Good Practice Guidance for Adult Hearing Aid Fittings and Services
`– Background to the Document and Consultation
`
`The International Society of Audiology (ISA) is developing a generic template of
`principles and practises for adult hearing aid fittings and services. Via the International
`Collegium of Rehabilitative Audiology (ICRA), ISA has commissioned Stuart
`Gatehouse and William Noble to convert a document generated under the auspices of
`United Kingdom National Health Service into one which is not constrained by any
`particular mode and funding of health care delivery system.
`
`The ISA has agreed a two stage consultation process. The first of these allows all
`parties to make more general comments about the form and content of such a
`document, whilst the second will concentrate on the detailed content and coverage.
`Although the document is developed under auspices of ISA, input is not limited to ISA
`members or affiliated organisations. The final document though will be submitted to,
`considered by and eventually ratified by the ISA council.
`
`The first stage consultation will take place up to 1st March 2005, and a first draft of the
`document is provided on this website as part of the process to receive input regarding
`the general content and coverage. The document is available as a Word for Windows
`file and the mechanism for feedback is via Stuart Gatehouse. His contact details are:
`MRC Institute of Hearing Research, Scottish Section, Queen Elizabeth Building,
`Glasgow Royal Infirmary, 16 Alexandra Parade, Glasgow, G31 2ER, Telephone No.
`+44 141 211 4695, Fax No. 44 141 552 8411, e-mail stuart@ihr.gla.ac.uk. Input in any
`form is welcome, though electronic rather than fax or regular mail is of course
`preferable.
`
`As indicated in the preliminary paragraphs of the document, the content concentrates
`in the first instance on services for patients and clients accessing systems for the first
`time rather than maintenance or re-assessment of people already undergoing
`management. The document is intended to provide a generic template which can be
`endorsed internationally and tailored to suit the constraints of individual services.
`
`HIMPP 1012
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` The document attempts to establish good practice from a published evidence base and
`international consensus regarding good practice, making the assumption that good practice
`should not be constrained in the first instance by the availability of resources.
`
`It is hoped that a wide range of parties and perspectives can feed into the two-stage
`consultation process, with the second phase running from 1st April 2005 till 1 June 2005.
`The documents to be submitted to the International Society of Audiology and considered by
`the ISA Executive Board in July 2005.
`
`Any difficulties in downloading the document either at this website or elsewhere (the
`documents are to be lodged at www.ISA-audiology.org, www.icra.nu, www.ihr.gla.ac.uk and
`www.une.edu.au/psychology/staff/noble.htm.) should be addressed to Stuart Gatehouse
`using the above contact details.
`
` SEE DOCUMENT ON FOLLOWING PAGES
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`GOOD PRACTICE GUIDANCE FOR
`ADULT HEARING AID FITTINGS AND SERVICES
`
`Prepared for the International Society of Audiology, November 2004, by the
`Good Practice Working Group of the International Collegium of Rehabilitative
`Audiology
`
`1. Background
`
`1.1.This document contains a set of statements and recommendations for good practice
`in hearing aid fittings and services. It attempts to distil the results of current
`evidence and consensus practice into a series of statements which can be used to
`frame service provision. It addresses technical aspects of hearing aid fittings and
`rehabilitative support, but does not address in any detail the resource requirements
`(e.g. accommodation, staff and hardware) for service delivery.
`
`1.2.The guidance is framed in the context of adults with mild, moderate and severe
`hearing impairment who are accessing a service for the first time. Profound
`impairments may require separate processes. In addition the guidance does not
`cover specialist services such as cochlear implants or bone anchored hearing aids.
`For existing hearing aid fittings procedures will differ, though probably will contain a
`sub-set of the recommendations.
`
`1.3.The document is written as though the whole process is delivered by a single
`integrated service. Where different professionals or agencies are responsible for
`different elements, local documents should acknowledge the local structure and
`hand-over between agencies. Systems should be in place to ensure that all
`elements are included, and that information flow and cross-referral occurs in a
`seamless manner.
