AD_027___APR15_11. pdf Page 27 6/ 4/ 11, 4: 20 PM HowtoTreat PULL-OUT SECTION www.australiandoctor.com.au COMPLETE HOW TO TREAT QUIZZES ONLINE (www.australiandoctor.com.au/cpd) to earn CPD or PDP points. inside Classifying types of loss HearingHearing lossloss Management Hearing-assistive inin thethe ageingageing listening devices Hearing aids and patientpatient implants

The authors

DR PHIL SALE, cochlear implant research fellow, Kolling Deafness Research Centre, University of Sydney, Background and pathology NSW.

HEARING loss in the ageing patient is secondary to the ageing process and is thought to be largely due to the differ- logical ageing and have been found to common. In recent Australian surveys, presumed to be the result of multiple, ences in noise exposure experienced by cause difficulty in judging the duration 26.6% of the population have some repeated insults to a patient’s cochlear men and women in occupational and of , perceiving gaps in sounds hearing impairment, while in the 70+ function. Presbycusis is both a diag- recreational activities. Cell population and localising sounds in space.2 age group this prevalence rises to nosis of exclusion and an umbrella decline has been observed at all loca- Secondary brain changes occur in 87.5%.1 Deterioration of hearing with term for multiple presumed pathologi- tions along the auditory pathway. situations of auditory deprivation increasing age is not inevitable. As a cal processes. Central changes leading to difficulty from due to pathology CLINICAL ASSOCIATE case in point, the Mabaan people of Damage to the cochlea occurs due with hearing can be classified as pri- anywhere in the . Hearing-loss- PROFESSOR NIRMAL PATEL, Sudan are known to maintain a to the age-related accumulation of mary or secondary. Primary changes induced neuroplasticity, or central clinical director, Northside healthy diet, exercising daily, avoiding genetic damage and gradual decline in include reduced volume of brain tissue effects of peripheral pathology, can Cochlear Implant Clinic, and tobacco smoke and noisy environ- the numbers of neural and supporting involved in auditory processing. Lipo- increase the sensitivity (decreased Director, Kolling Deafness ments; most of this population main- cells within the cochlea. Other possible fuscin accumulation has also been decibel threshold) of the deprived Research Centre, University of tain their hearing in the normal range causes of cochlear damage include: noted in ageing central auditory neu- central auditory neurons, typically Sydney, NSW. well into old age. • Noise. rons, as it has in ageing tissues else- at the expense of frequency and tem- The normal processes of ageing • Repeated exposure to ototoxic med- where in the body. poral resolution. There is, however, affect all subsections of the ear, but it is ications. This senescent change is in addition evidence for beneficial neuroplastic- the effects on the inner ear and the • Vascular pathology. to other pathologies common in the ity when auditory input is restored, resultant sensorineural hearing loss • Inflammation from nearby middle- elderly that affect brain health, such as such as with ‘aiding’ of a previously that causes elderly patients the most ear disease. arteriosclerosis or respiratory failure. unaided ear (ie, use of a hearing aid morbidity. Presbycusis is the term used The higher incidence and greater Overall, these hearing-related changes or implanted device). to describe sensorineural hearing loss severity of presbycusis in men is are referred to as central effects of bio- cont’d next page

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HOW TO TREAT Hearing loss in the ageing patient

Classifying types of hearing loss

Based on audiology find- Hearing loss is middle-ear bones. Sen- Retrocochlear pathologies Figure 1: A: Audiogram demonstrating bands of hearing loss ings, the severity of hearing sorineural hearing loss (see table 1) are often associ- severity and notation. B: Pure tone audiogram, demonstrating a loss is described as mild, broadly refers to that due to damage ated with disproportionately largely symmetrical, down-sloping, mild-to-severe moderate, severe or pro- categorised into a of the cochlea, the cochlear poor speech understanding sensorineural hearing loss. C: A largely flat, mild to moderate, found (figure 1A). Basic nerve or higher auditory scores compared with the right-sided conductive hearing loss. D: Audiogram audiograms are used to loss of either centres. A mixed hearing patient’s actual decibel hear- demonstrating a largely flat, moderate mixed hearing loss on the left side. There is a mild-to-moderate sensorineural hearing identify and classify hearing loss implies a component of ing thresholds. Cochlear conductive or loss in most frequencies with about 20dB of conductive overlay. loss with standard notation sensorineural conductive and sen- pathology is generally associ- as indicated in figure 1A. sorineural hearing loss ated with speech under- A Hearing loss is broadly origin. (figure 1B, C, D). standing scores in line with categorised into a loss of Hearing loss in the elderly the patient’s hearing thresh- either conductive or sensori- is predominantly sen- olds, but decreased dynamic neural origin. Conductive sorineural in nature. It is range of hearing (the differ- hearing loss refers to a loss accepted that the exact site ence between the softest in the conduction of sensorineural hearing loss sound we can perceive and system of the external ear, has an effect on the type of the loudest [painful]; normal tympanic membrane and/or disability experienced. is about 120 dB).

