Telephone usage in the hearing-impaired population

Benefits of Text Supplementation on Sentence Recognition and Subjective Ratings With and Without Facial Cues for Listeners With Normal Hearing

OBJECTIVES

Recognizing speech through telecommunication can be challenging in unfavorable listening conditions. Text supplementation or provision of facial cues can facilitate speech recognition under some circumstances. However, our understanding of the combined benefit of text and facial cues in telecommunication is limited. The purpose of this study was to investigate the potential benefit of text supplementation for sentence recognition scores and subjective ratings of spoken speech with and without facial cues available.

DESIGN

Twenty adult females (M = 24 years, range 21 to 29 years) with normal hearing performed a sentence recognition task and also completed a subjective rating questionnaire in 24 conditions. The conditions varied by integrity of the available facial cues (clear facial cues, slight distortion facial cues, great distortion facial cues, no facial cues), signal-to-noise ratio (quiet, +1 dB, -3 dB), and text availability (with text, without text). When present, the text was an 86 to 88% accurate transcription of the auditory signal presented at a 500 ms delay relative to the auditory signal.

RESULTS

The benefits of text supplementation were largest when facial cues were not available and when the signal-to-noise ratio was unfavorable. Although no recognition score benefit was present in quiet, recognition benefit was significant in all levels of background noise for all levels of facial cue integrity. Moreover, participant subjective ratings of text benefit were robust and present even in the absence of recognition benefit. Consistent with previous literature, facial cues were beneficial for sentence recognition scores in the most unfavorable signal-to-noise ratio, even when greatly distorted. It is interesting that, although all levels of facial cues were beneficial for recognition scores, participants rated a significant benefit only with clear facial cues.

CONCLUSIONS

The benefit of text for auditory-only and auditory-visual speech recognition is evident in recognition scores and subjective ratings; the benefit is larger and more robust for subjective ratings than for scores. Therefore, text supplementation might provide benefit that extends beyond speech recognition scores. Combined, these findings support the use of text supplementation in telecommunication, even when facial cues are concurrently present, such as during teleconferencing or watching television.

The effect of internet telephony and a cochlear implant accessory on mobile phone speech comprehension in cochlear implant users

PURPOSE

In individuals with severe hearing loss, mobile phone communication is limited despite treatment with a cochlear implant (CI). The goal of this study is to identify the best communication practice for CI users by comparing speech comprehension of conventional mobile phone (GSM) calls, Voice over Internet Protocol (VoIP) calls, and the application of a wireless phone clip (WPC) accessory.

METHODS

This study included 13 individuals (mean age 47.1  ± 17.3 years) with at least one CI. Frequency response and objective voice quality were tested for each device, transmission mode and the WPC. We measured speech comprehension using a smartphone for a GSM call with and without WPC as well as VoIP-calls with and without WPC at different levels of white background noise.

RESULTS

Frequency responses of the WPC were limited (< 4 kHz); however, speech comprehension in a noisy environment was significantly improved compared to GSM. Speech comprehension was improved by 9-27% utilizing VoIP or WPC compared to GSM. WPC was superior in noisy environments (80 dB SPL broadband noise) compared to GSM. At lower background noise levels (50, 60, 70 dB SPL broadband noise), VoIP resulted in improved speech comprehension with and without WPC. Speech comprehension scores did not correlate with objective voice quality measurements.

CONCLUSION

Speech comprehension was best with VoIP alone; however, accessories such as a WPC provide additional improvement in the presence of background noise. Mobile phone calls utilizing VoIP technology, with or without a WPC accessory, result in superior speech comprehension compared to GSM.

Factors Affecting the Accessibility of Voice Telephony for People with Hearing Loss: Audio Encoding, Network Impairments, Video and Environmental Noise

This paper describes four studies with a total of 114 individuals with hearing loss and 12 hearing controls that investigate the impact of audio quality parameters on voice telecommunications. These studies were first informed by a survey of 439 individuals with hearing loss on their voice telecommunications experiences. While voice telephony was very important, with high usage of wireless mobile phones, respondents reported relatively low satisfaction with their hearing devices’ performance for telephone listening, noting that improved telephone audio quality was a significant need. The studies cover three categories of audio quality parameters: (1) narrowband (NB) versus wideband (WB) audio; (2) encoding audio at varying bit rates, from typical rates used in today's mobile networks to the highest quality supported by these audio codecs; and (3) absence of packet loss to worst-case packet loss in both mobile and VoIP networks. Additionally, NB versus WB audio was tested in auditory-only and audiovisual presentation modes and in quiet and noisy environments. With WB audio in a quiet environment, individuals with hearing loss exhibited better speech recognition, expended less perceived mental effort, and rated speech quality higher than with NB audio. WB audio provided a greater benefit when listening alone than when the visual channel also was available. The noisy environment significantly degraded performance for both presentation modes, but particularly for listening alone. Bit rate affected speech recognition for NB audio, and speech quality ratings for both NB and WB audio. Packet loss affected all of speech recognition, mental effort, and speech quality ratings. WB versus NB audio also affected hearing individuals, especially under packet loss. These results are discussed in terms of the practical steps they suggest for the implementation of telecommunications systems and related technical standards and policy considerations to improve the accessibility of voice telephony for people with hearing loss.

