| 1. |
- Alickovic, Emina, et al.
(author)
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Effects of Hearing Aid Noise Reduction on Early and Late Cortical Representations of Competing Talkers in Noise
- 2021
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In: Frontiers in Neuroscience. - : Frontiers Media S.A.. - 1662-4548 .- 1662-453X. ; 15
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Journal article (peer-reviewed)abstract
- Objectives Previous research using non-invasive (magnetoencephalography, MEG) and invasive (electrocorticography, ECoG) neural recordings has demonstrated the progressive and hierarchical representation and processing of complex multi-talker auditory scenes in the auditory cortex. Early responses (<85 ms) in primary-like areas appear to represent the individual talkers with almost equal fidelity and are independent of attention in normal-hearing (NH) listeners. However, late responses (>85 ms) in higher-order non-primary areas selectively represent the attended talker with significantly higher fidelity than unattended talkers in NH and hearing-impaired (HI) listeners. Motivated by these findings, the objective of this study was to investigate the effect of a noise reduction scheme (NR) in a commercial hearing aid (HA) on the representation of complex multi-talker auditory scenes in distinct hierarchical stages of the auditory cortex by using high-density electroencephalography (EEG). Design We addressed this issue by investigating early (<85 ms) and late (>85 ms) EEG responses recorded in 34 HI subjects fitted with HAs. The HA noise reduction (NR) was either on or off while the participants listened to a complex auditory scene. Participants were instructed to attend to one of two simultaneous talkers in the foreground while multi-talker babble noise played in the background (+3 dB SNR). After each trial, a two-choice question about the content of the attended speech was presented. Results Using a stimulus reconstruction approach, our results suggest that the attention-related enhancement of neural representations of target and masker talkers located in the foreground, as well as suppression of the background noise in distinct hierarchical stages is significantly affected by the NR scheme. We found that the NR scheme contributed to the enhancement of the foreground and of the entire acoustic scene in the early responses, and that this enhancement was driven by better representation of the target speech. We found that the target talker in HI listeners was selectively represented in late responses. We found that use of the NR scheme resulted in enhanced representations of the target and masker speech in the foreground and a suppressed representation of the noise in the background in late responses. We found a significant effect of EEG time window on the strengths of the cortical representation of the target and masker. Conclusion Together, our analyses of the early and late responses obtained from HI listeners support the existing view of hierarchical processing in the auditory cortex. Our findings demonstrate the benefits of a NR scheme on the representation of complex multi-talker auditory scenes in different areas of the auditory cortex in HI listeners.
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| 2. |
- Alickovic, Emina, et al.
(author)
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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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In: Frontiers in Neuroscience. - : FRONTIERS MEDIA SA. - 1662-4548 .- 1662-453X. ; 14
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Journal article (peer-reviewed)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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| 3. |
- Chiossi, Julia S. C., et al.
(author)
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Phonological discrimination and contrast detection in pupillometry
- 2023
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In: Frontiers in Psychology. - : FRONTIERS MEDIA SA. - 1664-1078. ; 14
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Journal article (peer-reviewed)abstract
- IntroductionThe perception of phonemes is guided by both low-level acoustic cues and high-level linguistic context. However, differentiating between these two types of processing can be challenging. In this study, we explore the utility of pupillometry as a tool to investigate both low- and high-level processing of phonological stimuli, with a particular focus on its ability to capture novelty detection and cognitive processing during speech perception.MethodsPupillometric traces were recorded from a sample of 22 Danish-speaking adults, with self-reported normal hearing, while performing two phonological-contrast perception tasks: a nonword discrimination task, which included minimal-pair combinations specific to the Danish language, and a nonword detection task involving the detection of phonologically modified words within sentences. The study explored the perception of contrasts in both unprocessed speech and degraded speech input, processed with a vocoder.ResultsNo difference in peak pupil dilation was observed when the contrast occurred between two isolated nonwords in the nonword discrimination task. For unprocessed speech, higher peak pupil dilations were measured when phonologically modified words were detected within a sentence compared to sentences without the nonwords. For vocoded speech, higher peak pupil dilation was observed for sentence stimuli, but not for the isolated nonwords, although performance decreased similarly for both tasks.ConclusionOur findings demonstrate the complexity of pupil dynamics in the presence of acoustic and phonological manipulation. Pupil responses seemed to reflect higher-level cognitive and lexical processing related to phonological perception rather than low-level perception of acoustic cues. However, the incorporation of multiple talkers in the stimuli, coupled with the relatively low task complexity, may have affected the pupil dilation.
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| 4. |
- Classon, Elisabet, et al.
