ETSI TR 103 225 V1.1.1 (2018-01)

Speech and multimedia Transmission Quality (STQ); Transmission quality and speech intelligibility for hearing impaired people

DTR/STQ-222

General Information

• Status: Published
• Publication Date: 03-Jan-2018
• Technical Committee: STQ - Speech and multimedia Transmission Quality
• Current Stage: 12 - Completion
• Due Date: 28-Dec-2017
• Completion Date: 04-Jan-2018

Standards Content (Sample)

ETSI TR 103 225 V1.1.1 (2018-01)






TECHNICAL REPORT
Speech and multimedia Transmission Quality (STQ);
Transmission quality and speech intelligibility
for hearing impaired people

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2 ETSI TR 103 225 V1.1.1 (2018-01)



Reference
DTR/STQ-222
Keywords
hearing aid, hearing impairment, intelligibility,
model, QoS, speech
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3 ETSI TR 103 225 V1.1.1 (2018-01)
Contents
Intellectual Property Rights . 4
Foreword . 4
Modal verbs terminology . 4
Executive summary . 4
Introduction . 5
1 Scope . 6
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 6
3 Definitions and abbreviations . 8
3.1 Definitions . 8
3.2 Abbreviations . 8
4 Coupling between hearing aids and phones . 9
4.1 ETSI Standards on coupling of phones with Hearing aids . 9
4.2 Impact of wideband on speech understanding . 9
5 Subjective tests . 9
5.1 Introduction . 9
5.2 Subjective test methodology for assessing speech intelligibility . 10
5.3 Summary of existing studies . 10
5.3.1 References of studies and projects . 10
5.3.2 Summary of the study Voice telecommunications accessibility for individuals with hearing loss . 11
6 Models for intelligibility assessment . 11
6.1 Summary of existing studies . 11
6.2 Need for a new model . 12
7 Potential benefits of RTT for intelligibility . 12
7.1 Introduction . 12
7.2 Real Time Text performance . 12
7.3 Combination of speech communications and RTT . 12
Annex A: Bibliography . 13
History . 14

