Mr Ryan Johnson-HuntMNZAS Senior Audiologist

Bay Audiology

16:30 - 17:25 WS #167: Understanding the Relationship Between Hearing Loss and Dementia

17:35 - 18:30 WS #179: Understanding the Relationship Between Hearing Loss and Dementia

(Repeated)

Understanding the Relationship Between Hearing Loss and Dementia

Ryan Johnson-Hunt Audiologist MNZAS

Outline for Today1. Hearing system refresher

2. The (very close) link between hearing and the brain

3. How hearing loss changes the brain

4. The association between hearing loss and dementia

5. What can we do about it?

6. Hearing loss in General Practice

7. Question Time

Disclosure Statement• I am employed by Bay Audiology, which is part of

the Amplifon Group. We are independent of any Hearing Aid Manufacturer.

• CME sessions will not promote products, brands or incentives, and will give a balanced view of all therapeutic options available for good quality patient management.

• Information presented is unbiased and based on scientific evidence.

Why should you listen to me?

Part 1: Hearing System Refresher

Part 1: Hearing System Refresher

Conductive Hearing Loss

• Wax

• Eustachian tube dysfunction

• Cholesteatoma

• Otitis media

• Otosclerosis

• Ossicular disorders

Otitis Media

Otosclerosis

Sensorineural Hearing Loss

• Aging/Presbycusis

• Noise Induced Hearing Loss (NIHL)

• Hereditary

• Virus

• Ototoxic drugs

Healthy Hair Cells

Normal Sensory Nerves

Damaged Hair Cells

Damaged Auditory Nerves

Presbycusis Audiogram

• Age Related and wear & tear

• Bilateral

• Hair cell damage, high frequency hearing affected first

• Affects clarity/speech intelligibility first, then volume later

Prevalence:

• Over 60 – 1 in every 2 (55%)

• Over 80 – 9 out of 10 (93%)

Noise Induced Hearing Loss (NIHL) Audiogram

• Mainly high frequencies

• Usually bilateral

• Historically difficult to correct

• Problem with clarity/speech intelligibility

• Volume is not usually affected

Part 2: The (very close) link between

hearing and the brain

Left: map of cerebral cortical areas that perform several sensory and motor functions, as known until a few years ago.Right: Revised map of the brain indicating multiple areas that respond to hearing.

The different colours on the semantic map define areas where the various word clusters are located based on meaning

Every word lights up the various areas are present in many parts of the cortex and in both hemispheres.

Sensory auditory stimuli have a “widespread” semantic and cognitive correlate in the entire brain

(Huth et al., Nature 2016)

A study on people aged 50 to 79 included testing peripheral hearing levels, central auditory processing and cognitive skills.

The most predictive factor of speech comprehension in a noisy environment was central processing of sound information, followed by cognitive skills (such as working memory and short-term memory), and by life experiences.

(Anderson et al., 2013)

72 first-time hearing aid users were tested for speech recognition in noise with and without hearing aids.

Cognitive function was assessed by tests of working memory and verbal information-processing speed.

Results showed high cognitive performance was associated with high performance in the speech recognition task, even after controlling for age and hearing loss.

Significant correlations exist between the measures of cognitive performance and speech recognition in noise, both with and without hearing aids.

(Lunner 2009)

In summary, there is a “dual track” association between hearing and cognition.

On the one side auditory stimuli are important because they activate the entire cerebral cortex, and on the other, cognitive processes influence “how” we hear

Part 3: How hearing loss changes the

brain

Reduced volume of the Auditory CortexEpidemiologist and ENT Frank Lin of Johns Hopkins University analyzed brain volume measurements from magnetic resonance brain scans of individuals with normal hearing versus hearing impairment scanned annually for 10 years as part of the Baltimore Longitudinal Study of Aging (n=126)

Peripheral hearing impairment was independently associated with accelerated brain atrophy in whole brain and regional volumes concentrated in the right temporal lobe

(Lin 2014)

Reduced integrity of neuronal connectionsMagnetic resonance diffusion tensor imaging technique analyses the diffusion and direction of water molecules in tissues in vivo to study of the microstructural architecture of the brain (to map connections and reconstruct the 3D structure of the white matter).

