3 September 2018

The role of aids in managing hearing loss

Clinical Patients

Hearing loss, especially undiagnosed hearing loss can have a profound effect on the patient’s quality of life.

In children, a fluctuating hearing loss from recurrent middle ear fluid/infection can affect language development, selective attention development, communication skills and delay maturation of the central auditory pathway.1

Referral for an auditory processing assessment should be considered in children who are not progressing well in developing literacy skills and/or who have difficulty hearing in competing noise, maintaining attention to instructions and conversation or remembering auditory information. 

Universal hearing screening of newborns was implemented over 10 years ago across Australia. Early identification of a hearing loss means a child can begin early intervention, have access to speech therapy as early as possible and families can get appropriate advice and support right from the beginning, giving babies with a hearing loss the best start in life. 

It is important to recognise that the hearing screening excludes babies with a mild high frequency hearing impairment. 

This population of babies will be very small, but it is likely their hearing loss will be progressive and have a functional impact once they reach school age.

A sudden onset sensorineural hearing loss (sudden sensorineural hearing loss) is considered a medical emergency because of the short window of time (two weeks) where steroid medication may be effective. Associated symptoms can include vertigo, tinnitus and a sensation of aural fullness. These symptoms can be readily misdiagnosed as due to Eustachian tube dysfunction.

In older adults, presbycusis (age-related hearing loss) is the most common cause of acquired sensorineural hearing loss and is often slowly progressive. 

The degree of hearing loss and the age at which presbycusis develops tends to run in families so there is a strong genetic predisposition. 

Other factors such as noise damage, ototoxic medication and any health conditions which affect the blood supply to the inner ear can cause or contribute to an acquired hearing loss.

PREVALENCE AND SELF AWARENESS

In 2006, Access Economics estimated the financial costs and the loss of wellbeing from hearing loss in Australia in 2005, to raise awareness of the economic cost of hearing impairment in Australia and to inform policy making. The Hearing Care Industry Association commissioned Deloitte Access Economics to update this report in 2017.2   

The prevalence of hearing loss, in the better ear, was estimated to be 3.6 million people in Australia in 2017, or 14.5% of the population. This represents a 38.5% increase in estimated prevalence from 2005 to 2017. Prevalence rates increase with age: 74% of people aged 71+ are estimated to have a hearing loss: 87.7% of men and 63.8% of women.2 The hearing loss represents mild to profound hearing loss.

There is a low incidence of hearing aid use among those with a hearing loss. In Australia, 21% of working age people with a hearing loss use hearing aids.2 

A mild sensorineural hearing loss is often not apparent to the person affected. A moderate and even severe high frequency sensorineural hearing loss – the most common pattern of acquired hearing loss – is also not readily self-diagnosed. 

Audiologists regularly see patients referred at the urging of their family members, who are at the receiving end of the impaired communication resulting from an unmanaged hearing loss. Denial can be a factor, but more broadly a slowly progressive hearing loss develops insidiously, making it difficult to self-diagnose. A mild/moderate hearing loss is often not apparent during a 1:1 clinical or medical encounter in a quiet room.  

The degree of hearing loss is merely a first step in identifying whether hearing aid use is recommended. Not all patients with a mild hearing loss need to use hearing aids and may benefit from other assistive listening devices. 

The functional requirements vary from person to person and there are many factors to consider, in particular the impact of a hearing loss on effective communication, fatigue, cognitive function, social connection, and employment opportunities.    

COGNITIVE IMPAIRMENT AND DEMENTIA

An undiagnosed hearing loss in the elderly can be confused with cognitive impairment. An unmanaged hearing loss has been shown to increase the risk of developing cognitive impairment/dementia and the pace of cognitive decline.3-5 

The Lancet Commission on Dementia Prevention, Intervention, and Care published a report in 2017 showing the results of a meta-analysis of a large set of potential and preventable risk factors for dementia.6

The commission analysed 13 studies investigating the link between hearing loss and risk of cognitive decline and dementia. They reasoned that hearing loss may add to the cognitive load of an aging brain. It may also lead to social isolation, which is associated with faster cognitive decline and depression. The commission concluded that mid-life hearing loss is a significant but potentially modifiable risk factor for dementia. 