(author)
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Reading span performance in 339 Swedish 50-89 year old individuals with hearing impairment : Effects of test version and age, and relation to speech recognition in noise
- 2013
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Other publication (other academic/artistic)abstract
- The Swedish reading span test (Rönnberg, Lyxell, Arlinger, & Kinnefors, 1989) is often used to assess working memory capacity (WMC) in the field of cognitive hearing science. The test has proven useful as a predictor of speech recognition in noise in adverse conditions. It has been used in a wide range of experimental studies and has been translated to several languages. The purpose of this paper was to provide reference data for the Swedish reading span test (Rönnberg et al., 1989) in a large sample of adults with hearing impairment aged 50-89 years that are representative of patients seeking rehabilitation at audiological clinics. Data from finished and ongoing projects were collated and reanalyzed for this purpose. The original full version and a shortened version of the test were compared, in terms of percentage correct. In addition, performance on the full version was compared across two different age-cohorts, 50-69 year olds and 70-89 year olds. Frequency distributions and percentile scores are reported, as well as relations with demographic variables, and speech recognition in noise. Results showed that reading span performance was related to age, but not sex, with lower scores in older participants. Pure tone hearing thresholds accounted for a small but significant amount of the variance such that higher reading span scores were related to better hearing. The frequency distributions of scores did not differ across the two versions of the test, but the long version seemed to be more sensitive to age. Performance in both versions was significantly correlated with speech recognition in noise. Regression analyses however showed that reading span explained additional variance in speech in noise recognition, after the effects of age and pure tone hearing thresholds were accounted for, only in the 50-69 year olds. These findings are discussed in relation to age-related differences in the ability to recruit cognitive resources in the service of speech communication.
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| 5. |
- Lunner, Thomas, et al.
(author)
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Immediate effects of signal processing on memory systems
- 2011
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Conference paper (other academic/artistic)abstract
- Traditionally, hearing instrument signal processing schemes are evaluated where the speech recognition tests in noise are most sensitive, i.e. around 50 percent correct. However, such testing typically leads to ecologically unrealistic negative signal-to-noise ratios. Therefore, memory performance has been suggested as a more ecologically valid outcome measure in conditions with interfering background noises, and where participants perform closer to 100 percent correct. In a recent study by Sarampalis et al. (2009) they used an Ephraim-Mallah noise reduction algorithm and found beneficial effects for normal hearing participants on memory function. However, such memory effects have not been shown for hearing impaired participants. The current study on hearing-impaired subjects evaluated ‘aggressive’ ideal binary masking (IBM, see Wang, et al., 2009), as a proof-of-concept not only for improving speech comprehension but also for its potential effects of masking on memory systems. Furthermore, binary masks estimated from directional microphones (Boldt et al., 2008) were used as a realistic version of binary mask processing. Results show significant main effects of noise type and noise reduction. Noise reduction techniques improved the memory performance in the four-talker babble background, while no such improvement was observed in the steady-state noise background. Participants with higher reading span scores performed significantly better in the memory task, but only in the four-talker babble background.The study demonstrates the binary-masking noise reduction technique helps freeing up cognitive resources and hence enhances memory task performance in the four-talker babble background for hearing-impaired listeners with high reading span performance. The findings suggest that there is a cognitive challenge for the hearing aid industry to improve signal processing options for individuals to improve immediate perception and encoding into memory.
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| 6. |
- Lunner, Thomas, et al.
(author)
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Three New Outcome Measures That Tap Into Cognitive Processes Required for Real-Life Communication
- 2020
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In: Ear and Hearing. - : Lippincott Williams & Wilkins. - 0196-0202 .- 1538-4667. ; 41, s. 39S-47S
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Journal article (peer-reviewed)abstract
- To increase the ecological validity of outcomes from laboratory evaluations of hearing and hearing devices, it is desirable to introduce more realistic outcome measures in the laboratory. This article presents and discusses three outcome measures that have been designed to go beyond traditional speech-in-noise measures to better reflect realistic everyday challenges. The outcome measures reviewed are: the Sentence-final Word Identification and Recall (SWIR) test that measures working memory performance while listening to speech in noise at ceiling performance; a neural tracking method that produces a quantitative measure of selective speech attention in noise; and pupillometry that measures changes in pupil dilation to assess listening effort while listening to speech in noise. According to evaluation data, the SWIR test provides a sensitive measure in situations where speech perception performance might be unaffected. Similarly, pupil dilation has also shown sensitivity in situations where traditional speech-in-noise measures are insensitive. Changes in working memory capacity and effort mobilization were found at positive signal-to-noise ratios (SNR), that is, at SNRs that might reflect everyday situations. Using stimulus reconstruction, it has been demonstrated that neural tracking is a robust method at determining to what degree a listener is attending to a specific talker in a typical cocktail party situation. Using both established and commercially available noise reduction schemes, data have further shown that all three measures are sensitive to variation in SNR. In summary, the new outcome measures seem suitable for testing hearing and hearing devices under more realistic and demanding everyday conditions than traditional speech-in-noise tests.
