Automatic analysis of cochlear response using electrocochleography signals during cochlear implant surgery

Developing an International Core Outcome Set for SSD Interventions

The cochlea plays a key role in the transmission from acoustic vibration to neural stimulation upon which the brain perceives the sound. A cochlear implant (CI) is an auditory prosthesis to replace the damaged cochlear hair cells to achieve acoustic-to-neural conversion. However, the CI is a very coarse bionic imitation of the normal cochlea. The highly resolved time-frequency-intensity information transmitted by the normal cochlea, which is vital to high-quality auditory perception such as speech perception in challenging environments, cannot be guaranteed by CIs. Although CI recipients with state-of-the-art commercial CI devices achieve good speech perception in quiet backgrounds, they usually suffer from poor speech perception in noisy environments. Therefore, noise suppression or speech enhancement (SE) is one of the most important technologies for CI. In this study, we introduce recent progress in deep learning (DL), mostly neural networks (NN)-based SE front ends to CI, and discuss how the hearing properties of the CI recipients could be utilized to optimize the DL-based SE. In particular, different loss functions are introduced to supervise the NN training, and a set of objective and subjective experiments is presented. Results verify that the CI recipients are more sensitive to the residual noise than the SE-induced speech distortion, which has been common knowledge in CI research. Furthermore, speech reception threshold (SRT) in noise tests demonstrates that the intelligibility of the denoised speech can be significantly improved when the NN is trained with a loss function bias to more noise suppression than that with equal attention on noise residue and speech distortion.

Background: Regarding the strong auditory spatial plasticity capability of the central auditory system and the effect of short-term and long-term rehabilitation programs in elderly people, it seems that an auditory spatial training can help this population in informational masking release and better track speech in noisy environments. The main purposes of this study are developing an informational masking measurement test and an auditory spatial training program. Protocol: This study will be conducted in two parts. Part 1: develop and determine the validity of an informational masking measurement test by recruiting two groups of young (n=50) and old (n=50) participants with normal hearing who have no difficulty in understanding speech in noisy environments. Part 2 (clinical trial): two groups of 60-75-year-olds with normal hearing, who complain about difficulty in speech perception in noisy environments, will participate as control and intervention groups to examine the effect of auditory spatial training. Intervention: 8 sessions of auditory spatial training. The informational masking measurement test and Speech, Spatial and Qualities of Hearing Scale will be compared before intervention, immediately after intervention, and one month after intervention between the two groups. Discussion: Since auditory training programs do not deal with informational masking release, an auditory spatial training will be designed, aiming to improve hearing in noisy environments for elderly populations. Trial registration: Iranian Registry of Clinical Trials (IRCT20190118042404N1) on 25th February 2019.

Persons with sensorineural hearing loss experience difficulty in speech perception in noisy environments. They can benefit from signal processing for suppressing the background noise in their hearing aids. For such an application, a speech enhancement technique using spectral subtraction and noise spectrum estimation based on dynamic quantile tracking is presented. It does not involve voice activity detection or storage and sorting of past spectral samples. Enhancement of speech corrupted with different types of additive stationary and non-stationary noise showed improvement in speech quality to be equivalent to an SNR advantage of 3 – 6 dB. The technique is implemented and tested for satisfactory real-time operation, with sampling frequency of 10 kHz, on a 16-bit fixed-point DSP processor with on-chip FFT hardware.

A cochlear implant (CI) is a hearing device introduced in the 1980s for profoundly deaf subjects who gained little or no benefit from powerful hearing aids. This device comprises an electrode array inserted in the cochlea, connected to an internal receiver, and an externally worn speech processor. The CI transforms acoustic signals into electrical currents which directly stimulate the auditory nerve. Since the early 1990s, cochlear implantation in children has been developing rapidly. Although it is still difficult to predict how a child will perform with a cochlear implant, the success of cochlear implantation can no longer be denied. In this paper, some recent papers and reports, and the results of the various Nijmegen cochlear implant studies, are reviewed. Issues about selection, examinations, surgery and the outcome are discussed. Overall, our results were comparable with those of other authors. It can be concluded that cochlear implantation is an effective treatment for postlingually deaf as well as prelingually (congenital or acquired) deaf children with profound bilateral sensorineural deafness.

