocal acoustic features could allow discrimination between depressive patients and healthy controls.Methods: Subjects were 36 patients who met the criteria for major depressive disorder and 36 healthy controls with no current or past psychiatric disorders. Voices of reading out digits before and after verbal fluency task were recorded. Voices were analyzed using OpenSMILE. The extracted acoustic features, including MFCCs, were used for group comparison and discriminant analysis between patients and controls.Results: The second dimension of MFCC (MFCC 2) was significantly different between groups and allowed the discrimination between patients and controls with a sensitivity of 77.8% and a specificity of 86.1%. The difference in MFCC 2 between the two groups reflected an energy difference of frequency around 2000-3000Hz.Conclusions: The MFCC 2 was significantly different between depressive patients and controls. This feature could be a useful biomarker to detect major depressive disorder.Limitations: Sample size was relatively small. Psychotropics could have a confounding effect on voice. [ABSTRACT FROM AUTHOR]

Vowels are complex sounds with four to five spectral peaks known as formants. The frequencies of the two lowest formants, F1 and F2, are sufficient for vowel discrimination. Behavioral studies show that many birds and mammals can discriminate vowels. However, few studies have quantified thresholds for formant-frequency discrimination. The present study examined formant-frequency discrimination in budgerigars (Melopsittacus undulatus) and humans using stimuli with one or two formants and a constant fundamental frequency of 200 Hz. Stimuli had spectral envelopes similar to natural speech and were presented with random level variation. Thresholds were estimated for frequency discrimination of F1, F2, and simultaneous F1 and F2 changes. The same two-down, one-up tracking procedure and single-interval, two-alternative task were used for both species. Formant-frequency discrimination thresholds were as sensitive in budgerigars as in humans and followed the same patterns across all conditions. Thresholds expressed as percent frequency difference were higher for F1 than for F2, and were unchanged between stimuli with one or two formants. Thresholds for simultaneous F1 and F2 changes indicated that discrimination was based on combined information from both formant regions. Results were consistent with previous human studies and show that budgerigars provide an exceptionally sensitive animal model of vowel feature discrimination. [ABSTRACT FROM AUTHOR]

Within search-on-speech, Spoken Term Detection (STD) aims to retrieve data from a speech repository given a textual representation of a search term. This paper presents an international open evaluation for search-on-speech based on STD in Spanish and an analysis of the results. The evaluation has been designed carefully so that several analyses of the main results can be carried out. The evaluation consists in retrieving the speech files that contain the search terms, providing their start and end times, and a score value that reflects the confidence given to the detection. Two different Spanish speech databases have been employed in the evaluation: MAVIR database, which comprises a set of talks from workshops, and EPIC database, which comprises a set of European Parliament sessions in Spanish. We present the evaluation itself, both databases, the evaluation metric, the systems submitted to the evaluation, the results, and a detailed discussion. Five different research groups took part in the evaluation, and ten different systems were submitted in total. We compare the systems submitted to the evaluation and make a deep analysis based on some search term properties (term length, within-vocabulary/out-of-vocabulary terms, single-word/multi-word terms, and native (Spanish)/foreign terms). [ABSTRACT FROM AUTHOR]

A new set of features and feature enhancement techniques are proposed to recognize emotion and stress from speech signal. The speech waveforms and the glottal waveforms (derived from the recorded emotional/stress speech waveforms) were processed by using third order statistics called bispectrum and 28 (14 from speech waveforms and 14 from glottal waveforms) bispectral based features. In this work, mean shift clustering was used to enhance the discrimination ability of the extracted Bispectral Features (BSFs). Four classifiers were used to distinguish different emotional and stressed states. The performance of the proposed method is tested with three databases. Different experiments were conducted and recognition rates were achieved in the range between 93.44% and 100% for Berlin emotional speech database (BES), between 73.81% and 97.23% for Surrey audio-visual expressed emotion database (SAVEE), between 93.8% and 100% for speech under simulated and actual stress simulated domain (SUSAS) (recognition of multi-style speech under stress-neutral, loud, lombard and anger) and 100% for SUSAS actual domain (recognition of three different levels of stress – high, medium and low). The obtained results indicate that the proposed bispectral based features and mean shift clustering provide promising results to recognize emotion and stress from speech signal. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is an increasingly prevalent cognitive disorder in which memory, language, and executive function deteriorate, usually in that order. There is a growing need to support individuals with AD and other forms of dementia in their daily lives, and our goal is to do so through speech-based interaction. Given that 33% of conversations with people with middle-stage AD involve a breakdown in communication, it is vital that automated dialogue systems be able to identify those breakdowns and, if possible, avoid them. In this article, we discuss several linguistic features that are verbal indicators of confusion in AD (including vocabulary richness, parse tree structures, and acoustic cues) and apply several machine learning algorithms to identify dialogue-relevant confusion from speech with up to 82% accuracy. We also learn dialogue strategies to avoid confusion in the first place, which is accomplished using a partially observable Markov decision process and which obtains accuracies (up to 96.1%) that are significantly higher than several baselines. This work represents a major step towards automated dialogue systems for individuals with dementia. [ABSTRACT FROM AUTHOR]