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| 7. |
- Lunner, Thomas, et al.
(author)
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Using Speech Recall in Hearing Aid Fitting and Outcome Evaluation Under Ecological Test Conditions
- 2016
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In: Ear and Hearing. - : Lippincott Williams & Wilkins. - 0196-0202 .- 1538-4667. ; 37:1, s. 145S-154S
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Journal article (peer-reviewed)abstract
- In adaptive Speech Reception Threshold (SRT) tests used in the audiological clinic, speech is presented at signal to noise ratios (SNRs) that are lower than those generally encountered in real-life communication situations. At higher, ecologically valid SNRs, however, SRTs are insensitive to changes in hearing aid signal processing that may be of benefit to listeners who are hard of hearing. Previous studies conducted in Swedish using the Sentence-final Word Identification and Recall test (SWIR) have indicated that at such SNRs, the ability to recall spoken words may be a more informative measure. In the present study, a Danish version of SWIR, known as the Sentence-final Word Identification and Recall Test in a New Language (SWIRL) was introduced and evaluated in two experiments. The objective of experiment 1 was to determine if the Swedish results demonstrating benefit from noise reduction signal processing for hearing aid wearers could be replicated in 25 Danish participants with mild to moderate symmetrical sensorineural hearing loss. The objective of experiment 2 was to compare direct-drive and skin-drive transmission in 16 Danish users of bone-anchored hearing aids with conductive hearing loss or mixed sensorineural and conductive hearing loss. In experiment 1, performance on SWIRL improved when hearing aid noise reduction was used, replicating the Swedish results and generalizing them across languages. In experiment 2, performance on SWIRL was better for direct-drive compared with skin-drive transmission conditions. These findings indicate that spoken word recall can be used to identify benefits from hearing aid signal processing at ecologically valid, positive SNRs where SRTs are insensitive.
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| 8. |
- Micula, Andreea, et al.
(author)
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A Glimpse of Memory Through the Eyes : Pupillary Responses Measured During Encoding Reflect the Likelihood of Subsequent Memory Recall in an Auditory Free Recall Test
- 2022
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In: Trends in Hearing. - : Sage Publications. - 2331-2165. ; 26
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Journal article (peer-reviewed)abstract
- The aim of the current study was to investigate whether task-evoked pupillary responses measured during encoding, individual working memory capacity and noise reduction in hearing aids were associated with the likelihood of subsequently recalling an item in an auditory free recall test combined with pupillometry. Participants with mild to moderately severe symmetrical sensorineural hearing loss (n = 21) were included. The Sentence-final Word Identification and Recall (SWIR) test was administered in a background noise composed of sixteen talkers with noise reduction in hearing aids activated and deactivated. The task-evoked peak pupil dilation (PPD) was measured. The Reading Span (RS) test was used as a measure of individual working memory capacity. Larger PPD at a single trial level was significantly associated with higher likelihood of subsequently recalling a word, presumably reflecting the intensity of attention devoted during encoding. There was no clear evidence of a significant relationship between working memory capacity and subsequent memory recall, which may be attributed to the SWIR test and RS test being administered in different modalities, as well as differences in task characteristics. Noise reduction did not have a significant effect on subsequent memory recall. This may be due to the background noise not having a detrimental effect on attentional processing at the favorable signal-to-noise ratio levels at which the test was conducted.
