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Cochlear Implantation Process, Performance, and Culture


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Cochlear Implantation process, performance, and cultural implications.

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Cochlear Implantation Process, Performance, and Culture

  1. 1. Alexandra D. Costlow, B.S.
  2. 2. Cochlear Implant (CI) Appointments General Points <ul><li>Implantation requires an ongoing commitment of time and resources </li></ul><ul><li>The appointment process begins at the candidacy stage </li></ul><ul><ul><li>However, there may have been appointments with related professionals prior to the candidacy stage </li></ul></ul><ul><ul><li>Referral to the audiologist, CI center, etc… </li></ul></ul>
  3. 3. CI Appointments General Points <ul><li>Each appointment should support a successful implantation process as a whole </li></ul><ul><li>“ Progress is not always a straight line” in reference to the implantation process </li></ul><ul><ul><li>The normal series of appointments may be individualized based on the needs of the patient </li></ul></ul>
  4. 4. CI Appointments Stages <ul><li>Candidacy </li></ul><ul><li>Surgical Implantation </li></ul><ul><li>Follow-Up Care </li></ul>
  5. 5. CI Candidacy Appointments Review <ul><li>Preoperative assessment should be performed at a CI center staffed with clinicians offering experience in postimplantation management. </li></ul><ul><li>Clinicians analyze risk-to-benefit ratio through outcome predictors and modifiers </li></ul><ul><ul><li>Factors that affect performance, perceived benefit, and long-term use of a CI </li></ul></ul><ul><ul><li>An assessment of relative benefit aids in the decision-making process and helps in aligning the candidate’s expectations with probable outcomes </li></ul></ul>
  6. 6. CI Candidacy Appointments Review <ul><li>Hearing Assessment, including Auditory Skills Assessment </li></ul><ul><li>Otologic and Medical Assessment </li></ul><ul><li>Opthalmology </li></ul><ul><li>Psychological Assessment </li></ul><ul><li>Language, Educational, and </li></ul><ul><li>Development of Multimodal Processing </li></ul><ul><li>Assessment (for the pediatric/school-aged </li></ul><ul><li>population) </li></ul>
  7. 7. CI Candidacy Appointments Hearing Assessment <ul><li>Hearing Assessment by a licensed audiologist </li></ul><ul><ul><li>Determines a baseline through characterization of </li></ul></ul><ul><ul><ul><li>Residual hearing </li></ul></ul></ul><ul><ul><ul><li>Functional hearing </li></ul></ul></ul><ul><ul><ul><li>Response to amplification </li></ul></ul></ul><ul><ul><ul><li>Changes to Hearing Assessment </li></ul></ul></ul><ul><ul><ul><li>Movement away from hearing sensitivity </li></ul></ul></ul><ul><ul><ul><li>alone </li></ul></ul></ul><ul><ul><ul><li>Instead, consider the patient’s experience with effectively accessing speech with amplification </li></ul></ul></ul><ul><ul><ul><li>Note the constraints of hearing aid usage (Niparko, 2009) </li></ul></ul></ul>
  8. 8. CI Candidacy Appointments <ul><li>Auditory Skills Assessment </li></ul><ul><ul><li>“… Evaluates child’s ability to attend to and integrate sound using conventional amplification” (Niparko, 2009). </li></ul></ul><ul><ul><ul><li>Speech and environmental sounds over a range of frequencies </li></ul></ul></ul><ul><ul><ul><li>Integrate auditory perception with speech production in order to imitate sounds </li></ul></ul></ul><ul><ul><ul><li>Make meaningful associations for sounds from single words to conversation </li></ul></ul></ul><ul><ul><ul><li>Overall, to integrate hearing into communication </li></ul></ul></ul>
