| 1. |
- Ala, Tirdad Seifi, et al.
(författare)
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Alpha Oscillations During Effortful Continuous Speech: From Scalp EEG to Ear-EEG
- 2023
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Ingår i: IEEE Transactions on Biomedical Engineering. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0018-9294 .- 1558-2531. ; 70:4, s. 1264-1273
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The purpose of this study was to investigate alpha power as an objective measure of effortful listening in continuous speech with scalp and ear-EEG. Methods: Scalp and ear-EEG were recorded simultaneously during presentation of a 33-s news clip in the presence of 16-talker babble noise. Four different signal-to-noise ratios (SNRs) were used to manipulate task demand. The effects of changes in SNR were investigated on alpha event-related synchronization (ERS) and desynchronization (ERD). Alpha activity was extracted from scalp EEG using different referencing methods (common average and symmetrical bi-polar) in different regions of the brain (parietal and temporal) and ear-EEG. Results: Alpha ERS decreased with decreasing SNR (i.e., increasing task demand) in both scalp and ear-EEG. Alpha ERS was also positively correlated to behavioural performance which was based on the questions regarding the contents of the speech. Conclusion: Alpha ERS/ERD is better suited to track performance of a continuous speech than listening effort. Significance: EEG alpha power in continuous speech may indicate of how well the speech was perceived and it can be measured with both scalp and Ear-EEG.
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| 2. |
- Ala, Tirdad Seifi, et al.
(författare)
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An exploratory Study of EEG Alpha Oscillation and Pupil Dilation in Hearing-Aid Users During Effortful listening to Continuous Speech
- 2020
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Ingår i: PLOS ONE. - : PUBLIC LIBRARY SCIENCE. - 1932-6203. ; 15:7
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Tidskriftsartikel (refereegranskat)abstract
- Individuals with hearing loss allocate cognitive resources to comprehend noisy speech in everyday life scenarios. Such a scenario could be when they are exposed to ongoing speech and need to sustain their attention for a rather long period of time, which requires listening effort. Two well-established physiological methods that have been found to be sensitive to identify changes in listening effort are pupillometry and electroencephalography (EEG). However, these measurements have been used mainly for momentary, evoked or episodic effort. The aim of this study was to investigate how sustained effort manifests in pupillometry and EEG, using continuous speech with varying signal-to-noise ratio (SNR). Eight hearing-aid users participated in this exploratory study and performed a continuous speech-in-noise task. The speech material consisted of 30-second continuous streams that were presented from loudspeakers to the right and left side of the listener (+/- 30 degrees azimuth) in the presence of 4-talker background noise (+180 degrees azimuth). The participants were instructed to attend either to the right or left speaker and ignore the other in a randomized order with two different SNR conditions: 0 dB and -5 dB (the difference between the target and the competing talker). The effects of SNR on listening effort were explored objectively using pupillometry and EEG. The results showed larger mean pupil dilation and decreased EEG alpha power in the parietal lobe during the more effortful condition. This study demonstrates that both measures are sensitive to changes in SNR during continuous speech.
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| 3. |
- Alickovic, Emina, et al.
(författare)
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A System Identification Approach to Determining Listening Attention from EEG Signals
- 2016
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Ingår i: 2016 24TH EUROPEAN SIGNAL PROCESSING CONFERENCE (EUSIPCO). - : IEEE. - 9780992862657 - 9781509018918 ; , s. 31-35
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Konferensbidrag (refereegranskat)abstract
- We still have very little knowledge about how ourbrains decouple different sound sources, which is known assolving the cocktail party problem. Several approaches; includingERP, time-frequency analysis and, more recently, regression andstimulus reconstruction approaches; have been suggested forsolving this problem. In this work, we study the problem ofcorrelating of EEG signals to different sets of sound sources withthe goal of identifying the single source to which the listener isattending. Here, we propose a method for finding the number ofparameters needed in a regression model to avoid overlearning,which is necessary for determining the attended sound sourcewith high confidence in order to solve the cocktail party problem.
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| 4. |
- Alickovic, Emina, et al.