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| 9. |
- Micula, Andreea, 1991-
(author)
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Cognition Seen Through the Eyes of Hearing Aid Users : Working Memory Resource Allocation for Speech Perception and Recall
- 2022
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Doctoral thesis (other academic/artistic)abstract
- This thesis investigates how hearing aid users allocate working (WM) memory resources under various task demands when listening to and storing speech in memory for later recall. This was done by combining an auditory recall task, the Sentence-final Word Identification and Recall (SWIR) test, with pupillometry. Different pupillary responses were used to obtain insights into momentary WM resource allocation and overall WM resource allocation over time. The task demands were manipulated by varying hearing aid noise reduction settings, as well as by varying the task difficulty of the SWIR test and the task difficulty predictability.The findings from the first two studies showed that recall performance in competing speech was better, and baseline pupillary responses were higher when noise reduction was activated compared to when it was not. This indicates that attenuating background noise frees up WM resources to be used for storing speech in memory rather than speech processing. While unpredictable task difficulty elicited higher baseline pupillary responses than predictable task difficulty, it did not have any effect on recall performance. This finding suggests that task difficulty predictability does not affect WM resource allocation. Instead, unpredictable task difficulty may lead to increased alertness in anticipation of the end of the SWIR test list. The findings of the third study showed that increased transient task-evoked pupillary responses, which reflect the momentary intensity of attention during encoding, were associated with a higher likelihood of subsequent recall. Moreover, higher WM capacity was also linked to higher likelihood of subsequent recall, presumably due to the ability to allocate more attentional resources during encoding. Lastly, the findings from the fourth study indicated that the combination of the SWIR test and pupillometry is suitable for capturing WM resource allocation. Although arousal decreased over time, recall performance remained stable, suggesting that participants did not reach the point of disengagement.Overall, a novel learning from this thesis is that increased pupillary responses may be a marker of “successful effort” when additional WM resources are allocated to achieve a better recall performance in the SWIR test. Furthermore, this thesis gives insights into which factors affect WM resource allocation and how to reduce the amount of processing resources required to understand speech, which may contribute to optimizing auditory rehabilitation in the future.
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| 10. |
- Micula, Andreea, et al.
(author)
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The effects of task difficulty, background noise and noise reduction on recall
- 2020
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In: International Journal of Audiology. - : TAYLOR & FRANCIS LTD. - 1499-2027 .- 1708-8186. ; 59:10, s. 792-800
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Journal article (peer-reviewed)abstract
- Objective:In the present study, we investigated whether varying the task difficulty of the Sentence-Final Word Identification and Recall (SWIR) Test has an effect on the benefit of noise reduction, as well as whether task difficulty predictability affects recall. The relationship between working memory and recall was examined. Design:Task difficulty was manipulated by varying the list length with noise reduction on and off in competing speech and speech-shaped noise. Half of the participants were informed about list length in advance. Working memory capacity was measured using the Reading Span. Study sample:Thirty-two experienced hearing aid users with moderate sensorineural hearing loss. Results:Task difficulty did not affect the noise reduction benefit and task difficulty predictability did not affect recall. Participants may have employed a different recall strategy when task difficulty was unpredictable and noise reduction off. Reading Span scores positively correlated with the SWIR test. Noise reduction improved recall in competing speech. Conclusions:The SWIR test with varying list length is suitable for detecting the benefit of noise reduction. The correlation with working memory suggests that the SWIR test could be modified to be adaptive to individual cognitive capacity. The results on noise and noise reduction replicate previous findings.
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| 11. |
- Micula, Andreea, et al.
(author)
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The Effects of Task Difficulty Predictability and Noise Reduction on Recall Performance and Pupil Dilation Responses
- 2021
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In: Ear and Hearing. - : Lippincott, Williams & Wilkins. - 0196-0202 .- 1538-4667. ; 42:6, s. 1668-1679
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Journal article (peer-reviewed)abstract
- Objectives: Communication requires cognitive processes which are not captured by traditional speech understanding tests. Under challenging listening situations, more working memory resources are needed to process speech, leaving fewer resources available for storage. The aim of the current study was to investigate the effect of task difficulty predictability, that is, knowing versus not knowing task difficulty in advance, and the effect of noise reduction on working memory resource allocation to processing and storage of speech heard in background noise. For this purpose, an "offline" behavioral measure, the Sentence-Final Word Identification and Recall (SWIR) test, and an "online" physiological measure, pupillometry, were combined. Moreover, the outcomes of the two measures were compared to investigate whether they reflect the same processes related to resource allocation. Design: Twenty-four experienced hearing aid users with moderate to moderately severe hearing loss participated in this study. The SWIR test and pupillometry were measured simultaneously with noise reduction in the test hearing aids activated and deactivated in a background noise composed of four-talker babble. The task of the SWIR test is to listen to lists of sentences, repeat the last word immediately after each sentence and recall the repeated words when the list is finished. The sentence baseline dilation, which is defined as the mean pupil dilation before each sentence, and task-evoked peak pupil dilation (PPD) were analyzed over the course of the lists. The task difficulty predictability was manipulated by including lists of three, five, and seven sentences. The test was conducted over two sessions, one during which the participants were informed about list length before each list (predictable task difficulty) and one during which they were not (unpredictable task difficulty). Results: The sentence baseline dilation was higher when task difficulty was unpredictable compared to predictable, except at the start of the list, where there was no difference. The PPD tended to be higher at the beginning of the list, this pattern being more prominent when task difficulty was unpredictable. Recall performance was better and sentence baseline dilation was higher when noise reduction was on, especially toward the end of longer lists. There was no effect of noise reduction on PPD. Conclusions: Task difficulty predictability did not have an effect on resource allocation, since recall performance was similar independently of whether task difficulty was predictable or unpredictable. The higher sentence baseline dilation when task difficulty was unpredictable likely reflected a difference in the recall strategy or higher degree of task engagement/alertness or arousal. Hence, pupillometry captured processes which the SWIR test does not capture. Noise reduction frees up resources to be used for storage of speech, which was reflected in the better recall performance and larger sentence baseline dilation toward the end of the list when noise reduction was on. Thus, both measures captured different temporal aspects of the same processes related to resource allocation with noise reduction on and off.