B

Table 1: Glossary of commonly used audiology terms

Head shadow Head shadow is exactly what it sounds like, an acoustic shadow due to obstruction of sound by the head. In binaural hearing, the effect of the head shadow is vital in sound localisation. Head shadow causes particular difficulty for people with single-sided deafness.

Interaural attenuation Interaural attenuation is the sound energy lost between presentation of an auditory stimulus at one ear, and perception of the sound by the contralateral cochlea. Interaural attenuation for a given source depends on both the frequency of the sound (higher frequencies are attenuated less than lower frequencies) and the way that the sound is presented. There is no attenuation of sound presented C directly on bone. Conventional air-conduction earphones still transmit a portion of their output directly into bone, with a result that interaural attenuation of their stimulus is between 40 and 60dBHL (decibel hearing level). Inset earphones transmit very little stimulus directly to bone, with resultant interaural attenuation of >70dBHL.

Loudness recruitment Elevated hearing thresholds with a narrow dynamic range of hearing. Once above the threshold, the perceived increase in sound intensity is greater than the actual increase in sound intensity. A small increase in sound intensity above threshold can therefore lead to an uncomfortable increase in perceived sound intensity, occasionally resulting in pain.

Post-lingual deafness Refers to the onset of deafness after the time at which a patient has developed speech and language skills. Auditory memory developed between development of language and the onset of deafness has implications for hearing rehabilitation. In the context of cochlear implantation, rehabilitation can involve months of re-education/rehabilitation with an audiologist before a patient gains maximal benefit from their new hearing.

Pure tone average Average of the pure tone thresholds (in dBHL) at 500, 1000 and 2000Hz (the usual range of human communication). D Retrocochlear pathology Refers to pathology in the eighth (Cochlear) nerve or the cerebellopontine angle in the area of the eighth nerve. Gadolinium-enhanced MRI is the investigation of choice for possible retrocochlear lesions, though audiological investigations can be reasonably accurate in determining the site of eighth-nerve dysfunction.

Rollover An audiological phenomenon characteristically seen in retrocochlear pathology. The patient’s speech discrimination increases with increasing sound intensity to a point before falling rapidly with further increases.

Telecoil A telecoil is a magnetic coil within a hearing aid or speech processor for the purpose of receiving auditory information transmitted by an individual or large-area inductive loop.

Tonotopic organisation Cell populations throughout the auditory system are organised ‘tonotopically’, or according to the frequency of auditory stimulus to which they will respond. This is particularly important in the cochlea, where the basal portion of the cochlea (closest to the round and oval windows) is responsible for perception of high frequency sounds. Lower frequency sounds are perceived further towards the apex of the cochlea. cont’d page 30

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HOW TO TREAT Hearing loss in the ageing patient

Management

The effects of hearing loss on Advice a GP can give to family and friends of deaf patients the ageing patient Management of hearing loss in the ageing patient THE psychological, emotional and DO financial burdens of hearing loss • Counselling the patient about the impact of hearing loss and how it affects them • Wait until the hearing-impaired person can see you before speaking. Touch is on the ageing patient are signifi- helpful to get their attention cant and well established. Hearing loss can cause feelings of isolation, • Tips for family and friends on how to talk to the deaf patient • Position yourself close to the person when speaking both on the part of the patient and • Speak at a normal rate and try to enunciate clearly • Hearing assistive listening devices the people close to them. • Reduce background and competing noise When combined with a lack of understanding on the part of the • Alerting devices • Clue the person into any changes in the conversation topic people attempting to communicate DON’T with the patient, hearing loss • Hearing aids (air and bone conduction) • Speak from another room or while walking away strains relationships. Dissatisfac- • Speak directly into the person’s ear (this distorts the message and hides tion with, or unwillingness to use, • Hearing implants: visual clues) hearing aids can cause family mem- — bone anchored hearing implants bers and friends to feel that the • Shout (this may distort the message) — middle-ear implants patient does not care about them • Cover your mouth with your hands while speaking enough to try to communicate. — cochlear Implants • Repeat the statement if it is not understood (it is better to rephrase) Although some patients may be accepting of hearing loss, others — hybrid (half implant/ half hearing aid) cochlear implants For a downloadable PDF patient handout see: www.northsidehearing.com.au may feel that acknowledging their disability by seeking treatment is auditory alerts (ie, to dangers), and Counselling the ageing deaf patient is having trouble, educating being well fitted with hearing aids. an admission of either their age, or because of interference with par- patient, family and friends the patient about the effects of hear- The GP should not assume that may reveal their vanity. ticipation in medical and allied The GP plays a critical role in iden- ing loss as well as providing useful because the patient is hearing well Furthermore, hearing loss can health interventions. Elderly tifying and treating hearing loss in tips on how family and friends may in a one-to-one situation that no compromise a patient’s ability to patients with a hearing disability the ageing patient. Often the GP help with communicating to the problem exists. Rather, questions perform their activities of daily have also been found to have rates will be the first point of contact for deaf patient (see box above). about their hearing in real-world living as well as reducing their of depression almost twice as high a patient having difficulty hearing A good screening question for situations are far more important. enjoyment of these activities. Diffi- as those in the same age group with (or a spouse who is having diffi- the GP to ask patients troubled by After an audiogram and confirma- culties in communication can also preserved hearing.3,4 culty with their partner’s hearing). hearing loss is whether they are tion of poor hearing, a referral to jeopardise a patient’s health both Key management options are The GP can play a role in under- coping in social situations or where the ENT surgeon is generally the because of the inability to perceive summarised in the box above. standing the situations in which the there is background noise after next step.