Background Speech perception in noisy environments is significantly influenced by a listener’s ability to segregate competing auditory streams, a process in which fundamental frequency (F0) plays a crucial role, particularly under informational masking conditions. F0 differences, quantified in semitone shifts, facilitate stream segregation by enhancing perceptual distinctiveness between target and masker signals. Although this phenomenon has been extensively studied in various languages, there is limited research on its effects in Malayalam, a Dravidian language characterized by rich prosodic features. The present study investigated how semitone-based variations in F0 affect the perception of low-frequency PB Malayalam words in the presence of gender-specific speech maskers. Twenty-seven young adults (13 males, 14 females) aged 18 to 25 years, all native Malayalam speakers with normal hearing sensitivity, participated in the study. An adaptive SNR-50 paradigm was employed to assess speech perception across eight experimental conditions involving four semitone shifts (0, 4, 8, and 12 ST) and two-talker babble maskers of either male or female voices. Stimuli were presented binaurally, and participants completed a closed-set image selection task to indicate their responses. Results Significant main effects were observed for masker gender, with better performance in the different-gender (male) masker condition. Although semitone shifts alone did not yield significant differences, a significant interaction between semitone and masker gender was noted. Performance was consistently highest at 0 ST across both masker types. Conclusion These findings suggest that while increased F0 separation can aid speech perception, voice naturalness at 0 ST may offer greater perceptual stability. Results have implications for understanding pitch-based stream segregation in Malayalam and improving clinical speech perception strategies.

If speech is reproduced in an acoustically disturbed environment via a loudspeaker, the perception in terms of intelligibility or listening effort may be impaired. Typical situations arise in connection with mobile phones or public address systems. The location of the listener is called the near-end while the speech signal is received from the far-end. Usually, the acoustical background noise cannot be influenced, but speech perception may be enhanced by digital pre-processing of the loudspeaker signal. This pre-processing technique is called Near-End Listening Enhancement (NELE). The received signal is filtered adaptively, by taking the instantaneous characteristics of the background noise into account and by exploiting psychoacoustic properties of the auditory system such as the masking threshold. The increase of the loudspeaker volume is often not allowed or very limited, to avoid injury of hearing or damages of the loudspeaker and because of the listening comfort. In this contribution, state-of-the-art NELE algorithms operating in the short-term frequency domain are reviewed and novel time domain approaches are presented. Furthermore, the differing NELE constraints of public address systems and mobile phones are discussed.

Background and Aim: Many older adults experience difficulty in speech perception in noisy environments and fast speech. Speech perception is dependent on bottom-up and top-down auditory processing information. This study aimed to investigate the relationship between Interaural Time Difference (ITD) and speech processing speed in older adults with difficulty in speech perception in noise. Methods: In this study, 36 Iranian older adults with normal hearing (23 men and 13 women) aged 65–75 years who had complaints about the difficulty with speech perception in noise, participated. The ITD test with two stimuli (high-pass and low-pass noise) was used to asess the auditory localization ability. Time-Compressed Speech Test (TCST) and reaction time test were used to measure their speech processing speed. Pearson correlation test was performed to examine the relationship between ITD and speech processing speed. Results: The auditory localization errors were more significant for ITDs with low-pass noise than high-pass noise. The results showed a negative correlation between localization errors and the TCST score at time compression ratios of 40% (p=0.005) and 60% (p=0.002). The highest correlation was observed between ITD (low-pass noise) and the TCST score at the time compression ratio of 60% in the right ear (r=–0.66). The mean ITD errors were not significantly correlated to the reaction time test score (p>0.05). Conclusion: Word recognition in the elderly declines with increasing speech rate. The findings of this study can be used in clinical practice for consultation and rehabilitation of older adults with communication difficulties. Keywords: Sound localization; speed processing; speech perception; elderly

