Research Request – Unilateral Hearing Loss

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Research Request – Unilateral Hearing Loss

We currently have an application for access to the scheme from a person with a unilateral hearing loss (UHL), and with technology seeming to improve function we may have more people seeking the scheme. Can you please look into: Brief • What are the functional impacts of unilateral hearing loss? • What strategies can be utilised to support function? • The effectiveness of these strategies in overcoming the functional impact of UHL?

Date 17/09/19

Requester Susan s22(1)(a)(ii) - irrele (Advisor - TAT)

Researcher Craigs22(1)(a)(ii) - irr (Tactical Research Advisor – TAT)

Contents Research Summary ………………………………………………………………………………………………………………… 2 What is Unilateral Hearing Loss (UHL)? …………………………………………………………………………………….. 2 Causes of UHL ……………………………………………………………………………………………………………………….. 3 How someone with UHL may present ………………………………………………………………………………………. 4 Prevalence - Global ………………………………………………………………………………………………………………… 5 Overview …………………………………………………………………………………………………………………………… 5 Social and Economic Impact ………………………………………………………………………………………………… 5 Prevalence - Australia …………………………………………………………………………………………………………….. 6 Overview …………………………………………………………………………………………………………………………… 6 Social and Economic Impact ………………………………………………………………………………………………… 7 Functional Impacts of UHL ………………………………………………………………………………………………………. 7 General Impacts …………………………………………………………………………………………………………………. 8 Impacts on Children ……………………………………………………………………………………………………………. 8 Strategies to support functional impacts of UHL ………………………………………………………………………… 9 Overview …………………………………………………………………………………………………………………………… 9 Early Intervention ………………………………………………………………………………………………………………. 9 Behavioural Strategies ………………………………………………………………………………………………………… 9 Devices and Technologies used in the management of UHL …………………………………………………….. 9 Effectiveness of strategies to support functional impacts of UHL ……………………………………………….. 11

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BAHA (Bone Anchored Hearing Aid) and CROS/BiCROS …………………………………………………………. 11 BAHA …………………………………………………………………………………………………………………………… 11 CROS/BiCROS ……………………………………………………………………………………………………………….. 12 Cochlear Implants (CI) ……………………………………………………………………………………………………….. 13 SoundBite™ ……………………………………………………………………………………………………………………… 14 Reference List ………………………………………………………………………………………………………………………. 15

Research Summary

• The prevalence of hearing loss globally and in Australia is immense. • The immensity of the prevalence of hearing loss in Australia is reflected by the Australian government’s current inquiry into and report on the Hearing Health and Wellbeing of Australia, together with its current examination of the issue of how hearing services are transitioned to, and delivered through, the NDIS. • Whilst Unilateral Hearing Loss (UHL) is included in hearing loss studies, studies specific to Unilateral Hearing Loss are largely US based. • No statistics with regard to global prevalence specific to UHL could be found. • No statistics with regard to prevalence in Australia specific to UHL could be found. • There is plentiful literature and research on the functional impacts of UHL. • The predominant strategy to support functional impacts of UHL is the use of technological hearing devices. • A Bone Anchored Hearing Aid (BAHA) appears to be the most common and successful device used for UHL. • The review of studies on Cochlear Implants for UHL indicate positive results.

What is Unilateral Hearing Loss?

Unilateral Hearing Loss (UHL) is also known as Single Sided Deafness (SSD), although the former term appears to be the most frequently used.

A unilateral hearing loss means that hearing has been found to be different in each ear. On one side, hearing is at a level considered within the normal range. On the other side, hearing is below the normal range. There are different levels of hearing loss. They are described as mild, moderate, severe or profound. A unilateral loss can be at any of these levels. 1

According to the World Health Organisation:

1 New Zealand Government, Ministry of Health, “What is unilateral hearing loss?”, [website], 2014, https://www.nsu.govt.nz/system/files/resources/unilateral-hearing-loss.pdf, (accessed 11 September 2019)

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Deafness means complete loss of the ability to hear from one or both ears; this is profound hearing impairment, 81 dB or greater hearing threshold, averaged at frequencies 0.5, 1, 2, 4 kHz.

Hearing impairment means complete or partial loss of the ability to hear from one or both ears; this is mild or worse hearing impairment, 26 dB or greater hearing threshold, averaged at frequencies 0.5, 1, 2, 4 kHz.

Disabling hearing impairment means moderate or worse hearing impairment in the better ear; that is the permanent unaided hearing threshold level for the better ear of 41 or 31 dB or greater in age over 14 or under 15 years respectively, averaged at frequencies 0.5, 1, 2, 4 kHz. 2

Grades of Hearing Impairment (WHO, 2008) *

Corresponding Grade of impairment” audiometric ISO Performance Recommendations value”

• Grades 2, 3 and 4 are classified as disabling hearing impairment (for children, it starts at 31 dB) ** The audiometric ISO values are averages of values at 500, 1000, 2000, 4000 Hz. 0 - No impairment 25 dB or better No or very slight hearing problems. (better ear) Able to hear whispers. wae : 26-40 dB Able to hear and repeat words Counselling. Hearing 1 - Slight impairment . . : (better ear) spoken in normal voice at 1 metre. || aids may be needed. 2 - Moderate impairment 41-60 dB Able to hear and repeat words Hearing aids usually (better ear) spoken in raised voice at 1 metre. recommended. Hearing aids needed. If heari . . . 61-80 dB Able to hear some words when ne earing aids 3 - Severe impairment . available, lip-reading (better ear) shouted into better ear. - and signing should be taught. Hearing aids may help understanding words. . . Additional 4 - Profound impairment 81 dB or greater Unable to hear and understand wpe, ge . . . rehabilitation needed. including deafness (better ear) even a shouted voice. . . Lip-reading and sometimes signing essential.

