Lecture 1- Basic operation of Cochlear Implants

Question 1

What does the microphone do?

Answer 1

• Captures acoustic signals

- Transduces the input into an electrical signal

Question 2

What is the electrical signal?

Answer 2

• Preamplifier improves SNR during transmission

- Boosts high-frequency region

Question 3

How does a CI analyze incoming signals?

Answer 3

• Digital signal processor (DSP) classifies the sound according to intensity, frequency, and time domains
• DSP converts signal into electrical code that represents these features at the level of the auditory nerve

Question 4

What is the RF coil?

Answer 4

• Coil that converts signal from electrical to electromagnetic signal and transmits to internal antennae

Question 5

How are incoming signals transmitted from the external to internal pieces?

Answer 5

• Magnetic lines of flux allow the information to be sent between coil and antennae

Question 6

How does the magnet help with sound transmission?

Answer 6

Makes an electromagnetic field so the signal can go from the RF coil to internal antennae

Question 7

What is the RF signal?

Answer 7

• Serves as power supply for internal device

- No battery on internal device

Question 8

What is the internal stimulator?

Answer 8

• Receives electrical signal from antenna
• Contains another DSP which converts the signal to digital code
• Determines the stimulation needs for the user and converts the code to electrical pulses based on the input signal and processing strategy

Question 9

What is the electrode array?

Answer 9

• Wire with electrodes inserted into the cochlea

- Electrical pulses sent down the array stimulate intracochlear electrode contacts

Question 10

What are the basic sound processor features?

Answer 10

• Ear hook
• Processor
• Coil
• Magnet
• Battery
• Cable