HA Technology Lecturer: Christian Pelzmann Hearing-Aid Technology Subjects • Development of Hearing-Aid Technology • Parts of the Hearing-Aid • Different Types of Hearing-Aid • Use of the Types of Hearing-Aid • Possibilities of Modern Hearing-Aid Technology Hearing-Aid Technology • Development of HA Technology • Parts of the Hearing-Aid • Different Types of Hearing-Aid • Use of theTypes of Hearing-Aid • Possibilities of Modern Hearing Aid Technology Hearing-Aid Technology • Development of HA Technology • Parts of the Hearing-Aid • Different Types of Hearing-Aid • Use of the Types of Hearing-Aid • Possibilities of Modern Hearing-Aid Technology Parts of Hearing-Aids Block Diagram of the Hearing-Aid Microphone Amplifier Receiver Parts of Hearing-Aids - Microphone Microphone picks up soundwaves and converts them into electric signals Microphone Connections Pre-amplifier Wire / Electret Sheet (Live) Membrane Front Space Parts of Hearing-Aids Function of the Microphone Live Plate Membrane Air Space Soundwaves Transferral of > 10,000 Hz Parts of Hearing-Aids - Receivers Characteristics of Microphones: •Very small design possible •Hearing-aids normally contain 2 microphones (directional effect) •Microphones are sensitive to moisture, HA sound is muffled by dirt •In wind the microphones make noises (turbulence) Parts of Hearing-Aids - Amplifiers Amplifier amplifies the electrical signal coming from the microphone. The modified signal is passed on to the receiver. Characteristics of Amplifiers: •The entire signal processing is integrated here (fully digital) •Adaptation of the hearing-aid to hearing ability •Documentation of the adaptation steps possible through NOAH •At least 2 channels – high-frequency and low-frequency •Restriction of output sound pressure level Parts of Hearing-Aids - Receivers Electrical signals are converted back into soundwaves in the receiver Connections Coil Plastic Rivet Membrane Magnet Holder Parts of Hearing-Aids - Receivers Function of the Receiver Transferral of up to 10,000 Hz Parts of Hearing-Aids - Receivers Characteristics of Receivers: •Different sizes yield different performances – powerful receivers for powerful devices •Large receivers do not have a high frequency range (only up to approx. 6,000 Hz) •Small receivers do not have high performance for e.g. musicians (CIC not good) •There is usually hearing protection for the receiver (IE devices) •Membrane can be destroyed in the case of operation at the performance limit •Receivers can be destroyed by moisture (cerumen, sweat) Structure of a Behind-the-Ear Hearing-Aid Microphones Volume Adjuster Ear Hook Amplifier Receiver/Loudspeaker Programme Telephone Coil Switch Battery Contacts Battery Drawer Parts of the BTE Hearing-Aid - Housing: all parts of the hearing-aid are housed here - Ear hook: this is for joining the hearing-aid to the otoplastic and passes the sound on from the receiver, it can contain dampers - Volume adjuster – rocker or wheel – the customer can use this to influence the volume - Programme switch – the customer can use this to select the spec. programmes - Telephone coil – this picks up all magnetic waves, e.g. in the cinema, theatre and public buildings -Battery contacts/drawer – with these, the battery is held in place and electricity is supplied to the amplifier Parts of the Hearing-Aid – BTE Device Earpiece Microphon Volume e Adjuster T-Coil Receiver Housing Amplifier Switch Battery Battery Contact Drawer E.g.: / Oticon Personic / Phonak / Widex Senso C8T+ Parts of the IE Hearing-Aid - Housing shells: individually produced, there must be space for all parts - Faceplate: the part that one sees from outside when the IE hearing-aid is worn in the ear – can be flesh-coloured or brown (CIC) -Ventilation: for equalisation when worn in the ear. Produce as open as possible. -Electronics carrier: carries the amplifier, is latched in the faceplate Parts of the Hearing-Aid – IE-Device Faceplate Housing Shell Ventilation Receiver Battery