Available evidence supports the effect of hearing aid use in protecting against cognitive decline.4 By partially restoring communication abilities, hearing aids may serve as a buffer against social and emotional loneliness and depression, thereby improving the patients’ mood, boosting the quality and quantity of their social interactions, and enabling their participation in cognitively-stimulating activities.7,8 

In hearing impaired patients with Alzheimer’s disease, no significant effect of hearing aid use on their cognitive status was observed after six months of follow-up. Hearing aid use in this patient population needs to be considered on a case by case basis. Patients with any form of dementia, who have not worn hearing aids before, can find the challenges involved in accepting, wearing and maintaining hearing aids, as well as adapting to hearing aid amplification for the first time, difficult. 

Those with an established history of successful hearing aid use often continue to do well, although may need support with regard to handling and maintenance.  

SCREENING AND ASSESSMENT

Early screening and reframing management of hearing loss as a lifestyle intervention may yield significant benefits.7

A hearing screening test for all patients should be considered as part of their ?75 year older person’s health assessment. A dementia work-up should include a diagnostic assessment of hearing status and communication function.

Patients can be referred to an audiologist under a Chronic Disease Management plan to receive a rebate from Medicare. For those who require GP referral to an ENT specialist or neurologist, Medicare rebates are available for audiological assessment – either by the specialist practice or by an independent audiologist at the specialist’s request.

Independent Audiologists Australia (IAA) has prepared a table of benefits of Extras cover offered by Australian Health funds for audiology and hearing devices.10 

In Australia, a Hearing Services Program is provided and administered by the Home Support & Hearing Branch / In Home Aged Care Division Department of Health. This program funds hearing assessments and hearing aid fitting/maintenance vouchers to eligible people. Eligible persons hold a Pensioner Concession Card, or are a member of the Australian Defence Force, or are a National Disability Insurance Scheme participant with hearing needs referred by a planner from the National Disability Insurance Agency. 

Although the Hearing Services Program serves some people aged 25-64 years, most people in this age group need to purchase hearing aids privately.

There’s no recommended retail price on hearing aids. Dispensers can charge what they wish

REHABILITATION AND DISPENSING

Communication is a complex process, and the fitting of appropriate hearing aids is only one part of an effective aural rehabilitation program. To ensure patients obtain a successful hearing aid fitting, a detailed diagnostic hearing loss and communication assessment with thorough follow-up rehabilitative support are essential. 

Hearing aids are delicate devices and the ear canal is a hostile environment to in-ear circuitry. Ongoing and readily accessible maintenance support is essential. 

A broad range of hearing aids is available, with seven major companies to choose from in Australia. It is incorrect to consider that modern hearing aids need minimal service and adjustments compared to older hearing technology. Despite the rapidly changing improvements in hearing aid technology, too many hearing aids are used infrequently in the wider community, often with disappointment at the level of benefit obtained.

Hearing aid technology and programming software have become increasingly sophisticated, so that the skills required by the clinician in fine-tuning hearing aids for a personalised, optimal result have substantially increased. 

No formal regulation of the minimum level of training is required by hearing aid dispensers in Australia, so protection for the consumer is lacking. Under the Hearing Services Program, providers can be business owners without clinical qualifications in audiology or audiometry and so need not belong to any professional body that sets rules of conduct. 

Practitioners under the Hearing Services Program may be audiometrists who hold TAFE diploma qualifications or university-trained audiologists. In fact, as audiology is not currently a registered profession, anyone can call themselves an audiologist.

The consumer alone rarely has a sophisticated enough level of understanding of the dispensing process to protect them from inadequate hearing assessment, inappropriate advice about hearing aid selection, uncomfortable fit, inadequate application of the technology, overcharging and lack of rehabilitative support. 

There is no recommended retail price on hearing aids, and each dispenser is free to charge what they wish. 

