Noise Discrimination Research Articles

Phonemic discrimination and reproduction in 4-5-year-old children: Relations to hearing

ObjectiveThe long-term objective of this research is to highlight the importance of speech perception assessment in children with developmental language disorder (DLD), and to investigate how hearing contributes to speech and language skills. As a first step in fulfilling this aim, the present study explored relations between phonemic discrimination and reproduction, and sensitive measures of hearing in young healthy children. MethodsThe American Listen-Say test was developed and served as speech perception tool. This test reports speech discrimination of phonemic contrasts quantitatively for both quiet and in noise conditions, along with reproduction scores, all measured within one session. Speech tokens were perceptually homogenized in noise. Forty-one 4-5-year-old American children participated. Phonemic discrimination (quiet and speech shaped noise) and phonemic reproduction, audiometric thresholds in the conventional (1–8 kHz) and extended high frequency (EHF; 10–16 kHz) range, and distortion product otoacoustic emissions (DPOAEs) were examined. ResultsAll children had normal hearing thresholds within the conventional range (mean PTA bilaterally 8.6 dB HL). Ten (24.3%) of the children had elevated EHF thresholds (> 20 dB HL) for one or more frequencies or ears, and six (14.6%) had DPOAE signal to noise ratios (SNR) < 6 dB. EHF thresholds and DPOAE SNRs were significantly associated. Children's phonemic discrimination was impaired in noise, relative to quiet. There was a moderate, significant correlation between overall phonemic discrimination in noise and EHF audiometric thresholds. ConclusionsOverall, the present study showed that sensitive hearing measures enabled the detection of subtle hearing difficulties in young healthy children. In particular, phonemic discrimination in noise showed associations with hearing. Implications of including sensitive hearing measures in children with DLD are discussed.

The effect of vocal tract parameters on aspiration noise discrimination.

Previous research showed that aspiration noise difference limens in moderately breathy /a/ vowels decreased as the spectral slope of the glottal source spectrum became increasingly steep [Kreiman and Gerratt, J. Acoust. Soc. Am. 131(1), 492-500 (2012)]. The current study investigated whether discrimination of aspiration noise levels was affected by differences in spectral shape due to vowel quality (/æ/ and /i/) and speaker identity (three male speakers) when the slope of the glottal source spectrum was fixed. The results showed that discrimination performance was worse overall for /i/ than /æ/, but the result may have resulted from relatively poor performance for the /i/ vowel of one speaker. Acoustic analyses of the stimuli were performed to estimate the association between acoustic properties and the perceptual outcomes. The results showed that both the smoothed cepstral peak prominence and the harmonic energy level between 2 and 5 kHz may account for the observed differences in aspiration noise discrimination among speakers within each vowel, but not for differences between vowel categories. It is possible that the relationship between the aspiration noise discrimination and aforementioned acoustic properties may be modulated by the spectral distribution of energy across frequency.

Long-term evolution of the electrical stimulation for cochlear implant adult patients. The role of a progressive adaptation method

Background: In clinical experience patients who do not frequently check the cochlear implant (CI) maps have poor auditory performance and poor acceptance of map variations over time.Aims: The aim of the present study was to evaluate the effect of CI map optimization on both speech perception and subjective hearing in a group of CI patients with a long-standing map.Material and methods: 14 patients (6 females and 8 males; age range 16–77, mean age 45.86 ± 23.85 years) fitted with a unilateral CI (Cochlear Ltd, Sydney, Australia) and a map unchanged for at least 12 months were evaluated. All CIs were remapped using mapping method with progressive adaptation. The speech discrimination in noise and subjective hearing perception (SSQ questionnaire) were evaluated with old and new map.Results: The differences in electrode level with old and new map were significantly different both for T and C- Levels (p < .001). Speech discrimination in noise was significantly better (22.9%; p < .0001) after map optimization. The SSQ questionnaire showed no statistically significant difference in the overall scores, except the listening effort sub-scale.Conclusions: Longstanding MAPs are associated with poor speech discrimination. Degradation of electrical stimulation is associated with increased mental effort.

