How EAS (Electric & Acoustic
Stimulation) Works

EAS is the combination of cochlear implant technology (electric stimulation) and acoustic amplification (acoustic stimulation)  in one system. The parallel processing of both acoustic and electric sound information together enables users to enjoy an enriched hearing experience. Here is how it works:


A cochlear implant converts everyday sounds into coded electrical pulses. These pulses stimulate the auditory nerve. The brain interprets these signals as sound.

  1. Mid and high frequency sounds are picked up by the microphone of the DUET 2 Audio Processor and are converted into a special code.
  2. This code is sent to the coil and is transmitted across the skin.
  3. The implant interprets the code and sends electrical pulses to the electrodes in the cochlea.
  4. The auditory nerve relays these signals to the brain.


Acoustic amplification turns up the volume on the sounds that the cochlea is still able to hear. For EAS, only the low frequencies are amplified.

  1. Low frequency sounds are picked up by the microphone and are digitally processed.
  2. Sounds are amplified by the loudspeaker located in the ear hook and are relayed via the ear mould to the ear canal.
  3. Sounds reach the undamaged areas of the cochlea responsible for processing low-frequency sound.
  4. The auditory nerve sends the signals to the brain.

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