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| 12. |
- Moradi, Shahram, et al.
(author)
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Visual Cues Contribute Differentially to Audiovisual Perception of Consonants and Vowels in Improving Recognition and Reducing Cognitive Demands in Listeners With Hearing Impairment Using Hearing Aids
- 2017
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In: Journal of Speech, Language and Hearing Research. - : American Speech-Language-Hearing Association. - 1092-4388 .- 1558-9102. ; 60:9, s. 2687-2703
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Journal article (peer-reviewed)abstract
- Purpose We sought to examine the contribution of visual cues in audiovisual identification of consonants and vowels—in terms of isolation points (the shortest time required for correct identification of a speech stimulus), accuracy, and cognitive demands—in listeners with hearing impairment using hearing aids.Method The study comprised 199 participants with hearing impairment (mean age = 61.1 years) with bilateral, symmetrical, mild-to-severe sensorineural hearing loss. Gated Swedish consonants and vowels were presented aurally and audiovisually to participants. Linear amplification was adjusted for each participant to assure audibility. The reading span test was used to measure participants' working memory capacity.Results Audiovisual presentation resulted in shortened isolation points and improved accuracy for consonants and vowels relative to auditory-only presentation. This benefit was more evident for consonants than vowels. In addition, correlations and subsequent analyses revealed that listeners with higher scores on the reading span test identified both consonants and vowels earlier in auditory-only presentation, but only vowels (not consonants) in audiovisual presentation.Conclusion Consonants and vowels differed in terms of the benefits afforded from their associative visual cues, as indicated by the degree of audiovisual benefit and reduction in cognitive demands linked to the identification of consonants and vowels presented audiovisually.
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| 13. |
- Ng, Hoi Ning Elaine
(author)
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Cognition in Hearing Aid Users : Memory for Everyday Speech
- 2013
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Doctoral thesis (other academic/artistic)abstract
- The thesis investigated the importance of cognition for speech understanding in experienced and new hearing aid users. The aims were 1) to develop a cognitive test (Sentence-final Word Identification and Recall, or SWIR test) to measure the effects of a noise reduction algorithm on processing of highly intelligible speech (everyday sentences); 2) to investigate, using the SWIR test, whether hearing aid signal processing would affect memory for heard speech in experienced hearing aid users; 3) to test whether the effects of signal processing on the ability to recall speech would interact with background noise and individual differences in working memory capacity; 4) to explore the potential clinical application of the SWIR test; and 5) to examine the relationship between cognition and speech recognition in noise in new users over the first six months of hearing aid use. Results showed that, for experienced users, noise reduction freed up cognitive resources and alleviated the negative impact of noise on memory when speech stimuli were presented in a background of speech babble spoken in the listener’s native language. The possible underlying mechanisms are that noise reduction facilitates auditory stream segregation between target and irrelevant speech and reduces the attention captured by the linguistic information in irrelevant speech. The effects of noise reduction and SWIR performance were modulated by individual differences in working memory capacity. SWIR performance was related to the self-reported outcome of hearing aid use. For new users, working memory capacity played a more important role in speech recognition in noise before acclimatization to hearing aid amplification than after six months. This thesis demonstrates for the first time that hearing aid signal processing can significantly improve the ability of individuals with hearing impairment to recall highly intelligible speech stimuli presented in babble noise. It also adds to the literature showing the key role of working memory capacity in listening with hearing aids, especially for new users. By virtue of its relation to subjective measures of hearing aid outcome, the SWIR test can potentially be used as a tool in assessing hearing aid outcome.
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| 14. |
- Ng, Hoi Ning, Elaine, et al.