Speech perception in noisy environments is a common challenge among older adults, even for those with clinically normal hearing. Cognitive decline may be one of the contributing factors, and, as such, auditory-cognitive training may enhance speech perception in these conditions. This study aims to determine if auditory-cognitive training can improve speech-in-noise listening in normal-hearing, older adults using neural and behavioral measures, supplemented with comparisons across younger and older adults. Neural responses were obtained using magnetoencephalography (MEG) while participants listened to long, narrative passages (60 s) under four noise conditions. Neural measures employed reverse correlation using encoding and decoding models, via the temporal response function (TRF) framework, to predict neural responses and reconstruct stimulus features, respectively, with the boosting algorithm to enforce sparsity. Behavioral measures, such as working memory (reading span; RSPAN), speech perception in noise (SPIN), and nonlinguistic auditory stream segregation (stochastic figure-ground; SFG) showed improvement post-training, along with neural and subjective ratings for listening effort. Additionally, auditory-cognitive training may enhance the neural contrast between the selectively attended and unattended stimulus reconstructions, and pre-training SFG performance may predict the extent of this neuroplasticity change. These results provide promising, additional insight into the effects of auditory-cognitive training, both perceptually and neurally.

This study investigates the effectiveness of Deep Neural Network (DNN)-generated virtual humans in enhancing audiovisual speech perception in noisy environments, with a focus on using neural measures to quantify these effects. Lip movements are essential for speech comprehension, especially when auditory cues are degraded by noise. Traditional recording methods produce high-quality audiovisual materials but are resource intensive. This research explores the use of DNN avatars as a promising alternative, utilizing a commercially available tool to create realistic virtual humans. The study included both simple sentences and a short story to improve ecological validity.Eleven young, normal-hearing participants proficient in Flemish-Dutch listened to semantically meaningful sentences and a short story with various speaker types: a female FACS avatar, male and female DNN avatars, and a video of a human male speaker. The study included behavioral measures which consisted of an adaptive recall procedure and an adaptive rate procedure and electrophysiological measures consisting of neural tracking.Findings in the adaptive recall procedure showed consistent audiovisual benefits, with the human speaker offering the greatest benefit (−4.75 dB SNR), followed by the DNN avatar (−4.00 dB SNR) and the FACS avatar (−1.55 dB SNR). Additionally in the adaptive rate procedure, the DNN avatar improved speech intelligibility, with average SRTs enhancing from −7.17 dB SNR (audio-only) to −9.02 dB SNR (audiovisual). The results from the neural tracking procedure indicated that most participants experienced audiovisual benefits, particularly in the −9 dB SNR range, revealing that audiovisual cues provided by DNN avatars can enhance speech perception, validating these avatars as effective tools for studying audiovisual effects when using both behavioral measures and electrophysiological measures.