  9. 9. CI Candidacy Appointments <ul><li>Otologic Assessment </li></ul><ul><ul><li>Determination of the etiology of the hearing loss helps guide the implantation process </li></ul></ul><ul><ul><ul><li>Ex.: Usher Syndrome patients will </li></ul></ul></ul><ul><ul><ul><li>also have gradual onset vision loss </li></ul></ul></ul><ul><ul><li>Ex.: Patients with Neurofibromatosis II </li></ul></ul><ul><ul><li> who have bilateral acoustic tumors will benefit </li></ul></ul><ul><ul><li> more from Auditory Brainstem implants </li></ul></ul><ul><li>Medical Assessment </li></ul><ul><ul><li>Evaluates patient’s fitness for general anesthetic and mastoid surgery, as well as device programming and postimplantation rehabilitation </li></ul></ul>
  10. 10. Candidacy Appointments <ul><li>Opthalmology </li></ul><ul><ul><li>Vision plays a critical role in the deaf child’s development in that it allows the child to associate meaning with auditory inputs (Niparko, 2009). </li></ul></ul><ul><ul><li>An opthalmology exam can identify visual abnormalities associated with congential sensorineural hearing loss </li></ul></ul><ul><ul><ul><li>Refractive errors and cataracts </li></ul></ul></ul><ul><ul><ul><ul><li>These visual abnormalities can help to </li></ul></ul></ul></ul><ul><ul><ul><ul><li>diagnose etiologies such as Usher and </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Waardenburg syndrome </li></ul></ul></ul></ul>
  11. 11. CI Candidacy Appointments <ul><li>Psychological Testing </li></ul><ul><ul><li>Screen for psychopathology and cognitive deficits </li></ul></ul><ul><ul><ul><li>Mood disorders can cause elevations in depression, social introversion, suspiciousness, social anxiety, and loneliness in adult CI candidates (Knutson, Johnson, & Murray, 2006) </li></ul></ul></ul><ul><ul><ul><li>Cognitive defects can indicate the need for unique rehabilitation strategies </li></ul></ul></ul>
  12. 12. CI Candidacy Appointments <ul><li>Counseling to ensure suitability and motivation to participate in the process </li></ul><ul><ul><li>Expectations of what the CI can and can not do </li></ul></ul><ul><ul><li>Determination of family and/or social support </li></ul></ul><ul><ul><li>Patient acknowledgement and acceptance of the time and resources required for care a follow-up service </li></ul></ul>
  13. 13. Device Discussion <ul><li>To ensure that the patient and his/her family understand the motivation and resources required for successful CI implantation and use </li></ul><ul><li>May discuss differences between the different implants </li></ul><ul><li>May discuss insurance coverage or funding </li></ul><ul><li>Reiterate that pre-implantation expectations will shape post-implantation success </li></ul>
  14. 14. CI Candidacy Appointments <ul><li>Tests performed by the surgeon </li></ul><ul><li>Analysis of the brain and middle and inner ear </li></ul><ul><ul><li>Computerized Axial Tomography (CAT Scan)/X-rays </li></ul></ul><ul><ul><ul><li>CT scanner x-rays around the circumference of the patient </li></ul></ul></ul><ul><ul><ul><li>Detectors in the CT scanner measure how much x-ray is transmitted through the area of the body of interest </li></ul></ul></ul><ul><ul><ul><li>CT Scan analyzes soft tissue (including organs), bone, and blood vessels </li></ul></ul></ul><ul><ul><ul><ul><li>Is there new bone growth in cochlea due to meningitis? </li></ul></ul></ul></ul><ul><ul><ul><li>3D images of organs are created by stacking slices of images </li></ul></ul></ul><ul><ul><ul><li>New, multidetector scanners scan the body in about 30 seconds </li></ul></ul></ul>
  15. 15. CT Scan of Cochlea /2008/04/080425151819.htm
