Improve Speech Intelligibility Research Articles

Room acoustics of Mycelium Textiles: the Myx Sail at the Danish Design Museum

Abstract Taking the Myx Sail displayed at the Danish Design Museum as a case study, this article investigates the room acoustics of an architectural installation made of Mycelium Textiles. Mycelium Textiles represent a novel typology of mycelium-based composites (MBC). The Myx Sail absorbers are grown on a composition of different layers of plant fibres combining woven jute textile with hemp mat and loose wood wool substrate enhancing the mechanical and acoustic properties of the composite. Two complementary acoustic tests were conducted to measure the absorbing properties of the mycelium material and its effects on the acoustics of the exhibition hall. The results show that the sail acts effectively as an acoustic absorber especially in higher range of frequencies, reducing the reverberation time and improving speech intelligibility. The effect of the sail on the overall room acoustics is especially effective, if the sound source is placed directly underneath the sail. The results of a complementary survey amongst visitors on their subjective perception of comfort and well-being however indicate that the degree to which a grown surface (and by extension, a grown building) is perceived positively or negatively depends on the relationship the individual has with Nature.

Focusing on Positive Listening Experiences Improves Speech Intelligibility in Experienced Hearing Aid Users.

Negativity bias is a cognitive bias that results in negative events being perceptually more salient than positive ones. For hearing care, this means that hearing aid benefits can potentially be overshadowed by adverse experiences. Research has shown that sustaining focus on positive experiences has the potential to mitigate negativity bias. The purpose of the current study was to investigate whether a positive focus (PF) intervention can improve speech-in-noise abilities for experienced hearing aid users. Thirty participants were randomly allocated to a control or PF group (N = 2 × 15). Prior to hearing aid fitting, all participants filled out the short form of the Speech, Spatial and Qualities of Hearing scale (SSQ12) based on their own hearing aids. At the first visit, they were fitted with study hearing aids, and speech-in-noise testing was performed. Both groups then wore the study hearing aids for two weeks and sent daily text messages reporting hours of hearing aid use to an experimenter. In addition, the PF group was instructed to focus on positive listening experiences and to also report them in the daily text messages. After the 2-week trial, all participants filled out the SSQ12 questionnaire based on the study hearing aids and completed the speech-in-noise testing again. Speech-in-noise performance and SSQ12 Qualities score were improved for the PF group but not for the control group. This finding indicates that the PF intervention can improve subjective and objective hearing aid benefits.

Statistically Guided Near-End Speech Intelligibility Improvement Through Voice Transformation and Transfer Learning

Statistically Guided Near-End Speech Intelligibility Improvement Through Voice Transformation and Transfer Learning

Improved speech intelligibility in the presence of congruent vibrotactile speech input

Vibrotactile stimulation is believed to enhance auditory speech perception, offering potential benefits for cochlear implant (CI) users who may utilize compensatory sensory strategies. Our study advances previous research by directly comparing tactile speech intelligibility enhancements in normal-hearing (NH) and CI participants, using the same paradigm. Moreover, we assessed tactile enhancement considering stimulus non-specific, excitatory effects through an incongruent audio-tactile control condition that did not contain any speech-relevant information. In addition to this incongruent audio-tactile condition, we presented sentences in an auditory only and a congruent audio-tactile condition, with the congruent tactile stimulus providing low-frequency envelope information via a vibrating probe on the index fingertip. The study involved 23 NH listeners and 14 CI users. In both groups, significant tactile enhancements were observed for congruent tactile stimuli (5.3% for NH and 5.4% for CI participants), but not for incongruent tactile stimulation. These findings replicate previously observed tactile enhancement effects. Juxtaposing our study with previous research, the informational content of the tactile stimulus emerges as a modulator of intelligibility: Generally, congruent stimuli enhanced, non-matching tactile stimuli reduced, and neutral stimuli did not change test outcomes. We conclude that the temporal cues provided by congruent vibrotactile stimuli may aid in parsing continuous speech signals into syllables and words, consequently leading to the observed improvements in intelligibility.

