BY: SAM SPINK COCHLEAR IMPLANT

WHAT IS IT? System of external and internal devices that aim to restore hearing to sensorineural hearing loss patients Both pre- and post-lingual hearing loss Does not restore functionality to natural cochlea; stimulates auditory nerve directly Restored hearing is not exactly like natural hearing

PROBLEM BEING SOLVED Sensorineural hearing loss Most common form of hearing loss Damage to either brain, auditory nerve, but most commonly sensory cells of cochlea (cochlear implant used for patients with this type) 1.2 million Americans affected by hearing loss; sensorineural most common form Functioning cochlea: vibrations cause fluid movement, which is sensed by hair cells of cochlea causing action potential firing to auditory nerve These cells don’t function in those with cochlear implants

CURRENT TECHNOLOGY 5 major components External devices: Microphone-wraps around front of ear Speech processor-behind ear; attached to microphone Transmitter-above processor Internal devices: Receiver/stimulator-across from transmitter Electrode array-placed on natural cochlea; wired to receiver

HOW IT WORKS Microphone picks up sound, sends it to speech processor Speech processor filters sound, converts to electrical signals through fast Fourier Transforms Transmitter wirelessly sends signals to receiver/stimulator Receiver/stimulator sends electrical current according to received signal to electrodes Electrodes stimulate auditory nerve

EFFECTIVENESS One study shows ability of cochlear implant recipients to identify sentences over telephone with 82 % success rate (pre-lingual) and 70% success rate (post-lingual) With an adaptor increases to 93% and 88%, respectively Speech development in children For each 6 month period over first 30 months after receiving implant, subjects’ increase in “language age” was about double that of subjects without implants Some performed at around same level as non-impaired

LIMITATIONS Requires intense therapy post-implantation to achieve high level of speech comprehension (especially for post- lingual patients) Device has trouble processing late echoing effects that go unnoticed by non-impaired ears Costs between $45,000 and $125,000 Surgical complications include infection, facial muscle weakness, facial paralysis, damaged vestibular system, loss of all residual hearing

FUTURE DIRECTION Improvement in surgical techniques to keep residual hearing intact If cure came about, patients would want what natural hearing still remained Different electrode arrangements Longer electrode arrays have shown potential to increase pitch range Variations in electrode spacing at different points on the cochlea could improve sound quality

REFERENCES Hu, Y. and Kokkinakis, K. (2014). Effects of early and late reflections on intelligibility of reverberated speech by cochlear implant listeners. The Journal of the Acoustical Society of America, 135(1), pp Landsberger, D., Mertens, G., Punte, A. and Van De Heyning, P. (2014). Perceptual changes in place of stimulation with long cochlear implant electrode arrays. The Journal of the Acoustical Society of America, 135(2), pp Nidcd.nih.gov, (2014). Cochlear Implants. [online] Available at: [Accessed 27 Sep. 2014]. Rigotti, P., Costa, O., Bevilacqua, M., Nascimento, L. and Alvarenga, K. (2013). Assessment of telephone speech perception in individuals who received cochlear implant in the period (5), pp Svirsky, M., Robbins, A., Kirk, K., Pisoni, D. and Miyamoto, R. (2000). Language development in profoundly deaf children with cochlear implants. Psychological science, 11(2), pp Wikipedia, (2014). Cochlear implant. [online] Available at: [Accessed 27 Sep. 2014].