  16. 16. CI Candidacy Appointments <ul><ul><li>Magnetic Resonance Imaging (MRI) </li></ul></ul><ul><ul><ul><li>Uses powerful magnets and radio waves </li></ul></ul></ul><ul><ul><ul><li>The scanner contains a magnet whose field is ~10,000x greater than the earth’s magnetic field </li></ul></ul></ul><ul><ul><ul><li>Magnetic field causes hydrogen atoms in the body to align in a specific configuration </li></ul></ul></ul><ul><ul><ul><li>Radio waves are projected onto the hydrogen atoms, and bounce back </li></ul></ul></ul><ul><ul><ul><li>Computer records the signal, which is specific to the type of tissue </li></ul></ul></ul><ul><ul><ul><li>MRI more effectively images soft tissues (brain) than does CT </li></ul></ul></ul><ul><ul><ul><li>Single MRI images are also called slices </li></ul></ul></ul><ul><ul><ul><li>The exam usually takes 1 hour or longer, depending on the number of slice being analyzed </li></ul></ul></ul>
  17. 17. MRI (at 3 tesla) of Cochlea
  18. 18. CI Candidacy Appointments <ul><li>CAT Scan and MRI </li></ul><ul><ul><li>Analyze the structure (and presence or absence) of the 8 th Cranial Nerve (Auditory) </li></ul></ul><ul><ul><li>Can identify structural abnormalities of the cochlea and/or mastoid bone that could compromise the surgery </li></ul></ul><ul><ul><li>Can identify space-occupying lesions that result in hearing loss </li></ul></ul>
  19. 19. Surgery <ul><li>The patient is deemed a candidate and decides to go forth with implantation. </li></ul><ul><li>Surgery may involve an overnight stay at a hospital, but generally, it can be performed on an out-patient basis. </li></ul><ul><li>It takes place under general anesthesia and takes 1 to 2 hours. </li></ul>
  20. 20. Review of CI Components <ul><li>Microphone - picks up sound </li></ul><ul><li>from the environment </li></ul><ul><li>Speech Processor - placed behind the </li></ul><ul><li>ear or worn on the body , it selects and </li></ul><ul><li>arranges sounds detected by the </li></ul><ul><li>microphone </li></ul><ul><li>Coil- held in place by a magnet, radio </li></ul><ul><li>waves transmit the coded signal to the </li></ul><ul><li>transmitter </li></ul><ul><li>Transmitter - placed internally , it receives </li></ul><ul><li>signals from coil and converts them into electrical impulses </li></ul><ul><li>Electrode array - placed in the cochlea , it collects impulses from the transmitter and stimulates portions of the auditory nerve (NIDCD, 2009) </li></ul>
  21. 21. Surgery <ul><li>The surgeon makes a trans-mastoid facial recess incision </li></ul><ul><li>The surgeon drills into the mastoid bone in order to access the inner ear </li></ul><ul><li>A depression is created in bone behind the mastoid to accommodate the transmitter (receiver-stimulator) internal device </li></ul><ul><li>The electrode array is threaded into the scala tympani through the round window membrane or cochleostomy (25-30 mm is full insertion) </li></ul><ul><li>The cochleostomy is sealed around the electrode with fibrous tissue </li></ul>
  22. 22. Surgery <ul><li>The outer end of the electrode array is fastened to the skull </li></ul><ul><li>The scalp should be thinned to no more than 1cm to enable stable retention of the magnet </li></ul><ul><li>The incision is closed </li></ul><ul><li>The patient returns in about one week for suture removal </li></ul>
  23. 23. Surgery Part I <ul><li> </li></ul>
  24. 24. Surgery Part II <ul><li> </li></ul>
  25. 25. Activation and Initial Fitting <ul><li>Days after the surgical implantation of the receiver (just behind the ear) and the electrodes (in the cochlea), the patient returns to the CI center. </li></ul><ul><li>An audiologist fits the patient with: </li></ul><ul><ul><li>A microphone (resembles </li></ul></ul><ul><ul><li>a BTE hearing aid) </li></ul></ul><ul><ul><li>A speech processor (may be </li></ul></ul><ul><ul><li>housed with the microphone or </li></ul></ul><ul><ul><li>worn at chest-level) </li></ul></ul>
