Download Evaluation of children`s hearing aids

Paper on evaluation for MCHAS website: for discussion/comment.
Evaluation of children’s hearing aids
Summary
Evaluation is the process of gathering information and reaching a judgement
about the experience of amplification in both clinical and real world situations.
This paper outlines the purposes of evaluation, the reasons for doing it, and
the main techniques that can be employed. At the end is

an appendix with a list of questionnaires etc suitable for use with children.

a list of references for readers who wish to follow up the published
literature.

a list of abbreviations used in the text.
What is evaluation?
The process of hearing aid fitting comprises a number of stages.
1. the generation of amplification targets for the hearing aid wearer. It is
recommended that this is done using prescriptive formulae that have been
published in peer reviewed journals rather than proprietary software supplied
by hearing aid manufacturers.
2. the selection and fitting of a hearing aid that has the necessary gain output
and other required features.
3. verification, which involves measuring the hearing aid performance to
ensure that it meets the amplification targets. This should be done using Real
Ear Measures (either in situ REAR or in the 2cc coupler with measured RECD
accounted for).
1
4. evaluation, which involves gathering relevant information about the
effectiveness of the amplification provided. An important aspect of this is
subjective “real world” evaluation (e.g. questionnaires) which is increasingly
becoming a part of the evaluation process in modernised hearing aid services.
“Real world” evaluation is desirable because even if a hearing aid is producing
the gain required by the prescriptive targets, this may not be translated into
optimal speech recognition (as indicated by speech tests or predicted
audibility measures) and/or it may not be providing a listening experience in
everyday contexts that is helpful or pleasant for the user. Therefore,
evaluation is now recognised to be an essential element in ensuring that
hearing aid wearers are receiving the intended benefit of amplification.
How can it be done?
Methods of hearing aid evaluation include:

Measuring functional gain (eg aided threshold measurement).

Real Ear Measurements (REMs). These are more correctly placed in the
verification stage of the fitting process, but are sometimes referred to in the
context of evaluating hearing aid performance.

Sound and/or speech recognition tests (eg Ling, Parrot, CCT, Manchester
picture, AB word lists, BKB sentences, FAAF tests.)

Observation/video recording/checklists/measures of speech/spoken
language/communication development.

Calculation of predicted audibility indices (eg SII, AAI).

Questionnaires about matters such as the extent to which hearing aids are
used, the benefit experienced by the user, residual disability (or limitation
2
to hearing in everyday contexts), residual handicap (or impact of hearing
loss on lifestyle) and overall satisfaction. They may also seek information
about the effect of hearing aids on significant others and on the user’s
quality of life. In the case of children, such questionnaires may involve
proxy reporting, in which an appropriate adult (such as a parent or ToD)
provides information additional to or on behalf of the child.

Psychoacoustic (listening) and electroacoustic checks. These are more
commonly perceived as part of essential ongoing management and are
important in maintaining hearing aids’ optimal performance over time, but
do not help in evaluating aspects such as use, benefit or satisfaction.

Assessing the ergonomic aspects of hearing aids can be important as
these influence satisfaction – reliability, robustness, comfort (including
earmoulds) and cosmetic features.
The evaluation process seeks a comprehensive picture of how effective
hearing aids are in real world situations. This can then prompt further enquiry
as to factors that hinder or enhance the hearing aids’ effectiveness for an
individual.
All of these methods listed above have strengths and weaknesses. The more
“objective” measures that involve tests in a clinic or classroom are believed to
produce “hard” data free from the bias that may affect “subjective” self-reports.
However they usually produce data about artificial situations (e.g.
performance on a speech test) and test instruments tend to require calibrated
equipment and can be time-consuming. Subjective measures (e.g.
3
questionnaires) have the advantage that they can produce data about real
world listening contexts that are relevant to the hearing aid user and they are
relatively quick and easy to administer. However, in the case of children in
particular, there is little evidence about the extent to which they align with
more “objectively” gathered information. Despite this, they can still be useful in
giving an informative, and systematically obtained account of the respondents’
views (eg child, parent , ToD).
What questionnaires are available?
The appendix to this paper contains a list of twenty different questionnaires
that have been developed for use with children. Many of these have been
developed in the USA and few have any published data about their reliability,
validity or sensitivity. None have published norms for either normal hearing or
hearing-impaired populations. Hence it can be seen that there is a pressing
need for further research to establish this sort of benchmark information. In
the meantime, the MCHAS team recommend that in addition to whatever
evaluation is currently carried out, services should begin to use routinely two
questionnaires which have been modified or developed for use in the UK.
These are:

The Listening Inventory For Education – Individual Hearing Profile (LIFEIHP).