Troubleshooting Cochlear Implant Processors via Tele-Audiology

This case study examines the methods used to troubleshoot a cochlear implant processor via video visit with a nonagenarian (90+ years old) with a bimodal cochlear implant system. This article will discuss the evaluation and management as well as which specific issues could be addressed virtually and how they were resolved. Examples will be provided about how to virtually connect with the patient and how to best facilitate communication during a video visit. Additionally, this article will examine the captioning apps and other hearing assistive technology available for smartphones that can provide further assistance during a cell phone call along with their benefits and limitations.

Effects of text supplementation on speech intelligibility for listeners with normal and impaired hearing: a systematic review with implications for telecommunication

OBJECTIVE

Telecommunication can be difficult in the presence of noise or hearing loss. The purpose of this study was to systematically review evidence regarding the effects of text supplementation (e.g. captions, subtitles) of auditory or auditory-visual signals on speech intelligibility for listeners with normal or impaired hearing.

DESIGN

Three databases were searched. Articles were evaluated for inclusion based on the Population Intervention Comparison Outcome framework. The Effective Public Health Practice Project instrument was used to evaluate the quality of the identified articles.

STUDY SAMPLE

After duplicates were removed, the titles and abstracts of 2019 articles were screened. Forty-six full texts were reviewed; ten met inclusion criteria.

RESULTS

The quality of all ten articles was moderate or strong. The articles demonstrated that text added to auditory (or auditory-visual) signals improved speech intelligibility and that the benefits were largest when auditory signal integrity was low, accuracy of the text was high, and the auditory signal and text were synchronous. Age and hearing loss did not affect benefits from the addition of text.

CONCLUSIONS

Although only based on ten studies, these data support the use of text as a supplement during telecommunication, such as while watching television or during telehealth appointments.

Phone Speech Recognition Improvement in Noisy Environment: Use of a Bluetooth Accessory

OBJECTIVE

To evaluate speech understanding in noise and patient satisfaction using the new Cochlear Wireless Phone Clip device.

MATERIAL AND METHODS

Twenty-nine experienced cochlear implant (CI) users (>6 months usage) were situated in a soundproof room where a 65 dB SPL Spanish cocktail noise was generated continuously from 4 loudspeakers. Lists of disyllabic words were presented through the clinic landline telephone to the patients. Patients were tested first holding the phone and then with the Cochlear Phone Clip© paired to the CP910 using various mixing ratios (2:1, 4:1, and Phone Clip© only).

RESULTS

Statistically significant (P < .001) improvement of speech recognition performance was found in cell phone usage by wireless transmission and also when using this new device. Kepler questionnaire results showed that before using Phone Clip in everyday life, 55.2% of patients described themselves highly or greatly affected by their deafness for telephone use and 80% moderately to greatly affected. Kim questionnaire results showed statistically significant differences (P < .001) in the subjective satisfaction of the Bluetooth-implemented CI compared to the conventional mode for sound quality, noise interference, and sound accuracy.

CONCLUSIONS

The wireless Phone Clip© device helps implanted people to improve subjective and objective speech recognition performance through the phone in noisy environments.

Influence of Telecommunication Modality, Internet Transmission Quality, and Accessories on Speech Perception in Cochlear Implant Users

Background

Telecommunication is limited or even impossible for more than one-thirds of all cochlear implant (CI) users.

Objective

We sought therefore to study the impact of voice quality on speech perception with voice over Internet protocol (VoIP) under real and adverse network conditions.

Methods

Telephone speech perception was assessed in 19 CI users (15-69 years, average 42 years), using the German HSM (Hochmair-Schulz-Moser) sentence test comparing Skype and conventional telephone (public switched telephone networks, PSTN) transmission using a personal computer (PC) and a digital enhanced cordless telecommunications (DECT) telephone dual device. Five different Internet transmission quality modes and four accessories (PC speakers, headphones, 3.5 mm jack audio cable, and induction loop) were compared. As a secondary outcome, the subjective perceived voice quality was assessed using the mean opinion score (MOS).