  26. 26. Activation and Initial Fitting <ul><li>Audiologist runs standard check </li></ul><ul><li>of the speech processor </li></ul><ul><li>Initial activation and programming </li></ul><ul><li>(mapping) of the implant </li></ul><ul><ul><li>Mapping- a set of parameters of electrode stimulation that gives the patient maximum hearing </li></ul></ul><ul><ul><li>Establishment of electrical dynamic range (Level of Comfort* – Threshold** for each electrode) </li></ul></ul><ul><li>May occur over several appointments because the patient will adjust to sound as s/he gains experience with the implant </li></ul><ul><li>Appointments are generally 2 hours, of which 20-30 minutes are spent obtaining T and C Levels (Craver, 2010). </li></ul>
  27. 27. Activation and Initial Fitting <ul><li>How is mapping conducted? </li></ul><ul><li>Using speech (subjective) </li></ul><ul><li>Using tones/beeps/bursts </li></ul><ul><li>(subjective) </li></ul><ul><li>Neural Response Telemetry (objective) </li></ul><ul><ul><li>Telemetry is the remote measurement of various electrical parameters (in our case, through implant feedback) </li></ul></ul><ul><ul><li>Neural Response Telemetry measures the response of the auditory nerve to electrical stimulation via a cochlear implant (The Hearing House). </li></ul></ul><ul><ul><li>NRT takes about 5 minutes to complete (Craver, 2010). </li></ul></ul>
  28. 28. Neural Response Telemetry
  29. 29. Map Parameters <ul><li>Strategy - Method by which sound is analyzed and presented, which varies by manufacturer </li></ul><ul><li>Stimulation - Specifies the difference between active and indifferent electrode mode </li></ul><ul><li>Rate - Pulses per second (frequency) of electrical current </li></ul><ul><li>Pulse Width - Amount of time the electrical current (pulse) is delivered in microseconds (Carver, 2007) </li></ul>
  30. 30. Activation <ul><li>Cochlear Implant Activation – Captured </li></ul><ul><li> </li></ul>
  31. 31. Follow-Up to Initial Fitting <ul><li>May include several visits over the span of weeks or months </li></ul><ul><li>Why is this such a lengthy process? </li></ul><ul><ul><li>Each electrode in the cochlea is activated </li></ul></ul><ul><ul><li>Each electrode must be programmed and adjusted into the speech processor </li></ul></ul><ul><ul><li>Can create programs for special listening situations </li></ul></ul><ul><ul><li>The patient develops more skill from using the implant, thus more adjustments must be made as skill improves </li></ul></ul><ul><ul><li>Over time, less adjustments are necessary and the patient will return to the CI center every 6 months or annually </li></ul></ul><ul><ul><li>Appointment time can be spent on education and rehabilitation (Craver, 2010). </li></ul></ul>
  32. 32. Follow-Up to Initial Fitting <ul><li>Sample Programming Schedule </li></ul><ul><ul><li>Days 1, 2: Activation of the external equipment, which occurs approximately 4 weeks after surgery </li></ul></ul><ul><ul><li>1 week: Audiogram and reprogramming </li></ul></ul><ul><ul><li>1 month: Audiogram and reprogramming </li></ul></ul><ul><ul><li>3, 6, 9 months: Audiogram, Speech Perception Testing and reprogramming </li></ul></ul><ul><ul><li>1 year: Audiogram, Speech Perception Testing and reprogramming </li></ul></ul><ul><ul><li>Every 6-12 months thereafter: Audiogram, Speech Perception Testing and reprogramming (Carver, 2007). </li></ul></ul>
  33. 33. Aural Rehabilitation Previous vs. New Listeners <ul><li>Patients with previous experience hearing and listening should be counseled that speech will have a different sound quality. </li></ul><ul><li>They may report that CI speech sounds unnatural. </li></ul><ul><li>Patients who are new to hearing sound and speech will need to learn perceive sound and how to respond to it. </li></ul>