The Listening Situations Questionnaire (LSQ), Parent and Child versions.
Data are being gathered about the validity, reliability and sensitivity of these
measures. Both have had recent modifications: check www.mchas.man.ac.uk
for the latest versions.
4
These questionnaires are most appropriate for children aged seven years or
more. Therefore the MCHAS team currently recommends the Parent
Evaluation of Aural/oral performance in Children (PEACH) questionnaire,
which was developed in Australia for use with infants onwards. However, a
recent development in the UK which should help hearing aid evaluation
greatly at the younger end of this age range is the launch of the Early Support
Project and specifically the Common Monitoring Protocol (CMP) for deaf
babies. This has been designed to meet the need for standardisation in
monitoring all aspects of early development in deaf babies and children: see
www.earlysupport.org.uk . Monitoring the hearing aids in a systematic way is
built into this process within the “attending, listening and vocalisation” section
of the CMP and also to some extent within the “communication” section. The
Level Two materials also address attending/listening skill/vocalisation
(specifically, detailed recording of phoneme development) which are directly
relevant to assessing the benefit from hearing aids. Relevant information
about the development of listening skills and babies’ and toddlers’ responses
to amplification is being systematically collected where these protocols are in
use. Further development of the actual practice of extracting and sharing
relevant information for the specific purpose of a hearing aid review is
necessary.
Why should we use questionnaires?
The main advantages of using questionnaires can be summarised as follows:

They help to promote better understanding about children’s needs and
priorities in relation to the use, benefit from and satisfaction with their
5
amplification equipment (hearing aids, fm systems, other assistive listening
devices).

They can enhance education and hearing aid service quality by identifying
needs which can then be more closely examined. Ways of meeting these
needs are varied and may be innovative and personalised. For example,
there may be a need for a change in hearing aid settings or activation of
features (second listening program, directional microphone); provision of
additional equipment such as fm systems or sound field systems; provision
of practical help and emotional support or counselling in relation to
amplification; provision of guidance to mainstream teachers and Learning
Support Assistants.

Collecting information in a common format creates a record of the child’s
experience with hearing aids which is more easily shared between the
family and service providers and across different areas if the family moves
(subject to data protection requirements).

Collecting “standard” information facilitates research into the hearing aid
evaluation process. Local data could be fed back to researchers or into a
national database, and with other information also being recorded on
patient management systems (such as type of hearing aid, features, fitting
parameters etc) these and other variables (staffing ratios, provision of
support etc) could be statistically analysed to provide insight into the
factors which promote effective services and successful outcomes.

Use of questionnaires intensifies awareness of the use of audition in the
user and managers of the amplification systems.
6
When should we use them?

Before a hearing aid review, to facilitate the exchange of information
between families, education and health professionals.

At times of transition (eg into new class, school) to assess the new
situation.

At regular reviews of progress (according to the individual child’s level of
support).

To evaluate a particular change in amplification provision or support (eg
switch to DSP, ITE, CI provision, introduction of personal or Sound Field
fm systems).
Conclusion
At present, our knowledge of how best to evaluate children’s hearing aids is
much less advanced than other stages of the fitting process. We need more
research into the following areas:

the content of questionnaires (which is related to the purpose of using
them).

the reliability, validity and sensitivity of different questionnaires and norms
for hearing and hearing-impaired populations.

the timing and frequency of evaluation measures.

the administration of questionnaires : interview/self report/observations;
use of pictures/computers.

the different perspectives of parents, ToDs and peers in relation to both
their own and the children’s experiences with hearing aids; how these
perspectives mesh together.
7