Talk is one of the greatest unreasonable individual sorts of man or lady verbal trade, as a talk test bears records the sexual introduction, underline, ethnicity, and the excited joined conditions of the speaker close to the message content. Recorded talk is an uncommonly more noteworthy grounded condition of certification appeared differently in relation to different media. The protection of talk is seen legally furthermore; in several cases it is unlawful to document a man's talk without consent. In disdain of the considerable speculative and sensible advances in privateness-allowing methods of insight, little has been realized to talk responsibilities and most extreme existing talk taking care of figurings require finish persuade section to the talk recording. On this paper, we display the trouble of privateness-ensuring talk preparing. In this shape, the system is prepared to do effectively do the test essentially like a watchword gadget. In speaker character, we make utilization of a talk recording to arrange the speaker among a relationship of individuals. This meander reveals use in comment groups wherein a prosperity venture is interested about checking if a given talk investigate is have a place with suspect . [ABSTRACT FROM AUTHOR]

Introduction: Long latency auditory evoked potentials, especially P300, have been used for clinical evaluation of mental processing. Many factors can interfere with Auditory Evoked Potential - P300 results, suggesting large intra and inter-subject variations. Objective: The objective of the study was to identify the reliability of P3 components (latency and amplitude) over 4-6 weeks and the most stable auditory stimulus with the best test-retest agreement. Methods: Ten normal-hearing women participated in the study. Only subjects without auditory processing problems were included. To determine the P3 components, we elicited long latency auditory evoked potential (P300) by pure tone and speech stimuli, and retested after 4-6 weeks using the same parameters. We identified P300 latency and amplitude by waveform subtraction. Results: We found lower coefficient of variation values in latency than in amplitude, with less variability analysis when speech stimulus was used. There was no significant correlation in latency measures between pure tone and speech stimuli, and sessions. There was a significant intrasubject correlation between measures of latency and amplitude. Conclusion: These findings show that amplitude responses are more robust for the speech stimulus when compared with its pure tone counterpart. The P300 indicated stability for latency and amplitudemeasures when the test-retest was applied. Reliability was higher for amplitude than for latency, with better agreement when the pure tone stimulus was used. However, further research with speech stimulus is needed to clarify how these stimuli are processed by the nervous system. [ABSTRACT FROM AUTHOR]

Objectives: To assess longitudinal outcomes in a large and varied population of children receiving bilateral cochlear implants both simultaneously and sequentially.Methods: This observational non-randomized service evaluation collected localization and speech recognition in noise data from simultaneously and sequentially implanted children at four time points: before bilateral cochlear implants or before the sequential implant, 1 year, 2 years, and 3 years after bilateral implants. No inclusion criteria were applied, so children with additional difficulties, cochleovestibular anomalies, varying educational placements, 23 different home languages, a full range of outcomes and varying device use were included.Results: 1001 children were included: 465 implanted simultaneously and 536 sequentially, representing just over 50% of children receiving bilateral implants in the UK in this period. In simultaneously implanted children the median age at implant was 2.1 years; 7% were implanted at less than 1 year of age. In sequentially implanted children the interval between implants ranged from 0.1 to 14.5 years. Children with simultaneous bilateral implants localized better than those with one implant. On average children receiving a second (sequential) cochlear implant showed improvement in localization and listening in background noise after 1 year of bilateral listening. The interval between sequential implants had no effect on localization improvement although a smaller interval gave more improvement in speech recognition in noise. Children with sequential implants on average were able to use their second device to obtain spatial release from masking after 2 years of bilateral listening. Although ranges were large, bilateral cochlear implants on average offered an improvement in localization and speech perception in noise over unilateral implants.Conclusion: These data represent the diverse population of children with bilateral cochlear implants in the UK from 2010 to 2012. Predictions of outcomes for individual patients are not possible from these data. However, there are no indications to preclude children with long inter-implant interval having the chance of a second cochlear implant. [ABSTRACT FROM AUTHOR]

The objectives of the study were to (1) investigate the potential of using monopolar psychophysical detection thresholds for estimating spatial selectivity of neural excitation with cochlear implants and to (2) examine the effect of site removal on speech recognition based on the threshold measure. Detection thresholds were measured in Cochlear Nucleus® device users using monopolar stimulation for pulse trains that were of (a) low rate and long duration, (b) high rate and short duration, and (c) high rate and long duration. Spatial selectivity of neural excitation was estimated by a forward-masking paradigm, where the probe threshold elevation in the presence of a forward masker was measured as a function of masker-probe separation. The strength of the correlation between the monopolar thresholds and the slopes of the masking patterns systematically reduced as neural response of the threshold stimulus involved interpulse interactions (refractoriness and sub-threshold adaptation), and spike-rate adaptation. Detection threshold for the low-rate stimulus most strongly correlated with the spread of forward masking patterns and the correlation reduced for long and high rate pulse trains. The low-rate thresholds were then measured for all electrodes across the array for each subject. Subsequently, speech recognition was tested with experimental maps that deactivated five stimulation sites with the highest thresholds and five randomly chosen ones. Performance with deactivating the high-threshold sites was better than performance with the subjects' clinical map used every day with all electrodes active, in both quiet and background noise. Performance with random deactivation was on average poorer than that with the clinical map but the difference was not significant. These results suggested that the monopolar low-rate thresholds are related to the spatial neural excitation patterns in cochlear implant users and can be used to select sites for more optimal speech recognition performance. [ABSTRACT FROM AUTHOR]