Results

Speech telephone perception was significantly better (median 91.6%, P<.001) with Skype compared with PSTN (median 42.5%) under optimal conditions. Skype calls under adverse network conditions (data packet loss > 15%) were not superior to conventional telephony. In addition, there were no significant differences between the tested accessories (P>.05) using a PC. Coupling a Skype DECT phone device with an audio cable to the CI, however, resulted in higher speech perception (median 65%) and subjective MOS scores (3.2) than using PSTN (median 7.5%, P<.001).

Conclusions

Skype calls significantly improve speech perception for CI users compared with conventional telephony under real network conditions. Listening accessories do not further improve listening experience. Current Skype DECT telephone devices do not fully offer technical advantages in voice quality.

Speech perception benefits of internet versus conventional telephony for hearing-impaired individuals

Background

Telephone communication is a challenge for many hearing-impaired individuals. One important technical reason for this difficulty is the restricted frequency range (0.3–3.4 kHz) of conventional landline telephones. Internet telephony (voice over Internet protocol [VoIP]) is transmitted with a larger frequency range (0.1–8 kHz) and therefore includes more frequencies relevant to speech perception. According to a recently published, laboratory-based study, the theoretical advantage of ideal VoIP conditions over conventional telephone quality has translated into improved speech perception by hearing-impaired individuals. However, the speech perception benefits of nonideal VoIP network conditions, which may occur in daily life, have not been explored. VoIP use cannot be recommended to hearing-impaired individuals before its potential under more realistic conditions has been examined.

Objective

To compare realistic VoIP network conditions, under which digital data packets may be lost, with ideal conventional telephone quality with respect to their impact on speech perception by hearing-impaired individuals.

Methods

We assessed speech perception using standardized test material presented under simulated VoIP conditions with increasing digital data packet loss (from 0% to 20%) and compared with simulated ideal conventional telephone quality. We monaurally tested 10 adult users of cochlear implants, 10 adult users of hearing aids, and 10 normal-hearing adults in the free sound field, both in quiet and with background noise.

Results

Across all participant groups, mean speech perception scores using VoIP with 0%, 5%, and 10% packet loss were 15.2% (range 0%–53%), 10.6% (4%–46%), and 8.8% (7%–33%) higher, respectively, than with ideal conventional telephone quality. Speech perception did not differ between VoIP with 20% packet loss and conventional telephone quality. The maximum benefits were observed under ideal VoIP conditions without packet loss and were 36% (P = .001) for cochlear implant users, 18% (P = .002) for hearing aid users, and 53% (P = .001) for normal-hearing adults. With a packet loss of 10%, the maximum benefits were 30% (P = .002) for cochlear implant users, 6% (P = .38) for hearing aid users, and 33% (P = .002) for normal-hearing adults.

Conclusions

VoIP offers a speech perception benefit over conventional telephone quality, even when mild or moderate packet loss scenarios are created in the laboratory. VoIP, therefore, has the potential to significantly improve telecommunication abilities for the large community of hearing-impaired individuals.

Telephone use among cochlear implanted children

CONCLUSION

Telephone use among implanted children is significantly different from that of the normally hearing population of the same age.

OBJECTIVE

To characterize the use of telephone in cochlear implanted children and compare it to that of age-matched normal-hearing children.

METHODS

The study (n = 26) and control (n = 27) groups each consisted of children aged 5-17 years treated at a tertiary referral center. The study group included children who received a Med-El multichannel cochlear implant and had used it for at least 18 months. The control group comprised generally healthy children with normal hearing and no history of chronic ear disease or otologic surgery. The main outcome measures, evaluated through a questionnaire sent by mail, were comparison of telephone use and speech comprehension over the telephone between the study and control groups.

RESULTS

The median age of the study and control groups was 9 and 7 years, respectively (p = 0.12). There was a significant difference between the two groups in the reported rate of telephone use (mean 128 and 244 min/week, respectively, p = 0.006) and speech comprehension of familiar persons and strangers, which was highly significant among teenagers. The reported sound quality was similar for the two groups.