(author)
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Dynamic relation between working memory capacity and speech recognition in noise during the first six months of hearing aid use
- 2014
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In: Trends in Hearing. - : Sage Publications. - 2331-2165. ; 18, s. 1-10
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Journal article (peer-reviewed)abstract
- The present study aimed to investigate the changing relationship between aided speech recognition and cognitive function during the first six months of hearing aid use. Twentyseven first-time hearing aid users with symmetrical mild to moderate sensorineural hearing loss were recruited. Aided speech recognition thresholds in noise (SRTs) were obtained in the hearing aid fitting session as well as at three and six months post-fitting. Cognitive abilities were assessed using a reading span test, which is a measure of working memory capacity, and a cognitive test battery. Results showed a significant correlation between reading span and SRT during the hearing aid fitting session. This relation was significantly weakened over the first six months of hearing aid use. Multiple regression analysis showed that reading span was the main predictor of SRT when hearing aids were first fitted, but that pure-tone average hearing threshold (PTA) was the main predictor six months later. This indicates that working memory capacity plays a more important role in speech recognition in noise before than after six months of use. We argue that new hearing aid users engage working memory capacity to recognize unfamiliar processed speech signals but that as familiarization proceeds, engagement of working memory capacity is reduced.
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| 15. |
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| 16. |
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| 17. |
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| 18. |
- Ng, Hoi Ning, Elaine, et al.
(author)
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Effects of noise and working memory capacity on memory processing of speech for hearing-aid users
- 2013
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In: International Journal of Audiology. - : Informa Healthcare. - 1499-2027 .- 1708-8186. ; 52:7, s. 433-441
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Journal article (peer-reviewed)abstract
- Objectives: It has been shown that noise reduction algorithms can reduce the negative effects of noise on memory processing in persons with normal hearing. The objective of the present study was to investigate whether a similar effect can be obtained for persons with hearing impairment and whether such an effect is dependent on individual differences in working memory capacity.Design: A sentence-final word identification and recall (SWIR) test was conducted in two noise backgrounds with and without noise reduction as well as in quiet. Working memory capacity was measured using a reading span (RS) test.Study sample: Twenty-six experienced hearing-aid users with moderate to moderately severe sensorineural hearing loss.Results: Noise impaired recall performance. Competing speech disrupted memory performance more than speech-shaped noise. For late list items the disruptive effect of the competing speech background was virtually cancelled out by noise reduction for persons with high working memory capacity.Conclusions: Noise reduction can reduce the adverse effect of noise on memory for speech for persons with good working memory capacity. We argue that the mechanism behind this is faster word identification that enhances encoding into working memory.
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| 19. |
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| 20. |
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| 21. |
- Ng, Hoi Ning, Elaine, 1979-, et al.
(author)
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Hearing aid experience and background noise affect the robust relationship between working memory and speech recognition in noise
- 2020
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In: International Journal of Audiology. - : Taylor & Francis. - 1499-2027 .- 1708-8186. ; 59:3, s. 208-218
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Journal article (peer-reviewed)abstract
- Objective: The aim of this study was to examine how background noise and hearing aid experience affect the robust relationship between working memory and speech recognition.Design: Matrix sentences were used to measure speech recognition in noise. Three measures of working memory were administered. Study sample: 148 participants with at least 2 years of hearing aid experience.Results: A stronger overall correlation between working memory and speech recognition performance was found in a four-talker babble than in a stationary noise background. This correlation was significantly weaker in participants with most hearing aid experience than those with least experience when background noise was stationary. In the four-talker babble, however, no significant difference was found between the strength of correlations between users with different experience.Conclusion: In general, more explicit processing of working memory is invoked when listening in a multi-talker babble. The matching processes (cf. Ease of Language Understanding model, ELU) were more efficient for experienced than for less experienced users when perceiving speech. This study extends the existing ELU model that mismatch may also lead to the establishment of new phonological representations in the long-term memory.
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| 22. |
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| 23. |
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| 24. |
- Ng, Hoi Ning, Elaine, et al.
(author)
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Noise reduction can enhance memory for heard sentences
- 2011
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Conference paper (other academic/artistic)abstract
- It has been demonstrated that the benefit of signal processing intended for hearingaids is not limited to improvement in speech perception. Sarampalis et al.(2009) showed that the Ephraim-Malah noise reduction algorithm improvedcognitive performance and reduced listening effort for people with normal hearing.However, similar effects for hearing-impaired listeners have not been reported.The present study examines the effect of noise reduction in hearing aidson memory processing of speech perceived in stationary noise and competingspeech background. Twenty-six experienced hearing aid users with symmetricalsensorineural hearing loss were tested. A dual task paradigm, which consists ofa perceptual speech recognition task and a free recall memory task, was used tomeasure the cognitive outcomes with the use of binary time-frequency maskingnoise reduction technique (Wang et al., 2009). Working memory capacity wasmeasured using a reading span test. Results showed that free recall performancein the competing speech background improved with noise reduction in listenerswith better working memory capacity. No such improvement was found in thestationary noise. Listeners with better working memory also performed better inthe stationary noise than in the competing speech background. No effect of backgroundnoises or noise reduction was observed in listeners with limited workingmemory capacity. The study demonstrates that binary masking noise reductiontechnique enhances memory performance in competing speech background forpersons with good working memory capacity. In other words, working memorycapacity also predicts benefit of noise reduction signal processing.