(författare)
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A Tutorial on Auditory Attention Identification Methods
- 2019
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Ingår i: Frontiers in Neuroscience. - : FRONTIERS MEDIA SA. - 1662-4548 .- 1662-453X. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Auditory attention identification methods attempt to identify the sound source of a listeners interest by analyzing measurements of electrophysiological data. We present a tutorial on the numerous techniques that have been developed in recent decades, and we present an overview of current trends in multivariate correlation-based and model-based learning frameworks. The focus is on the use of linear relations between electrophysiological and audio data. The way in which these relations are computed differs. For example, canonical correlation analysis (CCA) finds a linear subset of electrophysiological data that best correlates to audio data and a similar subset of audio data that best correlates to electrophysiological data. Model-based (encoding and decoding) approaches focus on either of these two sets. We investigate the similarities and differences between these linear model philosophies. We focus on (1) correlation-based approaches (CCA), (2) encoding/decoding models based on dense estimation, and (3) (adaptive) encoding/decoding models based on sparse estimation. The specific focus is on sparsity-driven adaptive encoding models and comparing the methodology in state-of-the-art models found in the auditory literature. Furthermore, we outline the main signal processing pipeline for how to identify the attended sound source in a cocktail party environment from the raw electrophysiological data with all the necessary steps, complemented with the necessary MATLAB code and the relevant references for each step. Our main aim is to compare the methodology of the available methods, and provide numerical illustrations to some of them to get a feeling for their potential. A thorough performance comparison is outside the scope of this tutorial.
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| 5. |
- Alickovic, Emina, et al.
(författare)
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Neural Representation Enhanced for Speech and Reduced for Background Noise With a Hearing Aid Noise Reduction Scheme During a Selective Attention Task
- 2020
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Ingår i: Frontiers in Neuroscience. - : FRONTIERS MEDIA SA. - 1662-4548 .- 1662-453X. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Objectives Selectively attending to a target talker while ignoring multiple interferers (competing talkers and background noise) is more difficult for hearing-impaired (HI) individuals compared to normal-hearing (NH) listeners. Such tasks also become more difficult as background noise levels increase. To overcome these difficulties, hearing aids (HAs) offer noise reduction (NR) schemes. The objective of this study was to investigate the effect of NR processing (inactive, where the NR feature was switched off,vs.active, where the NR feature was switched on) on the neural representation of speech envelopes across two different background noise levels [+3 dB signal-to-noise ratio (SNR) and +8 dB SNR] by using a stimulus reconstruction (SR) method. Design To explore how NR processing supports the listeners selective auditory attention, we recruited 22 HI participants fitted with HAs. To investigate the interplay between NR schemes, background noise, and neural representation of the speech envelopes, we used electroencephalography (EEG). The participants were instructed to listen to a target talker in front while ignoring a competing talker in front in the presence of multi-talker background babble noise. Results The results show that the neural representation of the attended speech envelope was enhanced by the active NR scheme for both background noise levels. The neural representation of the attended speech envelope at lower (+3 dB) SNR was shifted, approximately by 5 dB, toward the higher (+8 dB) SNR when the NR scheme was turned on. The neural representation of the ignored speech envelope was modulated by the NR scheme and was mostly enhanced in the conditions with more background noise. The neural representation of the background noise was modulated (i.e., reduced) by the NR scheme and was significantly reduced in the conditions with more background noise. The neural representation of the net sum of the ignored acoustic scene (ignored talker and background babble) was not modulated by the NR scheme but was significantly reduced in the conditions with a reduced level of background noise. Taken together, we showed that the active NR scheme enhanced the neural representation of both the attended and the ignored speakers and reduced the neural representation of background noise, while the net sum of the ignored acoustic scene was not enhanced. Conclusion Altogether our results support the hypothesis that the NR schemes in HAs serve to enhance the neural representation of speech and reduce the neural representation of background noise during a selective attention task. We contend that these results provide a neural index that could be useful for assessing the effects of HAs on auditory and cognitive processing in HI populations.
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| 6. |
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| 7. |
- Andersen, Martin R., et al.
(författare)
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Side-Effects of Binaural Tone Vocoding on Recognising Target Speech Presented Against Spatially Separated Speech Maskers
- 2012
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Ingår i: Speech Perception and Auditory Disorders. - Speech perception and auditory disorders. Proceedings of the International Symposium on Audiological and Auditory Research (ISAAR), Denmark. ; , s. 103-110
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Previous experiments have indicated that monaural Temporal Fine Structure (mTFS) information aids Speech Reception. In these experiments mTFS was either kept or substituted using a tone-vocoder. Results showed that hearing-impaired (HI) subjects were not able to utilise mTFS information to the same degree as normal-hearing (NH) subjects. A first step towards a more ecological experiment would be to exploit the tone-vocoder paradigm in a simulated spatial setup, and measure binaural TFS (bTFS) benefit.However, by the introduction of a binaural tone-vocoder, a concern arose that not only will the original Interaural Time Difference (ITD) cues be removed, but artificial ITD cues pointing to a direction determined by the phase difference between the carriers of the two channels, will also be introduced.This experiment investigated this concern, by measuring speech reception for target speech presented against spatially separated speech maskers. 21 NH and 21 HI subjects were tested in a fixed spatial condition with either the artificial ITD pointing forward (0º azimuth) or ±50º. Furthermore, a third condition utilising a paradigm that did not make use of a tone-vocoder, was included.Results showed that the artificial ITD affected NH and HI listeners equally, favouring the source whose direction it was pointing towards.