Understanding speech within an auditory scene is constantly challenged by interfering noise in suboptimal listening environments when noise hinders the continuity of the speech stream. In such instances, a typical auditory-cognitive system perceptually integrates available speech information and "fills in" missing information in the light of semantic context. However, individuals with cochlear implants (CIs) find it difficult and effortful to understand interrupted speech compared to their normal hearing counterparts. This inefficiency in perceptual integration of speech could be attributed to further degradations in the spectral-temporal domain imposed by CIs making it difficult to utilize the contextual evidence effectively. To address these issues, 20 normal hearing adults listened to speech that was spectrally reduced and spectrally reduced interrupted in a manner similar to CI processing. The Revised Speech Perception in Noise test, which includes contextually rich and contextually poor sentences, was used to evaluate the influence of semantic context on speech perception. Results indicated that listeners benefited more from semantic context when they listened to spectrally reduced speech alone. For the spectrally reduced interrupted speech, contextual information was not as helpful under significant spectral reductions, but became beneficial as the spectral resolution improved. These results suggest top-down processing facilitates speech perception up to a point, and it fails to facilitate speech understanding when the speech signals are significantly degraded. [ABSTRACT FROM AUTHOR]

Listeners compensate for variation in speaking rate: In a fast context, a given sound is interpreted as longer than in a slow context. Experimental rate manipulations have been achieved either through linear compression or by using natural fast speech. However, in natural fast speech, segments are subject to processes such as reduction or deletion. If speaking rate is then defined as the number of segments per unit time, the question arises as to what impact such processes have on listeners' normalization for speaking rate. The present study tested the effect of sentence duration and fast-speech processes on rate normalization for a German vowel duration contrast. Results showed that a naturally produced short sentence containing segmental reductions and deletions led to the most 'long' vowel responses whereas the long sentence with clearly articulated segments led to the fewest. This suggests that speaking rate is not merely calculated as the number of segments realized per unit time. Rather, listeners associate properties of natural fast speech with a higher speaking rate. This contrasts with earlier results and a second experiment in which perceived speaking rate was measured in an explicit task. Models of speech comprehension are evaluated with regard to the present findings. [ABSTRACT FROM AUTHOR]

Low-frequency acoustic cues have been shown to enhance speech perception by cochlear-implant users, particularly when target speech occurs in a competing background. The present study examined the extent to which a continuous representation of low-frequency harmonicity cues contributes to bimodal benefit in simulated bimodal listeners. Experiment 1 examined the benefit of restoring a continuous temporal envelope to the low-frequency ear while the vocoder ear received a temporally interrupted stimulus. Experiment 2 examined the effect of providing continuous harmonicity cues in the low-frequency ear as compared to restoring a continuous temporal envelope in the vocoder ear. Findings indicate that bimodal benefit for temporally interrupted speech increases when continuity is restored to either or both ears. The primary benefit appears to stem from the continuous temporal envelope in the low-frequency region providing additional phonetic cues related to manner and F1 frequency; a secondary contribution is provided by low-frequency harmonicity cues when a continuous representation of the temporal envelope is present in the low-frequency, or both ears. The continuous temporal envelope and harmonicity cues of low-frequency speech are thought to support bimodal benefit by facilitating identification of word and syllable boundaries, and by restoring partial phonetic cues that occur during gaps in the temporally interrupted stimulus. [ABSTRACT FROM AUTHOR]

Background: Speech-related disorders may refer to impairment of temporal analysis in the human auditory system. By the advance of non-invasive brain stimulation new forms of therapy arise. In the present study, we examined the neuromodulatory effect of auditory tDCS on the perception of temporal modulated speech syllables. In three experimental sessions we assessed phonetic categorization of consonant-vowels (CV)-syllables (/da/,/ta/) with varying voice onset times (VOT) during sham, anodal, and cathodal tDCS delivered bilateral to the auditory cortex (AC). Subsequently, we recorded auditory evoked potentials (AEP) in response to voiced (/ba/,/da/,/ga/) and voiceless (/pa/,/ta/,/ka/) CV-syllables.Results: In result, we demonstrate that bilateral tDCS of the AC can modulate CV-syllable perception. Behaviorally, cathodal tDCS improved phonetic categorization abilities in a VOT continuum accompanied by an elevation of the P50 amplitude of the AEP to CV-syllables during the anodal tDCS after effect.Conclusions: The present study demonstrates the ability of bilateral tDCS over the AC to ameliorate speech perception. The results may have clinical implications by fostering potential approaches for a treatment of speech-related pathologies with a deficit of temporal processing. [ABSTRACT FROM AUTHOR]