`
`1.4.The guidance concentrates on good practice. Where local circumstances place
`constraints (e.g. in cash-limited State or insurance schemes or individual income in
`the private market), the guidance should be amended accordingly. Similarly, where
`in a private-pay environment individual financial resources limit access, there should
`be explicit local variations on the guidance.
`
`1.5.The document makes the assumption that management of hearing impairments,
`disabilities and handicaps (activity limitation and participation restriction in ICIDH-2)
` is a comprehensive process involving rehabilitative support, provision of personal
`amplification and assistive listening device options. It is not a simple technical
`matter of hearing aid provision alone.
`
`1.6.The guidance concentrates on the signal processing and fitting features associated
`with hearing aid management. It makes no assumptions regarding the mode of
`technological implementation (e.g. analogue or digital).
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`2.
`
`Infrastructure
`
`2.1.All facilities, test rooms and equipment for the assessment, fitting and evaluation of
`hearing and hearing aids should conform to the appropriate international and
`national standards and recommendations.
`
`2.2.All materials and methods used in assessment and management should conform to
`the appropriate recommended procedures.
`
`2.3.All procedures should be undertaken by staff with appropriate professional
`qualifications and training All staff should have an agreed structure and process for
`Continued Professional Development.
`
`2.4.All equipment used for testing and evaluation should be calibrated to the appropriate
`national and international standards on at least an annual basis.
`
`2.5.Service providers should have in place appropriate referral routes and information
`flow between the various agencies and professions responsible for service delivery.
`
`3. Assessment
`
`3.1.Necessary assessment of auditory impairment will take place prior to any decision
`that appropriate management includes the provision of personal amplification. This
`decision will require at least pure-tone air and bone conduction thresholds, though
`further assessment of impaired auditory function may be appropriate prior to any
`decisions concerning the details of hearing aid management and rehabilitation.
`
`3.2.The decision-making process regarding appropriate hearing aid management (as
`opposed, for example, to surgical or medical management) will be dependent upon
`local service and professional arrangements, but should be explicitly stated in local
`protocols and policies.
`
`4.
`
`Integration and Goal setting
`
`4.1.As an initial first stage of any intervention, a comprehensive assessment of needs
`should be conducted to formulate an Individual Management Plan. A formal self-
`report instrument with recognised properties such as the Client-Orientated Scale of
`Improvement (COSI) or the Glasgow Hearing Aid Benefit Profile (GHABP) should be
`used. The above are illustrative only and the choice of instrument is for each
`individual service provider, though it should be an explicit element of policy and
`employed throughout. The same instrument may be re-administered to assess
`outcome at subsequent follow-up.
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`4.2.The Individual Management Plan should address all issues including hearing aid
`fitting, rehabilitative support, and environmental modification (e.g. assistive
`listening devices). There will be hearing-impaired patients for whom a hearing aid
`is not an appropriate element of the Individual Management Plan.
`
`4.3.The Individual Management Plan should contain input from family members and
`significant others as appropriate. This involvement is particularly important in
`devising management plans for patients who do not appear to acknowledge
`hearing difficulties.
`
`4.4.All aspects of the Individual Management Plan should be informed by both the
`needs and goals of the hearing-impaired person, and the informed advice of the
`professional responsible for configuring and delivering the intervention.
`
`5. Fitting
`
`5.1.The minimum technical characteristics of an individual hearing aid fitting should
`consist of a linear hearing aid with low-distortion output compression limiting.
`Profound losses might require different policies. Note that this minimum standard
`does not imply a norm or default, but a true service baseline. Each fitting of the
`minimum standard should conform to a recognised rationale (e.g. NAL-RP) with
`established validity and performance in the scientific and clinical literature. The
`choice of rationale is for each individual service provider, though it should be an
`explicit element of policy and applied throughout.
`5.2.Current research evidence suggests that at least 75% of patients will gain clinically
`relevant additional benefit from hearing aid fittings with features over and above
`the minimum standard. Examples of such features include amplitude
`compression, directional microphones and feedback suppression. These additional
`features should be available to all patients as required. The fitting of devices
`above the minimum standard should conform to a recognised generic (eg NAL-
`NL1 or DSL[i-o]) or product-specific rationale and be documented as part of the
`clinical record.
