Amplification - Special Applications Flashcards
What are 5 special HA applications?
1) frequency transposes
2) CROS
3) bone conduction
4) BAHAs
5) ME Implants
What are frequency transposers?
Move info from one frequency region to another
What do frequency transposed commonly do? Why?
Move high freq speech cues down to lower freq regions, because listener has better sensitivity there
What does CROS stand for?
Contralateral Routing of Signal
What are CROS systems designed for?
For people with one normal ear and one unaidable ear
What do CROS systems do?
Pick up sound from the poor ear and deliver it to the good ear
In a CROS system where are the mic and receiver placed and how is the sound transmitted?
Mic is in the poor ears HA
Receiver is in the good ear HA
Sound is transmitted between them via a wire or via FM radio signals
What is a specific type of CROS system?
Transcranial
What is a transcranial CROS system?
A high gain HA is fit in the poor ear and then is transferred to the good ear using bone-conducation
When individuals with conductive HL do need HAs/amp what special application can we use?
Bone conduction
What do HAs we fit those with conductive losses do?
Overcome the conductive component of an HA and directly stimulate the inner ear
What are 2 cases when conventional HAs wont work for hearing losses?
1) chronically draining ears
2) abnormalities of the external ear
When conventional HAs dont work what do we use?
Bone conduction HAs
How do bone conduction HAs work?
The standard air-conduction receiver is replaced with a bone-conduction receiver that oscillates the mastoid
What are 2 issues of bone-conduction HAs?
1) sound quality
2) uncomfortablitiy
Why might bone conduction HAs be uncomfortable?
Metal headband and coupling of oscillator to the mastoid
Why can sound quality be an issue in bone conduction HAs
The dynamic range and frequency response of the bone-conduction oscillator is not as good as an air-conduction receiver
What solves the sound quality and uncomfortability issues with bone conduction HAs?
bone-anchored HAs
How does a BAHA work?
A titanium screw is surgically implanted into the temporal bone behind the pinna, with the processor/vibrator attached to the screw, and the sound vibrations are passed through it into the temporal bone
What were BAHA HAs originally designed for?
Individuals with conductive lose who were candidates for bone conduction HAs
BAHAs are also approved for people with _______-_______ _________
Single-sided
Deafness
How do BAHAs work for individuals with single sided deafness?
The sound is transmitted to the better ear from the processes on the “dead” ear side
What are the 2 advantages of BAHAs over bone conduction HAs?
1) Better comfort
2) better sound quality
What is the advantage of BAHA over a transcranial CROS?
Better transmission of sound via bone-conduction
What are the 2 disadvantages of BAHAs?
1) surgical procedure
2) cost
What are the 2 types of special implantable HAs
1) MEI
2) BAHA
What are middle ear implants designed for?
Replacements for standard HAs for individuals with sensorineural HL
What is the basic premise of how MEIs work?
The devices drive the ossicles directly
What are 4 good potentials of MEIs?
1) increased clarity
2) increased understanding in noise
3) decreased feedback
4) no occlusion effect
