Md.Kausher ahmed Electrical department

Biomedical engineering Code:6875

Lesson declared Prosthetic device and stimulator

Learning outcomes After finished this lesson student will able to # Say. About Cochlear implant. # Say about Parts of the cochlear implant. # Say about Transcutaneous electrical nerve stimulation.

Cochlear implant

Continue,,,

Continue,,,,, A cochlear implant (CI) is a surgically implanted electronic device that provides a sense of sound to a person who is profoundly deaf or severely hard of hearing. Cochlear implants may help provide hearing in patients who are deaf because of damage to sensory hair cells in their cochleas. In those patients, the implants often can enable sufficient hearing for better understanding of speech

Continue,,,,, The quality of sound is different from natural hearing, with less sound information being received and processed by the brain. However, many patients are able to hear and understand speech and environmental sounds. Newer devices and processing-strategies allow recipients to hear better in noise, enjoy music, and even use their implant processors while swimming.

Parts of the cochlear implant The implant is surgically placed under the skin behind the ear. The basic parts of the device include one or more microphones which picks up sound from the environment a speech processor which selectively filters sound to prioritize audible speech, splits the sound into channels and sends the electrical sound signals through a thin cable to the transmitter,

Continue,,,,,,,,,,, a transmitter, which is a coil held in position by a magnet placed behind the external ear, and transmits power and the processed sound signals across the skin to the internal device by electromagnetic induction,

Continue,,,,,,,,,, a receiver and stimulator secured in bone beneath the skin, which converts the signals into electric impulses and sends them through an internal cable to electrodes, an array of up to 22 electrodes wound through the cochlea, which send the impulses to the nerves in the scala tympani and then directly to the brain through the auditory nerve system.

Continue,,,,,,,,,, There are 4 manufacturers for cochlear implants, and each one produces a different implant with a different number of electrodes. The number of channels is not a primary factor upon which a manufacturer is chosen; the signal processing algorithm is also another important block.

Transcutaneous electrical nerve stimulation Transcutaneous electrical nerve stimulation (TENS) is the use of electric current produced by a device to stimulate the nerves for therapeutic purposes. TENS, by definition, covers the

Continue,,,,,,,,,, complete range of transcutaneously applied currents used for nerve excitation although the term is often used with a more restrictive intent, namely to describe the kind of pulses produced by portable stimulators used to treat pain. The unit is usually connected to the skin using two or more electrodes. A typical battery- operated TENS unit is able to modulate pulse width,

Continue,,,,,, frequency and intensity. Generally TENS is applied at high frequency (>50 Hz) with an intensity below motor contraction (sensory intensity) or low frequency (<10 Hz) with an intensity that produces motor contraction. While the use of TENS has proved effective in clinical studies, there is controversy over which conditions the device should be used to treat.

Disadvantages Some effects of implantation are irreversible; while the device promises to provide new sound information for a recipient, the implantation process inevitably results in shaving of the hair cells within the cochlea, which can result in a permanent loss of some or all residual natural hearing. However, with flexible electrodes and the right surgical methods, the hair cells can be

Continue,,,,,,,,,, preserved. While recent improvements in implant technology, and implantation techniques, promise to minimize such damage, the risk and extent of damage still varies. The goal of new implantation techniques is to reduce the risk of infection, operating time, and complications while improving the patient's ability to hear. Such improvements of implantation techniques

Continue,,,,,,,,,, include preserving low frequency hearing and using minimal invasive surgery to better secure the device. Still, the cause of deafness is not always identified before the surgery. It is possible but rare that the surgery does not restore hearing at all. Finished

Feedback # Explain. About Cochlear implant. # Explain about Parts of the cochlear implant. #Explain about Transcutaneous electrical nerve stimulation.

Thanks everybody