`
`5.3.Where a fitting rationale contains an acoustical target, each hearing aid fitting
`should be verified by real ear measurement using an input stimulus appropriate for
`the hearing aid under test prior to any fine-tuning. Tolerances to the prescription
`rationale of ± 5dB at frequencies of 250 Hz, 500 Hz, 1000 Hz and 2000 Hz and of
`± 8dB at 3000 and 4000 Hz should be achieved in all cases. In addition the slope
`in each octave should be within ± 5dB/octave of the target. Where it is not
`desirable or possible to achieve a prescriptive target (e.g. because of feedback
`issues) or where the measurement is not technically feasible, the clinical record
`should contain an explicit statement to this effect. Note that some losses can only
`be fitted to the appropriate target using the flexibility that accompanies digital
`implementation. Note also that some fitting rationales do not contain an acoustical
`target : in such cases this step is not required.
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`5.4.The maximum power output of each hearing aid fitting should be adjusted according
`to a recognised prescription rationale (e.g. based on prediction from hearing
`thresholds as in NAL-SSPL and/or loudness judgements for appropriate stimuli).
`This choice should be an explicit element of local policy.
`
`5.5.At the fitting session, the hearing aid frequency response and maximum power
`output (and other characteristics where appropriate) should be adjusted to achieve
`patient acceptability according to an explicitly laid-down local protocol. Fine-tuning
`for optimal (as opposed to an acceptable) fit is more appropriate at a subsequent
`follow-up visit following appropriate listening experience.
`
`5.6.The service should offer to patients the choice of post-aural (behind-the-ear, BTE)
`and in-the-ear (ITE/ITC) fittings where these are compatible with the patient’s needs
`and capabilities. The process leading to a decision of BTE or ITE/ITC should be an
`explicit element of the clinical record. A small number of patients will be best served
`by body-worn devices.
`
`5.7.The default for all hearing aid provision should be to offer bilateral fittings. Unilateral
`fittings should only be offered where a) one ear is not sufficiently impaired to merit
` amplification, b) one ear is so impaired that amplification would not be beneficial, or
`c) a specific audiological or other rationale. There will be a material proportion of
`patients for whom bilateral provision is not appropriate for audiological and other
`(e.g. manipulative ability, otological or age-related) reasons. Where unilateral
`provision is offered, this and the reasoning should be an explicit element of the
`clinical record.
`
`5.8.Where the patient declines a bilateral fitting, bilateral provision should be re-offered
`at a later stage of the rehabilitative process once the patient has experienced the
`benefits of unilateral amplification. Because of the perceptions raised by current
`policy of only offering bilateral fittings to severely and profoundly hearing impaired
`patients, a material proportion of users will decline bilateral fittings (“I’m not that deaf
`doctor”), but will accept and benefit from bilateral fittings following unilateral
`experience.
`
`5.9.Hearing aid provision should include appropriate information about hearing, listening
`skills, hearing aid technology and earmoulds. There should exist local protocols for
`the assessment of and instruction in manipulation skills with regard to hearing aids
`and earmoulds both at the hearing aid fitting session and at follow-up.
`
`5.10. Following the fine-tuning and other adjustments the acoustical properties of each
`hearing aid fitting used by patients in everyday listening should be documented
`using real ear measures, irrespective of whether the rationale used for fitting
`contains an acoustical target. The stimuli used for real ear measures should be
`appropriate for the signal processing in the hearing aid. This information is required
`for subsequent interpretation of listener’s comments about subsequent experience
`with the fitting at the follow-up visits.
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`5.11. All patients should have access to a facility to remediate listening problems by
`additional consultations prior to a formal follow-up visit.
`
`6. Follow-up
`
`6.1.The management of hearing-impaired patients will include sessions covering
`assessment, fitting and at least one follow-up session. The timing, time-allocation
`and content of each session should be explicit elements of local policy and should
`be sufficient for the application of each element of good practice. Aspects of these
`elements may depend on the hearing aid features available in any fitting and
`requirements for rehabilitative support.
