Module 5 Flashcards
What is feedback and what can we do about it?
-Feedback occurs as a result of sound (attempting to be delivered to the ear canal) leaks either around or through the earpiece, gets picked up and re-amplified by the microphone system, and re-amplified again, and again, and again
-Results in an unpleasant sound
-Hearing aids often have “feedback management systems” to avoid this, but we can minimize the potential by choosing appropriate coupling, venting, and physical fitting of device or earmold to ear
Why does the occlusion effect happen? How do we address it?
-Low frequency sounds (vowels in particular) have high SPL, and those high intensity sounds conduct through the mandible to the cartilaginous portion of the ear, causing vibration in the ear canal itself
-Normally these sounds would escape through the ear canal and do not bother us, but hearing aids can trap the sound energy and redirect it to the auditory system
-Increase can be about 20-30 dB
-Result: own voice sounds loud, hollow, boomy, chewing becomes aggravating
-How to address: modify to enlarge the vent, “open” the fitting, adjust low frequency gain
What batteries are used to power hearing aids?
-Zinc-air batteries for safety and efficacy
-Typically last 7-10 days (depending on amount of time worn)
Disposable Vs Rechargeable pros & cons
-Rechargeable:
·Pros: easier to use, minimizes waste
·Cons: need to be recharged every night
-Disposable:
·Pros: charge lasts longer
·Cons: batteries could be mistaken for pills
Ideal candidates for BTEs
-Pediatrics (earmolds, robustness, retention)
-Adults with configurations up to profound hearing losses
-Patients who require more of a physical device to “handle”
-Patients with excessive moisture and cerumen (electronics are not in the ear, earmold can be cleaned)
-Molds can be made from a variety of material for optimal comfort
Key Features of RICs
-Cosmetically appealing (small casing behind the ear, receiver wire is discreet)
-Generally can fit up to a moderately-severe hearing loss (dependant on the receiver and coupling)
-Receivers can be interchanged to accommodate different configurations (or changing hearing thresholds)
-In clinic, these devices can be stocked for same day fitting if custom shell is not required
-Recharcheable/battery options available
-Colour choices available
-Less overall gain compared to standard BTEs
Ideal candidates for custom aids (IICs, CICs, ITCs, and ITEs)
-Patients who cannot support an aid on the ear, or have a preference for the full device off the pinna (glasses, masks, helmets, etc)
-Patients whose dexterity limits them from handling two components
-Limited colour choices
-Generally, the larger the custom hearing aid, the greater the hearing loss it can accommodate
-Custom hearing aids can generally accommodate mild to severe hearing losses (dependant on the receiver power selected)
Who would benefit from an extended wear device (such as lyric)?
-Fitting range
-Contraindications
-Health considerations
-Lifestyle considerations
-Lyrics have no venting but occlusion effect is minimal/absent since it’s so close to the TM
What factors do we consider when selecting an appropriate hearing aid style (both audiological and non-audiological)?
-Audiological:
·Audiogram configuration to determine amount of gain at different frequencies
·Health of the ear
·Cerumen, moisture
·Physical shape of the ear
-Non-audiological:
·Preference and comfort of the patient
·Dexterity of the patient
·Other features desired (bluetooth, FM systems, partner microphones, TV connectors, etc)
·Face masks, glasses, helmets
OTC Hearing Aids
-OTC hearing aids are devices that may be purchased without the oversight of a hearing dispenser or physician
-Not available in canada yet (health canada), FDA has approved these devices in the USA
·Over the age of 18
·”Perceived” mild to moderate hearing loss
