Smartphone-based single-channel speech enhancement application for hearing aids.

This work presents a single-channel speech enhancement (SE) framework based on the super-Gaussian extension of the joint maximum a posteriori (SGJMAP) estimation rule. The developed SE algorithm is an open-source research smartphone-based application for hearing improvement studies. In this algorithm, the SGJMAP-based estimation for noisy speech mixture is smoothed along the frequency axis by a Mel filter-bank, resulting in a Mel-warped frequency-domain SGJMAP estimation. The impulse response of this Mel-warped estimation is obtained by applying a Mel-warped inverse discrete cosine transform (Mel-IDCT). This helps in filtering out the background noise and enhancing the speech signal. The proposed application is implemented on an iPhone (Apple, Cupertino, CA) to operate in real time and tested with normal-hearing (NH) and hearing-impaired (HI) listeners with different types of hearing aids through wireless connectivity. The objective speech quality and intelligibility test results are used to compare the performance of the proposed algorithm to existing conventional single-channel SE methods. Additionally, test results from NH and HI listeners show substantial improvement in speech recognition with the developed method in simulated real-world noisy conditions at different signal-to-noise ratio levels.

Communicating During COVID-19: The Effect of Transparent Masks for Speech Recognition in Noise.

OBJECTIVE: The purpose of this study was to assess the speech recognition in noise when using a transparent mask that allows greater visibility of the talker's face compared to an opaque mask in persons with normal and impaired hearing via an online format. DESIGN: A repeated-measures design was used to evaluate the auditory-visual recognition of sentences recorded in background noise with transparent and opaque face masks, and without a mask (N = 154). In a smaller follow-up study (N = 29), the same files were presented via auditory-only presentation to determine if differences observed in the transparent and opaque mask conditions were attributable to additional visual cues or to acoustic differences between the recordings of the two mask types. Listeners completed the 40-minute online session on a computer, laptop, or tablet in a quiet room via their personal listening devices (earbuds or hearing assistive device). The adult volunteers who used English as their first language were recruited through social media links and email and categorized into three groups: normal hearing and confirmed or suspected hearing loss either with or without the use of assistive listening devices. RESULTS: Auditory-visual recognition of sentences recorded with the transparent mask was significantly better (M = 68.9%) than for sentences recorded with the opaque mask (M = 58.9%) for all participants. There was a trend for those who used hearing assistive technology to score lower than the other two groups who had similar performance across all conditions regardless of the mask type. Subjective ratings of confidence and concentration followed the expected pattern based on objective scores. Results of the auditory-only presentation of the sentences to listeners with normal hearing suggested that the transparent mask benefits were not attributable to an acoustic advantage but rather to the addition of the visual cues of the talker's face available through the transparent mask. In fact, performance in the auditory-only presentation was significantly lower with the transparent mask (M = 40.7%) compared to the opaque mask (M = 58.2%). CONCLUSIONS: Use of transparent masks can significantly facilitate speech recognition in noise even for persons with normal hearing and thus may reduce stressful communication challenges experienced in medical, employment, and educational settings during the global pandemic. To mitigate the spread of COVID-19 and facilitate communication, safety-approved transparent masks are strongly encouraged over opaque masks.

Between the Listener and the Talker: Connectivity Options.

Hearing aids are often not sufficient for optimal communication between a listener and a talker. Therefore, numerous options for wireless connectivity between the listener and the talker designed to improve communication have become widely available. From the original wireless option of the induction loop system, most of the current solutions involve a digital signal with high quality and limited interference. Many are proprietary and only operate with a given manufacturer's devices, while others are more universal as long as the digital receiver can be connected to the listener's personal device. In addition, connectivity options to assist those with hearing loss are now readily available on the smartphone which can be used as a remote microphone. Therefore, it is paramount that the available wireless protocols be considered relative to the listener's experience with wireless technology so that solutions may be offered that are efficient, economical, and effective.

Behavioral Validation of the Smartphone for Remote Microphone Technology.