Effects of introducing low-frequency harmonics in the perception of vocoded telephone speech

Several studies have demonstrated that telephone use presents a challenge for most cochlear implant (CI) users, and this is attributed mainly to the narrow bandwidth (300-3400 Hz) introduced by the telephone network. The present study focuses on answering the question whether telephone speech recognition in noise can be improved by introducing, prior to vocoder processing, low-frequency harmonic information encompassing the missing (due to the telephone network) information residing in the 0-300 Hz band. Experiment 1 regenerates the main harmonics and adjacent partials within the 0-600 Hz range in corrupted (by steady noise) telephone speech which has been vocoded to simulate electric-acoustic stimulation (EAS). Results indicated that introducing the main harmonics alone did not produce any benefits in intelligibility. Substantial benefit (20%) was observed, however, when both main harmonics and adjacent partials were regenerated in the acoustic portion of EAS-vocoded telephone speech. A similar benefit was noted in Experiment 2 when low-frequency harmonic information was introduced prior to processing noise-corrupted telephone speech using an eight-channel vocoder. The gain in telephone speech intelligibility in noise obtained when low-frequency harmonic information was introduced can be attributed to the listeners having more reliable access to a combination of F0, glimpsing and lexical segmentation cues.

An investigation into the effect of limiting the frequency bandwidth of speech on speech recognition in adult cochlear implant users

The purpose of this study was to investigate the effect of the limited-frequency bandwidth employed by telephones (300-3400Hz) on speech recognition in adult cochlear implant users. The Four Alternative Auditory Feature (FAAF) test was used in four conditions: unfiltered and in three filtered conditions of 300-4500Hz, 300-3400Hz and 300-2500Hz. Ten subjects implanted with the Nucleus C124M device and 10 normal-hearing listeners were assessed to examine differences between word discrimination scores in each condition. Scores obtained from the 300-3400-Hz and 300-2500-Hz filtered conditions were significantly worse than those with unfiltered speech for the cochlear implant subjects, decreasing by 17.7% and 21.4%, respectively, from scores with unfiltered speech. By contrast, the normal-hearing listeners did not experience difficulties in discriminating between words in any of the conditions. Analysis of the word errors demonstrated that the reduction in implant subject scores with bandwidth arose from errors in place of articulation. Filtering speech in this way has a significant effect on speech recognition for cochlear implant subjects but not normal-hearing listeners. Hence, the limitations of the normal telephone bandwidth can be expected to have a negative effect on speech recognition for cochlear implant users using the telephone.

Effect of bandwidth extension to telephone speech recognition in cochlear implant users

The present study investigated a bandwidth extension method to enhance telephone speech understanding for cochlear implant (CI) users. The acoustic information above telephone speech transmission range (i.e., 3400 Hz) was estimated based on trained models describing the relation between narrow-band and wide-band speech. The effect of the bandwidth extension method was evaluated with IEEE sentence recognition tests in seven CI users. Results showed a relatively modest but significant improvement in the speech recognition with the proposed method. The effect of bandwidth extension method was also observed to be highly dependent on individual CI users.

User evaluation of a communication system that automatically generates captions to improve telephone communication

This study examined the subjective benefit obtained from automatically generated captions during telephone-speech comprehension in the presence of babble noise. Short stories were presented by telephone either with or without captions that were generated offline by an automatic speech recognition (ASR) system. To simulate online ASR, the word accuracy (WA) level of the captions was 60% or 70% and the text was presented delayed to the speech. After each test, the hearing impaired participants (n = 20) completed the NASA-Task Load Index and several rating scales evaluating the support from the captions. Participants indicated that using the erroneous text in speech comprehension was difficult and the reported task load did not differ between the audio + text and audio-only conditions. In a follow-up experiment (n = 10), the perceived benefit of presenting captions increased with an increase of WA levels to 80% and 90%, and elimination of the text delay. However, in general, the task load did not decrease when captions were presented. These results suggest that the extra effort required to process the text could have been compensated for by less effort required to comprehend the speech. Future research should aim at reducing the complexity of the task to increase the willingness of hearing impaired persons to use an assistive communication system automatically providing captions. The current results underline the need for obtaining both objective and subjective measures of benefit when evaluating assistive communication systems.

An HMM-based speech-to-video synthesizer

Emerging broadband communication systems promise a future of multimedia telephony, e.g. the addition of visual information to telephone conversations. It is useful to consider the problem of generating the critical information useful for speechreading, based on existing narrowband communications systems used for speech. This paper focuses on the problem of synthesizing visual articulatory movements given the acoustic speech signal. In this application, the acoustic speech signal is analyzed and the corresponding articulatory movements are synthesized for speechreading. This paper describes a hidden Markov model (HMM)-based visual speech synthesizer. The key elements in the application of HMMs to this problem are the decomposition of the overall modeling task into key stages and the judicious determination of the observation vector's components for each stage. The main contribution of this paper is a novel correlation HMM model that is able to integrate independently trained acoustic and visual HMMs for speech-to-visual synthesis. This model allows increased flexibility in choosing model topologies for the acoustic and visual HMMs. Moreover the propose model reduces the amount of training data compared to early integration modeling techniques. Results from objective experiments analysis show that the propose approach can reduce time alignment errors by 37.4% compared to conventional temporal scaling method. Furthermore, subjective results indicated that the purpose model can increase speech understanding.

