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Costa LD, Vaucher AVDA, Pagliarin KC, Costa MJ. The word-with-noise test: development, validation and reference values. Codas 2024; 36:e20230091. [PMID: 38836822 PMCID: PMC467000 DOI: 10.1590/2317-1782/20242023091pt] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 07/26/2023] [Indexed: 06/06/2024] Open
Abstract
PURPOSE To propose an instrument for assessing speech recognition in the presence of competing noise. To define its application strategy for use in clinical practice. To obtain evidence of criterion validity and present reference values. METHODS The study was conducted in three stages: Organization of the material comprising the Word-with-Noise Test (Stage 1); Definition of the instrument's application strategy (Stage 2); Investigation of criterion validity and definition of reference values for the test (Stage 3) through the evaluation of 50 normal-hearing adult subjects and 12 subjects with hearing loss. RESULTS The Word-with-Noise Test consists of lists of monosyllabic and disyllabic words and speech spectrum noise (Stage 1). The application strategy for the test was defined as the determination of the Speech Recognition Threshold with a fixed noise level at 55 dBHL (Stage 2). Regarding criterion validity, the instrument demonstrated adequate ability to distinguish between normal-hearing subjects and subjects with hearing loss (Stage 3). Reference values for the test were established as cut-off points expressed in terms of signal-to-noise ratio: 1.47 dB for the monosyllabic stimulus and -2.02 dB for the disyllabic stimulus. Conclusion: The Word-with-Noise Test proved to be quick to administer and interpret, making it a useful tool in audiological clinical practice. Furthermore, it showed satisfactory evidence of criterion validity, with established reference values.
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Costa LD, Vaucher AVDA, Costa MJ. The word-with-noise test: test-retest reliability in normal-hearing adults. Codas 2024; 36:e20230093. [PMID: 38597550 PMCID: PMC11042685 DOI: 10.1590/2317-1782/20232023093pt] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 07/06/2023] [Indexed: 04/11/2024] Open
Abstract
PURPOSE To investigate the reliability of the Word-with-Noise Test in a group of normal-hearing adults. METHODS Forty-five normal-hearing adult subjects participated in the research. The interval between the first and second assessment was 14 to 28 days, performed during the same time of the day and by the same evaluator. The comparison analysis between the test and the retest was performed considering the general result of the ears, totaling 90 ears evaluated. The inferential analysis included the comparison of the situations in the first and second assessment using the Wilcoxon Test, calculation, and interpretation of the Intraclass Correlation Index. RESULTS There was a statistically significant difference between the test and retest performances. The intraclass correlation coefficients obtained were indicative of good reliability (r=0.759; p<0.001) for the monosyllabic stimulus and moderate reliability (r=0.631; p<0.001) for the disyllabic stimulus. CONCLUSION The Word-with-Noise Test demonstrated satisfactory reliability for both the monosyllabic and disyllabic stimuli.
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Schilder AGM, Wolpert S, Saeed S, Middelink LM, Edge ASB, Blackshaw H, Pastiadis K, Bibas AG. A phase I/IIa safety and efficacy trial of intratympanic gamma-secretase inhibitor as a regenerative drug treatment for sensorineural hearing loss. Nat Commun 2024; 15:1896. [PMID: 38429256 PMCID: PMC10907343 DOI: 10.1038/s41467-024-45784-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 02/01/2024] [Indexed: 03/03/2024] Open
Abstract
Inhibition of Notch signalling with a gamma-secretase inhibitor (GSI) induces mammalian hair cell regeneration and partial hearing restoration. In this proof-of-concept Phase I/IIa multiple-ascending dose open-label trial (ISRCTN59733689), adults with mild-moderate sensorineural hearing loss received 3 intratympanic injections of GSI LY3056480, in 1 ear over 2 weeks. Phase I primary outcome was safety and tolerability. Phase lla primary outcome was change from baseline to 12 weeks in average pure-tone air conduction threshold across 2,4,8 kHz. Secondary outcomes included this outcome at 6 weeks and change from baseline to 6 and 12 weeks in pure-tone thresholds at individual frequencies, speech reception thresholds (SRTs), Distortion Product Otoacoustic Emissions (DPOAE) amplitudes, Signal to Noise Ratios (SNRs) and distribution of categories normal, present-abnormal, absent and Hearing Handicap Inventory for Adults/Elderly (HHIA/E). In Phase I (N = 15, 1 site) there were no severe nor serious adverse events. In Phase IIa (N = 44, 3 sites) the average pure-tone threshold across 2,4,8 kHz did not change from baseline to 6 and 12 weeks (estimated change -0.87 dB; 95% CI -2.37 to 0.63; P = 0.252 and -0.46 dB; 95% CI -1.94 to 1.03; P = 0.545, respectively), nor did the means of secondary measures. DPOAE amplitudes, SNRs and distribution of categories did not change from baseline to 6 and 12 weeks, nor did SRTs and HHIA/E scores. Intratympanic delivery of LY3056480 is safe and well-tolerated; the trial's primary endpoint was not met.