Hearing-assistive listening devices Alerting devices

HEARING-assistive listening Figure 2: A Bluetooth hands-free adaptor. This acts as an Output from an assistive Figure 3: A: The MiniVib, an alerting device commonly used in devices can be thought of as intermediary between the Alera hearing aid (pictured) and listening device can be inde- Australia. It receives alarms from four different sources. The hearing aids for particular Bluetooth devices such as mobile phones. pendent, through a headset combination of vibration and simple colour-coded alerts are tasks and environments, (Image courtesy of GN ReSound Australia.) or earphones, or routed via helpful in dual sensory loss. B: The Lynx Tactum. This integrates designed to transmit the the user’s existing hearing up to seven different sources into a working wristwatch. Each sound from source to indi- device. input has a vibratory alert as well as a pictorial indicator on the vidual as directly as possi- The proliferation of face of the watch. (Images courtesy of GN ReSound, Sweden.) ble, therefore reducing sur- mobile phones and their A rounding noise. Devices vary increasing acceptance among greatly in design and appli- the elderly sees additional cation, but in all cases the challenges. Susceptibility to device has an input, a radiofrequency interference method of transmission and from mobile telephones an output. Input methods varies between hearing aid may be a direct connection, designs, with newer designs such as the audio output generally more immune to from a computer or televi- radio frequency. Evolution sion, or a microphone such of mobile phone technology as in a classroom FM set- has also seen other benefits, ting. such as integrated telecoils. Transmission of sound by loops. Large area loops Integration of Bluetooth con- B an assistive listening device encircle a room or public nectivity is also improving, can be wired, or wireless. space, a common example with some hearing aids WE rely on a remarkable number of acoustic signals to gain our Wireless transmission has being the transmission of including the technology for attention or alert us to danger. The inability to hear a doorbell or traditionally been through audio from a film at a connecting to mobile tele- alarm clock may be an annoyance, but the inability to hear a FM radio, line-of-sight cinema. Individual loops, phones and personal music smoke alarm can be life threatening. infrared, or through an usually in the form of a pen- devices (figure 2). Other Alerting devices are designed to convert these alerts into either inductive loop directly to a dant, allow transmission of users can use a Bluetooth- vibro-tactile or visual stimuli. Alerting devices may be specific to telecoil (see table 1, page 28) sound from personal devices enabled (ie, wireless) individ- one device or source, or may integrate monitoring of several in a user’s hearing aid or such as personal music play- ual loop system, generally sources. Portable vibro-tactile receivers are generally packaged in implant. ers to a user’s telecoil- worn as a necklace, to the form of a wristwatch or pager, while alarm-clock receivers Inductive loops can be equipped hearing aids or receive the wireless signal via are typically attached to a vibrating pad, designed to be placed individual or large-area implant. their telecoil. under the patient’s pillow (figure 3A, B).

Hearing aids

Air-conduction hearing aids behind-the-ear (BTE) and the in-the- package allows for higher output blockage in the ear, called the occlu- chal bowl (ITE), solely within the ear HEARING aids are the next step in ear (ITE) aid. gain and battery capacity. sion effect. The separation of the canal (in-the-canal [ITC] or com- hearing loss management for the eld- Patients with poor manual dexter- microphone and output also means pletely-in-canal [CIC]). Unlike ITC erly when the above options have Behind the ear ity may find BTE aids difficult to fit, that acoustic feedback is reduced. aids, CIC aids do not protrude from been exhausted and the patient still BTE hearing aids consist of a micro- but the larger package does allow the lateral opening of the ear canal has many acoustically challenging phone, receiver and processor pack- manual volume or telecoil controls In the ear and so have a clear filament attached environments. Conventional hearing age that rests behind the pinna, con- to be made larger. The ear mould has ITE hearing aids consist of a single to their body to aid removal (figure aids are referred to audiologically as nected by a polyethylene tube to a ventilation ports to allow dehumidifi- package, containing microphone, 4C). air-conduction hearing aids, with custom-made ear mould for the cation of the ear canal. The ventila- receiver, processor and output, sur- As the size of the aid package sound being amplified and transmit- amplified output (figure 4A, B, page tion ports also lessen the amplifica- rounded by a custom-made shell to reduces, so does the available output ted through the normal auditory 32). BTE aids are generally less tion of low frequencies (which are fit within a particular subsection of gain (amplification) and battery system. There are two broad types of expensive than their ITE counter- generally preserved in the ageing the external ear. The ITE can be capacity. Correct fitting of the ear- air conduction hearing aid, the parts, and the bulky size of the BTE patient); this decreases the feeling of within the patient’s ear canal and con- mould is also more critical with CIC