Altered Auditory Feedback Improves Speech Intelligibility in Individuals Diagnosed with Parkinson’s Disease: A Pilot Study

Introduction: The purpose of the current study was to evaluate speech intelligibility and speech rate in individuals with Parkinson’s disease using altered auditory feedback (AAF) in comparison to age-matched healthy controls. Based on prior research, it is hypothesized that the use of AAF will improve participants’ speech intelligibility. Methods: Five individuals with Parkinson’s disease (clinical group) and five age-matched healthy controls aged 50 years and above participated in this pre-/post-group experiment. All participants completed reading and monologue tasks with and without AAF. The AAF delayed the participants’ auditory feedback by 150 ms and altered it by 1/20 octave. Thirty-two naïve listeners listened to the recorded participants’ speech samples (with and without AAF) randomly and rated the participants’ speech intelligibility. Results: Results of the mixed model ANOVA revealed that participants in the control group had significantly higher speech intelligibility scores than the participants in the clinical group. Post hoc tests indicated that only participants in the clinical group were more intelligible with AAF than without AAF. Participants in the clinical group had better speech intelligibility when reading the passage than speaking the monologue. With regards to speech rate, participants spoke more slowly with AAF than without. Finally, there was a negative correlation between speech rate and speech intelligibility. Discussion: The current findings support our hypothesis that AAF improves speech intelligibility in people with Parkinson’s disease, though not in healthy controls. Future research should evaluate the long-term effect of AAF use on speech intelligibility in people with Parkinson’s disease.

Performance of speech enhancement algorithms on the speech intelligibility of native Mandarin listeners immersed in English-speaking environment

Speech enhancement algorithms have been developed to improve speech intelligibility for listeners under noisy conditions. However, all existing algorithms were evaluated only by native listeners, the performance of such algorithms on non-native listeners was rarely investigated. This study conducts a subjective listening test on native New Zealand English listeners and native Mandarin listeners who have been immersed in New Zealand English-speaking environment for more than one year. The participants were asked to transcribe noisy English sentences processed by five widely used single-channel speech enhancement algorithms. The speech intelligibility of the two groups was quantified and compared to investigate the effectiveness of the speech enhancement algorithms on non-native listeners who are familiar with the target language.

Relation between sound absorption and speech intelligibility in room, part 1: Theoretical investigation

In Japan, requirements and design guidelines on sound absorption of a variety of ordinary spaces are currently under consideration. In general, sound absorption works for reverberation suppression and noise reduction, both of which contributes to improve speech intelligibility performance. However, its combined effect is not fully clarified, especially on the relationship among of reverberation time, average absorption coefficient and speech intelligibility indices. In this paper, two theoretical case studies are performed based on the formulations of the clarity C50 and the useful-to-detrimental ratio U50 in the conditions without and with background noise. For rectangular rooms with an aspect ratio of 1:2:4, those indices are calculated at three source-to-receiver distances, changing the room volume widely under different noise levels. The results demonstrated that the absorption coefficient required for a target C50 increases with increasing the room volume, but it decreases beyond a certain volume. Moreover, it was shown that under high background noise, U50 is not effectively improved by increasing the absorption coefficient if the communication distance is much longer than the critical distance.

The effects of temporal cues, point-light displays, and faces on speech identification and listening effort.

Among the most robust findings in speech research is that the presence of a talking face improves the intelligibility of spoken language. Talking faces supplement the auditory signal by providing fine phonetic cues based on the placement of the articulators, as well as temporal cues to when speech is occurring. In this study, we varied the amount of information contained in the visual signal, ranging from temporal information alone to a natural talking face. Participants were presented with spoken sentences in energetic or informational masking in four different visual conditions: audio-only, a modulating circle providing temporal cues to salient features of the speech, a digitally rendered point-light display showing lip movement, and a natural talking face. We assessed both sentence identification accuracy and self-reported listening effort. Audiovisual benefit for intelligibility was observed for the natural face in both informational and energetic masking, but the digitally rendered point-light display only provided benefit in energetic masking. Intelligibility for speech accompanied by the modulating circle did not differ from the audio-only conditions in either masker type. Thus, the temporal cues used here were insufficient to improve speech intelligibility in noise, but some types of digital point-light displays may contain enough phonetic detail to produce modest improvements in speech identification in noise.