`6.2.All patients should have a review visit between three and six weeks after hearing aid
`fitting. At this review visit, a measure of outcome in the self-report disability and
`handicap domains should be administered to assess benefit and guide ongoing
`management. This process may be deferred to a subsequent review visit if
`immediate remedial action is required to ensure acceptability of the fitting. This
`assessment will be directly linked to the needs assessment outlined above and
`often may employ the same measurement instrument. Alternatively an additional
`measure aimed solely at outcome assessment such as the Abbreviated Profile of
`Hearing Aid Benefit (APHAB) or the International Outcomes Inventory for Hearing
`Aids (IOI-HA) may be used. The data from the needs assessment and the outcome
`measure allow intra-departmental assessment of the effectiveness and cost
`effectiveness of local protocols and services as a whole and for patient sub-groups.
`
`6.3.Fine-tuning at follow-up after real-world aided listening experience is an essential
`second stage of any provision strategy and should include formal assessment of a
`range of listening circumstances relevant to the individual patient. This will include
`ratings (either absolute or paired-comparisons) of intelligibility and listening comfort
`for everyday signals (often speech) at a variety of levels in quiet and in noise. There
`should be an explicit local policy for fine-tuning. Following any fine-tuning or the
`activation of additional processing or fitting features a real ear measure should be
`used to document the acoustical properties of each hearing aid fitting.
`
`6.4.On the basis of either the initial Individual Management Plan, or the assessment of
`benefit and residual disability at follow-up (eg shortcomings in initial provision),
`hearing aid fittings with the appropriate features (e.g. single or multi-channel
`amplitude compression, directional microphone, feedback management, multi-
`programme etc.) should be available to all patients. Hearing aid provision should
`match technological features to listeners’ disabilities and lifestyle.
`
`6.5.The methods and criteria for the matching of hearing aid technology, earmould
`characteristics, rehabilitative support and environmental modification (eg assistive
`listening devices) to the Individual Management Plan should be laid down in a local
`protocol. The detailed decisions should be an explicit component of the clinical
`record.
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`6.6.Further fine-tuning of fittings and changes in provision should take place at
`subsequent follow-up visits as required. Each of the follow-up visits should detail
`the actions taken and the success or otherwise of those actions by repeat
`administration of the outcome measure of choice.
`
`6.7.Rehabilitative counselling and support services should be available to meet the
`needs of each Individual Management Plan, and to ensure optimum benefit from
`hearing aid fittings. All hearing impaired patients should be counselled with regard
`to hearing tactics and listening skills. The necessary staff skills and resources
`should be available in each service setting.
`
`6.8.Services for environmental modification (e.g. assistive listening devices) should be
`available as needed for all listeners even when these services are administered by
`other agencies. Each audiology service provider should establish effective liaison
`with relevant external agencies to meet the needs of each Individual Management
`Plan. Integration of these responsibilities and funding streams into a
`comprehensive care system should be achieved whenever possible.
`
`7. Ongoing Support
`
`7.1.Patients should only exit the cycle of follow-up visits when all available steps have
`been taken to satisfy the needs assessment or when they decline further support.
`All patients should be reviewed at least every three years as part of a process of
`continuing care. There should be an “open access” system in place for review
`before the due date if required by hearing aid users.
`
`7.2.Ongoing support for hearing aid users should be provided via repair clinics for
`routine service and “open access” clinics for emergency care.
`
`7.3.Each service should implement an information management system which allows
`ready access to process, activity and outcome data to facilitate audit and clinical
`governance as an ongoing monitoring of clinical effectiveness and cost-
`effectiveness of policy and protocols.
`
`7.4.This guidance refers repeatedly to local policies and protocols to implement good
`practice. Each service provider should prepare and publish a set of overall
`documentation, whose clinical effectiveness and cost effectiveness should be
`reviewed on an annual basis. Service providers may find it helpful to form
`consortia for the development of policies and protocols. There should be an
`annual audit of process (e.g. waiting times for appointments) and outcome (using
`the outcome measure of choice laid down in local policy).
`
`ISA Good practice guidance.doc
`November 2004
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