Usefulness of cochlear implantation in children with single sided deafness

ObjectivesChildren with single sided deafness (SSD) show a poorer performance at school, which is attributable to reduced speech discrimination in noise, to reduced localization ability, and to a decreased power of concentration due to faster hearing exhaustion. Therefore, it is important to provide children with SSD with adequate hearing amplification to restore binaural hearing. This can only be achieved by provision with a cochlear implant (CI). But these treatment option in children with SSD is still under discussion.The aim of the present study is to evaluate audiological and clinical results in children with SSD following cochlear implantation. A special focus was placed on the duration of deafness before implantation and on the frequency of CI-use in everyday life. MethodsSeven children with SSD of different etiologies who were provided with a CI between 3 and 16 years of age were evaluated. Every child underwent multiple audiological tests before and after cochlear implantation. After cochlear implantation speech recognition tests in noise using the HSM (Hochmair, Schulz and Moser 1997) test and localization tests were performed. Furthermore, the frequency of implant use was evaluated. ResultsSpeech recognition in noise with CI compared to the unaided condition significantly improved in all children in different settings. Improvement of the localization ability measured by the root mean square error (RMSE) was shown in all children. All children are very satisfied with the decision to have undergone cochlear implantation and are all full-time users. ConclusionsCochlear implantation benefits speech recognition in noise and sound localization ability in children with SSD at different ages. All implanted children are full-time users regardless of age or duration of deafness before implantation.

Suprathreshold Processing and Cocktail Party Listening in Younger and Older Adults with Normal Hearing

Present study aimed to investigate the effect of age and suprathreshold processing on cocktail party listening in individuals with normal hearing sensitivity. A total of 92 participants with normal hearing sensitivity were included in the study. They were divided into two groups based on their age. Fifty two young normal hearing adults in the age range of 20–40 years and 40 older normal hearing adults in the age range of 60-80 years. Tests administered included speech perception in noise test, spatial selective attention, gap detection thresholds, temporal modulation transfer function, inter-aural time difference, differential limen of frequency and ripple noise discrimination. Results showed that older adults performed poorer than younger adults in all the tests. Also, temporal cues showed a better relation with speech perception in noise compared to the spectral cues. This can be attributed to the disrupted neural synchrony which is due to poor frequency selectivity as observed through ripple noise discrimination. Individuals rely more on temporal cues due to poorer frequency resolution and phase locking mechanism and also on top down processes such as selective attention too. A degraded speech input would lead them to rely more on their higher cognition.

Vowel discrimination in noise with formant enhancement: Effects of hearing loss and aging

The aim of this study was to investigate whether formant enhancement of F2 would improve vowel formant discrimination in noise for three groups of listeners (i.e., older listeners with hearing loss, older listeners with normal hearing, and young listeners with normal hearing). Thresholds of vowel formant discrimination were examined for the F2 frequencies of three American English vowels: /ʌ/, /ɛ/, and /i/ in long-term speech-shaped noise with signal-to-noise ratio of + 6 dB and + 12 dB. F2 frequencies of three vowels were enhanced by 6 dB. Thresholds of vowel formant discrimination were significantly highest for older listeners with hearing loss, while young listeners with normal hearing had lowest thresholds with the older listeners with normal hearing in between. However, discrimination thresholds were improved significantly for all three groups after F2 enhancement was implemented regardless of low or high SNR of background noise. Hearing loss and aging resulted in higher thresholds of vowel formant discrimination in noise and F2 enhancements could improve discrimination performance for all listeners in noise.