A Transparent Mask and Clear Speech Benefit Speech Intelligibility in Individuals With Hearing Loss.

The purpose of the study is to investigate the impacts of a surgical mask and a transparent mask on audio-only and audiovisual speech intelligibility in noise (i.e., 0 dB signal-to-noise ratio) in individuals with mild-to-profound hearing loss. The study also examined if individuals with hearing loss can benefit from using a transparent mask and clear speech for speech understanding in noise. Thirty-one individuals with hearing loss (from 22 to 74 years old) completed keyword identification tasks to measure face-masked speech intelligibility in noise. A mixed-effects logistic regression model was used to examine the effects of face masks (no mask, transparent mask, surgical mask), presentation modes (audio only, audiovisual), speaking styles (conversational, clear), noise type (speech-shaped noise [SSN], four-talker babble [4-T babble]), hearing groups (mild hearing loss [MHL], greater than MHL: GHL), and their interactions on binary accuracy of keyword identification. In the audio-only mode, the GHL group showed reduced speech intelligibility regardless of other factors, whereas the MHL group showed decreased speech intelligibility for the transparent mask more than for the surgical mask. The use of a transparent mask was advantageous for both hearing loss groups. Clear speech remediated the detrimental effects of face masks on speech intelligibility in noise. Both groups tended to perform better in SSN versus 4-T babble. The findings indicate that, when using face masks, either a transparent mask or a surgical mask negatively affects speech understanding in noise for individuals with hearing loss. Using a transparent mask and clear speech could be a potential solution to improve speech intelligibility in communication with face masks in noise.

Single-channel speech enhancement by PSO-GSA with harmonic regeneration noise reduction

Speech quality significantly affects the performance of speech dependent systems. Noise in the background lowers the clarity and intelligibility of speech. The augmentation of speech can increase its quality. We propose a single-channel speech improvement framework that combines particle swarm optimization (PSO), gravitational search algorithm (GSA), and harmonic regeneration noise reduction (HRNR) to minimize speech signal noise and increase speech intelligibility. The proposed hybrid algorithm optimizes the amount of overlap between the noisy speech frames. This helps in reducing the overlapped noise. Then HRNR algorithm is applied to retain the speech harmonics. The algorithm gives improvement in the speech intelligibility for babble, car and exhibition noise. The segmental signal to noise ratio (SNR) is also improved for these noise types. There is improvement in speech intelligibility with minimal speech distortion.

The acoustic metasphere. A solution to improving speech intelligibility and acoustic measurements

The application of acoustic metamaterials has found utility in several disciplines ranging from biomedical ultrasound to architectural acoustics, and even the music industry. However, an underlying complication with these devices is their narrow bandwidth which limits the effectiveness of acoustic metamaterials in research and industry. Additionally, within architectural acoustics and noise control engineering, an issue that arises is speech intelligibility and clarity of the source. For example, within a populated and dense environment, such as an airport or shopping market, loudspeakers are placed every several feet to surmount the beaming directionality of these transducers at higher frequencies. Also, consequently, the gain must then be high enough to overcome this beaming effect and the noise floor generated by the environment and its occupants. Moreover, methods to more efficiently and cost effectively characterize the response of an acoustic space are needed to improve upon the noise control efforts within these locations. A solution to these obstacles is proposed with an acoustic metamaterial called the Acoustic Metasphere. Utilizing various twisting unit cells that fully envelop a loudspeaker, we demonstrate here that this acoustic metamaterial can improve the limitation of a loudspeaker due to its directionality, while simultaneously increasing the bandwidth of operation for this engineered structure.