Causes of UHL

The causes of UHL may include:

e acoustic neuroma (a benign tumour developing on the nerve that connects the ear to the brain).

e sudden idiopathic hearing loss, which is commonly due to viral infection

e blunt trauma to the head

2 World Health Organisation, “Facts about deafness”, [website], 2019, https://www.who.int/pbd/deafness/facts/en, (accessed 11 September 2019) 3 ibid

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• Vascular insults that damage the auditory pathway; congenital loss of hearing • Ménière’s disease, a disorder that affects balance and hearing, resulting from the build-up of fluid in part of the inner ear. 4

In addition to head or ear injuries or the presence of a foreign body in the ear, the following medical conditions can result in UHL:

• Eardrum rupture: a small hole or tear in the ear drum • Labyrinthitis: a disorder that causes the inner ear apparatus to become swollen and irritated • Neurofibromatosis type 2: an inherited disease that causes noncancerous growths to appear on the auditory nerve • Otitis externa (swimmer’s ear): inflammation of the outer ear and ear canal • Otitis media with effusion: an infection with thick or sticky fluid behind the eardrum • Shingles: an infection caused by the same virus that causes chickenpox • Reye’s syndrome: a rare disorder, most often seen in children • Temporal arteritis: inflammation and damage to the blood vessels in the head and neck • Vertebrobasilar insufficiency: poor blood flow to the back of the brain 5

UHL may also be the result of prescription medications like:

• chemotherapy drugs • diuretics such as furosemide • salicylate (aspirin) toxicity • antibiotics such as streptomycin and tobramycin 6

How someone with UHL may present Compiled from several references 7a person with profound UHL may present in the following ways:

• Irritability • Sound aversion: any presence of noise, no matter how low • Body language and mannerisms which appear socially awkward or unusual, like staring at others mouths or tilt the head frequently • Frequent headaches, stress • Social isolation • Chronic interpersonal communication difficulties due to inability of brain to isolate or beam form sounds and voices of other individuals • Appearance of anxiousness even in low noise situations • Jumpiness • Trouble figuring out where sounds are coming from. • Variable light dizziness • Trouble paying attention to what people are saying: “evasive” behaviour. • Misdiagnoses as ADHD

4 J. Weaver, “Single-Sided Deafness: Causes, and Solutions, Take Many Forms”, The Hearing Journal, Vol. 68, no. 3, 2015, pp. 20-24, https://urlzs.com/S8SAj 5 Healthline, “Hearing Loss on One Side”, [website], 2019, https://www.healthline.com/health/hearing-loss-on-one-side, (accessed 11 September 2019) 6 ibid 7 Wikipedia, “Unilateral hearing loss”, [website], 2019, https://en.wikipedia.org/wiki/Unilateral hearing loss, (accessed 11 September 2019)

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• Seeming lack of awareness of other people’s personal space and moods since brain is hyper- focused on deciphering auditory information in lieu of non-verbal social cues. • Lack of sound depth: any background noise (in the room, in the car) is flat and wrongly interpreted by the brain. The effect is similar to what happens when trying to hear someone speaking in a noisy crowd on a mono TV. The effect is also similar to talking on the phone to someone who is in a noisy environment • Inability to filter out background noise or selectively listen to only the important portion of the noise in the environment. • Talking loudly or “broadcasting”: the affected person cannot perceive the volume of his or her voice relative to other people in the same room or close company, resulting in being characterized by others (who may be located beyond normal auditory range) as domineering or boorish

Prevalence - Global

Overview Although there are plentiful studies on UHL outside of Australia, no recent global statistics could be found. However, a significant 2013 literature review which accessed papers from a published literature review and obtained additional detailed data tabulations from investigators, estimated “that 92.4% (89.1–94.4%) of children and 68.1% (62.0–73.1%) of adults have unilateral or no hearing impairment”. 8

It terms of general hearing loss:

• Over 5% of the world’s population, or 466 million people, has disabling hearing loss (432 million adults and 34 million children). • It is estimated that by 2050 over 900 million people will have disabling hearing loss. • 60% of childhood hearing loss is due to preventable causes • 1.1 billion young people (aged between 12–35 years) are at risk of hearing loss due to exposure to noise in recreational settings. • Approximately one third of people over 65 years of age are affected by disabling hearing loss. The prevalence in this age group is greatest in South Asia, Asia Pacific and sub-Saharan Africa. 9

Social and Economic Impact In 2017 the World Health Organisation reported on the global costs of unaddressed hearing loss. 10 The report found:

• The cost to the health-care sector, for adults and children, is estimated to be in the range $67–107 billion. This does not include the cost of providing hearing devices such as hearing aids and cochlear implants. • A conservative estimate of the cost to the education sector of providing support to children (5–14 years) with unaddressed hearing loss is $3.9 billion. This assumes that only children