  34. 34. Aural Rehabilitation <ul><li>Teaches the patient how to use the CI and respond </li></ul><ul><li>to auditory input </li></ul><ul><ul><li>Listen to an array of auditory stimuli </li></ul></ul><ul><ul><li>Improve speech (expressive and receptive) </li></ul></ul><ul><ul><li>Use speech-reading </li></ul></ul><ul><li>AR Programs </li></ul><ul><ul><li>DASL II </li></ul></ul><ul><ul><li>Speech that Works </li></ul></ul><ul><ul><li>Cottage Acquisition Scales for Listening, Language, & Speech </li></ul></ul><ul><ul><li>The Miami Cochlear Implant, Auditory & Tactile Skills Curriculum (CHATS ) </li></ul></ul>
  35. 35. Aural Rehabilitation Activities <ul><li>Adults </li></ul><ul><li>Children </li></ul><ul><li>May focus on social or occupational skills and/or demands </li></ul><ul><li>Occupation/trade specific vocabulary or communication skills </li></ul><ul><li>Practice communication skills using current events, popular television shows, etc… </li></ul><ul><li>Alerts: car horn, microwave, etc… </li></ul><ul><li>“ Mother May I?” </li></ul><ul><li>Board games: The child advances if he successfully speechreads or can hear and/or repeat stimuli correctly </li></ul><ul><li>Ability to follow directions common to school </li></ul><ul><li>Ability to function in a social setting (ex: playground, cafeteria, sports game) </li></ul><ul><li>Alerts: fire alarm, whistle, etc… </li></ul>
  36. 36. Outcomes of CI Performance Hearing Aid + CI <ul><li>Ching, Incerti, and Hill (2004) tested 21 adults who used a Nucleus CI-22 or CI-24 and either unilaterally or with a Ha set to NAL-NL1 and loudness-balanced to the CI. They found that CI+HA users, compared to unilateral CI or HA users, had better: </li></ul><ul><ul><li>Speech perception in noise on dichotic and diotic listening conditions </li></ul></ul><ul><ul><ul><li>Subjects who performed better in speech perception also had benefit in localization and functional performance in everyday life </li></ul></ul></ul><ul><ul><li>Horizontal localization </li></ul></ul><ul><ul><li>Functional performance in everyday life evaluated by a functional performance questionnaire </li></ul></ul><ul><ul><li>All subjects showed binaural benefit in at least one measure </li></ul></ul>
  37. 37. Hearing Aid + CI <ul><li>Litovsky, Parkinson, Arcaroli, Peters, Lake, Johnstone, and Gonqiang (2004) tested 17 adults and 3 children with one CI and then bilaterally. </li></ul><ul><li>Adults localize better with 2 bilateral CIs </li></ul><ul><li>Adults perform better hearing speech in noise with bilateral CIs when the noise is in the poorer ear </li></ul><ul><li>Children perform better on localization and speech recognition with bilateral CIs, but not remarkably </li></ul><ul><ul><li>One child did better with a unilateral CI and two children had better speech recognition when noise was presented to the ear that was implanted first </li></ul></ul>
  38. 38. Bilateral CIs vs. Unilateral CI <ul><li>Tyler, Gantz, Rubenstein, Wilson, Parkinson, Wolaver, Preece, and Lowder (2002) evaluated 9 post-lingually deafened adults using the Cochlear Corporation C24M implant for speech in quiet, speech in noise, and localization ability. </li></ul><ul><ul><li>Bilateral CIs showed a significant advantage over CI in th better ear for speech in quietand for speech in noise (located at 0 degrees azimuth) for 4/9 subjects </li></ul></ul><ul><ul><li>When CI was added to ear ipsilateral to noise, a significant advantage was noted for 4/7 subjects </li></ul></ul><ul><ul><li>3/7 subjects could discriminate noise at 45 degrees with one CI, but 7/7 could with bilateral CIs </li></ul></ul><ul><ul><li>Conclusion: Bilateral CIs offer advantage, especially when for ear contralateral to noise </li></ul></ul>