Speech Intelligibility Improvement with Concrete and Abstract Auditory Cues

Objectives: The present study investigated several acoustic parameters to determine intelligibility strategies implemented by eight normal healthy individuals (NHI) and eight individuals with dysarthria (IWD) following concrete and abstract auditory speech cues. Methods: Ten acoustic parameters reportedly sensitive to intelligibility changes were selected and analyzed. Those included fundamental frequency (<i>f</i><sub>0</sub>), vowel duration, vowel-consonant-vowel syllable duration, closure duration, aspiration duration, the ratio of closure duration to closure and aspiration combined duration, the 1st & 2nd formant (F1, F2) consonant-to-vowel (C/V) ratio, and the F2 slope. They were compared in three different auditory speech cue conditions: No cue (NC), Concrete cue (CC), and Abstract cue (AC) conditions. Results: IWD showed higher values in most of the measurements compared to the NHI group. Group differences appeared in seven out of ten measurements in the NC condition. Such group differences only appeared in the closure duration and the closure duration ratio in the CC condition. Group difference disappeared in the AC condition. The results suggested that while NHI manipulated pitch and durational aspects of speech to increase intelligibility, IWD manipulated only the durational aspect in the cue conditions. Conclusion: The pitch might already be heightened while IWD implement clear speech strategy regardless of the cue condition. The aspiration duration was unaffected by cue or group condition. Participants reduced group differences on the relational measurements (F2 C/V ratio or F2 slope) after cues suggesting that IWD maintained the ability to control relational aspects of speech because they are critical for distinctive stop production. Abstract cues appeared to make IWD’s speech closer to NHI.

A deep neural network-correlation phase sensitive mask based estimation to improve speech intelligibility

General masking-based speech enhancement using a deep learning architecture (DNN) approach focuses on the spectral values of the speech in order to show improvement in intelligibility. But, the residual noise present in the phase spectrum and inter-channel correlation dependency between noise and noisy speech can impact the results of intelligibility in speech enhancement. This research work proposes a correlation phase-sensitive novel mask which contains phase, magnitude spectral and inter-channel correlation for a tangible improvement in speech intelligibility. The correlation parameter finds the dependency between the signals and phase spectrum factor eliminates the residual noise. In addition, selecting the prior features from the feature combination also helps in reducing the dimensionality and increases the accuracy of the enhanced speech. This work also aims to decrease the complexity of the DNN by analysing the network with different parameters. The performance of the mask is evaluated with various intelligibility factors. The proposed mask has been compared with different mask estimators. The proposed mask has generated estimated speech with an increase in the intelligibility of 0.02-0.001 over six different noises and four different signal-to-noise (SNR) levels.

Comparison of speech perception in bimodal cochlear implant patients with respect to the cochlear coverage.

The hearing success of patients with bimodal fitting, utilizing both acochlear implant (CI) and ahearing aid (HA), varies considerably: While some patients benefit from bimodal CI and HA, others do not. This retrospective study aimed to investigate speech perception in bimodally fitted patients and compare it with the cochlear coverage (CC). The CC was calculated with the OTOPLAN software, measuring the cochlear duct length on temporal bone CT scans of 39patients retrospectively. The patients were categorized into two groups: CC ≤ 65% (CC500) and CC > 65% (CC600). Monaural speech intelligibility for monosyllables at asound pressure level (SPL) of 65 dB in afree-field setting was assessed before and after CI at various time points. The two groups, one with preoperative HA and one with postoperative CI, were compared. Additionally, speech intelligibility was correlated with CC in the entire cohort before CI and at the last available follow-up (last observation time, LOT). Overall, there was no significant difference in speech intelligibility between CC500 and CC600 patients, with both groups demonstrating aconsistent improvement after implantation. While CC600 patients tended to exhibit earlier improvement in speech intelligibility, CC500 patients showed aslower initial improvement within the first 3months but demonstrated asteeper learning curve thereafter. At LOT, the two patient groups converged, with no significant differences in expected speech intelligibility. There was no significant relationship between unimodal/unilateral free-field speech intelligibility and CC. Interestingly, patients with aCC of 70-75% achieved the highest speech intelligibility. Despite of the lack of asignificant correlation between CC and speech perception, patients appeared to reach their maximum in unimodal/unilateral speech perception primarily at acoverage level of 70-75%. Nevertheless, further investigation is warranted, as CC500 was associated with shorter cochlear duct length, and different types of electrodes were used in both groups.