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and ITC aids, as inadvertent Figure 4: Comparison of air-conduction hearing aids. Table 2: Why patients may not receive approval for Who is eligible for an ventilation can lead to consid- A: A high-powered BTE hearing aid. conventional air-conduction hearing aids Australian Government erable acoustic feedback. B: A mini-BTE air-conduction hearing aid. Hearing Services Smaller aid packages also C: A completely-in-canal air-conduction hearing aid. Condition Reason for non-approval voucher? means less accessible surfaces (Images courtesy of GN ReSound). for the controls, which make Microtia or aural Abnormalities in the conformation of the • Pensioner concession card automatic volume controls A atresia pinna may make fitting of a BTE hearing holders and speech detection systems aid impossible. Narrow ear canals in invaluable. Remote controls lower grades of aural atresia make fitting • Those receiving sickness are also an option for of moulds difficult, while higher-grade allowance from Centrelink patients with limited manual aural atresias will obtain little, if any dexterity. benefit from air-conduction aiding • Gold card holders Regardless of the choice of a BTE or an ITE package, Discharging : Discharge will decrease the effective • White card holders covered an ear mould is required, • Recurrent otitis output of an air-conduction aid, while the for hearing loss and changes to the external externa presence of the mould will make effective ear in older people make this • Discharging otitis treatment of the infection impossible • A dependent of any of the process more difficult. In the media above elderly, changes in wax pro- Dermatological Dermatological conditions affecting the duction and migration, hair • Members of the Defence conditions of the ear ear canal can be exacerbated by the density and skin quality may Forces canal presence of the ear mould, humidification mean that a correct fit is dif- of the ear canal and wax obstruction ficult to achieve and ports • Those undergoing, and are frequently blocked by B Further investigation An ENT surgeon may delay approval for referred by, a government wax. required aiding pending further investigation of a vocational rehabilitation Although many older patient’s hearing loss (see table 3) service patients are eligible for gov- ernment-subsidised hearing to the underlying bone, so a aids (see box, far right), they Table 3: Red flags that warrant referral for tight-fitting metal headband is may be dissatisfied with the further assessment generally used. This headband performance of these aids. can be both uncomfortable Extra features that older Red flag Reason and aesthetically unpleasing. patients may require are avail- able with co-payments to the Asymmetrical Can be a presenting feature of a Contralateral routing government scheme. sensorineural cerebellopontine angle tumour, eg, of sound Reasons why patients may hearing loss vestibular schwannoma Contralateral routing of not receive approval for hear- sound (CROS) refers to the Associated cranial Can be due to, eg, facial nerve palsy in ing aids are shown in table 2. gathering of auditory infor- nerve deficits destructive inflammatory or neoplastic When hearing aids are mation from one ear and processes of the temporal bone appropriately fitted and tuned, C transferring it to the better about 70% of patients will hearing ear (cross-aiding). In have notable reduction in their general, bone-conduction Ear canal or middle- Can be due to, eg, squamous cell hearing-related disability, hearing aids are cross-aids, ear mass carcinoma or adenoid cystic carcinoma while just over half will note as the vibration conducted of the ear canal presenting as a improvement in their quality through bone stimulates conductive hearing loss of life. both inner ears. With air- conduction CROS aids, the Single-sided deafness Deep ear pain May be indicative of a destructive patient wears a hearing-aid Single-sided deafness may go inflammatory or neoplastic process mould in their better-hear- undiagnosed for some time involving the temporal bone ing ear, typically connected because of relatively normal to the contralaterally placed Discharging ear May be indicative of a destructive hearing on the unaffected side. microphone package by a inflammatory or neoplastic process Patients with single-sided deaf- headband. involving the temporal bone ness are difficult to fit with The same complaints about conventional air-conduction poor comfort levels and aids, as a hearing aid in the affected side. The loss of bin- tions, leading to increased hearing aids employ a system tory stimulus into the bone as cosmesis apply to air-conduc- affected ear typically provides aural hearing has been shown tiredness and frustration. of microphones and signal a vibration that is perceived tion CROS aids as to bone- a distorted sound compared to reduce the ability to localise processors, as with any other as sound by the functional conduction CROS aids, but with the normal hearing on an unseen sound in space, as Bone-conduction devices modern hearing aid, but differ cochlea(e). with the added disadvantage their opposite side. well as to decrease perception Bone-conduction hearing in the method of output. The The oscillator must be held of occlusion of the better-hear- The disability caused by of speech in noisy environ- devices may be offered to signal processor is connected firmly against the skull to ing ear’s external canal. Hear- single-sided-deafness is greater ments. Additionally, the over- patients who are not suitable to an oscillator, which when facilitate transmission of the ing benefits from CROS aids than just the inability to per- all ‘effort of listening’ is for conventional air-conduc- placed adjacent to the bone of vibratory stimulus through are thought to be modest at ceive auditory stimuli on the increased in common situa- tion aids. Bone-conduction the skull, transmits the audi- skin and subcutaneous tissue best.