8 G. Stevens et al., “Global and regional hearing impairment prevalence: an analysis of 42 studies in 29 countries”, European Journal of Public Health, vol. 23, no. 1, 2013, pp. 146–152. https://academic.oup.com/eurpub/article/23/1/146/460112 9 World Health Organisation, “Deafness and hearing loss”, [website], 2019, https://www.who.int/news-room/fact-sheets/detail/deafness- and-hearing-loss, (accessed 11 September 2019) 10 World Health Organisation, “Global Costs Of Unaddressed Hearing Loss and Cost-effectiveness of Interventions, 2017, https://www.who.int/pbd/deafness/world-hearing-day/GlobalCostsOfUnaddressedHearingLossExeSum.pdf?ua=1

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with at least moderately severe hearing loss (hearing level greater than 50 dB in the better- hearing ear) require educational support. • Between 63% and 73% of the global costs to health and education sectors are incurred in low- and middle-income countries. • Loss of productivity, due to unemployment and premature retirement among people with hearing loss, is estimated to cost $105 billion annually. • Societal costs – the result of social isolation, communication difficulties and stigma – add a further $573 billion each year. These costs are calculated on the basis of the monetary value attached to avoidance of a year lived with disability and draw upon disability-adjusted life years (DALYs) attributed to hearing loss.

Overall, this analysis suggests that the annual cost of unaddressed hearing loss is in the range $750 - $790 billion globally. The analysis takes no account of certain aspects of hearing loss, the costs of which are not well documented in literature, such as the costs of providing informal care, or preschool learning and higher education for people with unaddressed hearing loss.

(NOTE: The costs above are estimated in 2015 international dollars, a unit of currency defined by the World Bank).

Prevalence - Australia

Overview In 2017, Hearing Care Industry Association (HCIA) commissioned Deloitte Access Economics to update a 2006 report which quantified the impact and estimated impact of both the financial costs and the loss of wellbeing from hearing loss in Australia.11 The intention of the new landmark report was to raise awareness of the economic cost of hearing impairment in Australia and to inform policy making. The report found that:

• The prevalence of hearing loss in Australia (better ear) in 2017 was estimated to be 3.6 million people – 2.2 million males and 1.4 million females. This represents 14.5% of the Australian population.

• In 2060, it is estimated that the prevalence of hearing loss (better ear) will reach up to 7.8 million people – 18.9% of the total population.

• Approximately 49% of child hearing loss is estimated to be preventable, while for adults it is thought that 37% of hearing loss is preventable.

The prevalence rates and number of people who have hearing loss in Australia in 2017 is shown in the table below.

11 Hearing Care Industry Association (HCIA), The Social and Economic Cost of Hearing Loss in Australia. DeLoitte Access Economics Australia, June 2017. https://www.hcia.com.au/about-hearing-loss/#.XW8DkCgzaUk

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Social and Economic Impact The Australian Government’s recent report on the inquiry into the Hearing Health and Wellbeing of Australia, 12indicates the severity of rising hearing loss in Australia, and amongst its recommendations suggesting that hearing health should be made a National Health Priority Area.

“On a broad scale, it has been estimated that hearing loss costs the Australian economy $33.3 billion, comprised of $15.9 billion in financial costs and $17.4 billion in lost wellbeing for individuals. The economic impact of balance disorders is less certain but one estimate suggested that their cost for hospital emergency departments alone could be as high as $148 million per year”.

“… the level of hearing loss among Aboriginal and Torres Strait Islander children is at a crisis. Among working age Australians hearing loss can make it difficult to find or retain a job, and among older people hearing loss may lead to social isolation and has been linked to an increased risk of cognitive decline and dementia”.

Functional Impacts of UHL

There is much research indicating that UHL has physical, cognitive, psychological, and social impacts on the individual.

“A unilateral hearing loss (UHL) can have a significant functional and social impact on children and adults, affecting their quality of life. In adults, UHL is typically associated with difficulties understanding speech in noise and sound localization, and UHL increases the self-perception of auditory disability for a range of listening situations. Furthermore, despite evidence for the negative

12 Parliament of the Commonwealth of Australia, “Report on the Inquiry into the Hearing Health and Wellbeing of Australia”, 2018. https://parlinfo.aph.gov.au/parlInfo/download/committees/reportrep/024048/toc pdf/Stillwaitingtobeheard….pdf;fileType=application% 2Fpdf

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effects of reduced unilateral auditory input on the neural encoding of binaural cues, the perceptual consequences of these changes are still not well understood.” 13

General Impacts

• Auditory abilities: UHL affects a range of auditory abilities, including speech detection in noise, sound localization, and self-perceived hearing disability. CAEPs elicited by speech sounds are sensitive enough to evidence changes within the auditory cortex due to an UHL. 14

In 2019 the National Acoustic Laboratories (NAL) explored the impacts of UHL in adults life, using semi-structured interviews and open ended surveys, with theme outcomes below:

• Difficulties with listening in noise and localisation: Difficulty in loud environments and when there were lots of sound sources. • Fatigue: From the increased cognitive load required during activities such as conversation in loud noise. • Fear/anxiety: The perception that the person’s safety, or the safety of those around them, might be at risk due to their hearing impairment • Self-esteem and difficulty in social situations: Poor perception of themselves, in which they felt like they were a burden to those around them, or felt anxious and self-conscious about their difficulties communicating. • Reduced social engagement: Problems with communication in social situations, resulting in feelings of disconnection from the world around them. • Stigma in the workplace: Strong perception of stigma, particularly in the workplace, where they did not want others to know and judge them for their hearing loss. • Coping mechanisms: Development of various coping mechanisms in response to the difficulties encountered because of their hearing loss. In some cases, coping mechanisms were applied through conscious effort or adapted without conscious thought. 15

Impacts on Children

• General communication difficulties • Psycholinguistic dysfunction (ability to learn language) • Social-emotional problems • Quality of life effects 16 • Academic: Children with UHL are 10 times more likely to need to repeat a year of school than children with normal hearing 17

13 O. Canete et al., “Impact of Unilateral Hearing Loss on Behavioral and Evoked Potential Measures of Auditory Function in Adults”, J Am Acad Audiol., vol. 30, no. 7, pp. 564-578, 2019. https://www.ncbi.nlm.nih.gov/pubmed/30424835 14 ibid 15 J. Galloway et al., “The Impact of Unilateral Hearing Loss on Adult Life”, Hearing Review, vol. 26, no. 4, 2019. http://www.hearingreview.com/2019/03/impact-unilateral-hearing-loss-adult-life 16 D. Bowers, “Unilateral Hearing Loss in Children: Impact and Solutions”, [website], 2017, https://www.audiologyonline.com/articles/unilateral-hearing-loss-in-children-19953, (accessed 11 September 2019) 17 F. Bess, & A. Tharpe, “Case history data on unilaterally hearing-impaired children”, Ear and Hearing, vol.7, pp. 14-19, 1986, https://www.ncbi.nlm.nih.gov/pubmed/3949096

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• Support Services: Children are 5 times more likely to need support services. 18

Strategies to support functional impacts of UHL

Overview Research of the literature indicates that the predominant strategy to support functional impacts of UHL is the use of technological hearing devices. Some patients may chose surgery over wearing a hearing aid as they may perform better with a bone-conductive option, and others prefer not to wear any device on their ear and a bone-anchored implant offers that opportunity. 19

Early Intervention No research could be found regarding adults with hearing loss who did not receive early intervention support. However, there is much literature on early intervention for children with hearing loss in terms of communication skills and social interaction.

The Australian government’s Hearing Australia asserts that “There is currently no high-quality evidence on how to best manage unilateral hearing loss in young children.” 20

“Research has shown that babies with a hearing loss of about 40dB or more in both ears benefit from wearing hearing aids in the first six months.

However, research hasn’t yet shown us the best approach to take for babies with a unilateral hearing loss.

Fitting a hearing aid early to children with a significant unilateral loss might stimulate the child’s brain to use hearing in the affected ear. This applies especially to children who have a moderate or severe hearing loss in the affected ear.

Children who have only very mild loss in the affected ear are unlikely to need or benefit from aid use. Children with a profound unilateral loss may not have any useable hearing in the affected ear even with a hearing aid.

Children with unilateral loss appear to be at higher risk than other children of developing hearing loss in the unaffected ear. While only a small risk, this may be another reason to consider early use of a hearing aid, as it may be wise to make greatest use of the hearing in the affected ear just in case the hearing in the good ear worsens in the future.” 21

Behavioural Strategies No research could be found with regard to using behavioural strategies such as Cognitive behavioural therapy, as a management option for unilateral hearing loss. However there have been studies conducted regarding such as applied to reducing mental stress of the impacts of the loss.

Devices and Technologies used in the management of UHL

18 R. Oyler et al., “Unilateral hearing loss: demographics and educational impact”, Language, Speech, and Hearing Services in Schools“, vol.19, pp.201–210, https://doi.org/10.1044/0161-1461.1902.201 19 Cleveland Clinic, “Single-Sided Deafness _ What Are Your Options”, [website], 2019, https://my.clevelandclinic.org/health/transcripts/1489 single-sided-deafness-what-are-your-options, (accessed 17 September 2019) 20 Hearing Australia, “NAL research is CUHL for kids with hearing loss”, [website], 2019, https://www.hearing.com.au/About-Hearing- Australia/Hearing-news/NAL-research-is-CUHL-for-kids-with-hearing-loss, (accessed 17 September 2019) 21 ibid

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Device/Technology Description

CROS (Contra Lateral CROS aids are hearing aids where one aid contains a microphone, and the Routing of Signal ) Hearing other the amplifier and receiver. CROS aids can be used by people who Aids / BiCROS have one good hearing ear and one ear where the loss is so great that a

hearing aid will provide no benefit. Essentially, a CROS aid is a hearing device with a microphone on one side carrying sound from that side of the head to the other side. 77

The technology allows two implementations: CROS and BiCROS. The BiCROS implementation is for a user with little or no hearing on one side and with some hearing loss in their better ear. It works just like the CROS implementation, except that the device on the good side is actually a fully capable hearing aid for hearing sounds from the good side that is also capable of receiving the sound transmitted from the CROS aid on the other side. Transmission in a CROS or BiCROS configuration can be via wire around the back of the neck or wirelessly via radio. 78

Transcranial CROS Transcranial CROS transmits a signal received by an air conduction hearing aid in the deaf ear to the contralateral cochlea via bone conduction. Theoretically, transcranial CROS represents an improvement over air conduction CROS because of a smaller reduction in the sound signal across bone versus electronically or wirelessly. *

A BAHA is a surgically implantable system for the treatment of hearing loss.