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Affiliation(s)
- Anne G M Schilder
- National Institute for Health Research University College London Hospitals Biomedical Research Centre, London, UK
- Ear Institute, University College London, London, UK
- Royal National ENT and Eastman Dental Hospitals, University College London Hospitals Trust, London, UK
| | - Stephan Wolpert
- Department of Otolaryngology, Head and Neck Surgery, University of Tübingen, Tübingen, Germany.
| | - Shakeel Saeed
- National Institute for Health Research University College London Hospitals Biomedical Research Centre, London, UK
- Ear Institute, University College London, London, UK
- Royal National ENT and Eastman Dental Hospitals, University College London Hospitals Trust, London, UK
| | | | - Albert S B Edge
- Department of Otolaryngology, Harvard Medical School, Boston, USA
| | - Helen Blackshaw
- National Institute for Health Research University College London Hospitals Biomedical Research Centre, London, UK
- Ear Institute, University College London, London, UK
| | - Kostas Pastiadis
- 1st Department of Otolaryngology, Hippocration Hospital Athens, National & Kapodistrian University of Athens, Athens, Greece
| | - Athanasios G Bibas
- 1st Department of Otolaryngology, Hippocration Hospital Athens, National & Kapodistrian University of Athens, Athens, Greece
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Öz O, D'Alessandro HD, Batuk MÖ, Sennaroğlu G, Govaerts PJ. Assessment of Binaural Benefits in Hearing and Hearing-Impaired Listeners. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2023; 66:3633-3648. [PMID: 37494143 DOI: 10.1044/2023_jslhr-23-00077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/28/2023]
Abstract
PURPOSE The purpose of this study was to (a) investigate which speech material is most appropriate as stimulus in head shadow effect (HSE) and binaural squelch (SQ) tests, (b) obtain normative values of both tests using the material decided to be optimal, and (c) explore the results in bilateral cochlear implant (CI) users. METHOD Study participants consisted of 30 normal-hearing (NH) persons and 34 bilateral CI users. This study consisted of three phases. In the first phase, three different speech materials (1) monosyllabic words, (2) spondee words, and (3) sentences were compared in terms of (a) effect size, (b) test-retest reliability, and (c) interindividual variability. In the second phase, the speech material selected in the first phase was used to test a further 24 NHs to obtain normative values for both tests. In the third phase, tests were administered to a further 23 bilateral CI users, together with localization test and the Speech, Spatial, and Qualities of Hearing scale. RESULTS The results of the first phase indicated that spondees and sentences were more robust materials compared with monosyllables. Although the effect size and interindividual variability were comparable for spondees and sentences, sentences had higher test-retest reliability in this sample of CI users. With sentences, the mean (± standard deviation) HSE and SQ in the NH group were 58 ± 14% and 22 ± 11%, respectively. In the CI group, the mean HSE and SQ were 49 ± 13% and 13 ± 14%, respectively. There were no statistically significant correlations between the test results and the interval between the implantations, the length of binaural listening experience, or the asymmetry between the ears. CONCLUSIONS Sentences are preferred as stimulus material in the binaural HSE and SQ tests. Normative data are given for HSE and SQ with the LiCoS (linguistically controlled sentences) test. HSE is present for all bilateral CI users, whereas SQ is present in approximately seven out of 10 cases.