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4 ETSI TR 103 225 V1.1.1 (2018-01)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (https://ipr.etsi.org/).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
Foreword
This Technical Report (TR) has been produced by ETSI Technical Committee Speech and multimedia Transmission
Quality (STQ).
Modal verbs terminology
In the present document "should", "should not", "may", "need not", "will", "will not", "can" and "cannot" are to be
interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
Executive summary
The present document provides data and information on studies that have shown that hearing impaired people are
suffering of insufficient intelligibility of transmitted speech, due to background noises, transmission impairments,
shapes of receivers, tandeming of speech processing and coupling between earphones and hearing aids.
It also shows that wideband bandwidth provides improved quality than achieved with narrowband for hearing impaired
people using hearing aids, cochlear implants.
The present document is intended as a first step of a potential work plan which needs to be constructed in order to
define scenarios to conduct subjective tests on intelligibility, listening effort and quality for hearing impaired people
with different hearing profiles, and to define and validate an objective model to predict speech intelligibility, listening
effort and quality for hearing impaired people, both by using hearing aids or not. The next phase should consist, at least,
to study:
• how the listening quality for hearing impaired people can be improved, with or without hearing devices
(including loudness, spectrum equalization or enhancement, etc.);
• how to determine the impact of the different transmission impairments on intelligibility for different types of
hearing profiles, such as the potential impact of coupling between phone receivers and hearing aids
(e.g. acoustical, inductive coupling);
• which kind of model(s) can best assess objectively the intelligibility of natural and synthesized speech;
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5 ETSI TR 103 225 V1.1.1 (2018-01)
• what kind of model could determine the listening effort needed to follow and understand a conversation.
The impairments from the distant send side may also have impacts on intelligibility of received speech, hence might
need performance improvements.
Introduction
Several studies have shown that hearing impaired people suffer from less sufficient intelligibility of transmitted speech,
due to background noises, transmission impairments, types of receivers, low quality coupling between earphones and
hearing aids. It was also noted that an important parameter to be assessed is the listening effort.
There is also a lack of subjective tests on intelligibility for hearing impaired people and there is no standardized
objective model to predict speech intelligibility as perceived by hearing impaired people. Such tests should be done, at
least, in wideband, as very few results are available for this bandwidth and it has been shown that wideband speech
provides improvements compared to narrowband speech for hearing impaired people.
The present document is a first step to improve and assess the intelligibility of transmitted speech for hearing impaired
people.
It is expected that new documents, specifications or standards could be produced for specific applications, e.g. to
associate text to speech in order to improve the intelligibility for the users, and to consider the best way to define
relevant standards for these combinations.
For further works, at least four topics have been identified. The three first topics could be developed by the ETSI TC
STQ and the fourth topic by the ETSI TC HF (Human Factors):
• Receive side for hearing impaired people, with or without hearing aids (including loudness, equalization, etc.),
including modeling the listening effort.
• Impact of the different transmission impairments on intelligibility, quality and listening effort.
• Impairments from the send side and consequences on intelligibility - improvements are expected.
• Association of text and speech, and consequences for intelligibility.
Acoustical, inductive, wireless and electrical couplings between phones and hearing aids should be taken into account,
as well as the different types of hearing aids (e.g. cochlear implants).
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6 ETSI TR 103 225 V1.1.1 (2018-01)
1 Scope
The present document provides a review of existing test methodologies to assess speech intelligibility, quality and
listening effort.
It should be noted that most test methods (for quality or intelligibility) have been developed with normal hearing people
and that there is a lack of data for hearing impaired people.
Some clauses of the present document provide a review of existing methods or test results that take into account
couplings between phones and listener's ears (acoustical coupling), and coupling between phones and hearing aids
(inductive, acoustical or via radio links). Different hearing impairments affecting the listening performance are also
considered.
2 References
2.1 Normative references
Normative references are not applicable in the present document.
2.2 Informative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] IEC 60118 series: "Hearing aids".
[i.2] Recommendation ITU-T P.10/G.100: "Vocabulary for performance and quality of service".
[i.3] Recommendation ITU-T P.16: "Subjective effects of direct crosstalk; thresholds of audibility and
intelligibility".
[i.4] Recommendation ITU-T P.85: "A method for subjective performance assessment of the quality of
speech voice output devices".
[i.5] ETSI EN 301 549: "Accessibility requirements suitable for public procurement of ICT products
and services in Europe".
[i.6] Recommendation ITU-T P.807: "Subjective test methodology for assessing speech intelligibility".
[i.7] Recommendation ITU-T P.1311: "Method for determining the intelligibility of multiple concurrent
talkers".
[i.8] ETSI ES 200 381-1 (V1.2.1) (10-2012): "Telephony for hearing impaired people; Inductive
coupling of telephone earphones to hearing aids; Part 1: Fixed-line speech terminals".
[i.9] ETSI ES 200 381-2 (V1.1.1) (10-2012): "Telephony for hearing impaired people; Inductive
coupling of telephone earphones to hearing aids; Part 2: Cellular speech terminals".
[i.10] ETSI ETS 300 488 ed.1 (01-1996): "Terminal Equipment (TE); Telephony for hearing impaired
people; Characteristics of telephone sets that provide additional receiving amplification for the
benefit of the hearing impaired".
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7 ETSI TR 103 225 V1.1.1 (2018-01)
[i.11] ETSI TR 102 949: "Speech and multimedia Transmission Quality (STQ); Wideband and
Superwideband speech terminals; Perceptually motivated parameters".
[i.12] ANSI/ASA S3.2-2009 (R2014): "Method For Measuring The Intelligibility Of Speech Over
Communication Systems".
[i.13] Recommendation ITU-T P.862: "Perceptual evaluation of speech quality (PESQ): An objective
method for end-to-end speech quality assessment of narrow-band telephone networks and speech
codecs".
[i.14] Recommendation ITU-T P.863: "Perceptual objective listening quality assessment".
[i.15] ETSI ES 202 396-1: "Speech and multimedia Transmission Quality (STQ); Speech quality
performance in the presence of background noise; Part 1: Background noise simulation technique
and background noise database".
[i.16] ETSI EG 202 396-2: "Speech Processing, Transmission and Quality Aspects (STQ); Speech
quality performance in the presence of background noise; Part 2: Background noise transmission -
Network simulation - Subjective test database and results".
[i.17] ETSI EG 202 396-3: "Speech and multimedia Transmission Quality (STQ); Speech Quality
performance in the presence of background noise; Part 3: Background noise transmission -
Objective test methods".
[i.18] Ute Jekosch, Technische Universität Dresden: "Test on overall quality as perceived by high
frequency hearing impaired subscribers", ITU-T SG12 - C101 - September 2007.
[i.19] John Beerends, Ronald Van Buuren, Jeroen Van Vugt, Jan Verhave: "Objective Speech
Intelligibility Measurement on the basis of natural speech in combination with perceptual
modeling", JAES, Vol.57, N 5, May 2009.
[i.20] Hearcom project (hearcom.eu).
[i.21] Directive 93/42/EEC of 14 June 1993 concerning medical devices.
[i.22] Report on 2012 HLAA Convention. NB versus WB Speech Study.
[i.23] ITU-T Contribution SG12 - C93 - November 2013: "Subjective and objective measurement of
synthesized speech intelligibility in modern telephone conditions".
[i.24] Sridhar Kalluri, Starkey Hearing Research Center (Berkeley): "High frequency sound for the
hearing impaired".
NOTE: Available at https://www.itu.int/dms_pub/itu-t/oth/06/17/T061700000D0011PDFE.pdf.
[i.25] Linda Kozma-Spytek. Technology Access Program. Gallaudet University; Washington, DC:
"Voice Telecommunications Accessibility for Individuals with Hearing Loss".
NOTE: Available at STQ(14)47_038_Voice_Telecommunications_Accessibility_for_Individuals_with_.zip.
[i.26] Hearing4all.
NOTE: Available at http://hearing4all.eu/EN/.
[i.27] ISO TR 22411: "Ergonomics data and guideline
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