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cochlear implantation
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    cochlear implantation cochlear implantation Presentation Transcript

      • Presented By-
      • Name :Pankaj Kumar Singh (12 ECE 07)
      • Univ. Roll No. : -
      • Name :Rahul Kumar Singh (09 ECE 07)
      • Univ. Roll No. : -
      • Introduction.
      • Anatomy of ear & mechanism of hearing.
      • Diseases of ear that results in loss of hearing.
      • History of cochlear implants.
      • Electronic Cochlea.
      • Limitations of cochlear implants.
      • Initiatives taken to remove the limitations.
      • Conclusions.
      • Any Questions?
      • Definition of cochlea.
      • Cochlea as a transducer.
      • Cochlear implant as bionic ear
      Fig: The internal part of a cochlea implant Fig: Cochlea implant as worn by user
      • Deafness is due to following reasons:
      • Bony deposits in the inner ear caused by the aging process.
      • Auricle and the opening into the outer auditory canal may be missing at birth.
      • Injury to the ear cartilage followed by internal bleeding and excessive production of ear tissue (cauliflower ear).
      • Perforation of the eardrum may be caused by injury from a sharp object or by sudden changes in atmospheric pressure.
      • Damage to the organ of Corti in the inner ear accounts for the condition of many people who are either totally deaf or severely hearing impaired.
      • It is a big question .We have hearing aids so why patient should go through operation?
      • So here is the difference that we can sort out between the two:
      Cochlear implants Hearing aids consonants and vowels are understandable Only vowels Unlimited possibilities for signal coding Limited signal coding Surgically implanted No surgery needed 3 batteries or charged battery 1 battery Battery life: 1 to 3 days Battery life: 1 to 2 weeks Success is individual and unpredictable Success is individual and unpredictable Rechargeable Non- rechargeable
    • The Procedure:
      • Ear Assessment
      • Hearing Assessment
      • X-Ray Assessment
      • Psychological Assessment
      • Physical Assessment
      • Research during the late 18th and 19th centuries.
      • 1. 18th century Alessandro Volta discovered Electrolytic cell.
      • 2. In 1950 Djourno and Charles Eyries Studied using current.
      • 3. In 1961 ,William House. He developed devices to stimulate acoustic nerves
      • We hear through the sound analyzing action of the cochlea (inner ear) and the auditory centers of the brain.
      • The mechanical-neural transducer of the hearing system is the hair cell,
      • The cochlear model was described by Lyon.
      • He combines a series of filters that model the traveling pressure waves with Half Wave Rectifiers (HWR) to detect the energy in the signal and several stages of
      Fig: The cochlear model (Lyon)
      • Parts of the cochlear implant:
      • External:
      • a microphone
      • a speech processor
      • a transmitter
      • Internal:
      • a receiver and stimulator
      • an array of up to 22 electrodes wound through the cochlea.
    • Fig: Floorplan of 100-stage cochlea chip,
    • Fig: Artist‘s conception of the cochlea Fig: Photomicrograph of 480-stage cochlea test chip.
      • Processing
      • Filter bank strategies use Fast Fourier Transforms.
      • Feature extraction strategies used features which are common to all vowels.
      • Transmitter
      • The transmitter attaches to the receiver using a magnet that holds through the skin.
      • It is used to transmit the processed sound information over a radio frequency .
      • Receiver
      • It receives directions from the speech processor by way of magnetic induction sent from the transmitter.
      • receiver is also a sophisticated computer .
      • It is embedded in the skull behind the ear.
      • Electrode array
      • The electrode array is made from a type of silicone rubber.
      • The electrodes are platinum or a similarly highly conductive material.
      • The mean length of human being cochlea is 33–36 mm.
      • 22 array electrodes within the cochlea and 2 extra-cochlear electrodes (ground).
      • Speech processors
      • It transforms the sounds picked up by the microphone into electronic signals .
      • There are primarily two forms of speech processors available
      • Programming the speech processor
      • The cochlear implant must be programmed individually for each user.
      • The programming is performed by an audiologist trained to work with cochlear implants.
      • Damage to nerve cells within the cochlea
      • It is not as good as the quality of sound processed by a natural cochlea.
      • VLSI technology limitations such as threshold variation
      • present an important challenge in designing systems with appropriate collective behavior.
      • Outer hair cells provide active and adaptive undamping to boost weak sounds and attenuate loud ones, there by providing the gain-control element of an AGC loop.
      • The key problems in sound perception are to cope with a very wide dynamic range of loudness and to separate sounds on the basis of their properties, such as frequency content and time structure.
      • The problems we must solve to build perception machines are mostly similar to those that nature had to solve biologically in the evolution of intelligent animal behavior.