Recent developments in man-machine interaction have motivated researchers to recognize human emotion from speech signals. In this study, we propose using nonlinear dynamics features (NLDs) for emotion recognition. NLDs are extracted from the geometrical properties of the reconstructed phase space of speech signals. The traditional prosodic and spectral features are also used as a benchmark. The Fisher discriminant ratio acts as a filter to remove irrelevant features quickly. Then a wrapper method based on a genetic algorithm and support vector machine is employed to find the best feature subset that obtains the maximum recognition rate. The classification accuracy of the proposed system is evaluated using a 10-fold cross-validation technique on the Berlin database. Our results show that combining the proposed features with prosodic and spectral features notably reduces the classification ambiguity between joy and anger, which are highly confused. The NLDs further render a substantial improvement of 3.32% for females and 7.27% for males in recognition performance when used to augment prosodic and spectral features. Finally, by using all types of features for classifying 7 emotion categories, overall recognition rates of 82.72% and 85.90% are obtained for females and males, respectively. [ABSTRACT FROM AUTHOR]

This research was conducted to evaluate the efficacy of an online speech perception test (SPT) for the measurement of hearing and hearing aid fitting in comparison with conventional methods. Phase 1 was performed with 88 people to evaluate the SPT for the detection of significant hearing loss. The SPT had high sensitivity (94%) and high selectivity (98%). In Phase 2, phonetic stimulus-response matrices derived from the SPT results for 408 people were used to calculate "Infograms™." At every frequency, there was a highly significant correlation (p < 0.001) between hearing thresholds derived from the Infogram and conventional audiograms. In Phase 3, initial hearing aid fittings were derived from conventional audiograms and Infograms for two groups of hearing impaired people. Unaided and aided SPTs were used to measure the perceptual benefit of the aids for the two groups. The mean increases between unaided and aided SPT scores were 19.6%, and 22.2% (n = 517, 484; t = 2.2; p < 0.05) for hearing aids fitted using conventional audiograms and Infograms respectively. The research provided evidence that the SPT is a highly effective tool for the detection and measurement of hearing loss and hearing aid fitting. Use of the SPT reduces the costs and increases the effectiveness of hearing aid fitting, thereby enabling a sustainable teleaudiology business model. [ABSTRACT FROM AUTHOR]

Speech perception has been a very productive and important area in psycholinguistics. In this review easy, I discuss Cutler's new book on native language listening. Cutler argues for a theory of speech perception, where all speech perception is accomplished by competence in native speech. I review this book and attempt to situate its main contributions in the broader context of cognitive science. [ABSTRACT FROM AUTHOR]

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The present study aims to provide a qualitative description and comparison of speech perception performance using model based tests like multisyllabic lexical neighborhood test (MLNT) and lexical neighborhood test (LNT), in early and late implanted (prelingual) hearing impaired children using cochlear implants. The subjects comprised of cochlear implantees; Group I (early implantees)-n = 15, 3-6 years of age; mean age at implantation-3½ years. Group II (late implantees)-n = 15, 7-13 years of age; mean age at implantation-5 years. The tests were presented in a sound treated room at 70 dBSPL. The children were instructed to repeat the words on hearing them. Responses were scored as percentage of words correctly repeated. Their means were computed. The late implantees achieved higher scores for words on MLNT than those on LNT. This may imply that late implantees are making use of length cues in order to aid them in speech perception. The major phonological process used by early implantees was deletion and by the late implantees was substitution. One needs to wait until the child achieves a score of 20 % on LNT before assessing other aspects of his/her speech perception abilities. There appears to be a need to use speech perception tests which are based on theoretical empirical models, in order to enable us to give a descriptive analysis of post implant speech perception performance. [ABSTRACT FROM AUTHOR]

For bimodal cochlear implant users, acoustic and electric hearing has been shown to contribute differently to speech and music perception. However, differences in test paradigms and stimuli in speech and music testing can make it difficult to assess the relative contributions of each device. To address these concerns, the Sung Speech Corpus (SSC) was created. The SSC contains 50 monosyllable words sung over an octave range and can be used to test both speech and music perception using the same stimuli. Here SSC data are presented with normal hearing listeners and any advantage of musicianship is examined. [ABSTRACT FROM AUTHOR]