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| 25. |
- Ng, Hoi Ning, Elaine, et al.
(author)
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Noise reduction improves memory for target language speech in competing native but not foreign language speech
- 2015
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In: Ear and Hearing. - : Wolters Kluwer. - 0196-0202 .- 1538-4667. ; 36:1, s. 82-91
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Journal article (peer-reviewed)abstract
- Objectives: A hearing aid noise reduction (NR) algorithm reduces the adverse effect of competing speech on memory for target speech for individuals with hearing impairment with high working memory capacity. In the present study, we investigated whether the positive effect of NR could be extended to individuals with low working memory capacity, as well as how NR influences recall performance for target native speech when the masker language is non-native.Design: A sentence-final word identification and recall (SWIR) test was administered to 26 experienced hearing aid users. In this test, target spoken native language (Swedish) sentence lists were presented in competing native (Swedish) or foreign (Cantonese) speech with or without binary masking NR algorithm. After each sentence list, free recall of sentence final words was prompted. Working memory capacity was measured using a reading span (RS) test.Results: Recall performance was associated with RS. However, the benefit obtained from NR was not associated with RS. Recall performance was more disrupted by native than foreign speech babble and NR improved recall performance in native but not foreign competing speech.Conclusions: Noise reduction improved memory for speech heard in competing speech for hearing aid users. Memory for native speech was more disrupted by native babble than foreign babble, but the disruptive effect of native speech babble was reduced to that of foreign babble when there was NR.
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| 26. |
- Ng, Hoi Ning, Elaine, et al.
(author)
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Relationships between self-report and cognitive measures of hearing aid outcome
- 2013
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In: Speech, Language and Hearing. - : Maney Publishing. - 2050-571X .- 2050-5728. ; 16:4, s. 197-207
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Journal article (peer-reviewed)abstract
- This present study examined the relationship between cognitive measures and self-report hearing aid outcome. A sentence-final word identification and recall (SWIR) test was used to investigate how hearing aid use may relate to experienced explicit cognitive processing. A visually based cognitive test battery was also administered. To measure self-report hearing aid outcome, the International Outcome Inventory – Hearing Aids (IOI-HA) and the Speech, Spatial and Qualities of Hearing Scale (SSQ) were employed. Twenty-six experienced hearing aid users (mean age of 59 years) with symmetrical moderate-tomoderately severe sensorineural hearing loss were recruited. Free recall performance in the SWIR test correlated negatively with item 3 of IOI-HA, which measures residual difficulty in adverse listening situations. Cognitive abilities related to verbal information processing were correlated positively with selfreported hearing aid use and overall success. The present study showed that reported residual difficulty with hearing aid may relate to experienced explicit processing in difficult listening conditions, such that individuals with better cognitive capacity tended to report more remaining difficulty in challenging listening situations. The possibility of using cognitive measures to predict hearing aid outcome in real life should be explored in future research.
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| 27. |
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| 28. |
- Rudner, Mary, et al.
(author)
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Cognitive spare capacity as a measure of listening effort
- 2011
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In: Journal of Hearing Science. - : Instytut Narzadow Zmyslow. - 2083-389X .- 2084-3127. ; 1:2, s. EA47-49
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Journal article (peer-reviewed)abstract
- There has been a recent interest in listening effort as a factor to be taken into account in the audiological clinic. However, the term “listening effort” is poorly determined and needs to be defined before it can be used as a clinical or research tool. One way of understanding listening effort is in terms of the cognitive resources expended during listening. Cognitive capacity is finite and thus if cognitive capacity is used up during the act of listening to speech there will be fewer cognitive resources left to process the content of the message conveyed. We have introduced the term Cognitive Spare Capacity (CSC) to refer to residual cognitive capacity once successful listening has taken place. This extended abstract described the work we have carried out to date on measures of CSC for research and clinical use. In the course of this work we have developed tests to assess the role of memory load, executive function and audiovisual integration in CSC under challenging conditions. When these tests are fully developed, our aim is that they should allow objective individual assessment of listening effort in cognitive terms. Results to date indicate that under challenging conditions, CSC is an arena for executive processing of temporarily stored information; it is related to individual working memory capacity and can be enhanced by hearing aid signal processing.