Processamento Auditivo Central em Pessoas Idosas: Resultados Preliminares

INTRODUÇÃO: A presbiacúsia acarreta dificuldades na interpretação do sinal sonoro com uma influência acrescida na perceção do discurso na presença de ruído. Pretende-se estudar as habilidades do processamento auditivo central na discriminação da fala no ruído, em pessoas idosas.MATERIAL E MÉTODOS: A amostra foi constituída por 20 sujeitos, com idades compreendidas entre os 67 e os 92 anos. Todos realizaram otoscopia, timpanograma, audiograma tonal simples e teste de fala no ruído. Este estudo é do tipo descritivo-correlacional e transversal.RESULTADOS: A curva audiométrica apresenta declínio significativo (p &lt; 0,001) com o aumento das frequências testadas, a partir da frequência dos 500 Hz, apresentando o ouvido esquerdo melhores resultados do que o ouvido direito, com significância estatística (p = 0,043), apenas nos 250 Hz. No teste de fala no ruído, os resultados do ouvido esquerdo evidenciaram uma média de acertos de 21,5% na relação sinal/ruído de 10 dB, tendo um aumento significativo (p &lt; 0,001) na relação sinal/ruído de 15 dB cuja média de acertos foi 26,3%. O ouvido direito exibe uma média de acertos de 17,3% e de 27,85% na relação sinal/ruído de 10 dB e de 15 dB respetivamente, com um aumento significativo (p = 0,002) na relação sinal/ruído de 15 dB.CONCLUSÃO: Tendo em conta os resultados, em que o teste de fala no ruído apresenta uma média de acertos inferior aos 50% em ambos os ouvidos, chegámos à conclusão que quanto menor for a relação sinal/ruído maiores as dificuldades na compreensão da fala. Assim, a avaliação audiológica da pessoa idosa deve incluir a avaliação periférica e central.

The first results of a totally implanted active middle ear device.

The aim of this study was to assess the first outcomes of a fully implantable active middle ear device. Retrospective observational nonrandomized group study. Private hospital. Fifteen patients underwent device implantation between December 2014 and June 2017. The pre-operative and post-operative air conduction (AC) and bone conduction (BC) thresholds were evaluated. The functional gain, speech perception in silence and in noise, and localization abilities were also analyzed. Sixteen active middle ear implantations were performed. Post-operatively, the mean pure tone thresholds were 50.5dB ( ± 12.64) for BC and 64.9dB ( ± 15.36) for AC. No differences were found between the post-operative and pre-operative audiometric thresholds before activating the system (p > 0.05). Post-operatively, the mean thresholds in the free field after the device was activated were 46.8dB, 45.75dB, 42.6dB, and 43.38dB at 1, 3, 6, and 12months, respectively. The global results of speech understanding in silence were 50.7dB, 47.18dB, 42dB, and 42dB for 1, 3, 6, and 12months, respectively. Patients with mixed hearing loss had better results than those with sensorineural hearing loss. Speech discrimination in noise and localization was improved. Despite the small number of patients, our results confirmed that this fully implantable active middle ear device is a viable treatment for patients with moderate-to-severe sensorineural hearing loss who cannot or do not want to use traditional hearing aids for clinical or cosmetic reasons.

Effect of wireless remote microphone application on speech discrimination in noise in children with cochlear implants

ObjectivesAlthough cochlear implantation has significantly contributed to the speech perception of cochlear implant (CI) users, these individuals still have significant difficulty in understanding speech, especially in noisy environments and keeping track of the target speaker in the presence of speech sounds of others. This study was aimed to evaluate the effect of wireless Remote Microphones (RM) on speech discrimination scores in noise in child CI users. Materials and methodsTwenty children with unilateral cochlear implantation were enrolled in this study with mean ± SD age of 5.8 ± 0.83 years who have undergone CI for at least one year. Speech discrimination scores in noise were assessed using the Words-in-Noise (WIN) test at a constant signal-to-noise ratio (SNR) of 0 dB, in the presence and absence of a wireless RM. Three loudspeakers were placed at a distance of 1 m in front of the child to present the speech and babble noise. The wireless microphone was placed on a base with a height equivalent to the height of the middle speech loudspeaker at a distance of 30 cm from it. FindingsThe mean speech discrimination score in noise in the absence of wireless RM in all children was obtained 34% (6.8 words out of 20 words), with minimum and maximum of 15% and 50% words. Findings revealed the mean speech discrimination score in noise in the presence of wireless RMs is equivalent to 65% (13 words out of 20 words), with the minimum and maximum scores of 35% and 95%, respectively. The result showed that speech discrimination scores in noise improved in the presence of wireless RM. ConclusionThe significant improvement was observed in speech discrimination in noise in all cochlear implanted children when the wireless RM was used, as compared to the absence of a wireless RM, which suggests the usefulness of this hearing aid accessory in CI users.