The recently issued report on the Hearing Health and Wellbeing of Australians provides evidence that the existing system of hearing services funding and service delivery has failed to protect the public.11

This report, along with an ACCC report in March 2017 into the sale of hearing aids12 and media reports (e.g: ABC’s The Checkout)13 have identified unethical and unsafe practices that take place under the current system. Bonuses to clinicians based on hearing aid sales have been widespread.  

University-trained audiologists carry out hearing and vestibular assessments, diagnose hearing disorders and prescribe hearing treatment plans – which may include hearing aids or a cochlear implant. They have the diverse range of skills and training to be able to comprehensively apply this technology. 

Being clinically certified by the peak professional body Audiology Australia requires meeting rigorous education and training requirements, and following their code of conduct, continuing professional development program and recency of practice requirements. All current Audiology Australia Accredited Audiologists are listed on this register: https://audiology.asn.au/Consumer_Hub/Register_of_Audiology_Australia_Accredited_Audiologist_

Independent Audiologists Australia (IAA) is a not for profit incorporated association supporting clinical practices at least 50% owned by university qualified audiologists.  Members agree to abide by a strict code of ethics and select hearing devices from all suppliers in Australia, so are not affiliated to a specific hearing aid manufacturer. A list of members can be found on the IAA website: https://independentaudiologists.net.au/

Audiometrists can opt to abide by the requirements and standards of practice, rules of conduct and practice standards set by either the Australian College of Audiology or the Hearing Aid Audiometrist Society of Australia, recently renamed the Hearing Aid Audiology Society of Australia.

Hearing aids cannot totally overcome the perceptual distortions produced by a sensorineural hearing loss. They are an aid, not a cure. Patients and their families should be made aware of both the advantages and the limitations of hearing aid use generally, as well as with their specific hearing aid choice. 

People who rarely communicate in groups or significant levels of background noise may not require a sophisticated and expensive level of hearing aid technology. The level of technological sophistication should be matched to the patient’s communication needs and budget. 

Cosmetic concerns, ease of handling/dexterity and degree of hearing loss will influence the choice of size and appearance of the hearing aids. Inappropriate hearing aid choice can increase the level of hearing disability if the patient cannot manage the complexity or size of their hearing aids.

Hearing aid companies generally offer a period ranging up to 90 days after purchase to return/exchange hearing aids if the patient is not satisfied with their choice. In my opinion, a dispenser should indicate the reasons for recommending a particular manufacturer and routinely include a return/exchange option. 

NEURAL ADAPTATION TO AMPLIFICATION 

The central auditory processing of sound includes the subconscious selection and highlighting of sounds that are important to us. Unimportant sounds are heard, but not fully perceived, unless we consciously pay attention to them. Because of the gradual onset of most sensorineural hearing losses, a person with a hearing loss will insidiously change their concept of “normal” hearing. 

With an initial hearing aid fitting, the patient’s concept of “normal” hearing will need to be redefined and the process of subconscious selection will need to be re-learnt, which can take up to several months. Unimportant sounds will seem both loud and unnaturally prominent through their hearing aids at first.  This is a major reason for hearing aid rejection in an unprepared patient and rehabilitative guidance/support during this period is essential for successful hearing aid fitting. Encouraging patients to wear their hearing aids most of the time will ensure that their concept of “normal” hearing will be successfully redefined.  

Gradually easing patients towards the level of optimum amplification for their hearing loss will help acceptance of amplification. The programming software with most brands allows for a series of adaptation levels to be set up in the aids, so the clinician can readily carry this out.

BENEFITS AND LIMITATIONS

The competitive market ensures that hearing aid technology is continually evolving with regards to speech in noise processing and connectivity to other devices such as TV, mobile phones et cetera. 

Hearing aids provide the required level of frequency-specific amplification to compensate for the loss of volume resulting from a hearing loss. They will automatically adapt to suit different sounds and different listening environments. 