In cochlear implant (CI) recipients with unilateral hearing loss (UHL) and normal hearing (NH) in the contralateral ear, the central auditory system receives signals of different auditory modalities, i.e. electrically via the CI ear as well as acoustically via the NH ear. The present study investigates binaural integration of bimodal stimulation in the central auditory system of 10 CI subjects with UHL by applying a modified version of the Rapidly Alternating Speech Perception (RASP) test to characterise speech recognition ability under monotic and dichotic listening arrangements. Subsequently, the results for each monotic and dichotic test condition were compared to quantify the binaural benefit from CI usage. The study results demonstrate significantly improved speech recognition under dichotic compared to monotic listening conditions, providing evidence that there is binaural integration of acoustically and electrically transmitted speech segments in the central nervous system at brainstem and cortical levels. In contrast to more commonly used tests of binaural integration, such as localisation, the RASP test provides the clinical option to investigate binaural integration involving structures at the cortical level. © 2015 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Purpose: to evaluate and compare the performance of elderly people with and without cochlear dead regions in speech recognition tests, in silence and in noise, using hearing aids with and without the activation of the nonlinear frequency compression algorithm. Methods: 38 elderly people with mild to moderate hearing loss and descending configuration, distributed based on the results of the white noise masking technique, in: Group A - 24 elderly people without evidence of cochlear dead regions; Group B - 14 elderly people with evidence of cochlear dead regions. The Lists of Sentences in Portuguese test was applied, seeking the Percentage Index of Sentence Recognition in Silence and in noise. The measurements were obtained using the hearing aids without and with nonlinear frequency compression. Results: both Group A and Group B showed statistically significant improvement in silence with the hearing aids with the algorithm; in noise no group presented significant difference without and with frequency compression. Comparing the groups, there was no significant difference in silence without and with frequency compression. In noise without the algorithm there was significant difference, Group B being the better of the two. In noise without frequency compression there was no significant difference. Conclusion: in silence, both groups presented significant improvement in performance using hearing aids with frequency compression. In noise, there was no difference between the results without or with frequency compression. Comparing the groups, the measurement obtained in noise with hearing aids without the algorithm was the only one that presented significant difference, in which the group with cochlear dead regions presented better performance. [ABSTRACT FROM AUTHOR]

Objective To report a case of cochlear ossification as a result of neurosarcoidosis in a patient with bilateral profound sensorineural hearing loss. Study design Case report. Setting University teaching hospital, tertiary referral center. Patient Forty-year-old man with neurosarcoidosis and bilateral profound sensorineural hearing loss. Intervention Unilateral cochlear implantation. Outcome measure Aided thresholds speech perception tests. Results Marked improvement in hearing following implant. Conclusion Patients with neurosarcoidosis are at risk of labyrinthitis ossificans. Early imaging of these patients is recommended and if early cochlear ossification is identified they should be offered rapid access to rehabilitation with a cochlear implant. [ABSTRACT FROM AUTHOR]

Objective Screening for cognitive impairment in the clinical or community setting is often hampered by the lack of a suitable assessment that is not overburdened with complex administration and scoring methods. We have developed non-verbal cognitive screening instrument: the Weigl Token Test (WTT) from two existing instruments, the Weigl's Colour-Form Sorting Test (WCFST) and the Token Test. The aim of this investigation is to compare the modified WTT with a battery of 'Gold Standard' cognitive assessments, to determine its utility, sensitivity and specificity as a brief cognitive screen in a cohort of Parkinson's disease (PD) patients. Methods A total of 50 PD patients consented to participate in this investigation. All participants were assessed with a battery of cognitive screening instruments including the WCFST, Mini Mental Status Examination, Addenbrooke's Cognitive Examination-Revised and Delis Kaplan Executive Function Systems. The sensitivity and specificity of the WTT to detect cognitive impairment were based upon psychiatric interview, neuropsychological assessment and application of DSM-IV criteria. Results The optimal cut-point of the WTT was 116/120, and its sensitivity and specificity to detect cognitive impairment were 88% and 89%, respectively. The diagnostic accuracy of the WTT as calculated by the area under the receiver operating curve was 0.83 (95% CI 0.76-0.95), suggesting that this instrument has acceptable psychometric properties to discriminate between case and non-cases of cognitive impairment. Conclusions The WTT demonstrated excellent concurrent validity with existing 'Gold Standard' assessments of cognitive impairment. We believe that this instrument will prove to be a valuable additional screening assessment in epidemiological, primary care, specialist mental health or clinical investigations. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Purpose: to analyze the relation between speech perception tests in cochlear implant users. Methods: questionnaires and speech perception tests were applied in 25 individuals from both genders with sensorioneural hearing loss and users of unilateral cochlear implant. Results: 48% of the participants had a good performance (50%) on speech perception tests. The participants who had the best results are not the ones with higher auditory age. 12 participants had a score higher than 50% and 10 (83%) of those, did the cochlear implant surgery before 5 years old. The use of hearing aid contralateral to the cochlear implant had a significant influence on the participants performances on tests. The participants who started using hearing aids earlier did not have the best results on the tests. Conclusion: the early activation of the cochlear implant is an important variable on the tests performance. The use of hearing aid contralateral to the cochlear implant had a significant influence on the speech recognition tests. [ABSTRACT FROM AUTHOR]