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Affiliation(s)
- Okan Öz
- The Eargroup, Antwerp, Belgium
- Department of Audiology, Faculty of Health Sciences, Hacettepe University, Ankara, Turkey
| | | | - Merve Özbal Batuk
- Department of Audiology, Faculty of Health Sciences, Hacettepe University, Ankara, Turkey
| | - Gonca Sennaroğlu
- Department of Audiology, Faculty of Health Sciences, Hacettepe University, Ankara, Turkey
| | - Paul J Govaerts
- The Eargroup, Antwerp, Belgium
- Faculty of Medicine and Health Sciences, Translational Neurosciences, Otorhinolaryngology & Head and Neck Surgery, University of Antwerp, Belgium
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Buisson Savin J, Reynard P, Bailly-Masson E, Joseph C, Joly CA, Boiteux C, Thai-Van H. Adult Normative Data for the Adaptation of the Hearing in Noise Test in European French (HINT-5 Min). Healthcare (Basel) 2022; 10:healthcare10071306. [PMID: 35885831 PMCID: PMC9315974 DOI: 10.3390/healthcare10071306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 07/07/2022] [Accepted: 07/11/2022] [Indexed: 12/05/2022] Open
Abstract
Decreased speech-in-noise (SpIN) understanding is an early marker not only of presbycusis but also of auditory processing disorder. Previous research has shown a strong relationship between hearing disorders and cognitive limitations. It is therefore crucial to allow SpIN testing in subjects who cannot sustain prolonged diagnostic procedures. The objectives of this study were to develop a rapid and reproducible version of the Hearing in Noise Test (HINT-5 min), and to determine its adult normative values in free-field and monaural or binaural headphone conditions. Following an adaptive signal-to-noise ratio (SNR) protocol, the test used a fixed noise level, while the signal level varied to reach the 50% speech reception threshold (SRT50). The speech material consisted of five lists of 20 sentences each, all recorded in European French. The whole semi-automated procedure lasted 5 min and was administered to 83 subjects aged 19 to 49 years with no reported listening difficulties. Fifty-two subjects were retested between 7 and 8 days later. For the binaural free-field condition, the mean SRT50 was −1.0 dB SNR with a standard deviation of 1.3 dB SNR. There was no significant difference between the results obtained at test and retest, nor was there any effect of listening condition, sex, or age on SRT50. The results indicate that the procedure is robust and not affected by any learning phenomenon. The HINT-5 min was found to be both a fast and reliable marker of the ability to understand speech in background noise.
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Affiliation(s)
- Johanna Buisson Savin
- Institut de l’Audition, Institut Pasteur, INSERM U1120, 75012 Paris, France; (J.B.S.); (P.R.); (C.-A.J.)
- Amplifon France, 94110 Arcueil, France; (E.B.-M.); (C.J.); (C.B.)
| | - Pierre Reynard
- Institut de l’Audition, Institut Pasteur, INSERM U1120, 75012 Paris, France; (J.B.S.); (P.R.); (C.-A.J.)
- Service d’Audiologie et d’Explorations Otoneurologiques, Hospices Civils de Lyon, Hôpital Edouard Herriot, 69003 Lyon, France
- Faculty of Medicine, University Claude Bernard Lyon 1, 69100 Villeurbanne, France
| | | | - Célia Joseph
- Amplifon France, 94110 Arcueil, France; (E.B.-M.); (C.J.); (C.B.)
| | - Charles-Alexandre Joly
- Institut de l’Audition, Institut Pasteur, INSERM U1120, 75012 Paris, France; (J.B.S.); (P.R.); (C.-A.J.)
- Service d’Audiologie et d’Explorations Otoneurologiques, Hospices Civils de Lyon, Hôpital Edouard Herriot, 69003 Lyon, France
- Faculty of Medicine, University Claude Bernard Lyon 1, 69100 Villeurbanne, France
| | | | - Hung Thai-Van
- Institut de l’Audition, Institut Pasteur, INSERM U1120, 75012 Paris, France; (J.B.S.); (P.R.); (C.-A.J.)