As part of a National Institutes of Health-National Institute on Deafness and Other communication Disorders (NIH-NIDCD)-supported project to develop open-source research and smartphone-based apps for enhancing speech recognition in noise, an app called Smartphone Hearing Aid Research Project Version 2 (SHARP-2) was tested with persons with normal and impaired hearing when using three sets of hearing aids (HAs) with wireless connectivity to an iPhone. Participants were asked to type sentences presented from a speaker in front of them while hearing noise from behind in two conditions, HA alone and HA + SHARP-2 app running on the iPhone. The signal was presented at a constant level of 65 dBA and the signal-to-noise ratio varied from -10 to +10, so that the task was difficult when listening through the bilateral HAs alone. This was important to allow for improvement to be measured when the HAs were connected to the SHARP-2 app on the smartphone. Benefit was achieved for most listeners with all three manufacturer HAs with the greatest improvements recorded for persons with normal (33.56%) and impaired hearing (22.21%) when using the SHARP-2 app with one manufacturer's made-for-all phones HAs. These results support the continued development of smartphone-based apps as an economical solution for enhancing speech recognition in noise for both persons with normal and impaired hearing.

The Acoustic Transparency of Waterproof Smartphone Cases.

Phone use is a critical communication event in many people's lives. Audiologists have aimed to assist individuals with hearing loss and phone usage through the use of technology and counseling. To counsel effectively, all contributions to hearing difficulty on the phone must be considered, including the effects of smartphone cases. The purpose of this study was to evaluate the effects on dB output caused by waterproof smartphone cases that cover the ear-level speaker. One waterproof case was tested with three smartphones, two iPhones, and one Android. A second waterproof case was tested with the two iPhones. Results revealed there was significant attenuation of the audio-signal by both waterproof smartphone cases that was great enough in one case/phone combination to potentially result in a complete lack of intelligibility of the signal.

Benefits in Speech Recognition in Noise with Remote Wireless Microphones in Group Settings.

BACKGROUND: Although hearing aids (HAs) and cochlear implants (CIs) can provide significant benefits to persons with hearing loss, users frequently report difficulty hearing in noisy environments, particularly when there are multiple talkers. Little is known about the benefits provided by currently available wireless microphones in multitalker situations. PURPOSE: The purpose of this study was to compare the benefits received in speech recognition in noise by adults with hearing loss when using two different wireless microphone types in a simulated group setting. RESEARCH DESIGN: A quasi-experimental, repeated-measures design was used where performance in a control condition, HA/CI alone, was compared with performance in two wireless microphone intervention conditions. STUDY SAMPLE: Participants included ten listeners, aged 20-92 years, with bilateral sensorineural hearing loss who were experienced HA or CI users. INTERVENTION: The two wireless microphones by Phonak, Roger Pen, and Roger Select used the same digital modulation protocol to transmit the signal to compatible receivers. However, the Roger Pen operated in a fixed omnidirectional mode, whereas the Roger Select operated in an adaptive directional mode. DATA COLLECTION AND ANALYSIS: Participants were asked to repeat Hearing in Noise Test sentences presented in restaurant noise in three conditions: HA/CI alone, HA/CI with a Roger Pen, or HA/CI with a Roger Select microphone placed in the center of a round table. Sentences were presented from one of five loudspeakers equally spaced with the participant, while restaurant noise was presented on each side at four signal-to-noise ratios (SNRs), including +5, 0, -5, and -10 dB. A two-way, repeated-measures analysis of variance was performed with main effects of listening condition and noise level. RESULTS: Significantly greater speech recognition performance was achieved with the wireless microphones than with listening with just the HA or CI. Furthermore, at the -5- and -10-dB SNR conditions, the Roger Select resulted in significantly better performance than the Roger Pen microphone. CONCLUSIONS: The results suggest that the Roger Select microphone can provide significant benefits in speech recognition in noise over the use of HA/CI alone (61%) and also significant benefits over the use of a Roger Pen (16%) in a simulated group dining experience.

Auditory training of speech recognition with interrupted and continuous noise maskers by children with hearing impairment.

Previous studies have indicated that individuals with normal hearing (NH) experience a perceptual advantage for speech recognition in interrupted noise compared to continuous noise. In contrast, adults with hearing impairment (HI) and younger children with NH receive a minimal benefit. The objective of this investigation was to assess whether auditory training in interrupted noise would improve speech recognition in noise for children with HI and perhaps enhance their utilization of glimpsing skills. A partially-repeated measures design was used to evaluate the effectiveness of seven 1-h sessions of auditory training in interrupted and continuous noise. Speech recognition scores in interrupted and continuous noise were obtained from pre-, post-, and 3 months post-training from 24 children with moderate-to-severe hearing loss. Children who participated in auditory training in interrupted noise demonstrated a significantly greater improvement in speech recognition compared to those who trained in continuous noise. Those who trained in interrupted noise demonstrated similar improvements in both noise conditions while those who trained in continuous noise only showed modest improvements in the interrupted noise condition. This study presents direct evidence that auditory training in interrupted noise can be beneficial in improving speech recognition in noise for children with HI.