Voice activity detection using smoothed-fuzzy entropy (smFuzzyEn) and support vector machine

In this paper a novel voice activity detection approach using smoothed fuzzy entropy (smFuzzyEn) feature using support vector machine is proposed. The proposed approach (smFESVM) uses total variation filter and Savitzky-Golay filter to smooth the FuzzyEn feature extracted from the noisy speech signals. Also, convolution of the first order difference of TV filter and noisy fuzzy entropy feature (conFETV') is also proposed. The obtained smoothed feature vectors are further normalized using min-max normalization and the normalized feature vectors train SVM model for speech/non-speech classification. The proposed smFESVM method shows better discrimination of noise and noisy speech when tested under various nonstationary background noises of different signal-to-noise ratio levels. 10 – fold cross validation was used to validate the efficacy of the SVM classifier. The performance of the smFESVM is compared against various algorithms and comparison suggests that the results obtained by the smFESVM is efficient in detecting speech under low SNR conditions with an accuracy of 93.88%.

The signal-to-noise ratio assessment in cochlear implanted patients through the Italian Matrix Sentence test (Oldenburg test)

Purpose: A lot of energy has been spent in advances in audiology to define a new strategy of diagnosis and rehabilitation in hearing-impaired patients, in particular for those rehabilitated with cochlear implants or hearing aids. The OLSA test or Matrix Sentence test is a new testing tool able to precisely define a signal-to-noise ratio in different clinical or diagnostic conditions. Spreading of this new test has a standardized level of reference which can help clinicians in comparing patients and data.Method: Implanted patients with contralateral hearing aid use were enrolled in the recent Italian Matrix Sentence test validated for the Italian language. Patients with good perceptual outcomes without post-operative complications were asked to undergo the Italian Matrix Sentence test twice in a day section with or without a cochlear implant and/or contralateral hearing aids.Results: Forty-five cochlear implanted patients with good outcomes and without major complications were enrolled in the present study to compare speech discrimination in noise with cochlear implants and/or hearing aids during bimodal or unimodal stimulation. Obviously, a significant difference was noticed in patients with cochlear implants or hearing aids when compared with patients without digital devices, as well as a statistically significant difference was found in patients with a cochlear implant only when compared with patients with hearing aids. Nevertheless, significant differences were found when comparing bimodal stimulation to unimodal stimulation with the cochlear implant: an ameliorative trend has been reported among patients with either the devices (hearing aids and cochlear implant).Conclusion: The Italian Matrix Sentence test is useful and automated speech audiometry allows a comprehensive evaluation of perceptual abilities in hearing impaired patient. Nevertheless, gives important information among implanted patients especially in the adaptive mode for central comprehension of the signal in noise.

Search for low-mass dark matter with CDMSlite using a profile likelihood fit

The Cryogenic Dark Matter Search low ionization threshold experiment (CDMSlite) searches for interactions between dark matter particles and germanium nuclei in cryogenic detectors. The experiment has achieved a low energy threshold with improved sensitivity to low-mass (<10 GeV/c$^2$) dark matter particles. We present an analysis of the final CDMSlite data set, taken with a different detector than was used for the two previous CDMSlite data sets. This analysis includes a data "salting" method to protect against bias, improved noise discrimination, background modeling, and the use of profile likelihood methods to search for a dark matter signal in the presence of backgrounds. We achieve an energy threshold of 70 eV and significantly improve the sensitivity for dark matter particles with masses between 2.5 and 10 GeV/c$^2$ compared to previous analyses. We set an upper limit on the dark matter-nucleon scattering cross section in germanium of 5.4$\times$10$^{-42}$ cm$^2$ at 5 GeV/c$^2$, a factor of $\sim$2.5 improvement over the previous CDMSlite result.