- Service d’Audiologie et d’Explorations Otoneurologiques, Hospices Civils de Lyon, Hôpital Edouard Herriot, 69003 Lyon, France
- Faculty of Medicine, University Claude Bernard Lyon 1, 69100 Villeurbanne, France
- Correspondence:
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Evans S, Rosen S. Who is Right? A Word-Identification-in-Noise Test for Young Children Using Minimal Pair Distracters. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2022; 65:159-168. [PMID: 34910569 DOI: 10.1044/2021_jslhr-20-00658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
PURPOSE Many children have difficulties understanding speech. At present, there are few assessments that test for subtle impairments in speech perception with normative data from U.K. children. We present a new test that evaluates children's ability to identify target words in background noise by choosing between minimal pair alternatives that differ by a single articulatory phonetic feature. This task (a) is tailored to testing young children, but also readily applicable to adults; (b) has minimal memory demands; (c) adapts to the child's ability; and (d) does not require reading or verbal output. METHOD We tested 155 children and young adults aged from 5 to 25 years on this new test of single word perception. RESULTS Speech-in-noise abilities in this particular task develop rapidly through childhood until they reach maturity at around 9 years of age. CONCLUSIONS We make this test freely available and provide associated normative data. We hope that it will be useful to researchers and clinicians in the assessment of speech perception abilities in children who are hard of hearing or have developmental language disorder, dyslexia, or auditory processing disorder. SUPPLEMENTAL MATERIAL https://doi.org/10.23641/asha.17155934.
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Affiliation(s)
- Samuel Evans
- Department of Psychology, University of Westminster, London, United Kingdom
| | - Stuart Rosen
- Department of Speech, Hearing and Phonetic Sciences, University College London, United Kingdom
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Pinheiro MMC, Vieira MG, Vieira LM, Koerich I, Rosseto I, Lazzarotto-Volcão C, Paul S. Updating sentences lists for assessment speech perception. Codas 2022; 34:e20200301. [PMID: 35019063 PMCID: PMC9886115 DOI: 10.1590/2317-1782/20202020301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 01/12/2021] [Indexed: 02/03/2023] Open
Abstract
PURPOSE Adapt a list of sentences for a speech intelligibility test. METHODS A speech material data base consisting of 200 phonetically balanced sentences was analyzed and partially updated. In the first stage, 60 reviewers, specialists in linguistics and speech and hearing science, analyzed the sentences in relation to the parameters of familiarity, meaning and predictability using an on-line questionnaire. Cronbach's Alpha coefficient was used to analyze the internal consistency of the questionnaire. In the second stage, the reviewers analyzed whether they were in accordance with the criteria indicated by the literature for the construction of sentences. RESULTS In the first stage, the responses of 15 reviewers who completed the entire questionnaire were analyzed. Agreement between reviewers was high for all criteria. 71 sentences were recommended for modification in the first stage, with predictability being the most indicated parameter as requiring change. In the second stage, 28 more sentences were selected for adjustment, with the presence of a proper name in the sentence being the most frequently cited criterion. CONCLUSION It was possible to adapt a list of sentences in order to provide speech language therapists with a free of charge speech perception protocol. It is hoped that this new test can assist in standardizing assessment for normal hearing adults and individuals with hearing loss in Brazilian Portuguese.
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Affiliation(s)
| | - Michele Gindri Vieira
- Centro Catarinense de Reabilitação/Centro Especializado em Reabilitação, Secretaria de Estado da Saúde de Santa Catarina- Florianópolis (SC), Brasil.
| | - Lara Malafaia Vieira
- Curso de Fonoaudiologia, Universidade Federal de Santa Catarina – UFSC - Florianópolis (SC), Brasil.
| | - Isadora Koerich
- Curso de Fonoaudiologia, Universidade Federal de Santa Catarina – UFSC - Florianópolis (SC), Brasil.
| | - Isadora Rosseto
- Curso de Fonoaudiologia, Universidade Federal de Santa Catarina – UFSC - Florianópolis (SC), Brasil.
| | - Cristiane Lazzarotto-Volcão
- Departamento de Língua e Literatura Vernáculas, Universidade Federal de Santa Catarina – UFSC - Florianópolis (SC), Brasil.
| | - Stephan Paul
- Departamento de Engenharia Mecânica, Universidade Federal de Santa Catarina – UFSC - Florianópolis (SC), Brasil.