Hearing implants

Bone-conduction Figure 5: The Cochlear Baha bone-anchored hearing implant sends sounds oscillator to bone eliminates sound • Inability to fit an air-conduction osseointegrated hearing directly through the skull, bypassing a defective conduction system to directly attenuation (loss of sound energy) hearing aid because of ear-canal implants stimulate the cochlea. (Image courtesy of Cochlear Corporation.) by soft tissue, said to be in the or pinna abnormalities (see table BONE-anchored hearing implants order of 10-15dBHL (decibel hear- 2). were first developed in Sweden in ing level).5 Firm attachment to the • Single-sided deafness. Auditory 1977 and have been commercially patient’s skull also allows the information gathered on the available since 1987. These devices microphone to be placed on the affected side is transmitted to the seek to build on the benefits of same side, allowing the patient to better-hearing ear through bone. bone-conduction hearing aids while hear auditory stimuli on the Although a patient may have per- reducing the perceived disadvan- implanted side. fect hearing in the opposite ear, tages. Depending on the manufacturer reducing the effect of ‘head The device consists of an external of the bone-anchored hearing shadow’ (see table 1) means that microphone, processor and oscilla- implants, ear-level or body-worn patients with a bone-anchored tor, which are usually combined in microphone and processor pack- hearing implant often notice a single package, together with a tita- ages are available, with body-worn improvements in directionality of nium coupling (the abutment) and a devices generally capable of higher hearing as well as hearing in titanium implant. The titanium outputs. Body-worn devices can be background noise. implant is inserted into mastoid or clipped onto a belt, popped in a • Mixed-hearing loss with an air- calvarial bone and allowed to shirt pocket, or carried in a pouch bone gap >30dBHL with reason- osseointegrate before being attached that hangs around the patient’s able sensorineural reserve. to the external package via the abut- neck. • Bone-anchored devices were ini- ment (figure 5). Bone-conduction devices have a tially developed for implantation This direct transmission from number of applications: cont’d next page

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HOW TO TREAT Hearing loss in the ageing patient