The Assistive Benefits of Remote Microphone Technology for Normal Hearing Children With Listening Difficulties.

Children often present with listening difficulties (LiD) but with normal sound detection thresholds. These children are susceptible to learning challenges, and struggle with the suboptimal acoustics of standard classrooms. Remote microphone technology (RMT) is one way to improve the listening environment. The aim of this study was to determine the assistive potential of RMT for speech identification and attention skills in children with LiD, and to investigate whether the benefits obtained by these children were greater than for those with no listening concerns. A total of 28 children with LiD and 10 control participants with no listening concerns aged 6 to 12 years were included in this study. Children attended two laboratory-based testing sessions, where their speech intelligibility and attention skills were behaviorally assessed with and without the use of RMT. There were significant improvements in speech identification and attention skills when RMT was used. For the LiD group, use of the devices improved speech intelligibility to being comparable or better than control abilities without RMT. Auditory attention scores also improved from being poorer than controls without RMT to comparable to control performance with device assistance. Use of RMT was found to have a positive effect on both speech intelligibility and attention. RMT should be considered a viable option for addressing common behavioral symptoms of LiD, including for the many children that present with concerns of inattentiveness.

Reconstruction of large defects of anterior floor of mouth with free flaps using a novel individualized flap design method

The purpose of this study was to introduce a novel individualized flap design method for large anterior floor of the mouth (AFOM) defect reconstruction, review experience with the use of this flap design method for large AFOM defect reconstruction, and assess its functional results.A retrospective study of patients who received large AFOM defect reconstruction with free flaps was conducted. There was a cohort of patients who were treated using the novel individualized flap design method and a cohort without flap design. Functional outcomes were evaluated with appropriate scales. Outcomes were analyzed, and a p-value <0.05 was considered significant.22 patients received the individualized flap design, while 21 patients were treated without a special flap design. All flaps survived. All free flaps harvested with the novel individualized flap design method better matched AFOM defects. Relative to patients without flap design, patients in the novel individualized flap design group showed significant improvement in speech intelligibility (p = 0.036) and swallowing function (p = 0.019).Within the limitation of the study it seems that large AFOM defect reconstruction with the novel individualized flap design method can not only cover and close the wound to avoid oral-neck fistulae, but also maintains tongue mobility to achieve better functional outcomes than in patients without flap design.

Effects of noise and noise reduction on audiovisual speech perception in cochlear implant users: An ERP study

ObjectiveHearing with a cochlear implant (CI) is difficult in noisy environments, but the use of noise reduction algorithms, specifically ForwardFocus, can improve speech intelligibility. The current event-related potentials (ERP) study examined the electrophysiological correlates of this perceptual improvement. MethodsTen bimodal CI users performed a syllable-identification task in auditory and audiovisual conditions, with syllables presented from the front and stationary noise presented from the sides. Brainstorm was used for spatio-temporal evaluation of ERPs. ResultsCI users revealed an audiovisual benefit as reflected by shorter response times and greater activation in temporal and occipital regions at P2 latency. However, in auditory and audiovisual conditions, background noise hampered speech processing, leading to longer response times and delayed auditory-cortex-activation at N1 latency. Nevertheless, activating ForwardFocus resulted in shorter response times, reduced listening effort and enhanced superior-frontal-cortex-activation at P2 latency, particularly in audiovisual conditions. ConclusionsForwardFocus enhances speech intelligibility in audiovisual speech conditions by potentially allowing the reallocation of attentional resources to relevant auditory speech cues. SignificanceThis study shows for CI users that background noise and ForwardFocus differentially affect spatio-temporal cortical response patterns, both in auditory and audiovisual speech conditions.