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Speech-in-Noise Test results of compensation claimants for noise induced hearing loss in Korean male workers: Words-in-Noise Test (WIN) and quick-Hearing-in-Noise Test (HINT). Ann Occup Environ Med 2021; 33:e11. [PMID: 34754472 PMCID: PMC8144841 DOI: 10.35371/aoem.2021.33.e11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 02/17/2021] [Indexed: 11/20/2022] Open
Abstract
Background Pure-tone audiometry is used as a gold standard for hearing measurement. However, since communication in the work environment occurs in noise, it might be difficult to evaluate the actual communication ability accurately based on pure-tone audiometry only. Therefore, the purpose of this study is to evaluate speech intelligibility in noisy environments by using Speech-in-Noise Tests and to check its relationship with pure-tone audiometry. Methods From January 2017 to September 2018, for 362 workers who visited a university hospital for the purpose of compensating for noise-induced hearing loss, several tests were conducted: pure-tone audiometry, speech reception threshold, speech discrimination score, and Speech-in-Noise Tests (Words-in-Noise Test [WIN] and quick-Hearing-in-Noise Test [quick-HINT]). The subjects were classified into serviceable hearing group and non-serviceable hearing group based on 40 dB hearing level (HL) pure-tone average. In both groups, we conducted age-adjusted partial correlation analysis in order to find out the relationship between pure-tone threshold, speech reception threshold, speech discrimination score and WIN and quick-HINT respectively. Results In non-serviceable hearing group, all results of partial correlation analysis were statistically significant. However, in serviceable hearing group, there were many results which showed little or no significant relationship between pure-tone threshold and Speech-in-Noise Tests (WIN and quick-HINT). Conclusions The relationship between Speech-in-Noise Tests and the pure-tone thresholds were different by the hearing impairment levels; in mild to moderate hearing loss workers, there was little or no relationship; in severe cases, the relationship was significant. It is not enough to predict the speech intelligibility of hearing-impaired persons, especially in mild to moderate level, with pure-tone audiometry only. Therefore, it would be recommended to conduct Speech-in-Noise Test.
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Holmes E, Utoomprurkporn N, Hoskote C, Warren JD, Bamiou DE, Griffiths TD. Simultaneous auditory agnosia: Systematic description of a new type of auditory segregation deficit following a right hemisphere lesion. Cortex 2021; 135:92-107. [PMID: 33360763 PMCID: PMC7856551 DOI: 10.1016/j.cortex.2020.10.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 09/17/2020] [Accepted: 10/22/2020] [Indexed: 11/27/2022]
Abstract
We investigated auditory processing in a young patient who experienced a single embolus causing an infarct in the right middle cerebral artery territory. This led to damage to auditory cortex including planum temporale that spared medial Heschl's gyrus, and included damage to the posterior insula and inferior parietal lobule. She reported chronic difficulties with segregating speech from noise and segregating elements of music. Clinical tests showed no evidence for abnormal cochlear function. Follow-up tests confirmed difficulties with auditory segregation in her left ear that spanned multiple domains, including words-in-noise and music streaming. Testing with a stochastic figure-ground task-a way of estimating generic acoustic foreground and background segregation-demonstrated that this was also abnormal. This is the first demonstration of an acquired deficit in the segregation of complex acoustic patterns due to cortical damage, which we argue is a causal explanation for the symptomatic deficits in the segregation of speech and music. These symptoms are analogous to the visual symptom of simultaneous agnosia. Consistent with functional imaging studies on normal listeners, the work implicates non-primary auditory cortex. Further, the work demonstrates a (partial) lateralisation of the necessary anatomical substrate for segregation that has not been previously highlighted.
