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

Abstract

BackgroundTelecommunication is limited or even impossible for more than one-thirds of all cochlear implant (CI) users.ObjectiveWe sought therefore to study the impact of voice quality on speech perception with voice over Internet protocol (VoIP) under real and adverse network conditions.MethodsTelephone 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).ResultsSpeech 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).ConclusionsSkype 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.

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

“…PESQ measurements were performed to quantify speech signal quality; however, PESQ scores were neither consistent with speech comprehension results nor with MOS scores. This discrepancy was also found in a previous study analyzing Digital Enhanced Cordless Technology (DECT) phones and their sound quality [ 9 ]. This raises the question: given its original purpose of measuring sound signal quality in conventional acoustic telephony for a normal hearing population, is the PESQ-score an adequate test of sound signal quality for VoIP in CIUs?…”

“…Restrictions of frequency range and signal intensity are often due to the device design and chosen hardware components. This has also been illustrated in previous studies, where different telephones or mobile devices were assessed in terms of voice quality and intelligibility [ 9 ]. In addition, telecommunication providers offering GSM apply speech codecs, which compress voice signals and restrict high-frequency transmission using 13kBit/s transmission rates (ITU recommendations, G-series).…”

“…The participants verbalized the HSM-sentences, and every correctly verbalized word contributed to the overall HSMscore (106 words = 106 points maximum score). After each measurement, participants were asked to quantify subjective comprehension of speech sound quality for all four scenarios by the mean opinion score (MOS, 5-point rating scale with 1 as the lowest and 5 as the highest score), a subjective speech quality test widely used in telecommunication [ 9 , 24 ].…”

“…Telephone speech comprehension is often compromised due to a limited frequency bandwidth of 300–3400 Hz and digital signal compression [ 6 , 7 ]. Voice over Internet Protocol (VoIP), however, transmits a wider frequency bandwidth (200–12,000 Hz), which results in improved speech comprehension independent of additional visual cues [ 6 – 9 ]. Mantokoudis et al measured speech comprehension during a conventional telephone call with background noise at different signal-to-noise ratios (SNR) [ 10 ].…”

Psychosocial Impact of Assistive Devices and Other Technologies on Deaf and Hard of Hearing People

“…In addition, other assistive technologies are frequently used like video relay services (VRS) [ 6 ], mobile phones [ 7 ] (mobile applications such as messaging or video call: Telegram, WhatsApp, Texmee, etc.) or Internet video telephony systems [ 8 , 9 ].…”