This prospective study aimed to determine speech understanding in neurofibromatosis type II (NF2) patients following implantation of a MED-EL COMBI 40+ auditory brainstem implant (ABI). Patients (n = 32) were enrolled postsurgically. Nonauditory side effects were evaluated at fitting and audiological performance was determined using the Sound Effects Recognition Test (SERT), Monosyllable-Trochee-Polysyllable (MTP) test and open-set sentence tests. Subjective benefits were determined by questionnaire. ABI activation was documented in 27 patients, 2 patients were too ill for testing and 3 patients were without any auditory perception. SERT and MTP outcomes under auditory-only conditions improved significantly between first fitting and 12-month follow-up. Open-set sentence recognition improved from 5% at first fitting to 37% after 12 months. The number of active electrodes had no significant effect on performance. All questionnaire respondents were 'satisfied' to 'very satisfied' with their ABI. An ABI is an effective treatment option in NF2 patients with the potential to provide open-set speech recognition and subjective benefits. To our knowledge, the data presented herein is exceptional in terms of the open-set speech perception achieved in NF2 patients. © 2013 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

We conducted two experiments to examine the influences of stimulus set size (the number of stimuli that are used throughout the session) and intertrial interval (ITI, the elapsed time between trials) in auditory short-term memory in monkeys. We used an auditory delayed matching-to-sample task wherein the animals had to indicate whether two sounds separated by a 5-s retention interval were the same (match trials) or different (nonmatch trials). In Experiment 1, we randomly assigned stimulus set sizes of 2, 4, 8, 16, 32, 64, or 192 (trial-unique) for each session of 128 trials. Consistent with previous visual studies, overall accuracy was consistently lower when smaller stimulus set sizes were used. Further analyses revealed that these effects were primarily caused by an increase in incorrect 'same' responses on nonmatch trials. In Experiment 2, we held the stimulus set size constant at four for each session and alternately set the ITI at 5, 10, or 20 s. Overall accuracy improved when the ITI was increased from 5 to 10 s, but it was the same across the 10- and 20-s conditions. As in Experiment 1, the overall decrease in accuracy during the 5-s condition was caused by a greater number of false 'match' responses on nonmatch trials. Taken together, Experiments 1 and 2 showed that auditory short-term memory in monkeys is highly susceptible to proactive interference caused by stimulus repetition. Additional analyses of the data from Experiment 1 suggested that monkeys may make same-different judgments on the basis of a familiarity criterion that is adjusted by error-related feedback. [ABSTRACT FROM AUTHOR]

Purpose: investigate the difference in the signal to noise ratio in subjects exposed and not exposed to occupational noise, with and without hearing loss using the Hearing in Noise Test, version in Portuguese of Brazil. Method: 206 subjects, 49 females and 157 males were evaluated and divided : 56 normal hearing without noise exposure (Group 1); 70 normal hearing exposed to occupational noise (Group 2); 80 exposed occupational noise with sensorineural hearing loss (Group 3). We analyzed the signal to noise ratio using the HINT Brazil in four presentation conditions: S-no noise, NF-noise front, NR-noise right, NL- noise left; RC-noise composite (weighted average of presentations with noise ) and the results were recorded in dB. Results: the mean values obtained were: G1: 25.0 (S), -5.0 (NF), -12.3 (NR), -12.4 (NL) and -8.7 (NC); G2 : 26.4 (S), -4.7 (NF), -11.9 (NR), -11.9 (NL) and -8.3 (NC); G3: 34.1 (S) - 2.8 (NF), -8.9 (NR), -8.8 (NL), -5.8 (NC). Conclusion: there was significant difference between the values of the group of unexposed subjects (G1) with the above (G2) only on condition Noise Composite (NC). The group of subjects with hearing loss (G3) showed a significant difference in the groups G1 and G2, with worse performance in all conditions. The worst performance for speech understanding in noise was related to the degree of hearing loss and noise exposure. [ABSTRACT FROM AUTHOR]

This paper presents results of research which aimed to describe the cognitive performance on tests of language in 6-14-year-old. In this study, the researchers chose a sample population of 92 participants coming from different socioeconomic strata. That is why tests of language, tests of controlled association, Boston Naming Test, and Token Test were applied. [ABSTRACT FROM AUTHOR]

Evaluation of speech perception in noisy environments for normally hearing children was conducted in order to provide normal data for speech perception testing in children with hearing impairments thus improving early intervention alternatives for Mandarin-speaking children with hearing impairments. The speech perception abilities of 174 developmentally normal children ranging aged 2-5 years, in four age groups, were evaluated in environments that were quiet or with high levels of competing noise using the Mandarin pediatric speech intelligibility (MPSI) test. The mean score of MPSI between the four age groups showed notable statistical differences, including a variation in mean score between the four age groups, clearly indicating that the speech perception abilities of young children in noisy environments improved greatly with age, most notably between the ages of 3 and 4 years old. Speech perception ability in noisy environments was shown to be significantly, but weakly, related to age, implying the presence of other, possibly environment factors, in speech perception development. Furthermore, no statistically significant difference between boys and girls was noted in the experimental MPSI scores. The ability of children to increasingly perceive speech in environments containing high competing noise levels was shown to gradually and progressively increase with age. These results indicated that the developing Mandarin speech perception abilities in noisy environments in normal hearing children develops substantially after the age of 3-4 years, suggesting that similar age ranges may be even more critical intervention points for children with hearing impairments. More studies are still needed to confirm that. [ABSTRACT FROM AUTHOR]