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Affiliation(s)
- Emma Holmes
- Wellcome Centre for Human Neuroimaging, UCL, London, UK.
| | - Nattawan Utoomprurkporn
- UCL Ear Institute, UCL, London, UK; NIHR University College London Hospitals Biomedical Research Centre, University College London Hospitals NHS Foundation Trust, UCL, London, UK; Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Bangkok, Thailand
| | - Chandrashekar Hoskote
- Lysholm Department of Neuroradiology, University College London Hospitals NHS Foundation Trust, UCL, London, UK
| | | | - Doris-Eva Bamiou
- UCL Ear Institute, UCL, London, UK; NIHR University College London Hospitals Biomedical Research Centre, University College London Hospitals NHS Foundation Trust, UCL, London, UK
| | - Timothy D Griffiths
- Wellcome Centre for Human Neuroimaging, UCL, London, UK; Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
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Ferreira MC, Zamberlan-Amorim NE, Wolf AE, Reis ACMB. Influence of different types of noise on sentence recognition in normally hearing adults. REVISTA CEFAC 2021. [DOI: 10.1590/1982-0216/20212352121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
ABSTRACT Objective: to analyze speech perception in normally hearing adults when listening in silence and with different types of noise. Methods: 40 individuals of both sexes, aged 18 to 45 years, participated in the study. Speech perception was assessed with the Lists of Sentences in Portuguese test, without a competing noise and with speech-spectrum, babble, and cocktail party noise. A mixed-effects linear regression model and the 95% confidence interval were used. Results: the subjects’ performance was worse in the three types of noise than in silence. When comparing the types of noise, differences were found in all combinations (speech-spectrum X babble, speech-spectrum X cocktail party, and babble X cocktail party), with a worse performance in babble, noise, followed by cocktail party. Conclusion: all noises negatively influenced speech perception, with a worse performance in babble, followed by cocktail party and speech-spectrum.
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Kegler M, Reichenbach T. Modelling the effects of transcranial alternating current stimulation on the neural encoding of speech in noise. Neuroimage 2020; 224:117427. [PMID: 33038540 DOI: 10.1016/j.neuroimage.2020.117427] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 09/11/2020] [Accepted: 10/01/2020] [Indexed: 11/29/2022] Open
Abstract
Transcranial alternating current stimulation (tACS) can non-invasively modulate neuronal activity in the cerebral cortex, in particular at the frequency of the applied stimulation. Such modulation can matter for speech processing, since the latter involves the tracking of slow amplitude fluctuations in speech by cortical activity. tACS with a current signal that follows the envelope of a speech stimulus has indeed been found to influence the cortical tracking and to modulate the comprehension of the speech in background noise. However, how exactly tACS influences the speech-related cortical activity, and how it causes the observed effects on speech comprehension, remains poorly understood. A computational model for cortical speech processing in a biophysically plausible spiking neural network has recently been proposed. Here we extended the model to investigate the effects of different types of stimulation waveforms, similar to those previously applied in experimental studies, on the processing of speech in noise. We assessed in particular how well speech could be decoded from the neural network activity when paired with the exogenous stimulation. We found that, in the absence of current stimulation, the speech-in-noise decoding accuracy was comparable to the comprehension of speech in background noise of human listeners. We further found that current stimulation could alter the speech decoding accuracy by a few percent, comparable to the effects of tACS on speech-in-noise comprehension. Our simulations further allowed us to identify the parameters for the stimulation waveforms that yielded the largest enhancement of speech-in-noise encoding. Our model thereby provides insight into the potential neural mechanisms by which weak alternating current stimulation may influence speech comprehension and allows to screen a large range of stimulation waveforms for their effect on speech processing.
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Affiliation(s)
- Mikolaj Kegler
- Department of Bioengineering and Centre for Neurotechnology, Imperial College London, South Kensington Campus, SW7 2BU London, United Kingdom
| | - Tobias Reichenbach
- Department of Bioengineering and Centre for Neurotechnology, Imperial College London, South Kensington Campus, SW7 2BU London, United Kingdom.
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