from previous page Figure 6: Cochlear implantation. A graphic demonstrating the Figure 8 A: An electro-acoustic stimulation system, consisting in patients with chronic sup- cochlear implant electrode array directly inserted into the of a Sonata cochlear implant with FlexEAS electrode and a References purative otitis media, in cochlea, stimulating the spiral ganglion neurons and in turn, combination of speech processor and air-conduction hearing 1. Wilson D, et al. Hearing whom frequently discharg- the cochlear nerve. (Image courtesy of Cochlear Corporation.) aid in the Duet 2 BTE package. Impairment in an ing ears made aiding of con- (Image courtesy of MED-EL GmbH.) Australian Population. ductive or mixed hearing B: A patient wearing a Cochlear Hybrid device. In: Epidemiology. Centre (Image courtesy of Cochlear Corporation.) losses difficult without wors- for Population Studies in ening the infection (see table Epidemiology, Adelaide, 2). A 1998. 2. Chisolm TH, et al. The Middle-ear implants aging auditory system: The goal of middle-ear anatomic and physiologic implants is amplification of changes and implications normal ossicular chain move- for rehabilitation. ment as an alternative to con- International Journal of ventional hearing aids in the Audiology 2003; 42:S3- treatment of patients with S10. moderate to severe sen- 3. Saito H, et al. Hearing sorineural loss. The most handicap predicts the commonly seen middle-ear development of implant, the Vibrant Sound- depressive symptoms bridge, from Med-El, uses an after 3 years in older electromagnetic driver community-dwelling attached to the incus to stimu- Japanese. Journal of the late the stapes. American Geriatric Surgery is required to place Society 2010; 58:93-97. the implant through the mas- 4. Lee AT, et al. Hearing Figure 7: A Cochlear implant device, demonstrating the Nucleus toid bone into the middle ear. impairment and receiver/stimulator package, straight ground electrode and The electromagnetic driver, precurved electrode array that is inserted into the cochlea. depressive symptoms in known as the floating mass (Image courtesy of Cochlear Corporation.) an older chinese transducer, is attached to a B population. Journal of receiver/stimulator package, Otolaryngology – Head which is placed underneath and Neck Surgery 2010; the skin, behind the mastoid 39:498-503. cavity. The external micro- 5. Tjellstrom A, et al. Bone- phone/processor unit is cou- anchored hearing aids: pled to the internal current status in adults receiver/stimulator via a and children. magnet and induction coil. Otolaryngology Clinics For a middle-ear implant the of North America 2001; patient must be fit to undergo 34:337-64. a surgical procedure and must have a healthy middle ear. Online resources Implanted devices such as • Northside Audiology: the Vibrant Soundbridge www.northsidehearing. allow treatment of moderate com.au to severe sensorineural losses • Hearing Aid Forums.com: while avoiding occlusion of www.hearingaidforums. the ear canal. Directly driving com the ossicular chain reduces the • Cochlear. Hearing and effect of acoustic distortion hearing loss: inherent in higher levels of Most cochlear nerve, completely bypassing between the middle ear and implant electrode for only www.cochlear.com/au/ amplification, with particular the conductive system (figure the mastoid air spaces) are part of the frequency spec- hearing-and-hearing-loss- advantages in amplification of implant recipients 6). Common community per- visualised. Bone is removed trum. Earlier implants and adults high frequencies. Direct stimu- each year are ception is that cochlear between the facial nerve and surgical techniques resulted • MED-EL — Hearing lation of the ossicular chain implantation is a procedure chorda tympani to allow in the destruction of any implant support: means that this is essentially adults, often for children. However, direct access into the middle residual acoustic (ie, natural) www.medel.com/int/show a single-sided stimulus and deafened by the cochlear implants were origi- ear from behind. A well is hearing during the implant 4/index/id/4/title/USER- patients can maintain two process of ageing, nally developed for adults often drilled in the skull bone procedure. Recent advances SUPPORT sound fields, with resultant with profound post-lingual to allow the implant receiver- mean that residual low-fre- • Advanced Bionics — benefits in terms of sound and who do not deafness (see table 1). Most stimulator package to be set quency hearing can be pre- Learning centre: localisation, compared with gain any benefit cochlear implant recipients into the bone. served reasonably reliably. www.advancedbionics. bone-conduction devices. each year are adults, often The cochlea is entered from An extension of this con- com/CMS/Rehab- More recently, patients have from conventional deafened by the process of the middle ear, either directly cept is combining electrical Education/Learning- been treated with a Vibrant BTE hearing aids. ageing, and who do not gain through the membrane of the stimulation of high frequen- Center/ Soundbridge device for mixed any benefit from conventional round window, or through a cies using a cochlear • Better hearing institute: or conductive losses in the BTE hearing aids. hole (a cochleostomy) drilled implant, and acoustic ampli- www.betterhearing.org mild to severe range. For this Originally, patients were adjacent to the round win- fication of low frequencies • RNID — Action on indication the floating mass required to have an unaided dow. The cochlear implant via an air-conduction hear- hearing loss: transducer is placed next to pure tone average (see table electrode (see figure 7) is then ing aid. The BTE compo- www.rnid.org.uk/ the round window in the 1) of at least 100dBHL and inserted into the lumen of the nents of the cochlear implant information_resources middle ear to provide direct of 60dBHL with best-fitting cochlea, preferably within the processor and air-conduction mechanical stimulation of the aids, along with no speech space known as the scala hearing aid are combined in round-window membrane. recognition ability. With re- tympani. Some surgeons will one package (figure 8A, B). Other strategies for middle- evaluation of results and evo- further fix the implant pack- This concept is referred to as ear implantation include lution in implant technology age in place with sutures. hybrid implantation or elec- placement of a magnet on the and surgical technique, the The skin and subcuta- tric-acoustic stimulation, ossicular chain, which is candidacy requirements have neous tissues are closed in depending on the manufac- driven by a coil, included in a relaxed substantially. layers over the cochlear turer of the equipment used. package similar in appearance implant and mastoid defect. The technique of hybrid to an ITE hearing aid. Given The surgical procedure While the patient is still implantation claims to have that the ear canal is still Most cochlear implants are anaesthetised, intraoperative the advantage of preserving occluded with these designs, inserted via a ‘transmastoid’ testing of the implant is natural hearing at lower fre- the advantages over a conven- approach. An incision is made often performed to test the quencies. This preservation tional air-conduction hearing behind the ear, and the perios- integrity of the implant. of hearing is said to improve aid are small. teum over the mastoid speech understanding in process is raised. The bone of Partial deafness cochlear noisy environments, and also Cochlear implantation the mastoid cortex is drilled implantation possibly improve musical Cochlear implants are hearing away under irrigation until Partial deafness cochlear appreciation, which is typi- devices surgically inserted into the facial nerve, chorda tym- implantation is the practice cally difficult for the conven- the cochlea. These devices pani nerve and the mastoid of electrical stimulation of tional cochlear implant directly stimulate the cochlear antrum (the connection the cochlea via a cochlear recipient. cont’d page 34