Drawer Microphone Amplifier Electronics Carrier E.g.: Widex Senso Cx+ / Senso CIC+ Hearing-Aid Technology Exercise: Parts of a Hearing-Aid Task: Write the names of the parts of a hearing-aid onto the sketch provided Duration: 20 min. Hearing-Aid Technology • Development of HA Technology • Parts of the Hearing-Aid • Different Types of Hearing-Aid • Use of Types of Hearing-Aid • Possibilities of Modern Hearing-Aid Technology Hearing-Aid Technology • Behind-the-Ear Hearing-Aid - standard - open • In-the-Ear Hearing-Aid – ITE/ITC hearing-aid – CIC hearing-aid Hearing-Aid Technology Behind-the-Ear Hearing-Aid Open Solutions Power Hearing-Aids Design Solutions Hearing-Aid Technology – BTE Hearing-Aids Advantages: • Use of directional microphones possible • Open fits possible • Enough space for latest developments • From small devices to power solutions • Universal use thanks to higher performance (suitable for all kinds of hearing loss) • Cosmetic solution possible thanks to tube systems • All control elements present • Connection of external devices via DAI possible • Replacement device can be provided in case of repairs Hearing-Aid Technology – BTE Hearing-Aids Disadvantages: • Location of the microphones above the ears not ideal • Wind noises are picked up strongly • Resonances due to conveying of the sound via tube and otoplastic Hearing-Aid Technology – ITE Hearing-Aids Distinguished by size: CIC MIC • Auditory Canal Hearing-Aids (CIC/MIC) (Completely in canal / Minicanal) – cosmetically discreet – ZL10 battery – automatic • ITC / ITE – Hearing-Aids (In the canal / In the ear) – control elements (Vc) possible ITC – ZL312 battery • Conch Hearing-Aids (entirely fill the conch) – all control elements present – simple handling – not a cosmetic solution Concha – powerful solutions Hearing-Aid Technology – ITE Hearing-Aids Advantages: • Small design – cosmetic advantages • No problem with wind with CIC hearing-aids • Better acoustics – microphone and receiver in the ear • Good level of comfort • Does not irritate behind the ear • Individual production – no standard solution Hearing-Aid Technology – ITE Hearing-Aids Disadvantages: • Slight feedback • Sometimes more difficult to operate • More occlusion – longer habituation time • More frequent repairs – cerumen, sweat in the ear Hearing-Aid Technology • Development of Hearing-Aid Technology • Parts of the Hearing-Aid • Different Types of Hearing-Aid • Use of Types of Hearing-Aid • Possibilities of Modern Hearing-Aid Technology Hearing-Aid Technology Exercise: Use of the Hearing-Aids Task: Based upon the advantages and disadvantages of the ITE and BTE hearing-aids one can draw conclusions about their application. Which group of customers is suitable for ITE hearing-aids and which for BTE? (from young-old, hearing loss, working people, pensioners) Duration: 15 min. Hearing-Aid Technology BTE Hearing-Aids: • Children – always require new otoplastics, have narrow auditory canals • Customers with more major hearing loss (strong receivers) • Customers who are less dextrous • Thrifty customers – lower electricity consumption – bigger batteries • Customers with a problem with their own voice – occlusion sensation • Musicians – higher performance in BTE ITE Hearing-Aids: • Cosmetic reasons (CIC hearing-aids) • More natural sound transferral – microphone is in a better place • Customers who are on the phone a lot • Working people who are exposed to wind a lot (less wind noises) Hearing-Aid Technology • Development of the HA-Technology • Parts of the Hearing-Aid • Different Types of Hearing-Aid • Use of the Types of Hearing Aid • Possibilities of Modern Hearing-Aid Technology Hearing-Aid Technology What are the generally known disadvantages of hearing- aids? Hearing-aids are always whistling! Hearing-aids cannot be used in company because everything is amplified and gets blended together! One‘s own voice is totally changed by the hearing-aid!
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