Service learning in auditory rehabilitation courses: the University of Texas at Dallas.

PURPOSE: The aim of this work was to review service learning (SL) principles and its implementation into the auditory rehabilitation (AR) curriculum at the University of Texas at Dallas and to evaluate the courses to determine whether potential benefits of SL are worth the substantial time commitment and course restructuring. METHOD: Via retrospective review, student outcomes for 25 students from 3 cohorts who completed the adult AR course prior to implementation of SL curriculum (pre-SL) were compared with those of 28 students from 3 SL cohorts. Data included final examination grades, ratings for overall course content, amount learned, clarity of responsibility, workload, relevance, and course comments. Student journals from the SL group and mentor surveys also were reviewed. RESULTS: The majority of student outcomes were comparable for pre-SL and SL cohorts. Clarity of responsibility and workload were rated lower for SL courses than for pre-SL classes, with medium and small to medium effect sizes, respectively. Mentors rated the projects and process of high value and benefit, and several projects remain in use beyond the end of the course. CONCLUSION: Continued use of an SL approach is supported, but additional guidance for students is needed for reflection and project analysis.

Electroacoustic evaluation of frequency-modulated receivers interfaced with personal hearing aids.

PURPOSE: The purpose of this study was to compare the electroacoustic outputs of frequency-modulated (FM) systems coupled to hearing aids. METHOD: Electroacoustic performance of FM systems coupled to hearing aids was determined for 3 FM receivers: body-worn with neck loop, ear-level nonprogrammable, and ear-level programmable. Systems were evaluated using the FM-advantage approach suggested by the American Speech-Language-Hearing Association's "Guidelines for Fitting and Monitoring FM Systems" (2002). Output differences between the hearing aid and FM system were examined for typical input levels with a complex signal to verify an FM advantage and for high-input levels with a pure-tone signal to confirm similarity in maximum output. RESULTS: Measurements from the FM receivers with neck loops showed significant low-frequency reduction and the most variable performance of the 3 types of systems. Less variable measurements were obtained with the ear-level FM receivers, and programmable FM receivers allowed for the most flexibility in obtaining an FM advantage. Findings of variability may be related to the type of system and the compression characteristics of the devices. CONCLUSION: Findings of great variability in electroacoustic performance of all systems support the need for electroacoustic evaluation, particularly when observing the effects of various settings on new technology.

Speech Recognition in noise in children with cochlear implants while listening in bilateral, bimodal, and FM-system arrangements.

PURPOSE: Speech recognition performance in noise was examined in children with cochlear implants (CIs) when using (a) a second CI (bilateral group), (b) a hearing aid (HA) on the nonimplant ear (bimodal group), and (c) a frequency modulation (FM) system on 1 or both sides. METHOD: While always maintaining use of the first CI, 2 groups participated in 6 conditions each using various listening arrangements with the second CI, HA, or FM system. Speech-in-noise thresholds were determined using simple phrases, classroom noise, and a method-of-limits approach. RESULTS: No group differences were detected across any conditions. In the no-FM-system conditions, no significant benefit of bilateral or bimodal input was found relative to a single CI. In the FM-system conditions, thresholds were significantly lower (up to 20 dB) relative to all other conditions when FM-system input was provided to the first-implanted side or to both sides simultaneously. CONCLUSIONS: Children's speech-in-noise thresholds did not improve when providing input to the second side with a CI or an HA relative to a single CI. However, children with CIs had better speech recognition in noise with the use of an FM system on one or both sides relative to the conditions with no FM system. Binaural conditions with a single FM receiver on the second CI or HA yielded significantly poorer performance than any other FM condition.

Speech recognition abilities of adults using cochlear implants with FM systems.

Speech recognition was evaluated for ten adults with normal hearing and eight adults with Nucleus cochlear implants (CIs) at several different signal-to-noise ratios (SNRs) and with three frequency modulated (FM) system arrangements: desktop, body worn, and miniature direct connect. Participants were asked to repeat Hearing in Noise Test (HINT) sentences presented with speech noise in a classroom setting and percent correct word repetition was determined. Performance was evaluated for both normal-hearing and CI participants with the desktop soundfield system. In addition, speech recognition for the CI participants was evaluated using two FM systems electrically coupled to their speech processors. When comparing the desktop sound field and the No-FM condition, only the listeners with normal hearing made significant improvements in speech recognition in noise. When comparing the performance across the three FM conditions for the CI listeners, the two electrically coupled FM systems resulted in significantly greater improvements in speech recognition in noise relative to the desktop soundfield system.