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HOW TO TREAT Hearing loss in the ageing patient

GP’s contribution

needed to provide a urine with hearing aids. Regular aid, such as either the acrylics one would hope that manu- phone users and non-users sample that I was left alone use of cerumenolytics may be or gold. Most patients with facturing costs of aids would were seen. However, there was with Mr B. It was only then beneficial for some patients, aid-related dermatitis will have fall. Overlap of technologies a trend towards an association that I realised how hard of but cerumen has protective problems related to the occlu- between hearing aids and between heavier long-term use hearing he actually was. I and clearing effects in the ear sion of their ear canal. Occlu- other devices such as mobile of mobile phones and an talked more slowly and more canal that will be lost with sion of the ear canal alters the phones and music devices increased rate of high-fre- loudly but he still found it frequent use of cerumenolyt- environment in the ear canal should further reduce manu- quency sensorineural hearing 1 DR CAROLYN BLOCK hard to make out what I was ics. Irritant dermatitis is also through humidification and facturing cost through higher losses. This study suffered saying. possible with frequent use of interruption of cerumen production volumes. This because of its small population Double Bay, NSW When Mrs B returned I these agents. migration. Excessively tight or decrease in cost for current and retrospective nature. asked her about this and the In general we would sug- mobile aids can also cause designs will inevitably be At this stage there is no con- Case study need for a hearing test and gest that prophylactic use of direct trauma to the canal skin. offset by the development and vincing evidence of a detrimen- I OFTEN find that my eld- maybe a hearing aid. Mrs B cerumenolytics is unnecessary, inclusion of emerging tech- tal effect of mobile phone use erly patients are a ‘two-for- said that Mr B had hearing with their primary purpose How often do you recom- nologies. on hearing. One caveat is the one’ deal. They always come aids but they made no differ- being softening of cerumen mend patients be reassessed When purchasing hearing use of earphones as part of a together to all their appoint- ence at all so he didn’t bother before manual removal. Olive regarding their hearing aids? aids, patients should be aware hands-free device, where the ments. Mr and Mrs B did just to wear them. I checked his oil (applied with an eye drop- A yearly visit to a hearing that the device with the most user has to be mindful of the this, but no matter which ears, and his canals were per, twice a week after pre- professional will allow for out-of-pocket expense may be recognised dangers of listening question I was asking and to filled with enough wax to warming in the patient’s hand) cleaning of hearing aids as well packed with the latest tech- at excessive volumes for long whom, it was always Mrs B make a candle or two! Both can be helpful in assisting wax as periodic re-evaluation of the nologies, but these technolo- periods. The European Union who answered the question. of them were amazed how to come out naturally. aid’s effectiveness. gies may be surplus to their requires manufacturers of Mr B seemed happy with this well his hearing aids worked requirements and may, espe- portable music players and arrangement; he never made after his ears had been The aids themselves can also There are many flaws in the cially in the case of miniaturi- mobile phones to impose a fuss — just sat there while syringed. cause irritation of the canal, current government scheme, sation, make their aids less volume limits, but this require- Mrs B did all the talking. and during treatment the users especially with an increasing user-friendly. ment has not been imposed in Mrs B often complained Questions are unable to wear their aids. proportion of elderly patients Australia. about her husband, and how Wax build-up is a constant Are there any suggestions to in the community. Can any of Have mobile phones been it was just easier for her to problem with hearing aid minimise these occurrences? the newer more effective hear- found to cause any noticeable Reference do everything, as he was use. Do you suggest regular Ear canal dermatitis second- ing aids be produced more increase in hearing loss? 1. Panda NK, et al. Audiologic becoming forgetful and dis- use of wax-clearing agents ary to hearing aids is often cost effectively to help alleviate In a frequently quoted study disturbances in long-term mobile tracted. as a preventive? multifactorial. Patients may the financial burden? in India, no significant differ- phone users. Otolaryngology — It was only during one Cerumen (wax) build-up is experience an irritant dermati- With advances in design ence in audiological measures Head and Neck Surgery 2010; consultation, when Mrs B indeed a frequent problem tis due to components of the and manufacturing processes, between long-term mobile 39:5-11.