Bone Anchored Hearing Aid . . 6 This device allows sound to be conducted through the bone rather than the (BAHA) . . . 5 middle ear - a process known as direct bone conduction. SoundgBite Intraoral bone A non-surgical bone conduction prosthetic device that transmits sound via conduction (SoundBite™ the teeth. It is an alternative to surgical bone conduction prosthetic Hearing System) devices, which require surgical implantation into the skull to conduct

sound. In the US the device has FDA clearance to treat patients with UHL

There are two parts to the SoundBite system: A small behind-the-ear (BTE) unit that picks up sounds in the environment, processes the sound, and then wirelessly transmits them to the second component: The in-the- mouth (ITM) device. This fits securely around the upper back portion of the teech but does not require any modifications to the teeth. It wirelessly picks up the sound detected by the BTE unit and transmits it into sound vibrations. These sound vibrations travel via the teeth through the bones of

your ear and into the cochlea (hearing organ) where the sound is detected. 26

2 Australian Government, Department of Health, “Hearing Services Program: Glossary of Terms”, [website], 2018, http://www.hearingservices.gov.au/wps/wcm/connect/hso/67959cbd-9683-4219-86d5- 486b41cb72cd/Glossary+of+Terms+Sept2018.pdf?MOD=AJPERES&CONVERT TO=url&CACHEID=67959cbd-9683-4219-86d5- 486b41cb72cd, (accessed 11 September 2019)

33 Hearing Loss Association of America, “CROS and BiCROS”, [website], 2018, http://www.nchearingloss.org/bicros.htm?fromneshhh, (accessed 11 September 2019)

24 C. Giardina et al., “Cochlear Implants in Single-Sided Deafness”, Curr Surg Rep, vol. 2, no. 75, 2014, https://link.springer.com/article/10.1007/s40137-014-0075-9#citeas

25 Australian Government, Department of Health, “Hearing Services Program: Glossary of Terms”, [website], 2018, http://www.hearingservices.gov.au/wps/wcm/connect/hso/67959cbd-9683-4219-86d5- 486b41cb72cd/Glossary+of+Terms+Sept2018.pdf? MOD=AJPERES& CONVERT TO=url&CACHEID=67959cbd-9683-4219-86d5- 486b41cb72cd, (accessed 11 September 2019)

26 Everyday Hearing, “SoundBite Hearing System — Is it right for me?”, [website],2019, https://www.everydayhearing.com/hearing- technology/soundbite-hearing-system-is-it-right-for-me, (accessed 11 September 2019)

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A cochlear implant is a surgically implanted device which enables a person to experience sounds by sending electrical signals to the nerve endings in the inner ear (the cochlear). 77

Device/Technology Description

Cochlear Implants (Cl)

Bone conduction implants Bone conduction implants are an alternative option to hearing aids, suitable for people with conductive and mixed hearing loss, as well as those with single sided deafness. Bone conduction implants can also help people who are physically unable to wear conventional hearing aids for medical or anatomical reasons. 78

Effectiveness of strategies to support functional impacts of UHL

BAHA (Bone Anchored Hearing Aid) and CROS/BiCROS

BAHA In researching the literature it appears that BAHA is currently the most used and most successful device in the management of UHL.

A recent systematic review study which was conducted on Pubmed and which retrieved 549 articles, evaluated the impact of different types of hearing rehabilitation after hearing loss and their impact on quality of life.

The main finding was that hearing rehabilitation is beneficial in all types of hearing loss and treatment regarding quality of life. However, bone-anchored hearing devices and cochlear implants were shown to produce greater improvements in terms of quality of life than conventional hearing aids. 7°

“The BAHA is increasingly used for single sided deafness (SSD) because it effectively eliminates the head shadow effect by bringing sound trancranially to the good ear. In SSD, BAHA shows significant benefits in situations involving background noise and reverberation and a reduced aversion to loud sounds in comparison to the unaided and conventional CROS conditions. These studies also were reassuring in finding that wearing the BAHA did not interfere with the function of the normal contralateral ear by the interference through bone conduction.” *°

A 2003 cohort study evaluated the effectiveness of BAHA in transcranial routing of signal by implanting the deaf ear. Eighteen patients with UHL were included in the study. They had a 1-month pre-implantation trial with a contralateral routing of signal (CROS) hearing aid. Their performance with BAHA was compared with the CROS device using speech reception thresholds, speech

?7 Australian Government, Department of Health, “Hearing Services Program: Glossary of Terms”, [website], 2018, http://www.hearingservices.gov.au/wps/wcem/connect/hso/67959cbd-9683-4219-86d5- 486b41cb72cd/Glossary+of+Terms+Sept2018.pdf?MOD=AJPERES&CONVERT_ TO=url&CACHEID=67959cbd-9683-4219-86d5-

486b41cb72cd, (accessed 11 September 2019)

——__—’

