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Cochlear Implants Abstract: When a person loses hearing, cochlear implants make it possible to restore their ability to hear. Through surgical procedure, a system of electronic components is able to replace a damaged biological system. The most important part of the system is the electrical to biological connection made by the electrodes. Presented by: Connor Abens EE 4611 Kevin Chan May 2, 2014
Outline • History of Cochlear Implant • How the ear works • Device structure • Bio-friendly materials • Pros/Cons • Potential Improvements • Future of Implant
History • 1800 Allesandro Volta stimulated inner ear with electricity • 1956 Cochlear implant was designed • 1978 First multi-channel cochlear implant • 1980 FDA began regulation of cochlear implants • 1984 First implant in an adult approved by FDA • 1990 FDA approved implant for children above 2 years old • 2000 FDA approved implant for infants above 12 months of age.
Development • Cochlear Limited • Cochlear™ Nucleus® • This is the timeline of their implant components • Advanced Bionics • Harmony™ processor • HiRes90K™ implant • Medical Electronics (MED-EL) • MAESTRO™ 3.0 system
How the ear works • Outer • Canal • Drum • Middle (bones) • Malleus, Incus, Stapes • Inner • Cochlea • Auditory Nerve
Types of Hearing Loss • Conductive • Middle ear • Sensorineural • Inner ear stereocilia • Cochlear Nerve • Connection to brain
Components • External • Microphone • Speech processor • Transmitter • Internal • Receiver/Stimulator • Electrode Array
Demonstrations of sound • Robotic-like • Fuzzy radio • Context helps understanding http://auditoryneuroscience.com/prosthetics/noise_vocoded_speech
Bio-friendly materials • Silicone (1,5) • Used to case the electronic • Ceramics (older models) • Weak and sensitive to external forces • Titanium (2) • Replaced ceramic components • Platinum (3) • Used for electrode contacts
Pros Cons • Hearing is possible immediately after surgery • Sensitivity to a variety of sounds • Eliminates the reliance upon other people • Potentially enjoy music • Upgradable components • Speech understanding without lip-reading • Loss of natural hearing • Possible negative side effects • Must avoid water damage • Electromagnetic noise • Relative Volume isn’t automatic • Static electricity damage • Costs $45,000 to $105,000
Potential Improvements • Completely internal • Water resistivity • Resolution • Battery Life • Manufacturing cost • Biomaterials
Laser-based cochlear implant • Electric stimulation isn’t precise • Modified cells react to light stimulation • Precision lasers instead of electrodes • Testing in rats and toadfish • Infrared light affects calcium ion flow • This causes nerve cells to release neurotransmitters
Summary • How the ear works • Device structure • Potential Improvements • Infrared light stimulation
Sources General Information http://www.medel.com/us/ https://wiki.engr.illinois.edu/download/attachments/48137228/ECE+415+Cochlear+Implant+Final.pdf http://www.asu.edu/clas/shs/cilab/documents/publications/2004dormanwilson.pdf http://www.nlm.nih.gov/medlineplus/ency/article/007203.htm https://www.nidcd.nih.gov/health/hearing/pages/coch.aspx http://www.asha.org/public/hearing/Cochlear-Implant-Frequently-Asked-Questions/ http://www.cdc.gov/ncbddd/hearingloss/types.html http://teamhearing.org/blogs/?tag=cochlear-implants Laser based implant http://www.popsci.com/technology/article/2012-04/how-it-works-artificial-hearing-device-made-lasers Biomaterials http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3199815/
5 Key Concepts • Sounds travels through the ear canal then causes mechanical vibration which creates waves in the cochlear fluid. Those waves move the small hairs that stimulate the nerve cells. • Cochlear implant directly stimulates nerve cells in the cochlea • Electronic Components consist of: microphone, processor, transmitter, stimulator. • Silicone, ceramics, titanium and platinum are the materials used and accepted by the body. • Electrode stimulation isn’t precise because electric current can disperse into tissue. Laser stimulation is being studied to improve the precision of implants.