This has revealed that the integrity of white matter networks in the hearing area is altered in people with hearing loss (Chang Y, 2004)

Increased Cognitive Load

Hearing loss has a negative impact on neuronal resources used for cognitive control which effects the capacity to perceive and process sounds. Greater cognitive effort is needed to suppress irrelevant information in auditory signals (background noise) and other types of sensory signals leaving a lower percentage of residual attention for the remaining cognitive activities (Cardin 2013)

People with a hearing loss present a 24% higher probability of demonstrating impairment in cognitive skills such as concentration, memory and planning capacity (Lin 2013)

Green: Grey matter volume reduction, and Red: Compensatory increments in people with unilateral hearing loss

(Wang et al., 2016)

The complex vicious circle that leads to hearing loss and cognitive decline

Part 4: The Association

Between Hearing Loss and Dementia

Prof Frank Lin monitored, for twelve years, more than 600 older adults with no initial diagnosis of dementia. He found that a mild, moderate or severe hearing loss was associated with a risk of cognitive decline that was respectively two, three and five-fold higher than in people who had no hearing disorders.

The correlation remained even taking into account other risk factors, including age, sex, diabetes, hypertension

Data collected on a group of 1000+ men who were monitored for 17 years indicated a strong association between hearing loss, cognitive decline and dementia. The risk of developing dementia was 2.7-fold higher for every 10 dB of hearing loss (Gallacher J. et al, 2012)

A study on almost 600 people without dementia who were monitored for a mean period of eight years. People diagnosed with dementia had a hearing problem in 77% of cases versus 46% of those who did not present cognitive disorders. After accounting for confounding factors, such as age, gender and lifestyle, the presence of age-related hearing loss was associated with an over 3-fold increase in the probability of manifesting dementia (Meusy A. et al, 2016)

A survey on more than 3,600 people aged 65+ tested hearing at beginning the study, monitored and reassessed the presence of cognitive disorders every two years, confirming that worse hearing was associated with lower cognitive efficiency scores and with greater decline in cerebral activity over a period of 25 years (Amieva H. et al, 2015)

This study used a longitudinal sample of 154,783 people aged 65+ from claims data of the largest German health insurer (containing 14,602 incident dementia diagnoses between 2006 and 2010)

Reduction in the percentage of patients without dementia related to hearing impairment (HI) under treatment or not with an ENT (who prescribe hearing aids in Germany)

(Fritze 2016)

Part 5: What can we do about it?

Emerging evidence that treatment of hearing impairment through hearing solutions is effective in delaying the onset of cognitive impairment while maintaining good cerebral function.

Pioneered by Prof Frank Lin in study that the use of hearing aids in people between 60 and 65 years old was associated with a higher score on cognitive tests (Lin 2011) .

Emerging Evidence for Amplificaton

Supported by a study with analysis of a larger sample of people aged 65+ who were monitored over 25 yrs in the Personnes Agées QUID Study (n=3,670)

Results revealed self-reported hearing loss is associated with accelerated cognitive decline in older adults; hearing aid use attenuates such decline. (Amieva H. et al, 2015)

Those with hearing loss who wear hearing aids demonstrated trajectories of cognitive decline which were comparable to those who had no hearing loss.

Emerging Evidence for Amplificaton

Prof Hélène Amieva, University of Bordeaux, stated during her lecture at the UNSAF congress in Paris in March 2017:

“one of the few modifiable risks to prevent the early onset of dementia is treating hearing loss with professional hearing care”

In the event of severe and profound hearing loss, solving the hearing problem clearly contributes to cognitive benefits.

A study of 94 people subjected to cochlear implantation for one year observed that cognitive capacity (measured by testing attention, memory, mental flexibility, executive function and other skills) improves after the intervention.