The value to parents, children, education, health and other services of
using questionnaires as well as other methods of evaluation.
Despite the lack of definitive information on these topics, there are strong
reasons to introduce a more systematic evaluation process which includes
children’s real world experiences, and there are adequate if not yet ideal tools
for doing so.
List of abbreviations used in the text
REAR – Real Ear Aided Response
RECD – Real Ear to Coupler Difference
REMs- Real Ear Measures
Ling – Ling 6 sounds test
Parrot/Phoenix – recorded automated version of the McCormick Toy Test *
CCT – Consonant Cluster Test (available from J.Marriage, CHEAR)
AB – Arthur Boothroyd word lists*
BKB – Bamford-Kowal-Bench sentence tests*
FAAF – Four Alternative Auditory Feature test*
SII – Speech Intelligibility Index
AAI – Aided Audibility Index
ToD Teacher of the Deaf
MCHAS – Modernisation of Children’s Hearing Aid Services
LIFE-IHP _ Listening Inventory For Education – Individual Hearing Profile
LSQ – Listening Situations Questionnaire
PEACH – Parent Evaluation of the Aural/oral performance of Children
8
ESP – Early Support Project
CMP – Common Monitoring Protocol
DSP – Digital Signal Processing
ITE – In The Ear
CI – Cochlear Implant
* Available from the Medical Research Council Institute of Hearing Research,
Nottingham.
Note: Phoenix, Manchester picture test and AB word lists are available from
www.soundbytesolutions.co.uk
References:
AAA (2003). Paediatric amplification protocol.
www.audiology.org/professional/positions/pedamp.pdf.
Anderson, K. and Smaldino, J. (1999). "Listening inventories for education: a
classroom measurement tool." The Hearing Journal 52: 74 - 76.
Andrews, E. (2005). The Early Support Programme (Personal communication)
ANSI (1993). ANSI S3.5 Draft v3.1-1993 Proposed American National
Standards methods for calculation of the speech intelligibility index. New York,
American National Standards Institute.
Athanasou, J. A. and Lamprianou, I. (2002). A teacher's guide to assessment.
Sydney, Social Science Press.
Bamford, J., McCracken, W., Peers, I. and Grayson, P. (1999). "Trial of a two
channel hearing aid (low-frequency compression - high frequency linear
amplification) with school age children." Ear and Hearing 20: 290 - 298.
9
Bamford, J., Skipp, A., Hostler, M., Davis, A., Barton, G. and Sithole, J.
(2004). Report on first wave studies (Modernisation of NHS Hearing Aid
Services: Paediatric Arm). Manchester, HCD Group, University of
Manchester.
Bond, T. and Fox, C. (2001). Applying the Rasch model: fundamental
measurement in the human sciences. Mahwah, New Jersey, Lawrence
Earlbaum Associates.
Canning, D. (1998). Listening inventory for education: UK IHP version.
www.hear2learn.com.
Ching, T. Y. C. and Hill, M. (2001). Hearing aid outcome measures in children:
how effective is amplification in real life? www.nal.gov.au.
Cox, R. M. (1997). "Administration and application of the APHAB." The
Hearing Journal 50: 32 - 48.
Cox, R. M. (2003). "Assessment of subjective outcome of hearing aid fitting:
getting the client's point of view." International Journal of Audiology 42: S90S96.
Dillon, H. (2000). Hearing aids. New York, Thieme.
Dillon, H., James, A. and Ginis, J. (1997). "Client oriented scale of
improvement (COSI) and its relationship to several measures of benefit and
satisfaction provided by hearing aids." Journal of the American Academy of
Audiology 8: 27-43.
DfES & DoH (2003). Together from the start.
Gagné, J.-P. (2003). "Treatment effectiveness research in audiological
rehabilitation: fundamental issues related to independent variables."
International Journal of Audiology 42: S104-S111.
10
Gatehouse, S. (1998). "Speech tests as measures of outcome." Scandinavian
Audiology Supplement.
Gatehouse, S. (1999). "Glasgow hearing aid benefit profile: derivation and
validation of a client-centred outcome measure for hearing aid services."
Journal of the American Academy of Audiology 10: 80 - 103.
Grimshaw, S. K. (1998). Assessing hearing impaired children's listening and
processing abilities: a questionnaire and cognitive approach. PhD thesis.
MRC Institute of Hearing Research, University of Nottingham.
Hostler, M. (2004a). Real world evaluation of amplification for children. MSc
thesis. HCD, University of Manchester.
Hostler, M. E. (2004b). Rasch analysis of MCHAS data from LIFE and LSQ
questionnaires (Personal communication)
Hutcheson, G. and Sofroniou, N. (1999). The multivariate social scientist.
London, Sage.
Johnson, C. E. and Danhauer, J. L. (2002). Handbook of outcomes
measurement in audiology. New York, Thomson.
Kopun, J. G. and Stelmachowicz, P. G. (1998). "Perceived communication
difficulties of children with hearing loss." American Journal of Audiology 7: 30 38.
Marriage, P. (2004). Speech tests with children. Paper presented to a
conference: Scotland and Wales Modernisation Training, Manchester.
MCHAS (2004). Training materials. www.mchas.man.ac.uk.
MHAS/MCHAS (2004). Quality Assurance Report.
Scollie, S. (2004). "SII predictions of aided speech recognition." The Hearing
Journal 57: 14-16.
11
Seewald, R. C., Moodie, K. S., Sinclair, S. T. and Cornelisse, L. E. (1996).
"Traditional and theoretical approaches to selecting amplification for infants
and young children." Amplification for children with auditory deficits. F. H.
Bess, J. S. Gravel and A.-M. Tharpe. Nashville TN, Bill Wilkerson Centre
Press.
Stelmachowicz, P. G. (1999). "Hearing aid outcome measures for children."
Journal of the American Academy of Audiology 10: 14-25.
Stelmachowicz, P. G., Lewis, D., Karasek, A. and Creutz, T. (1994).
Situational Hearing Aid Response Profile (SHARP, version 2) user's manual.
Omaha, Boys Town National Research Hospital.
Whitelaw, G. M., Williams, C. and Wynne, M. K. (2001). Children's Outcomes
Worksheets (COW): validation and efficiency. Paper presented to a
conference: American Academy of Audiology annual convention and
exposition 2001, American Academy of Audiology.
WHO (2001). International classification of functioning, disability and health.
Geneva, WHO.
12