Inner ear damage and neural changes with a significant sensorineural hearing loss will cause a loss of clarity, so that hearing of speech will be distorted. Hearing aids provide a clear undistorted sound to a patient’s ears, but the sound is distorted as it passes through the ears and neural pathways.  This distortion reduces the ability to discriminate speech through competing noise.  

Contemporary hearing aids help highlight a dominant speech sound but cannot fully separate a voice the person wants to hear from a competing sound. 

Additionally, effective localisation of sound is often impaired, so rapid communication in a large group where the person cannot source who is speaking is challenging, even with optimally fitted hearing aids.  

As a result of reduced speech clarity, a hearing-impaired person has to concentrate harder than someone with normal hearing to follow a conversation even while wearing their hearing aids. This is tiring, and concentration will be further affected by fatigue, stress et cetera. If the person speaking has rapid or unclear speech, additional difficulties will be experienced making sense of a conversation. If the hearing-impaired person hasn’t noticed someone is speaking to them, they may miss the start of a conversation.

If distortion reaches a level where amplification provides very little speech discrimination ability, hearing aids are of little benefit and cochlear implantation may be appropriate. Neural adaptation to electrical stimulation follows very similar processes to amplification, although may take a little longer.   

Overall, a GP plays an integral part of the team in managing hearing loss in both children and adults. From initially suspecting a diagnosis to referral and regular reviews of a hearing-impaired patient a GP and audiologist can significantly improve a patient’s quality of life. 

Myriam Westcott is an audiologist and director of Dineen Westcott Moore Audiology in Heidelberg, Victoria. She has specialised interests in aural rehabilitation, tinnitus, hyperacusis, acoustic shock disorder and central auditory processing.  

References:

1. http://pediatrics.aappublications.org/content/120/4/898.full

2. http://www.hcia.com.au/hcia-wp/wp-content/uploads/2015/05/Social-and-Economic-Cost-of-Hearing-Health-in-Australia_June-2017.pdf

3. FR Lin et al. Hearing Loss and Cognitive Decline in Older Adults., JAMA Intern Med. 2013;173(4):293-299.

4. Amieva et al. Self-reported Hearing Loss, Hearing Aids and Cognitive Decline in Elderly Adults: A 25-Year Study. H J Am Geriatr Soc.2015:63,10: 2099-2104 

5. https://www.dementia.org.au/files/helpsheets/Helpsheet-OtherInformation04-HearingLoss_english.pdf

6. Livingston, G et al. Dementia prevention, intervention, and care. The Lancet 2017. Published online July 20, 2017 http://dx.doi.org/10.1016/S0140-6736(17)31363-6

7. Weinstein, B. Dementia and Age-Related Hearing Loss – Part II. The Hearing Journal: November 2017 – Volume 70 – Issue 11 – p 26,28,30 doi: 10.1097/01.HJ.0000527209.66935.1e

8. Weinstein BE, Sirow LW, Moser S. Relating Hearing Aid Use to Social and Emotional Loneliness in Older Adults. Am J Audiol. 2016 Mar;25(1):54-61. doi: 10.1044/2015_AJA-15-0055.

9. Nguyen M et al. Efficacy of Hearing Aids on the Cognitive Status of Patients with Alzheimer’s Disease and Hearing Loss: A Multicenter Controlled Randomized Trial. J Alzheimers Dis. 2017;58(1):123-137. doi: 10.3233/JAD-160793

10. https://independentaudiologists.net.au/Private-Health-Funds

11. Still Waiting to be Heard….Report from the Parliamentary Inquiry into Hearing Health and Wellbeing. September 2017. Available from https://www.aph.gov.au/Parliamentary_Business/Committees/House/Health_Aged_Care_and_Sport/HearingHealth/Report_1. 

12. Issues Around the Sale of Hearing Aids. Report issued by the Australian Competition and Consumer Commission. 3 March 2017. Available from https://www.accc.gov.au/publications/issues-around-the-sale-of-hearing-aids . 

13. ABC The Checkout. Hearing Clinics: Had it up to Hear. 8 June 2017. Available from https://www.youtube.com/watch?v=9tVO-nvrIt4.