INSTRUCTIONS Complete this quiz online and fill in the GP evaluation form to earn 2 CPD or PDP points. We no longer accept quizzes How to Treat Quiz by post or fax. The mark required to obtain points is 80%. Please note that some questions have more than one correct answer. Hearing loss in the ageing patient ONLINE ONLY — 15 April 2011 www.australiandoctor.com.au/cpd/ for immediate feedback

1. Which TWO statements are correct? the person 6. Which THREE statements are correct the ear canal a) The hearing loss of ageing is primarily of the c) When speaking to a person with hearing loss regarding in-the-ear (ITE) hearing aids? c) A middle-ear implant reduces the acoustic conductive type you should speak directly into the person’s ear a) ITE hearing aids have a single package distortion associated with high amplification, b) Presbycusis is thought to be the result of d) When speaking to a person with hearing loss containing microphone, receiver, processor and especially of high frequencies multiple, repeated insults to a patient’s you should rephrase (rather than repeat) the output d) A middle-ear implant has no advantage over a cochlear function statement if it is not understood b) The size of the ITE aid package increases the bone-conduction implant in terms of benefits c) Deterioration in the central auditory neurons available amplification compared with BTE aids to sound localisation causes difficulty in perceiving gaps in 4. Which THREE statements are correct c) Correct fitting of the ear mould is more critical sounds and localising sounds in space regarding hearing-assistive listening with ITE aids, as inadvertent ventilation can 9. Which TWO statements are correct? d) Auditory deprivation from hearing loss due devices? lead to considerable acoustic feedback a) Cochlear implants directly stimulate the to peripheral ear pathology does not affect a) They are designed to transmit the sound from d) Changes to the external ear in older cochlear nerve, completely bypassing the central auditory processing the source (eg, audio from TV) to the individual individuals make the fitting of an ear mould conductive system as directly as possible more difficult b) Cochlear implantation is a procedure only for 2. Which TWO statements are correct? b) Wireless transmission of the source sound is children a) Sensorineural hearing loss is due to damage not currently available 7. Which TWO statements are correct? c) Deaf adults who do not gain any benefit from to the cochlea, the cochlear nerve or higher c) The output can be heard through a headset or a) Patients with single-sided deafness are good conventional BTE hearing aids may benefit auditory centres earphones, or via the user’s existing hearing candidates for conventional air-conduction from cochlear implantation b) Cochlear nerve pathology is associated with device aids, achieving near-normal binaural hearing d) The procedure of cochlear implantation always speech understanding scores in line with d) Alerting devices are designed to convert b) The disability in patients with single-sided destroys any residual natural hearing the patient’s hearing thresholds auditory alerts (doorbell, smoke alarm) into deafness is limited to the inability to perceive c) Cochlear pathology is often associated with either vibrotactile or visual stimuli auditory stimuli on the affected side 10. Which THREE statements are correct? disproportionately poor speech c) Bone-conduction hearing implants have an a) The electrode of a modern cochlear implant understanding scores, compared with the 5. Which TWO statements are correct externally located package and a titanium can selectively stimulate a specific part of the patient’s hearing thresholds regarding hearing aids? coupling implanted in bone frequency spectrum d) Elderly patients with a hearing disability a) Conventional hearing aids amplify and transmit d) The microphone of a bone-conduction hearing b) A cochlear implant and an air-conduction have rates of depression almost twice as the sound through the bone adjacent to the ear implant can be located near the affected ear, hearing aid are incompatible and should not high as those with preserved hearing b) Behind-the-ear (BTE) hearing aids allow easier or elsewhere on the body be used together adjustment of volume or telecoil function than c) Asymmetrical sensorineural hearing loss can 3. Which TWO statements are correct? in-the-ear (ITE) aids 8. Which TWO statements are correct? be a presenting feature of a cerebellopontine a) If the patient is hearing well in a one-to-one c) Ventilation ports placed in the ear-mould a) A bone-conduction hearing implant does not angle tumour situation with the GP, it is unlikely there is a component of BTE aids increase the improve directionality of hearing in patients d) A discharging ear with hearing loss may be functionally significant hearing loss amplification of low frequencies with single-sided deafness due to a destructive inflammatory or b) When speaking to a person with hearing d) Separation of the microphone and the output b) Middle-ear implants amplify normal neoplastic process involving the temporal loss you should position yourself close to of BTE aids reduces acoustic feedback ossicular chain movement without occluding bone

CPD QUIZ UPDATE The RACGP requires that a brief GP evaluation form be completed with every quiz to obtain category 2 CPD or PDP points for the 2011-13 triennium. You can complete this online along with the quiz at www.australiandoctor.com.au. Because this is a requirement, we are no longer able to accept the quiz by post or HOW TO TREAT Editor: Dr Giovanna Zingarelli fax. However, we have included the quiz questions here for those who like to prepare the answers before completing the quiz online. Co-ordinator: Julian McAllan Quiz: Dr Giovanna Zingarelli

NEXT WEEK The next How to Treat begins a two-part series focusing on retinal conditions. The authors are Associate Professor Samantha Fraser-Bell, Sydney Eye Hospital; Save Sight Institute, Univer- sity of Sydney; and Royal North Shore Hospital, NSW; and Professor Mark Gillies, Sydney Eye Hospital and Save Sight Institute, University of Sydney, NSW.

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