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HEARING_AID_TECHNOLOGY

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HEARING_AID_TECHNOLOGY Powered By Docstoc
					        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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