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| 29. |
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| 30. |
- Rönnberg, Jerker, et al.
(author)
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Hearing impairment, cognition and speech understanding : exploratory factor analyses of a comprehensive test battery for a group of hearing aid users, the n200 study
- 2016
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In: International Journal of Audiology. - : Informa UK Limited. - 1499-2027 .- 1708-8186. ; 55:11, s. 623-642
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Journal article (peer-reviewed)abstract
- Objective: The aims of the current n200 study were to assess the structural relations between three classes of test variables (i.e. HEARING, COGNITION and aided speech-in-noise OUTCOMES) and to describe the theoretical implications of these relations for the Ease of Language Understanding (ELU) model. Study sample: Participants were 200 hard-of-hearing hearing-aid users, with a mean age of 60.8 years. Forty-three percent were females and the mean hearing threshold in the better ear was 37.4 dB HL. Design: LEVEL1 factor analyses extracted one factor per test and/or cognitive function based on a priori conceptualizations. The more abstract LEVEL 2 factor analyses were performed separately for the three classes of test variables. Results: The HEARING test variables resulted in two LEVEL 2 factors, which we labelled SENSITIVITY and TEMPORAL FINE STRUCTURE; the COGNITIVE variables in one COGNITION factor only, and OUTCOMES in two factors, NO CONTEXT and CONTEXT. COGNITION predicted the NO CONTEXT factor to a stronger extent than the CONTEXT outcome factor. TEMPORAL FINE STRUCTURE and SENSITIVITY were associated with COGNITION and all three contributed significantly and independently to especially the NO CONTEXT outcome scores (R2 = 0.40). Conclusions: All LEVEL 2 factors are important theoretically as well as for clinical assessment.
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| 31. |
- Signoret, Carine, 1981-, et al.
(author)
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Well-Being of Early-Career Researchers: Insights from a Swedish Survey
- 2019
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In: Higher Education Policy. - : Springer Science and Business Media LLC. - 0952-8733 .- 1740-3863. ; 32:2, s. 273-296
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Journal article (peer-reviewed)abstract
- Several studies have documented the importance of optimal work situation and the general well-being of early-career researchers (ECRs) for enhancing the academic performance of universities. Yet, most studies focused on specific categories of ECRs, or on specific academic disciplines as well as on specific outcomes. With this study, we recognize the need for a broader sample encompassing different categories of ECRs across academic disciplines. In a national survey of Swedish universities, the National Junior Faculty of Sweden (NJF) collected data from ECRs in order to study the influence of work situation and well-being on perceived scientific environment. We observed that work situation and well-being are interdependent and jointly influence each other in shaping the conditions for ideal scientific environment. Importantly, we employ structural equation model (SEM) analysis to account for the endogenous relationship between work situation and personal well-being in predicting perceived scientific environment. Results from SEM indicate that support from the university, work time management, job clarity, contract length and quality of life satisfaction were related to the perceivedpossibility of conducting the best science. Our research also highlighted individual differences across demographic factors and contract length in the perceived work situation and the possibility of conducting the best science.
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| 32. |
- Wong, Lena L. N., et al.
(author)
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Characterization of speech understanding in various types of noise
- 2012
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In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 132:4, s. 2642-2651
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Journal article (peer-reviewed)abstract
- This study examined (1) the effects of noise on speech understanding and (2) whether performance in real-life noises could be predicted based on performance in steady-state speech-spectrum-shaped noise. The noise conditions included a steady-state speech-spectrum-shaped noise and six types of real-life noise. Thirty normal-hearing adults were tested using sentence materials from the Cantonese Hearing In Noise Test (CHINT). To achieve the first aim, the performance–intensity function slopes in these noise conditions were estimated and compared. Variations in performance–intensity function slopes were attributed to differences in the amount of amplitude fluctuations and the presence of competing background speech. How well the data obtained in real-life noises fit the performance–intensity functions obtained in steady-state speech-spectrum-shaped noises was examined for the second aim of the study. Four out of six types of noise yielded performance–intensity function slopes similar to that in steady-state speech-spectrum-shaped noise. After accounting for individual differences in sentence reception threshold (SRT) and the offset between the signal-to-noise ratio for 50% intelligibility across different types of noise, performance in steady-state speech-spectrum-shaped noise was found to predict well the performance in most of the real-life noise conditions.
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