csd 3000 deafness in society topic 8 hearing aids and assistive technology
Post on 21-Dec-2015
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Modern Hearing Aid Design
MiniturizationEnhanced signal processing
Multiple memories Noise reduction Feedback control Programmability Digital processing Multiple channels
Important Hearing Aid Components
1. BatteriesSizes and materials
2. MicrophonesDirectional and omnidirectional
3. Amplifiers4. Receivers
External air conduction, bone conduction, vibrotactile
Other Optional Features
1. On/off switch2. Telecoil
Separate circuit to use with a telephone receiver or an induction loop system
Reduces feedback and improves interference from background noise
3. Volume Control4. Earmold
CD-ROM Ch.07.06 shows some examples of common earmold styles
CD-ROM Ch.07.07 shows a video example of taking an earmold impression
Hearing Aid Fitting Considerations
What does the audiologist consider when making the recommendation for amplification?
1. Hearing aid style
Major Hearing Aid Styles
1. Body hearing aids2. Eyeglass hearing aids3. Behind the ear hearing aids4. In the ear hearing aids5. Completely in the canal hearing aids
CD-ROM Ch.07.01 illustrations of every angle of BTE, ITE, ITC, and CIC
Body and Eyeglass Hearing Aids
Popular in the1950’s and 1960’s CD-ROM Ch7.03 shows image of body hearing
aidReceiver is externalNeeds an earmold
AdvantagesHigh gain, no feedback, large controls
DisadvantagesStigma, monaural fittings only,microphone placement
Eyeglass styleAll components are internal but breakdown is
common
Behind the Ear Hearing Aids
All hearing aid components built into a case that fits behind the ear
Couples to the ear via earmold CD-ROM Ch.07.04 Advantages
1. Flexibility2. Good choice for kids3. Compatibility with direct audio input4. Good feedback control5. Microphone placement6. True binaural fittings7. Durable
In the Ear Hearing Aids
All hearing aid components fit completely in the ear
CD-ROM Ch.07.05Biggest advantage is customizing
the hearing aid to the individual
Completely in the Canal Hearing Aids
All hearing aid components fit completely in the external canal
CD-ROM Ch.07.01 Advanages
Easy to use, Reduction of occlusion effect, Reduced feedback, Improved localization ability, Less gain needed, No wind noise, No cerumen problem, Easy use with phone, Invisible, Greater high frequency emphasis
DisadvantageSize demands
Hearing Aid Fitting Considerations
What does the audiologist consider when making the recommendation for amplification?
1. Hearing aid style2. Level of technology
Hearing Aid Technology
1. Analog Oldest form of signal processing The signal is processed in a manner that is
continuously varying over time
2. Programmable Uses analog signal processing with digital
control
3. Digital Signal is digitized, manipulated, then
converted back to analog form
Hearing Aid Fitting Considerations
What does the audiologist consider when making the recommendation for amplification?
1. Hearing aid style2. Level of technology3. Monaural vs binaural fitting
Advantages to Binaural Amplification
1. Localization2. Binaural summation3. Elimination of a bad side4. Binaural squelch5. Auditory deprivation
Koop video
Other Kinds of Amplification Devices
Tactile hearing aids Used by individuals who can’t benefit
from traditional amplification Delivers vibrotactile stimulation Limited frequency resolution Main advantage is as a supplement to
visual and contextual cues
Other Kinds of Amplification Devices
Implantable hearing aids Middle ear implants Bone-anchored hearing aids Cochlear implants
Cochlear ImplantsInternal components
Internal receiver Electrode array CD-ROM Ch.07.10
External components Microphone Connecting cables Speech processor Transmitter CD-ROM Ch.07.08 shows first body worn speech
processor CD-ROM Ch. 07.09 is typical earlevel processor
What the Major Components Do..
MicrophoneSpeech processorTransmitterElectrode arrayCD-ROM Ch.07.11 illustrates what
the implant looks like worn
Wireless Amplification Systems
Environmental factors that make speech understanding difficult
1. Reverberation2. Background noise
CD ROM Ch.07.15 and Ch.07.16 illustrate typical listening conditions in a classroom
Major Types of Wireless Systems
FM systems Personal FM trainers CD-ROM Ch. 07.12 shows an example Soundfield FM systems
Infared systemsInduction loop systemsCD-ROM Ch.07.13 audio example