Introduction: In recent years, the benefits associated with the use of cochlear implants (CIs), especially with regard to speech perception, have proven to surpass those produced by the use of hearing aids, making CIs a highly efficient resource for patients with severe/profound hearing loss. However, few studies so far have assessed the satisfaction of adult users of CIs. Objective: To analyze the relationship between the level of speech perception and degree of satisfaction of adult users of CI. Method: This was a prospective cross-sectional study conducted in the Audiological Research Center (CPA) of the Hospital of Craniofacial Anomalies, University of São Paulo (HRAC/USP), in Bauru, São Paulo, Brazil. A total of 12 users of CIs with prelingual or post-lingual hearing loss participated in this study. The following tools were used in the assessment: a questionnaire, "Satisfaction with Amplification in Daily Life" (SADL), culturally adapted to Brazilian Portuguese, as well as its relationship with the speech perception results; a speech perception test under quiet conditions; and the Hearing in Noise Test (HINT) Brazil under free field conditions. Results: The participants in the study were on the whole satisfied with their devices, and the degree of satisfaction correlated positively with the ability to perceive monosyllabic words under quiet conditions. The satisfaction did not correlate with the level of speech perception in noisy environments. Conclusion: Assessments of satisfaction may help professionals to predict what other factors, in addition to speech perception, may contribute to the satisfaction of CI users in order to reorganize the intervention process to improve the users' quality of life. [ABSTRACT FROM AUTHOR]

Auditory-verbal short-term memory deficits (STM) are prevalent in aphasia and can contribute to sentence comprehension deficits. This study investigated the effectiveness of a novel STM treatment in improving STM (measured with span tasks) and sentence comprehension (measured with the Token Test and the Test for the Reception of Grammar, TROG) in a person with severe aphasia (transcortical motor). In particular, the research questions were: (1) Would STM training improve STM? (2) Would improvements from the STM training generalise to improvements in comprehension of sentences? STM was trained using listening span tasks of serial word recognition. No other language or sentence comprehension skills were trained. Following treatment, STM abilities improved (listening span, forward digit span). There was also evidence of generalisation to untreated sentence comprehension (only on the TROG). Backward digit span, phonological processing and single word comprehension did not improve. Improvements in sentence comprehension may have resulted from resilience to rapid decay of linguistic representations within sentences (words and phrases). This in turn facilitated comprehension. [ABSTRACT FROM PUBLISHER]

Congenital amusia is a lifelong disorder of music processing that has been ascribed to impaired pitch perception and memory. The present study tested a large group of amusics (n = 17) and provided evidence that their pitch deficit affects pitch processing in speech to a lesser extent: Fine-grained pitch discrimination was better in spoken syllables than in acoustically matched tones. Unlike amusics, control participants performed fine-grained pitch discrimination better for musical material than for verbal material. These findings suggest that pitch extraction can be influenced by the nature of the material (music vs speech), and that amusics' pitch deficit is not restricted to musical material, but extends to segmented speech events. [ABSTRACT FROM AUTHOR]

This study investigated the relationship between audibility and predictions of speech recognition for children and adults with normal hearing. The Speech Intelligibility Index (SII) is used to quantify the audibility of speech signals and can be applied to transfer functions to predict speech recognition scores. Although the SII is used clinically with children, relatively few studies have evaluated SII predictions of children's speech recognition directly. Children have required more audibility than adults to reach maximum levels of speech understanding in previous studies. Furthermore, children may require greater bandwidth than adults for optimal speech understanding, which could influence frequency-importance functions used to calculate the SII. Speech recognition was measured for 116 children and 19 adults with normal hearing. Stimulus bandwidth and background noise level were varied systematically in order to evaluate speech recognition as predicted by the SII and derive frequency-importance functions for children and adults. Results suggested that children required greater audibility to reach the same level of speech understanding as adults. However, differences in performance between adults and children did not vary across frequency bands. [ABSTRACT FROM AUTHOR]

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) of bandwidth for the perception /s/ between different groups at 1 KHz, 2 KHz, 3 KHz, 4 KHz, 5 KHz, 6 KHz, 7 KHz and 8 KHz and no 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. [ABSTRACT FROM AUTHOR]