Bioacoustic detection of Callosobruchus chinensis and Callosobruchus maculatus in bulk stored chickpea (Cicer arietinum) and green gram (Vigna radiata)

Insects are one of the major reasons for post-harvest losses in stored food legumes. Real time detection at an early stage of insect infestation can overcome the foremost problem of infestation. Acoustic detection method detects the hidden as well as moving insects by amplifying and filtering their motility and feeding sounds. Crawling and feeding activities of two insects Callosobruchus chinensis and Callosobruchus maculatus in chickpea (Cicer arietinum) and green gram (Vigna radiata) were detected by using an insect detection probe placed in an acoustically insulated bin. Temperature and relative humidity were also measured through sensors mounted on the same probe. Captured sounds were pre-screened and analysed by using sound analysis software. Significant differences were found between the amplitude of two insects in both the legumes. Amplitudes of Callosobruchus chinensis were 79.32 dB and 84.01 dB for 59 ms duration in chickpea and green gram, respectively, whereas, the amplitude of Callosobruchus maculatus was 97.65 dB and 95.53 dB for 68 ms in chickpea and green gram, respectively. The detection range of the acoustic sensor was 300 mm omnidirectional. Formants (F1, F2, F3 and F4), formant bandwidth (FBW3), frequency and spectral power were observed as principal components for the detection of insects’ infestation (C. chinensis and C. maculatus) in bulk stored food legumes (chickpea and green gram). Formants of sound spectra found a specific role in the discrimination of insect and background noise. The findings of this study elucidated that acoustic detection method will provide rapid and non-destructive detection of infestation in bulk stored food legumes.

Performance of cochlear implant patients while using bimodal stimulation and FM system

Objectives: To study the effectiveness of bimodal stimulation coupled to FM system on the speech discrimination in noise, temporal discrimination and temporal resolution in patients with unilateral cochlear implant.Method: A total number of 28 subjects were examined in this study, they were divided into group I (19 subjects) with pre-lingual hearing loss and group II (9 subjects) with post-lingual hearing loss. Both groups had a residual hearing in the non-implanted ear that permits benefit from amplification. Full history taking, Questionnaire, Aided warble tone response, Arabic monosyllabic word test in quiet and in presence of background noise, Pitch discrimination test, Pitch pattern sequence test and Auditory fusion test-subtest 3.Results: There is significant statistical difference in CI patients' performance in most of tests while using bimodal stimulation with FM system coupled to CI than with bimodal stimulation alone or CI alone condition.Conclusions: It is recommended to use hearing aid in non-implanted ear in order to improve speech discrimination in noise, temporal discrimination and temporal resolution abilities.

Detecting topological variations of DNA at single-molecule level

In addition to their use in DNA sequencing, ultrathin nanopore membranes have potential applications in detecting topological variations in deoxyribonucleic acid (DNA). This is due to the fact that when topologically edited DNA molecules, driven by electrophoretic forces, translocate through a narrow orifice, transient residings of edited segments inside the orifice modulate the ionic flow. Here we utilize two programmable barcoding methods based on base-pairing, namely forming a gap in dsDNA and creating protrusion sites in ssDNA for generating a hybrid DNA complex. We integrate a discriminative noise analysis for ds and ss DNA topologies into the threshold detection, resulting in improved multi-level signal detection and consequent extraction of reliable information about topological variations. Moreover, the positional information of the barcode along the template sequence can be determined unambiguously. All methods may be further modified to detect nicks in DNA, and thereby detect DNA damage and repair sites.

