Chapter 3 : Adult Sensorineural Hearing Loss Flashcards
linear amplification
Oldest type of hearing aid amplification/amplifies all inputs the same amount / does not address nonlinear nature of SNHL / uses peak clipping to prevent LDL / causes some distortion at high input levels
Term
ALD (assistive listening devices), examples
TV ears /fm system / alarm devices / caption call
distortion
makes things louder but not clearer and hard to hear in background noise
Hearing loss effects how many people
32 million
what microphone mode best helps a user in noisy situations
directional
how many people use hearing aids
4.5 million
basic hearing aid structure
acoustic to mechanical
mechanical to acoustic
boosts electrical signal
electric to acoustic
ITE Cons
visible hearing aid does not take advantage of pinna and concha / one piece design means it has to be sent in for common repairs like cerumen and moisture / need some dexterity to insert
BTE Cons
large size / uncomfortable / does not take advantage of pinna and concha / mic above pinna is vulnerable to scalp sweat
ITC Cons
easily dislodged / need dexterity to insert, remove, and adjust
Digitally Controlled Analog
multiple parameters can be adjusted under computer control / allows more options in smaller size aids / one size fits all / can be adjusted easily as hearing loss progresses or fluctuates / memories for special listening situations
Microphone Stage
acoustic to mechanical / mechanical to electric
Amplifier Stage
boosts electrical signal
What is Peak Clipping
when a signal is so loud a hearing aid does not reproduce that sound to prevent LDL
Middle Ear Implant
Attached to the tympanic membrane, ossicular chain, and window membrane / the vibrant sound bridge is a middle ear implant / transformation of sound vibrations through electromagnetic device which directly move the ossicular chain / eliminates feed back, occlusion effect / cuts down on distortion
What is a FM System
a wireless system that allows the transmission of a signal from a person wearing a microphone to a hearing aid user
Ossicular Chain
3 bones in the middle ear (malleus, incus, and stapes) that connect the eardrum to the inner ear and help to amplify sounds
What is the las stage before output to the external auditory meatus ?
Receiver Stage
ITE Advantages
fits in concha / mic at ear canal level / mild to severe hearing loss
When are hearing aids not enough
Attention Sounds
Benefits of Cochlear Implants
can hear conversation and environment at comfortable levels / can hear warning signals / most have improved lip reading / improved communication in quiet and noise without lip reading / 35 - 51% can use phone better / better sentence recognition scores
How does a cochlear implant work
inner coil is placed in a cavity in the skull during surgery / electrode array is placed through a cochleostomy. into the scala tympani / multichannel multi-electrode implants take advantage of tonotopic organization of the cochlea
Analog
receivers and mics are analog / converts acoustic to mechanical to electric signal and back
What is Attentuation
loss of auditory sensitvity
What is recruitment
very small amount between most comfortable and leas comfortable level
FMT
Floating mass transducer is a small portion of the middle ear implant that connects the implant to the stapes
What part of a cochlear implant is placed into the cochlea
implanted electrode array
what % use hearing aids
10-20%
Name some implantable devices
bone anchored hearing aids / middle ear implants / cochlear implants / canal implants
what type of amplification amplifies soft speech, average speech, and loud speech the same
compression
which stage transforms acoustic, mechanical, and electrical signals
microphone stage
What is ALD
Assistive listening devices provide assistance for special occasions
CIC Cons
need extremely good dexterity to place and remove / easily lost due to small size / some circuitry not available in this size / feedback can be an issue / need to teach patient how to adjust, insert, remove, and clean
Amplifier Stage
boosts electrical signal
Receiver Stage
electrical to acoustic
ITE Cons
visible / doesn’t take advantage of pinna and concha / one piece design means the whole thing needs to be sent back for repairs for common problems like cerumen and moisture / need some dexterity to insert
ITE Benefits
fits in concha/ mic at ear canal level / mild to severe hearing loss
CIC Benefits
hidden in canal / full effect of auricle / receiver closer to tympanic membrane so requires less amplification
BICROS
Use with bad hearing ear and worse hearing ear /, signal is sent from worse ear to bad ear / provides amplification to better hearing ear
Year first all transistor hearing aid
1953
Adult Selection Criteria for Cochlear Implants
bilateral severe to profound hearing loss / minimal benefit to conventional hearing aids / no medical contraindications for surgery / results best in post-lingual hearing loss
Receiver Stage
electrical to acoustic
Why do implants take advantage of tonotopic organization in the cochlea
multi-electrode implants in the cochlea are for specific frequencies and location is approximated by tonotopicity
Microphone Stage
acoustic to mechanical / mechanical to electric
3 factors of SNHL
attenuation recruitment distortion
CROS
Route signal from one ear to the other/ used with one good hearing ear and one bad hearing ear / prevents head shadow effect / mic at bad ear sends signal to good ear
What is dynamic range?
How soft and loud someone can hear and everything in between
DSP
Latest technology / convert sound to numeric data / higher fidelity sound / allows for more complex algorithms for control of environment and noise
Which hearing aids take advantage of the Pinna and concha
ITE ITC CIC
People with hearing loss suffer from
emotional social communicative dysfunction
What circuitry allows for an individuals dynamic range
Compression
What component of SNHL does LDL indirectly measure
recruitment
Three Main parts of cochlear implant
microphone speech processor implanted electrode array
Which hearing AIDS require a custom ear mold
BTE / ITC
ITC advantages
Only face sticks out into concha / wide range of hearing loss / mic at opening of ear canal / takes advantage of pinna and concha
What implant utilizes an electromagnetic device to vibrate the ossicular chain
Middle ear implant
Which do patients tend to prefer more peak clipping or nonlinear dynamic compression
Compression