Eighty-one percent of patients with cognitive impairment prior to implantation showed an overall improvement in cognitive functions, while the other 19% remained stable. Moreover, among patients with the best cognitive performance before implantation, 76% remained stable and only 24% showed a very slight decline

Over the course of time the use of cochlear implant improves all parameters related to the perception of sound and to the production of speech as well as elements such as social interaction or self-esteem (Mosnier et al. 2015)

Hearing TherapyListening strategies

Assistive Listening Devices• Amplified telephones

• Wireless headphones for TV

• Integrated home systems

Amplification through Hearing Aids

Open Fit Behind the

Ear

Receiver in the Ear

In the Canal

Behind the Ear

In the Ear

In the Canal

Advances in Hearing Aid Technology• Smaller, lighter

• Better feedback management (SQUEALING)

• Faster processing

• Better performance in crowds and background noise

• Water and dust resistance

• Wireless - Mobile phones, TV

• CROS and BiCROS systems

Levels of Hearing Aid Technology

Part 6: Hearing Loss in General Practice

Role of the GP in Hearing Related Issues• Long term relationship of trust - refer to

audiologist

• Widespread impact on overall health, well-being and independence.

• Promotes healthy ageing

How can you detect hearing loss in your patients?

Some questions you could ask:

• Do you often think people mumble?• Do you ask others to repeat themselves?• Do your family members tell you the TV is too loud?• Do you have difficulty hearing when someone faces away from you?• Do you find that background noise frequently overwhelms your ability to hear

conversation• Do you feel like you miss out on the conversation in a group, miss the punch

lines, or have difficulty keeping up?

Hearing Aid Subsidy(Ministry of Health)

Available for ALL NZ citizens and permanent residents

• $511 per aid ($1022 for pair), eligible again 6 years later

• This alone will cover basic entry level hearing aids - good option if finances very limited or reluctant to commit to amplification

Hearing Aid Funding Scheme (Ministry of Health)

Hearing aid(s) fully funded, patient pays a fixed clinical management fee ($1200-$1500) often with WINZ help

• NZ citizens and permanent residents that fit one of these criteria for extra assistance:

1. Have had a significant hearing loss from childhood

2. Have a dual disability (eg blind, disabled)

3. Have a Community Services Card and meet certain criteria (eg caring for dependants, job seeking, volunteering)

War Pensions (Veterans Affairs NZ)• Eligible if have served overseas in a

recognised conflict and had hearing loss recognised as a result of their service

• Audiologist liaises directly with Veterans Affairs regarding the Veterans needs

• Fully funded hearing aids and repairs, receive money in pension for batteries

ACCFor NIHL, Trauma and Medical Misadventure Claims

• GP to start claim process using ACC45 form, no prior HT necessary

• ACC allocates lump sum based on % loss work related (different criteria for trauma or medical claims), 3 funding bands: approx$3000, $4000, $5000

• Topping up optional - ALWAYS a “no top up” option

WINZ Loan (Work and Income)• WINZ often provide a grant or an advance,

where patient pays back small amount each week from their benefit.

• Maximum limit is on a case by case basis, but $1500 is common, $3000+ with justification.

Who can receive a cochlear implant in New Zealand?• Severe to profound hearing loss in both ears.

• Hearing isn't helped by standard (acoustic) hearing aids.

• Have been assessed as likely to benefit from a cochlear implant.

• Eligible for publicly funded health and disability services.

• Live permanently in New Zealand.

Also – ACC, Private

When to refer to an Audiologist

It is recommended that any patient over the age of 55 years old has a hearing check (baseline)

Patient concerns about hearing

Tinnitus assessment

Unilateral hearing loss or tinnitus

Sudden loss

Refer earlier rather than later, no matter the level of difficulty.

Feel free to contact me for a copy of the presentation or for any audiology enquiries:

Ryan.johnsonhunt@bayaudiology.co.nz

Any

Questions?