Recognition of simulated telephone speech by cochlear implant users

PURPOSE

To evaluate cochlear implant users' understanding of telephone speech.

METHOD

Telephone speech was simulated by band-limiting broadband speech stimuli. Multitalker vowel, consonant, and sentence recognition was measured for both simulated telephone speech and broadband speech in 10 postlingually deafened adult cochlear implant users. The study was approved by the St. Vincent's Hospital institutional review board, and signed, informed consent was obtained from all participants.

RESULTS

There was no significant difference in vowel recognition scores between broadband and telephone speech. However, mean consonant and sentence recognition scores were significantly poorer with telephone speech.

CONCLUSIONS

The limited telephone bandwidth significantly reduced cochlear implant users' understanding of telephone speech. The effect of band-limited speech was highly variable, suggesting that the contribution of high-frequency information to speech recognition varied significantly among the cochlear implant users.

An Investigation of Telephone Use Among Cochlear Implant Recipients

The purpose of this study was to examine telephone use among cochlear implant recipients. A questionnaire was constructed and mailed to 803 adults who received a Clarion cochlear implant system manufactured by Advanced Bionics Corporation. Question-naire recipients were implanted at least 12 months prior to receiving the questionnaire (i.e., they were implanted in 1998 or 1999). Approximately 60% ( n = 478) responded, of whom 70% ( n = 336) were considered "telephone users" (i.e., they answered the telephone and/or initiated calls). Telephone users were significantly younger and had significantly more daily hours of cochlear implant use than nonusers. Not surprisingly, there were differences between groups with respect to method of communication (i.e., more users employed oral communication, while more nonusers employed both oral and manual communication) and ability to understand words without lipreading (i.e., more users were able to understand). Thirty-seven percent of the telephone users were male, and 63% were female. The average age was 51.8 years ( SD = 15.5). Ninety-five percent of users initiated calls to family and friends, 65% made appointments by phone, and approximately 50% asked for information about a product or service and conducted business over the phone. Over 95% of users could identify a dial tone, a busy signal, and voices. The average telephone use per week was 5.4 hr. Approximately 85% indicated that they were able to interact with strangers on the telephone within 5 months of receiving the sound processor. Approximately 30% communicated via a cellular phone for personal use. The findings of this survey suggest an increase in cochlear implant users' telephone use relative to a decade earlier. Advances in cochlear implant and telephone technologies are 2 of several factors that may contribute to the changes observed.

A phone-assistive device based on Bluetooth technology for cochlear implant users

Hearing-impaired people, and particularly hearing-aid and cochlear-implant users, often have difficulty communicating over the telephone. The intelligibility of telephone speech is considerably lower than the intelligibility of face-to-face speech. This is partly because of lack of visual cues, limited telephone bandwidth, and background noise. In addition, cellphones may cause interference with the hearing aid or cochlear implant. To address these problems that hearing-impaired people experience with telephones, this paper proposes a wireless phone adapter that can be used to route the audio signal directly to the hearing aid or cochlear implant processor. This adapter is based on Bluetooth technology. The favorable features of this new wireless technology make the adapter superior to traditional assistive listening devices. A hardware prototype was built and software programs were written to implement the headset profile in the Bluetooth specification. Three cochlear implant users were tested with the proposed phone-adapter and reported good speech quality.

Hearing ability by telephone of patients with cochlear implants

We investigated the telephone communication ability of patients with cochlear implants who could understand conversations in natural voice without difficulty. The hearing ability of those patients with telephone adapters, which usually are used to reduce noise level in the telephone and to record into a tape recorder, was also investigated. Vowel-confusion, consonant-confusion, and speech-tracking test results of patients listening to voices by telephone and by telephone adapter were compared with those of patients listening to natural, nontelephone voices. The average score of the speech-tracking test with natural voice was 111.5 phrases per 5 minutes. This score dropped to 62.4 by telephone. However, with a telephone adapter, the score of the speech-tracking test was 109.3 phrases per 5 minutes. This was almost the same score as that of the natural voice. So, generally speaking, the telephone communication ability of cochlear implant patients was not good enough. However, hearing ability with a telephone adapter came close to hearing ability during natural speech.