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| 8. |
- Andersson, Gerhard, et al.
(författare)
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Internet and Audiology: A Review of the First International Meeting
- 2015
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Ingår i: American Journal of Audiology. - : AMER SPEECH-LANGUAGE-HEARING ASSOC. - 1059-0889 .- 1558-9137. ; 24:3, s. 269-270
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Forskningsöversikt (refereegranskat)abstract
- Purpose: The purpose of this research forum article is to describe the impetus for holding the First International Meeting on Internet and Audiology (October 2014) and to introduce the special research forum that arose from the meeting. Method: The rationale for the First International Meeting on Internet and Audiology is described. This is followed by a short description of the research sections and articles appearing in the special issue. Six articles consider the process of health care delivery over the Internet; this includes health care specific to hearing, tinnitus, and balance. Four articles discuss the development of effective Internet-based treatment programs. Six articles describe and evaluate Internet-based interventions specific to adult hearing aid users. Conclusion: The fledgling field of Internet and audiology is remarkably broad. The Second International Meeting on Internet and Audiology ocurred in September 2015.
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| 9. |
- Arehart, Kathryn, et al.
(författare)
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Relationship Among Signal Fidelity, Hearing Loss, and Working Memory for Digital Noise Suppression
- 2015
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Ingår i: Ear and Hearing. - : LIPPINCOTT WILLIAMS and WILKINS. - 0196-0202 .- 1538-4667. ; 36:5, s. 505-516
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: This study considered speech modified by additive babble combined with noise-suppression processing. The purpose was to determine the relative importance of the signal modifications, individual peripheral hearing loss, and individual cognitive capacity on speech intelligibility and speech quality. Design: The participant group consisted of 31 individuals with moderate high-frequency hearing loss ranging in age from 51 to 89 years (mean = 69.6 years). Speech intelligibility and speech quality were measured using low-context sentences presented in babble at several signal-to-noise ratios. Speech stimuli were processed with a binary mask noise-suppression strategy with systematic manipulations of two parameters (error rate and attenuation values). The cumulative effects of signal modification produced by babble and signal processing were quantified using an envelope-distortion metric. Working memory capacity was assessed with a reading span test. Analysis of variance was used to determine the effects of signal processing parameters on perceptual scores. Hierarchical linear modeling was used to determine the role of degree of hearing loss and working memory capacity in individual listener response to the processed noisy speech. The model also considered improvements in envelope fidelity caused by the binary mask and the degradations to envelope caused by error and noise. Results: The participants showed significant benefits in terms of intelligibility scores and quality ratings for noisy speech processed by the ideal binary mask noise-suppression strategy. This benefit was observed across a range of signal-to-noise ratios and persisted when up to a 30% error rate was introduced into the processing. Average intelligibility scores and average quality ratings were well predicted by an objective metric of envelope fidelity. Degree of hearing loss and working memory capacity were significant factors in explaining individual listeners intelligibility scores for binary mask processing applied to speech in babble. Degree of hearing loss and working memory capacity did not predict listeners quality ratings. Conclusions: The results indicate that envelope fidelity is a primary factor in determining the combined effects of noise and binary mask processing for intelligibility and quality of speech presented in babble noise. Degree of hearing loss and working memory capacity are significant factors in explaining variability in listeners speech intelligibility scores but not in quality ratings.
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| 10. |
- Arehart, Kathryn, et al.
(författare)
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Relationship between distortion and working memory for digital noise-reduction processing in hearing aids
- 2014
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Ingår i: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 133:5
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Tidskriftsartikel (refereegranskat)abstract
- Several recent studies have shown a relationship between working memory and the ability of older adults to benefit from specific advanced signal processing algorithms in hearing aids. In this study, we quantify tradeoffs between benefit due to noise reduction and the perceptual costs associated with distortion caused by the noise reduction algorithm. We also investigate the relationship between these tradeoffs and working memory abilities. Speech intelligibility, speech quality, and perceived listening effort were measured in a cohort of elderly adults with hearing loss. Test materials were low-context sentences presented in fluctuating noise conditions at several signal-to-noise ratios. Speech stimuli were processed with a binary mask noise-reduction strategy. The amount of distortion produced by the noise reduction algorithm was parametrically varied by manipulating two binary mask parameters, error rate, and attenuation rate. Working memory was assessed with a reading span test. Results will be discussed in terms of the extent to which intelligibility, quality, and effort ratings are explained by the amount of distortion and/or noise and by working memory ability. [Funded by NIH, Oticon, and GN ReSound.].
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