Artificial Bionic Ear

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Artificial Bionic Ear
Hassanain Ali
M.Sc. in Medical Engineering
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EAR considers the most communicating
Organ for the Human Beings.
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• Human Ear is divided
• into three sections
• Outer Ear,
• Middle Ear and
• Inner Ear.
• Each section plays an important and a unique part
  in decomposing and translating acoustical waves
  into electrical impulse signals that are used by
  the Brain.

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• Sound waves travel through the Pinna along the
  external canal of the Outer Ear and cause the
  Tympanic Membrane (Ear Drum) to vibrate, then
  this motion is transferred to the Middle Ear.
• The Stapes (Stirrup) is connected to the ear drum
  by the other middle ear bones, the Incus (Anvil)
  and the Malleus (Hammer).
• A difference in the pressure causes the stapes to
  move and it stimulates the perception of sound.
  The three bones carry the vibrations to the
  Cochlea of the Inner Ear.

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Ossicles of the
Middle Ear
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• The Cochlea is the part of the Inner Ear where
  mechanical motion of the auditory vibration is
  converted to electrical impulses,
• so it considers the
• Sensory Organ of Hearing.
• Cochlea is composed of three
• fluid filled chambers that extend along the
  length of the structure and help to maintain the
  Body Balance. The cochlear duct
  contains the Basilar Membrane upon which lies the
  Organ of Corti. This organ has ten thousands of
  sensory Hair Cells which are connected to the
  nerve endings of the Auditory Nerve.

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Hearing Mechanism
efferent signals ( from both ears )
Middle Ear Ossicles

other Ear
Sound
efferent signals
Fast Open Hair Cells Loop
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Structure of Cochlea

• Three main chambers
• Scala Vestibuli
• Scala Media
• Scala Tympani

cross section of the Cochlea
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Function of Cochlea
Organ of Corti
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• Hearing Loss can be rated on a scale based on
  the threshold of hearing.
• Severe hearing loss is defined as a bilateral
  hearing threshold of 70-90 dB and profound
  hearing is defined as a hearing threshold of 90
  dB and above.
• Hearing Loss is divided primarily into
• two general categories
• Conductive and Sensorineural.

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• Conductive hearing loss results from diseases or
  disorders that limit the transmission of sound
  through the outer or middle ear. This loss can
  usually be treated medically or surgically. In
  some cases, a hearing aid can provide sufficient
  hearing improvement.
• Sensorineural hearing loss affects the auditory
  nerve and hair cells inside the cochlea that
  excite it. In this case, sound is transmitted
  normally through the outer and middle ears, but
  the inner ear is less efficient in transmitting
  the sound. The result is an impaired ability to
  hear sound and to understand speech.
• This loss is usually treated with a cochlear
  implant which amplifies sound to overcome the
  decrease in sensitivity of the fine nerve endings
  within the cochlea.

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Sensorineural
Conductive
Otosclerosis Stiff Ossicles
Damaged Hair Cells
Wax
Otitis Media Fluid in middle ear
Torn Eardrum
Damaged Nerve
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Healthy Cochlea
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Damaged Cochlea
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• The Bionic Ear
• bypasses damaged parts of
• the inner ear and electronically stimulates the
  nerve of hearing that converts sound into
  electrical impulses.
• Part of the device is
• surgically implanted in the Skull behind the ear
• and tiny wires are inserted
• into the cochlea.
• The other part
• of the device is external, and battery powered.

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• Cochlear Implant is a type of neural prosthetic
  device that can restore the lost hearing
  sensation for the severe hearing disabled and
  profound deaf.
• All devices have the following features in common
  
• A microphone that picks up the sound,
• A speech processor that converts the sound into
  electrical signal,
• A transmission system that transmits the
  electrical signals to the implanted electrodes
  with transcutaneous RF link,
• And an intra-cochlear electrodes array that is
  inserted in the cochlea by surgery.

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Cochlea Implant Components
The hearing process with using a bionic ear can
be summarized as follows
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• 1- Sounds are detected by the Microphone.
• 2- The information from the microphone is sent to
  the Speech Processor.
• 3- The speech processor analyses the information
  and converts it into an
  electrical code.
• 4- The coded signal travels via a cable to the
  transmitting coil in the headset. Radio waves
  from the transmitter coil carry the
  coded signal through the skin to the implant
  inside.
• 5- The implant package decodes the signal. This
  signal contains information that determines how
  much electrical current will
  be sent to the different electrodes array.
• 6- The appropriate amount of electrical current
  passes down the appropriate
  lead wire to the chosen electrodes.
• 7- The position of stimulating electrodes within
  the cochlea will determine
  the frequency of the sounds. The amount of
  electrical current will determine the loudness
  of the sounds.
• 8- Once the nerve endings in the cochlea are
  stimulated, the message is sent up to
  the Brain along the auditory nerve. The Brain
  can then try to interpret the
  stimulation as a meaningful sound.

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Electrodes Array

• Electrodes Array is inserted in the cochlea so
  that different auditory nerve fibers can be
  stimulated at different places.
• Electrodes stimulation is depending on the signal
  frequency. Electrodes near the base of cochlea
  are stimulated with high frequency
  signals, while electrodes near the apex
  are stimulated with low frequency signals.

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• The signal processing strategy consists of band
  pass filters that divide the acoustic wave into
  four channels.
• The envelopes of the band-passed waveforms are
  then detected by rectification and low pass
  filtering.
• The generated pulses are delivered to the
  appropriate electrodes through a radio frequency
  link.

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Components of Bionic Ear
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• For centuries, people believed that only a
  miracle could restore hearing to the Deaf. It
  was not until fifty years ago that scientists
  first attempted to restore normal hearing to the
  deaf by electrical stimulation of the impaired
  auditory nerve.

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Artificial Bionic Ear
Hassanain Ali
M.Sc. in Medical Engineering