How Internet Telephony Could Improve Communication for Hearing-Impaired Individuals

Abstract

Objective: To test, whether modern Internet telephony with a broadband transmission (0.1Y8 kHz) of speech improves speech perception in comparison to conventional telephony (0.3Y3.5 kHz) in hearing-impaired and normal-hearing adults. Study Design: Experimental clinical study. Setting: Audiologic laboratory in a tertiary referral center in Bern, Switzerland. Patients: Twenty-one adult hearing-impaired patients consisting of 11 users of cochlear implants and 10 users of hearing aids were selected from the institution_s database based on pure tone audiograms, speech perception scores, and device settings. Ten normal-hearing adults served as controls. Intervention: Superiority trial of speech perception assessed with Internet versus conventional telephone quality and noninferiority trial of Internet telephone versus frequency restricted, uncompressed audio CD quality. A modern broadband codec was chosen to simulate Internet telephone quality, and ideal network conditions without packet loss were assumed.Main Outcome Measures: Speech perception scores of a monosyllabic word test in quiet and a sentence test in background noise assessed in different audio qualities. Results: Test scores were, on average, 15% (4Y33) higher in the monosyllabic word and 25% (8Y51) higher in the sentence test using Internet versus conventional telephone quality across all subject groups. Speech perception was not significantly different when Internet telephone quality was compared with high-cut CD quality. Conclusion: Internet telephony offers significantly improved speech perception to hearing-impaired and normal-hearing adults under ideal laboratory conditions through doubling the frequency range and through conserving audio quality during digital sound processing.

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

“…This phenomenon was also shown in normal hearing subjects and was not related to any speech coding strategy of a CI [21]. …”

“…A proof of concept was given by a previous experimental study showing a superior voice quality of Internet telephony resulting in better speech understanding, provided that the Internet connection quality was ideal [21]. This phenomenon was also shown in normal hearing subjects and was not related to any speech coding strategy of a CI [21].…”

“…A two-tailed Wilcoxon matched pairs signed-rank test was used to compare Skype with PSTN. For the ideal condition with no Internet data PL (condition 0% PL), a one-tailed test was applied because of the expected superiority of Skype under this condition [21,23]. A P value<.05 was considered significant after applying a Bonferroni correction for multiple testing.…”

“…Recent laboratory studies showed advantages of Internet telephony (voice over Internet protocol, VOIP) with improved voice quality caused by a wider frequency bandwidth (200-8500Hz) than the conventional telephone [20,21]; however, all these studies were performed under laboratory conditions. There is currently no study showing this advantage under real network conditions.…”

Improvement of Telephone Communication in Elderly Cochlear Implant Patients

“…Recently, Mantokoudis et al [2010] explored the potential of Internet telephony in both normal-hearing and deaf subjects, as modern phones via the Internet have a transmission bandwidth of 100-8,000 Hz and minimal compression of the audio signal. 'Software' changes have also been proposed for CI users, including creation of T-maps through the reallocation of frequency bands to electrodes [Milchard and Cullington, 2004] or the use of algorithms that emphasize high-frequency [Liu et al, 2009] or low-frequency [Hu and Loizou, 2010] representation.…”