Physical-random number generation via a diode laser’s frequency noise: an investigation into frequency discriminator

Diode Lasers (DLs) are influenced by fast frequency noise stemming from fluctuations in spontaneous emissions, a phenomenon that is of great use when generating fast physical-random numbers. This paper describes a physical-random number generator that uses a DLs frequency noise and rubidium (Rb) absorption lines as frequency noise sources and frequency discriminators. This device actually produced physical-random numbers at a rate of 500 megabits per second, but it depends on the relation between the DL frequency noise and frequency discriminator characteristics. This relation is investigated and the conditions for physical-random number generation are explained.

Application of Big Data Analysis to Acoustic Emission Testing for Noise Discrimination

Application of Big Data Analysis to Acoustic Emission Testing for Noise Discrimination

Design of a steady-state in situ test to determine the air permeability coefficient of covercrete

An in situ air permeability test method that does not require assumptions for the often-difficult unidirectional flow has been developed to calculate the air permeability coefficient of the near surface concrete. The proposed method involves applying a constant pressure head to a surface mounted ring and measuring the steady state air flow rates. The analysis is based on modification of the flownet theory, which needs a calibration factor accounting for the influence of specimen and ring geometries. Effects of test area, width of seal, depth and width of test specimen were investigated using numerical simulation of the air flow. The repeatability of the proposed test method was assessed by the signal noise ratio (SNR) and discrimination ratio (DR). A new formula is offered and it only requires the steady state air flow rate to calculate the coefficient of air permeability, thus assisting engineers and researchers to quickly determine this property of structural concretes.

Protocolo de Avaliação da Discriminação da Fala no Ruído com Implantes Auditivos

INTRODUÇÃO: A discriminação da fala no ruído tal como a interpretação musical estão entre os maiores desafios de um doente portador de um implante auditivo.O objetivo do estudo foi apresentar os testes de avaliação de discriminação da fala em ambientes com ruído e apreciar a sua utilização na prática clínica diária.MÉTODOS: Os autores propõem um protocolo de avaliação da discriminação da fala em ambientes com ruído para doentes candidatos a implantes auditivos, com o intuito de avaliar a integração da informação binaural. Foram utilizadas quatro colunas, dispostas no azimute 0°, 90°, 180° e 270°. Foi apresentada a conjugação de palavras/ frases com ruído branco ou som de cafetaria em quatro condições possíveis, sendo no global avaliados 16 parâmetros.RESULTADOS: O resultado é a percentagem de palavras e frases que o doente repete corretamente. Foi realizada a comparação pré e pós-operatória.CONCLUSÃO: Paralelamente ao estudo da localização espacial do som, considera-se que esta avaliação permitirá compreender a assimilação da informação auditiva dos doentes com implantes auditivos e avaliar a sua real integração binaural.

Aging effects on categorical perception of Mandarin tones in noise

The current study aimed at investigating the aging effect on the categorical perception of Mandarin lexical tones with varied fundamental frequency (F0) contours in noise. Mandarin tone identification and tone discrimination in quiet and noise were measured for younger and older listeners in a categorical perception paradigm where the stimuli continua varied their F0 contour systematically from the level to the rising/falling tones. Results reported that older listeners, in contrast with their younger counterparts, performed with less stimulus-tuned changes in both identification and discrimination functions and smaller peakedness in the discrimination function for both level-rising and level-falling tones. The aging effects on Mandarin tone categoricality were observed in both quiet and noise. Moreover, noise aggravated the aging effects, especially with the high SNR condition. Plus, older listeners’ identification and discrimination functions in CP paradigm positively correlated with their performance in general speech identification in noise; such correlation was not found with younger listeners. Our study suggested that older listeners had less categoricality in both identification and discrimination functions for the level-rising and level-falling tones, probably due to the aging-related decline in temporal processing.