28 Ear Science Clinic, “Bone Conduction Implants”, [website], 2019, https://www.earscience.org.au/clinic/hearing-implants/bone- conduction-implants, (accessed 16 September 2019)

?? A. Brodie et al., “The impact of rehabilitation on quality of life after hearing loss: a systematic review”, Eur Arch Otorhinolaryngol, vol. 275, no. 10, pp 2435-2440, 2018. https://link.springer.com/article/10.1007/s00405-018-5100-7

3° A. Abdulrahman, “BAHA: Bone-Anchored Hearing Aid”, Int J Health Sci (Qassim), vol., 1, no. 2, pp. 265-276, 2007. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3068630

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recognition performance in noise, and the Abbreviated Profile Hearing Benefit and Single Sided Deafness questionnaires. • Patients reported a significant improvement in speech intelligibility in noise and greater benefit from BAHA compared with CROS hearing aids. • Patients were satisfied with the device and its impact on their quality of life. No major complications were reported. The study concluded that “BAHA is effective in unilateral deafness. Auditory stimuli from the deaf side can be transmitted to the good ear, avoiding the limitations inherent in CROS amplification”. 31

CROS/BiCROS A 2019 study compared the CROS/BiCROS and a soft-band bone-anchored hearing aid (BAHA) in patients with UHL, and assessed the relationship between hearing aid benefits and personal factors. Sound localization, consonant, hearing in noise, and psychoacoustic tests were performed. The study found: • Sound localization ability in the horizontal plane was significantly decreased in the CROS/BiCROS condition because it diminished the monaural level and spectral cues for monaural listeners. • A CROS/BiCROS hearing aid provided a slight but significant additional benefit for speech perception in a quiet and speech-in-noise perception when speech and noise were presented from the front. • Both the CROS/BiCROS hearing aid and BAHA helped reduce the head shadow effect, and they significantly enhanced speech-in-noise perception when the target speech was presented to the poorer ear. • A CROS/BiCROS hearing aid was superior to a BAHA in overcoming the head shadow effect. • A CROS/BiCROS hearing aid appeared to have a rather negative effect when the noise was delivered to the better ear. 32 A contemporary literature review on the comparison of CROS hearing devices and BAHA suggested that “there is indication in the literature that BAHA provides greater relief of hearing handicap associated with USNHL than CROS hearing aids; however, both have been found to provide limited patient satisfaction and seemingly fall short of restoring true sound localization”. 33 An article which referenced and interviewed several practicing physicians looked at the benefits on both BAHA and CROS devices. Although each device has its advantages and disadvantages, BAHA appeared to be the preferred option due to better hearing quality and patient comfort, according to the physicians interviewed for the article: • Although CROS doesn’t require surgery, Baha tends to have a high level of user satisfaction • Baha routes sound more efficiently, and the patient receives a clearer, stronger sound in the hearing impaired ear than with traditional or transcranial CROS • One recent study (Otol Neurotol 2006; 27:172-82) of 23 patients with unilateral deafness conducted by Dr. Niparko and his colleagues found that Baha used for single-sided deafness provided greater benefits for patients than CROS. Advantages of Baha were related to averting the interference of speech signals delivered to the better ear, as occurs with

31 J. Eazen et al., “Transcranial Contralateral Cochlear Stimulation in Unilateral Deafness”, Sage Journals, vol. 129, no.3, pp. 248-254, 2003, https://journals.sagepub.com/doi/abs/10.1016/S0194-5998(03)00527-8 32 J. Choi et al., “A comparison between wireless CROS/BiCROS and soft-band BAHA for patients with unilateral hearing loss”, PLoS ONE, vol. 14, no. 2, 2019, https://doi.org/10.1371/journal.pone.0212503 33 C. Bishop and T. Eby, “The current status of audiologic rehabilitation for profound unilateral sensorineural hearing loss”, The Laryngoscope, vol. 120, no. 3, 2009, https://onlinelibrary.wiley.com/doi/abs/10.1002/lary.20735

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conventional CROS amplification, while alleviating the negative head-shadow effects of unilateral deafness. • In a recent study (Otolaryngol Head Neck Surg. 2003;129:248-54), Dr. Wazen and his colleagues studied 30 patients who received a CROS hearing aid for a one-month period and then switched to the BAHA system. Patients reported a significant improvement in speech intelligibility in noise, greater improvement in perceived benefit, increased satisfaction, and better quality of life with BAHA than with CROS. 34

Cochlear Implants (CI) Whilst BAHA devices appear to be the most used in the management of UHL, the review of studies of Cochlear Implants indicate positive results. A recent systematic literature review (2016) studied the influence of cochlear implantation in patients with unilateral hearing loss with regards to (a) sound localization, (b) speech perception, (c) tinnitus, and, (d) quality of life. 35 The study concluded: • A cochlear implant is the only option that provides ear-specific information and, thus, potentially benefits SDD patients’ bilateral listening. • Outcomes regarding enhancement of sound localization, speech perception, and, mainly, improvement of tinnitus are promising indications as well; however, high quality studies are required before standardizing cochlear implantation as a treatment for single-sided deafness. • Results obtained up to this point from cochlear implantation in patients with single-sided deafness are encouraging in deeming this procedure a reasonable treatment. • Given that the cochlear implant seems to bring greater benefits than contralateral routing of sound (CROS) and osseointegrated implants, it should be the first choice of treatment for patients with SSD in that which pertains to satisfactory selection criteria. A cohort study aimed to investigate:

1. How a hearing aid needs to be adjusted for an adult who uses a cochlear implant in the contralateral ear
2. Whether the use of a hearing aid with a cochlear implant leads to interference
3. Whether adults derive binaural benefits from using a hearing aid with a cochlear implant for speech perception, localization, and functional performance in everyday life. Twenty one patients who used a cochlear implant system in one ear participated in the study. The study concluded that “binaural advantages can be obtained from using a hearing aid with a cochlear implant in opposite ears. It is recommended that bimodal stimulation be standard practice for rehabilitation of adults who wear unilateral cochlear implants. A hearing aid should be fitted to the non-implanted ear using the NAL-NL1 prescription as a starting point, and the frequency response slope and gain could be fine-tuned to suit individual needs”. 36

34 H. Lindsay, “CROS and Baha-Which Type of Hearing Assistance Is Better?”, ENTtoday [website], 2009, https://www.enttoday.org/article/cros-and-baha-which-type-of-hearing-assistance-is-better/?singlepage=1, (accessed 17 September 2019) 35 F. Cbral et al., “Cochlear Implantation and Single-sided Deafness: A Systematic Review of the Literature”, Int Arch Otorhinolaryngol, vol. 20, no. 1, pp. 69-75, 2016, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4687988 36 T. Ching et al., “Binaural Benefits for Adults Who Use Hearing Aids and Cochlear Implants in Opposite Ears, Ear and Hearing, vol. 25, no. 1, pp. 9-21, https://journals.lww.com/ear-hearing/Abstract/2004/02000/Binaural Benefits for Adults Who Use Hearing Aids.2.aspx

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SoundBite™ There is very little research available on the SoundBite Hearing System which was introduced to the US in 2010 and which has FDA clearance to treat patients with UHL. A cohort study compared the effectiveness of BAHA and SoundBite. Participants wore one device for 30 days and then swapped for the other device for 30 days. Measures included unaided and aided sound-field thresholds, sound localization, and perception of speech in babble. The study concluded that “Speech perception and sound localization were similar for the two types of device, but the SoundBite led to lower aided thresholds and better APHAB scores than the BAHA”. The outcomes of the study were: • Mid-frequency aided thresholds were lower for SoundBite than for BAHA • Both devices gave benefits for localization after 30 days, but there was no difference between devices. • Speech perception was better for both devices than for unaided listening when the target speech came from the poorer hearing side or in front, and the interfering babble came from the better-hearing side. • There was no consistent difference between devices. • APHAB scores were better for SoundBite than for BAHA. 37

37 B. Moore and G. Popelka, “Preliminary comparison of bone-anchored hearing instruments and a dental device as treatments for unilateral hearing loss”, International Journal of Audiology, vol. 52, no.10, pp. 678-686, 2013. https://www.tandfonline.com/doi/abs/10.3109/14992027.2013.809483

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Reference List A. Abdulrahman, “BAHA: Bone-Anchored Hearing Aid”, Int J Health Sci (Qassim), vol., 1, no. 2, pp. 265–276, 2007. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3068630

A. Brodie et al., “The impact of rehabilitation on quality of life after hearing loss: a systematic review”, Eur Arch Otorhinolaryngol, vol. 275, no. 10, pp 2435–2440, 2018. https://link.springer.com/article/10.1007/s00405-018-5100-7

Australian Government, Department of Health, “Hearing Services Program: Glossary of Terms”, [website], 2018, http://www.hearingservices.gov.au/wps/wcm/connect/hso/67959cbd-9683- 4219-86d5- 486b41cb72cd/Glossary+of+Terms+Sept2018.pdf?MOD=AJPERES&CONVERT TO=url&CACHEID=6 7959cbd-9683-4219-86d5-486b41cb72cd, (accessed 11 September 2019)

B. Moore and G. Popelka, “Preliminary comparison of bone-anchored hearing instruments and a dental device as treatments for unilateral hearing loss”, International Journal of Audiology, vol. 52, no.10, pp. 678-686, 2013. https://www.tandfonline.com/doi/abs/10.3109/14992027.2013.809483

C. Bishop and T. Eby, “The current status of audiologic rehabilitation for profound unilateral sensorineural hearing loss”, The Laryngoscope, vol. 120, no. 3, 2009, https://onlinelibrary.wiley.com/doi/abs/10.1002/lary.20735

C. Giardina et al., “Cochlear Implants in Single-Sided Deafness”, Curr Surg Rep, vol. 2, no. 75, 2014, https://link.springer.com/article/10.1007/s40137-014-0075-9#citeas

Cleveland Clinic, “Single-Sided Deafness _ What Are Your Options”, [website], 2019, https://my.clevelandclinic.org/health/transcripts/1489 single-sided-deafness-what-are-your- options, (accessed 17 September 2019)

D. Bowers, “Unilateral Hearing Loss in Children: Impact and Solutions”, [website], 2017, https://www.audiologyonline.com/articles/unilateral-hearing-loss-in-children-19953, (accessed 11 September 2019)

Ear Science Clinic, “Bone Conduction Implants”, [website], 2019, https://www.earscience.org.au/clinic/hearing-implants/bone-conduction-implants, (accessed 16 September 2019)

