Specialist Hearing Aids Flashcards
what are some types of specialist aids?
- Body Worn Hearing Aids
- Spectacle Hearing Aids
- Bone Conduction Hearing Aids
- Bone Anchored Hearing Aids
- CROS and BiCROS aids
- Cochlear Implants
- Middle Ear Implants
What are body-worn hearing aids?
- Body-worn hearing aids consist of a small box housing the microphone and amplifier, which is clipped to clothing or placed in a pocket.
- Sound is transmitted to the ear via a lead, with the receiver held in place by an earmould.
Who might benefit from using body-worn hearing aids?
They can be beneficial for clients who struggle with managing controls on behind-the-ear (BTE) aids or positioning the BTE over the ear, such as those with poor vision or dexterity.
What advantages do body-worn hearing aids offer?
- Body-worn aids are suitable for mild to profound hearing losses as they can achieve high output levels with less risk of feedback, thanks to the separation of the microphone and receiver.
- However, they are less commonly used now compared to other types of hearing aids.
What are spectacle aids?
- Spectacle aids are spectacles with hearing aids integrated into the frames.
- They typically feature behind-the-ear (BTE) aids, although body-worn (BW) aids or bone conduction can also be used.
- Sound is transmitted to the ear via tubing and earmoulds for BTE-style aids.
What are some drawbacks associated with bone conduction hearing aids?
- Bone conduction aids often have poor cosmetic appeal and can be uncomfortable to wear, which may limit their widespread use.
Who might benefit from using spectacle aids?
- Spectacle aids are useful for individuals with moderate to profound hearing losses and vision problems, particularly those who wear both hearing aids and spectacles throughout the day.
Who might benefit from using bone conduction hearing aids?
- Individuals with conductive hearing losses, particularly those with conditions like atresia of the external auditory canal or chronic ear infections, may benefit from bone conduction aids.
- They are also useful for those with single-sided deafness.
What are some disadvantages of spectacle aids?
Spectacle aids are not widely popular due to their bulky frames, which can be heavy and uncomfortable for some users.
What are bone conduction hearing aids?
- Bone conduction hearing aids are suitable for conductive hearing losses when conventional aids are not viable, such as: in cases of atresia of the external auditory canal, chronic ear infections, or single-sided deafness.
- They typically consist of a bone conductor mounted on a rigid headband or a “Softband” headband for children, which keeps the conductor in place.
What are Bone Anchored Hearing Aids (BAHAs)?
- BAHAs operate on the same principle as Bone Conduction Hearing Aids but involve a surgical procedure to attach a small titanium pin to the skull.
- Once healed, a small box containing the microphone and amplifier is connected to the pin.
- Sound is delivered from the hearing aid to the inner ear via bone conduction through the titanium pin.
How do BAHAs function compared to traditional hearing aids?
- BAHAs deliver sound through bone conduction to both cochleae, allowing both to respond to louder sounds.
- They are suitable for average bone conduction thresholds up to 65dB HL and air-bone gaps of around 30dB on average.
- BAHAs can provide less gain than traditional hearing aids for the same degree of hearing loss because they bypass the traditional air conduction route.
What are the main advantage of BAHAs?
- BAHAs offer a solution for individuals with conductive or mixed hearing losses who may not benefit from traditional hearing aids.
- They can also be beneficial for those with single-sided deafness or chronic ear infections.
What are some disadvantages of Bone Anchored Hearing Aids (BAHAs)?
*Possible problems at the site of the pin:
- Infections
- Growth of the skin flap
*Cannot restore true binaural hearing:
- The aid does not stimulate each ear separately with signals from either side of the head
- The patient loses the advantage of binaural listening
What does CROS stand for?
CROS stands for Contralateral Routing Of Signals.
How does a CROS aid work?
Sounds arriving at the worse ear are transmitted to the receiver in the better ear without amplification, just transferred from one ear to the other.
What does a CROS aid consist of?
A CROS aid consists of a microphone worn on the worse ear connected to a receiver worn on the better ear with an open mould.
Who is CROS suitable for?
CROS is suitable for patients with “Single Sided Deafness,” which is a severe to profound unilateral sensorineural loss where the hearing in the better ear is normal or has mild loss.
Are CROS aids typically wired or wireless?
While CROS aids can be wired, wireless systems are much more common.
what are some advantages of CROS aids?
- Sounds can be heard no matter which side they are from.
- Some patients report sound localisation is possible due to differences in sound quality and the timing of sounds arriving at the ear.
- Wireless versions are less visible.
what are some disadvantages of CROS aids?
- If the hearing in the better ear is particularly good then the wearer may find the quality of sound from the CROS aid unacceptable.
What does BiCROS stand for?
BiCROS stands for Bilateral Contralateral Routing of Signals.
What does a BiCROS aid consist of?
A BiCROS aid consists of a microphone worn at each ear, with an amplifier and receiver at the better hearing ear.