<p style="text-align: justify;"><span lang="EN-US">Objectives</span><span lang="EN-US">. Children with Autism Spectrum Disorder (ASD) often face difficulties in speech perception, particularly in noisy environments. These problems are associated with central auditory processing disorders. FM systems, which improve the signal-to-noise ratio, can be used to enhance speech perception. The aim of this study was to investigate the effects of FM systems when working with children with ASD in noisy conditions and their use in a school setting. Methods. The pilot study was conducted in two stages. In the first stage, the “Words in Noise” test and the “Sentence Repetition” task were used to assess children’s ability to recognize speech in noisy conditions with and without the use of FM systems. Fourteen children with ASD and 14 typically developing peers participated in the experiment. In the second stage, FM systems were studied in real school environments with 10 elementary school students with autism. Changes in auditory abilities were assessed using the L.I.F.E.-R scale. Results. In the first stage, it was found that children with ASD recognized significantly fewer words in noisy conditions compared to their typically developing peers. In the “Sentence Repetition” task, the use of FM systems improved the performance of children with ASD from 58.3% to 76.9% (p=0.0005). In the second stage, most participants showed minimal changes in auditory ability scores on the L.I.F.E.-R scale: the average score before using FM systems was 54.9, and after using them it was 57</span><span lang="EN-US">.4 (p=0.2322). However, several students showed improvements of 8–13 points, reflecting individual variability in the effect of using FM systems. Discussion. FM systems have demonstrated their effectiveness in improving speech perception in noisy environments for children with ASD. However, the integration of FM systems into the school process requires further research on their effectiveness in real conditions, as well as adaptations to minimize discomfort for children and improve interaction with teachers and tutors.</span></p>

Background and Objectives：In this study, we evaluated the effect of bimodal hearing in the speech perception test and the increasing level of bimodal hearing over cochlear implantation in speech perception score regarding residual hearing. Subjects and Method：Nineteen prelingually deaf patients, who had used bimodal hearing over a period of 8 months, were divided in two groups in accordance to their low frequency residual hearing. The children were tested in open-set speech perception under +10 SNR and +20 SNR. The scores of bimodal hearing and unilateral cochlear implantation were compared by the Wilcoxon signed-rank test. Also, the increased level of speech perception scores of bimodal hearing over cochlear implantation alone were calculated using the formula, [bimodal score (%) - unilateral cochlear implantation (%)], and was compared between groups. Results：In pure tone audiometry under silent condition, the result of bimodal hearing was similar to unilateral cochlear implantation in magnitude in both groups. Under the noisy condition, both groups had better result in bimodal hearing in terms of speech perception. Also, the increased level was higher in bimodal hearing over unilateral cochlear implantation in the better residual hearing group. However, since the sample size was small enough, it is considered that there was no statistical significance. Conclusion：Cochlear implanted patients with residual hearing are expected to get better speech perception in noisy environment with bimodal hearing regardless of the level of residual hearing. (Korean J Otorhinolaryngol-Head Neck Surg 2009;52:29-35)

Recent advancements toward minimizing surgical trauma and preserving residual hearing during cochlear implantation have promoted the use of intracochlear electrocochleography (ECochG) for intraoperative surveillance. However, variations in the distribution of response generators throughout the cochlea complicate the interpretation of signal changes during electrode array insertion. This exploratory study aimed to investigate whether simultaneous recordings from 2 locations within the cochlea could address this issue. This was done by (1) comparing recordings acquired simultaneously from an apical and a more basal electrode contact during atraumatic electrode array insertions; and (2) comparing these response patterns with preoperative pure-tone audiograms. In 10 standard CI recipients, ECochG recordings were obtained during stepwise insertion of a short-temporary electrode array. Simultaneous intracochlear recordings were acquired from 2 contacts separated by 4.2mm in response to 500Hz tone bursts. For both electrode contacts, the differences between responses to alternating-polarity stimuli, hereafter named "ECochG responses," were derived. After completion of the recordings, the temporary electrode array was removed and a standard CI electrode array inserted. In 6 of 10 participants, ECochG response amplitude decreases of ≥3dB were recorded at the more basal electrode contact. In 4 cases, these amplitude drops were preceded by amplitude drops recorded at the apical electrode contact, with both occurring no more than 1.7mm apart along the cochlear duct. Trauma would be expected to produce a simultaneous amplitude drop-at different recording locations-for both electrodes. In contrast, a drop at the basal electrode that is preceded by a drop in the ECochG recording at the apical electrode, with both drops occurring at approximately the same location, is likely atraumatic. These atraumatic drops may also be associated with large phase shifts. Overall, the ECochG response tracks recorded at the apical and more basal contact were similar, while the ECochG response patterns and audiogram did not show a strong resemblance. The proposed approach could facilitate the detection of ECochG response changes relevant for predicting hearing preservation during cochlear implantation. By distinguishing between simultaneous and sequential amplitude drops, this method could provide additional insights into the atraumatic nature of certain ECochG response changes.