The Influence of a Single Therapeutic Dose of Methadone on Selected Auditory Functions in Patients Addicted to Opioids and Undergoing Substitution Therapy – a Preliminary Study

The main purpose of this research was to determine the influence of a therapeutic dose of an opioid drug (methadone) on selected auditory functions in patients addicted to opioids (recognition ICD-10; F11) and undergoing substitution therapy. Various hearing tests were used in this research – pure tone audiometry, impedance audiometry, otoacoustic emission measurement, and a speech in noise test – in two sessions, before and after methadone intake. It was found that methadone causes an improvement in speech intelligibility when speech is presented in speech-like noise, and slightly decreases hearing thresholds [dB HL]. Methadone consumption has no significant impact on distortion product otoacoustic emissions levels (DPOAE). In summary, a prescribed methadone dose does not worsen the hearing of opioid-dependent subjects.

A novel flap design technique for subtotal tongue reconstruction with an “Individualized and Convenient Tongue Model”

BackgroundTo achieve improved functional outcomes in subtotal tongue reconstruction, a flap design with sufficient volume and appropriate shape is necessary. In this study, we introduce an “Individualized and Convenient Tongue Model” (ICTM) for flap design in subtotal tongue reconstruction. MethodsBy studying the anatomical morphology of the tongue, we found a similar geometry within the dorsum and body of the tongue as well as the mouth floor. This can be used to create an ICTM through folding and splicing. We can simulate tongue defects in the ICTM and transform defect shapes into guide plates for flap design. In this study, fifty-eight patients requiring subtotal tongue reconstruction were randomly divided into two groups: an ICTM group (35 patients) and a conventional group (31 patients). In the ICTM group, we individually designed profunda artery perforator flaps (PAPFs) or anterolateral thigh flaps (ALTFs) using the ICTM method. In the conventional group, the flap was designed according to the surgeon’s clinical experience. Patient demographics, operative and follow-up data were recorded. Swallowing, speech intelligibility, and cosmetic results were assessed using appropriate scales. ResultsAll flaps survived, although there were no significant differences in tumor size, operation time, flap size, and complication rate compared to the conventional group. Patients in the ICTM group had significantly improved speech intelligibility (p = 0.019), cosmetic appearance (p = 0.009), and swallowing ability (p = 0.003). ConclusionsThe ICTM technique is an effective and convenient solution for subtotal tongue reconstruction that provides an individualized flap design and improves functional outcomes compared to the conventional design.

Long-term effects of subthalamic nucleus deep brain stimulation on speech in Parkinson’s disease

Bilateral subthalamic nucleus deep brain stimulation (STN-DBS) is an effective treatment in advanced Parkinson’s Disease (PD). However, the effects of STN-DBS on speech are still debated, particularly in the long-term follow-up. The objective of this study was to evaluate the long-term effects of bilateral STN-DBS on speech in a cohort of advanced PD patients treated with bilateral STN-DBS. Each patient was assessed before surgery through a neurological evaluation and a perceptual-acoustic analysis of speech and re-assessed in the long-term in different stimulation and drug conditions. The primary outcome was the percentage change of speech intelligibility obtained by comparing the postoperative on-stimulation/off-medication condition with the preoperative off-medication condition. Twenty-five PD patients treated with bilateral STN-DBS with a 5-year follow-up were included. In the long-term, speech intelligibility stayed at the same level as preoperative values when compared with preoperative values. STN-DBS induced a significant acute improvement of speech intelligibility (p < 0.005) in the postoperative assessment when compared to the on-stimulation/off-medication and off-stimulation/off-medication conditions. These results highlight that STN-DBS may handle speech intelligibility even in the long-term.