How does a BiCROS aid work?
Sounds arriving at both ears are amplified before being delivered to the better ear.
How does a cochlear implant work?
Sound from the external processor is delivered electromagnetically to the electrodes, which electronically stimulate the hearing nerve.
What does the cochlear implant procedure involve?
- The procedure involves an operation to insert a chain of electrodes into the cochlea (specifically the scala tympani).
- Once healed, an external sound processor is attached.
what are some advantages of BiCROS aids?
- Sounds can be heard no matter which side they are from
- Can now get wireless versions via Bluetooth which are less visible
Who are cochlear implants suitable for?
- Individuals with bilateral severe to profound hearing losses where normal hearing aids provide little benefit.
- Those who get some benefit from a hearing aid or have some hearing but are missing significant parts of the speech spectrum.
- People with auditory neuropathy, who may have good hearing but cannot understand speech (more research needed).
what is a disadvantage of BiCROS aids?
- Signal from the worse hearing side reduces the clarity of the signal from the better side
Who benefits from a Cochlear Implant?
- People who have lost their hearing after acquiring normal speech and language.
- Children or infants who are born hearing impaired or lose their hearing before acquiring normal speech and language ability.
*Note: The longer the duration of profound deafness, the harder it is to learn to hear with an implant.
What are the 2019 NICE guidelines for cochlear implant candidacy in the UK?
- For individuals hearing only sounds equal to or louder than 80 dB HL at two or more frequencies (500 Hz, 1,000 Hz, 2,000 Hz, 3,000 Hz, and 4,000 Hz) bilaterally without acoustic hearing aids.
- For adults, a phoneme score of 50% or less on the Arthur Boothroyd word test presented at 70 dBA (in the best-aided condition).
- For children, speech, language, and listening skills that are not appropriate to their age, developmental stage, and cognitive ability.
What peripheral factors can affect the outcomes of cochlear implants?
- Poor neural survival in the spiral ganglion
- Degeneration of auditory nerve cells
- Cochlear pathology (e.g., bone growth)
What central factors can affect the outcomes of cochlear implants?
- Degeneration of central auditory pathways
- Plastic changes in language areas of the brain
How has the criteria for cochlear implantation evolved over time?
The criteria for cochlear implantation have relaxed as research indicates that individuals with more residual hearing often achieve better outcomes with an implant compared to those without.
How might cochlear implants benefit individuals with auditory neuropathy?
Cochlear implants can be beneficial for individuals with auditory neuropathy by improving their speech understanding and communication abilities.
How can cochlear implant sound be effectively combined with other forms of hearing assistance?
Cochlear implant sound can be successfully combined with hearing aids and residual hearing, offering a comprehensive approach to auditory rehabilitation.
What are the options for individuals considering both a hearing aid and a cochlear implant?
Options include bimodal hearing, where a hearing aid is worn in one ear and a cochlear implant in the other, or electroacoustic hearing, where both a hearing aid and a cochlear implant are used in the same ear.
What challenges exist regarding the funding of cochlear implantation?
Funding poses a significant challenge as the assessment, surgical, and rehabilitation processes associated with cochlear implantation are expensive.
What is a Middle Ear Implant and how does it improve hearing?
A Middle Ear Implant is a mechanical device surgically implanted in the middle ear that improves hearing by vibrating the ossicles in response to sound.
Where is the sound processor for a Middle Ear Implant located?
The sound processor is situated on the skin of the head.
What components are implanted under the skin in a Middle Ear Implant?
A receiver is implanted under the skin.
To what part of the ear is the device driver of a Middle Ear Implant attached?
The device driver is attached to the ossicles.
How are the components of a Middle Ear Implant connected?
Wires connect the receiver to the device driver.
How do Middle Ear Implants work?
- Sound is collected by the sound processor.
- The sound is processed (amplified) and transmitted to the receiver beneath the skin, similar to a cochlear implant.
- The electrical signal passes through connecting wires to the driver.
- The driver converts the electrical signal into mechanical movement.
- The mechanical movement moves the ossicles.
- The movement of the ossicles stimulates the cochlea in the normal way.
Who is suitable for a Middle Ear Implant?
- People with mild to severe sensorineural or mixed hearing loss who have:
- Earmould allergies
- Skin problems in their ears
- Outer ear infections
- Narrow, collapsed or closed ear canals, or malformed ears
- Excessive wax production
- Excessive perspiration affecting hearing aid use
- There must be no active infection or chronic fluid in the middle ear
What is the pathway for getting a Middle Ear Implant?
- Detailed assessment by Audiology and Ear Nose and Throat to ensure suitability.
- If the person consents, then surgery is booked and carried out.
- The implant is turned on 8 weeks after surgery.
- Fine tuning is carried out 4 weeks later.
- Additional hearing assessment is conducted to check the patient’s benefit from the device.