Children with profound hearing loss can gain access to sound through cochlear implants (CIs), but these devices must be worn consistently to promote auditory development. Although subjective parent reports have identified several factors limiting long-term CI use in children, it is also important to understand the day-to-day issues which may preclude consistent device use. In the present study, objective measures gathered through datalogging software were used to quantify the following in children: (1) number of hours of CI use per day, (2) practical concerns including repeated disconnections between the external transmission coil and the internal device (termed "coil-offs"), and (3) listening environments experienced during daily use. This study aimed to (1) objectively measure daily CI use and factors influencing consistent device use in children using one or two CIs and (2) evaluate the intensity levels and types of listening environments children are exposed to during daily CI use. Retrospective analysis. Measures of daily CI use were obtained from 146 pediatric users of Cochlear Nucleus 6 speech processors. The sample included 5 unilateral, 40 bimodal, and 101 bilateral CI users (77 simultaneously and 24 sequentially implanted). Daily CI use, duration, and frequency of coil-offs per day, and the time spent in multiple intensity ranges and environment types were extracted from the datalog saved during clinic appointments. Multiple regression analyses were completed to predict daily CI use based on child-related demographic variables, and to evaluate the effects of age on coil-offs and environment acoustics. Children used their CIs for 9.86 ± 3.43 hr on average on a daily basis, with use exceeding 9 hr per day in ∼64% of the children. Daily CI use reduced significantly with increasing durations of coil-off (p = 0.027) and increased significantly with longer CI experience (p < 0.001) and pre-CI acoustic experience (p < 0.001), when controlled for the child's age. Total time in sound (sum of CI and pre-CI experience) was positively correlated with CI use (r = 0.72, p < 0.001). Longer durations of coil-off were associated with higher frequency of coil-offs (p < 0.001). The frequency of coil-offs ranged from 0.99 to 594.10 times per day and decreased significantly with age (p < 0.001). Daily CI use and frequency of coil-offs did not vary significantly across known etiologies. Listening environments of all children typically ranged between 50 and 70 dBA. Children of all ages were exposed to speech in noisy environments. Environment classified as "music" was identified more often in younger children. The majority of children use their CIs consistently, even during the first year of implantation. The frequency of coil-offs is a practical challenge in infants and young children, and demonstrates the need for improved coil retention methods for pediatric use. Longer hearing experience and shorter coil-off time facilitates consistent CI use. Children are listening to speech in noisy environments most often, thereby indicating a need for better access to binaural cues, signal processing, and stimulation strategies to aid listening. Study findings could be useful in parent counseling of young and/or new CI users.

A clinically focused music training program was developed, aimed at enhancing a listener's music appreciation levels. The program was pilot tested on 18 adult cochlear implant (CI) recipients and 13 adult hearing aid (HA) users, with each device group divided into a control and training group. The training groups were asked to use the program four times a week for 10 weeks. Both the training and control groups were assessed on their quality ratings of the musical stimuli as well as tests of instrument and style identification and pitch ranking, before and after the “training” period. In addition to examining the potential benefit of training on appreciation, we examined the relationship between appreciation and perceptual accuracy. The results showed that the training program improved CI recipients' quality ratings for ensemble stimuli, as well as both CI and HA users' subjective ratings of their music perception skills; however, there were no significant improvements for CI or HA users on the timbre identification or pitch ranking tasks. This suggests that CI recipients' music enjoyment can be improved with training, independent of perceptual accuracy. The pretraining baseline scores highlight that music appreciation and perception are two different issues, that everyday experience with the device does not improve music listening, and that music appreciation is still a significant issue for both CI and HA users.