Hearing aids Flashcards
Describe normal hearing physiology.
- Sound waves –> ear canal
- TM vibrates
- Osscicles vibrate (malleus –> anvil –> stapedius)
- Oval window vibrates –> changes in cochlea fluid pressure
- Pressure change is sensed by stereocilia in Organ of Corti
- Stereocili produce electrical signals –> cochlea ganglion (auditory nerve)
- Impulses –> auditory nerve pathways –> auditory cortex
- You perceive sounds
What is the gold standard for hearing testing?
Pure tone audiometry (exclude impacted earwax and infections like otitis externa first)
What are the other tests for hearing loss?
- Audiometry brainstem response
- Acoustic reflex response
- Bone conduction testing
- Play audiometry
- Tympanography
What does Rinne’s positive mean?
Normal i.e. air>bone conduction
What is the difference between conductive and sensorineural hearing loss? What is the usual pattern of mixed hearing loss?
What medication may be tried initially to treat idiopathic sudden sensorineural hearing loss?
Steroids
List different options for hearing amplification in adults.
Acoustic or bone conduction hearing aids
Hearing implants
* Cochlear implants
* Bone-anchored hearing aids
* Middle ear implants
* Auditory brain stem implants
Assistive listening devices
Communication strategies
What are the indications for hearing aids?
- Hearing loss which affects ability to communicate and hear - usually a minimum of 10dB over 2-3 frequencies
- Reduced awareness of warning sounds and the environment
- Reduced appreciation of music
What kind of settings exist on hearing aids?
Directional microphone and noise reduction settings whihc help the person hear in background noise
Patient should learn how to use these to meet their needs
Give some examples of assistive listening devices.
Personal loops
Personal communicators
TV amplifiers
Telephone devices
Smoke alarms
Doorbell sensors
Government, social services, fire service can provide these.
When should you follow up a patient with new hearing aids?
6-12 weeks to check for concerns
Do hearing aids restore hearing to normal?
No - common misconception; only restore hearing to about one half of the loss e.g. 60dB hearing loss may be restored to 30dB
Describe the different styles of hearing aids.
Not all patients are candidates for small devices. BTE devices may be needed to generate enough power for better hearing. Smaller devices also have fewer features.
List 3 types of hearing implants.
Bone anchored hearing aids (BAHA)
Cochlear implants
Auditory brainstem implants
Middle ear implants
Which two types of hearing implants have this or similar appearance?
BAHA - picks up sounds and sends it to inner ear by vibrating the bones near your ear
MEI (middle ear implant) - device picks up sound and turns it into an electrical signal that is sent along a wire in the skin to the inner ear bones
Which two types of hearing implants have this or similar appearance?
**Cochlear implant **- microphone connected to device placed in skull that sends signals to the cochlea
**Auditory brainstem implant **- same as above but there are problems with the auditory nerve so signal is sent straight to the brainstem (not restorative but improves hearing to a degree)
What are the indications for cochlear implants?
Sensorineural hearing loss - best candidates are those who are postlingual (speech and language developed before the hearing loss)
Partial deafness
NB: cochela with semicircular canals is part of the inner ear