Everyday Hearing, “SoundBite Hearing System – Is it right for me?”, [website],2019, https://www.everydayhearing.com/hearing-technology/soundbite-hearing-system-is-it-right-for- me, (accessed 11 September 2019)

F. Bess, & A. Tharpe, “Case history data on unilaterally hearing-impaired children”, Ear and Hearing, vol.7, pp. 14-19, 1986, https://www.ncbi.nlm.nih.gov/pubmed/3949096

F. Cbral et al., “Cochlear Implantation and Single-sided Deafness: A Systematic Review of the Literature”, Int Arch Otorhinolaryngol, vol. 20, no. 1, pp. 69-75, 2016, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4687988

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G. Stevens et al., “Global and regional hearing impairment prevalence: an analysis of 42 studies in 29 countries”, European Journal of Public Health, vol. 23, no. 1, 2013, pp. 146–152. https://academic.oup.com/eurpub/article/23/1/146/460112

H. Lindsay, “CROS and Baha-Which Type of Hearing Assistance Is Better?”, ENTtoday [website], 2009, https://www.enttoday.org/article/cros-and-baha-which-type-of-hearing-assistance-is- better/?singlepage=1, (accessed 17 September 2019)

Healthline, “Hearing Loss on One Side”, [website], 2019, https://www.healthline.com/health/hearing-loss-on-one-side, (accessed 11 September 2019)

Hearing Australia, “NAL research is CUHL for kids with hearing loss”, [website], 2019, https://www.hearing.com.au/About-Hearing-Australia/Hearing-news/NAL-research-is-CUHL-for- kids-with-hearing-loss, (accessed 17 September 2019)

Hearing Care Industry Association (HCIA), The Social and Economic Cost of Hearing Loss in Australia. DeLoitte Access Economics Australia, June 2017, https://www.hcia.com.au/about- hearing-loss/#.XW8DkCgzaUk

Hearing Loss Association of America, “CROS and BiCROS”, [website], 2018, http://www.nchearingloss.org/bicros.htm?fromncshhh, (accessed 11 September 2019)

J. Choi et al., “A comparison between wireless CROS/BiCROS and soft-band BAHA for patients with unilateral hearing loss”, PLoS ONE, vol. 14, no. 2, 2019, https://doi.org/10.1371/journal.pone.0212503

J. Eazen et al., “Transcranial Contralateral Cochlear Stimulation in Unilateral Deafness”, Sage Journals, vol. 129, no.3, pp. 248-254, 2003, https://journals.sagepub.com/doi/abs/10.1016/S0194- 5998(03)00527-8

J. Galloway et al., “The Impact of Unilateral Hearing Loss on Adult Life”, Hearing Review, vol. 26, no. 4, 2019. http://www.hearingreview.com/2019/03/impact-unilateral-hearing-loss-adult-life

J. Weaver, “Single-Sided Deafness: Causes, and Solutions, Take Many Forms”, The Hearing Journal, Vol. 68, no. 3, 2015, pp. 20-24, https://urlzs.com/S8SAj

New Zealand Government, Ministry of Health, “What is unilateral hearing loss?”, [website], 2014, https://www.nsu.govt.nz/system/files/resources/unilateral-hearing-loss.pdf, (accessed 11 September 2019)

O. Canete et al., “Impact of Unilateral Hearing Loss on Behavioral and Evoked Potential Measures of Auditory Function in Adults”, J Am Acad Audiol., vol. 30, no. 7, pp. 564-578, 2019. https://www.ncbi.nlm.nih.gov/pubmed/30424835

Parliament of the Commonwealth of Australia, “Report on the Inquiry into the Hearing Health and Wellbeing of Australia”, 2018. https://parlinfo.aph.gov.au/parlInfo/download/committees/reportrep/024048/toc pdf/Stillwaitin gtobeheard….pdf;fileType=application%2Fpdf

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R. Oyler et al., “Unilateral hearing loss: demographics and educational impact”, Language, Speech, and Hearing Services in Schools“, vol.19, pp.201–210, https://doi.org/10.1044/0161- 1461.1902.201

T. Ching et al., “Binaural Benefits for Adults Who Use Hearing Aids and Cochlear Implants in Opposite Ears, Ear and Hearing, vol. 25, no. 1, pp. 9-21, https://journals.lww.com/ear- hearing/Abstract/2004/02000/Binaural Benefits for Adults Who Use Hearing Aids.2.aspx

Wikipedia, “Unilateral hearing loss”, [website], 2019, https://en.wikipedia.org/wiki/Unilateral hearing loss, (accessed 11 September 2019)

World Health Organisation, “Deafness and hearing loss”, [website], 2019, https://www.who.int/news-room/fact-sheets/detail/deafness-and-hearing-loss, (accessed 11 September 2019)

World Health Organisation, “Facts about deafness”, [website], 2019, https://www.who.int/pbd/deafness/facts/en, (accessed 11 September 2019)

World Health Organisation, “Global Costs Of Unaddressed Hearing Loss and Cost-effectiveness of Interventions, 2017, https://www.who.int/pbd/deafness/world-hearing- day/GlobalCostsOfUnaddressedHearingLossExeSum.pdf?ua=1

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