Purpose: to quantify the signal-to-noise ratios in which the sentence recognition in the noise (SRN) in the sound field can be obtained. The research aimed at subjects with normal hearing and subjects with sensorineural hearing loss and compared the results for both groups. Method: 62 subjects took part in the study, their age ranged from 18 to 64 years old, among these 32 had normal hearing and 30 had sensorineural hearing loss varying from mild to moderately severe degree. The exams were performed in an acoustical booth. The sentences were evaluated in the presence of a competitive noise, making use of the Sentences List in Portuguese. Results: for the group of people with normal hearing, the SRN were obtained at the S/R ratio of -7,57 dB and for the group with hearing loss the SRN were obtained at the S/R ratio of -2,10 dB. The statistical analysis showed a statistically significant difference between the SRN among the groups (p<0,001). Conclusions: the signal-to-noise ratios where the SRN obtained, in the sound field, and were -7,57 dB for normal hearing subjects and -2,10 dB for subjects with sensorineural hearing loss; there was a statistically significant difference among the results of the studied groups. [ABSTRACT FROM AUTHOR]

The masking effect of a piano composition, played at different speeds and in different octaves, on speech-perception thresholds was investigated in 15 normal-hearing and 14 moderately--hearing-impaired subjects. Running speech (just follow conversation, JFC) testing and use of hearing aids increased the everyday validity of the findings. A comparison was made with standard audiometric noises [International Collegium of Rehabilitative Audiology (ICRA) noise and speech spectrum--filtered noise (SPN)]. All masking sounds, music or noise, were presented at the same equivalent sound level (50 dBA). The results showed a significant effect of piano performance speed and octave (P<.01). Low octave and fast tempo had the largest effect; and high octave and slow tempo, the smallest. Music had a lower masking effect than did ICRA noise with two or six speakers at normal vocal effort (P<.01) and SPN (P<.05). Subjects with hearing loss had higher masked thresholds than the normal-hearing subjects (P<.01), but there were smaller differences between masking conditions (P<.01). It is pointed out that music offers an interesting opportunity for studying masking under realistic conditions, where spectral and temporal features can be varied independently. The results have implications for composing music with vocal parts, designing acoustic environments and creating a balance between speech perception and privacy in social settings. [ABSTRACT FROM AUTHOR]

We are developing technology to translate acoustic characteristics of speech into visual cues that can be used to supplement speech reading when hearing is limited. Research and theory have established that perceivers are influenced by multiple sources of sensory and contextual information in spoken language processing. Previous research has also shown that additional sources of information can be learned and used to supplement those that are normally available but have been degraded by sensory impairment or difficult environments. We tested whether people can combine or integrate information from the face and information from newly learned cues in an optimal manner. Subjects first learned the visual cues and then were tested under three conditions. Words were presented with just the face, just the visual cues, or both together. Performance was much better with both cues than with either one alone. Similar to the description of previous results with audible and visible speech, the present results were well described by the Fuzzy Logical Model of Perception (Massaro, 1998), which predicts optimal or maximally efficient integration. [ABSTRACT FROM AUTHOR]

Residual acoustic hearing can be preserved in the same ear following cochlear implantation with minimally traumatic surgical techniques and short-electrode arrays. The combined electric-acoustic stimulation significantly improves cochlear implant performance, particularly speech recognition in noise. The present study measures simultaneous masking by electric pulses on acoustic pure tones, or vice versa, to investigate electric-acoustic interactions and their underlying psychophysical mechanisms. Six subjects, with acoustic hearing preserved at low frequencies in their implanted ear, participated in the study. One subject had a fully inserted 24 mm Nucleus Freedom array and five subjects had Iowa/Nucleus hybrid implants that were only 10 mm in length. Electric masking data of the long-electrode subject showed that stimulation from the most apical electrodes produced threshold elevations over 10 dB for 500, 625, and 750 Hz probe tones, but no elevation for 125 and 250 Hz tones. On the contrary, electric stimulation did not produce any electric masking in the short-electrode subjects. In the acoustic masking experiment, 125-750 Hz pure tones were used to acoustically mask electric stimulation. The acoustic masking results showed that, independent of pure tone frequency, both long- and short-electrode subjects showed threshold elevations at apical and basal electrodes. The present results can be interpreted in terms of underlying physiological mechanisms related to either place-dependent peripheral masking or place-independent central masking. [ABSTRACT FROM AUTHOR]

How are laminar circuits of neocortex organized to generate conscious speech and language percepts? How does the brain restore information that is occluded by noise, or absent from an acoustic signal, by integrating contextual information over many milliseconds to disambiguate noise-occluded acoustical signals? How are speech and language heard in the correct temporal order, despite the influence of contexts that may occur many milliseconds before or after each perceived word? A neural model describes key mechanisms in forming conscious speech percepts, and quantitatively simulates a critical example of contextual disambiguation of speech and language; namely, phonemic restoration. Here, a phoneme deleted from a speech stream is perceptually restored when it is replaced by broadband noise, even when the disambiguating context occurs after the phoneme was presented. The model describes how the laminar circuits within a hierarchy of cortical processing stages may interact to generate a conscious speech percept that is embodied by a resonant wave of activation that occurs between acoustic features, acoustic item chunks, and list chunks. Chunk-mediated gating allows speech to be heard in the correct temporal order, even when what is heard depends upon future context. [ABSTRACT FROM AUTHOR]