  39. 39. Bilateral CIs vs. CI+HA <ul><li>Litovsky, Johnstone, and Godar (2006) evaluated 20 children (20 use bilateral CIs, 10 use CI+HA) in their ability to hearing in quiet and in noise, and to localize sound. </li></ul><ul><ul><li>Both groups have similar speech reception thresholds </li></ul></ul><ul><ul><li>Improved localization and speech thresholds with bilateral CI group compared to CIHA group </li></ul></ul><ul><ul><li>Individual variability suggests that some children perform as well as normal hearing children while others do not </li></ul></ul>
  40. 40. Where to Go from Here? <ul><li>CI+HA and bilateral CIs offer benefit over unilateral CI </li></ul><ul><li>Bilateral CIs offer benefit over CIHA (Litovsky, Johnstone, & Godar, 2006). </li></ul><ul><li>HA should be programmed to NAL-NL1 Rx for adults and then adjusted on an individual basis (Ching, Incerti, & Hill, 2004). </li></ul><ul><li>Facilitate bimodal amplification by setting stable maps and then adjust HAs (Ching, Psarros, Dillon, & Incerti, 2001). </li></ul><ul><li>Should further investigate the differences in success with bilateral CIs between adults and children ( Litovsky, Parkinson, Arcaroli, et al., 2004) </li></ul><ul><li>Should determine why some children are more successful with CIs than are others (Litovsky, Johnstone, & Godar, 2006). </li></ul><ul><li>Many complicating factors to CI success </li></ul>
  41. 41. Deaf Culture The Basics <ul><li>Deaf Culture is linguistically unified through American Sign Language (ASL) </li></ul><ul><ul><li>ASL is not a manual translation of English </li></ul></ul><ul><ul><li>ASL has its own syntax, morphology, and vocabulary </li></ul></ul><ul><ul><li>ASL does not have a written correlate </li></ul></ul><ul><li>Deaf individuals share an identity based on a culture rather than a medical diagnosis </li></ul><ul><li>“ Deafness, particularly when early in onset, confers a life experience that is radically different owing to a systematically different language base not shared by the majority of hearing culture” (Niparko, 2009). </li></ul>
  42. 42. Deaf Culture and Cochlear Implants Conflict of Cross-Cultural Values <ul><li>Child as Recipient </li></ul><ul><li>Impact on Deaf Culture </li></ul><ul><li>Parental Authority- Hearing parents who implant deaf children are viewed as “ill-founded” and “ill-fated” in their decision </li></ul><ul><li>Deaf do not view deafness as a disease, and it is unethical to operate on a healthy child </li></ul><ul><li>CIs fail to foster language acquisition in children born deaf (Lane & Bahan, 1998). </li></ul><ul><li>Socio-cultural genocide </li></ul><ul><li>Undermines the survival of Deaf culture </li></ul>
  43. 43. Deaf Culture and Cochlear Implants <ul><li>Advocates for Deaf individuals </li></ul><ul><ul><li>The National Association of the Deaf </li></ul></ul><ul><ul><li>The World Federation of the Deaf </li></ul></ul><ul><ul><li>This cross-cultural conflict is without a resolution that is morally valid (Lane & Bahan, 1998) </li></ul></ul><ul><ul><li>Research is needed to determine why some children with CIs are successful in the hearing world and other are not </li></ul></ul><ul><ul><ul><li>Clinical trials </li></ul></ul></ul><ul><ul><ul><li>High quality, generalizable results </li></ul></ul></ul>
  44. 44. References <ul><li>American Speech-Language Hearing Association (ASHA). Cochlear implants. Retrieved from </li></ul><ul><li>Carver, C.L. (2007). Cochlear implant mapping: What every CI user and candidate should know. </li></ul><ul><li>Children’s Hospital and Health System. (2010). Cochlear implantation clinic. Retrieved from </li></ul><ul><li>Ching, T.Y., Incerti, P., & Hill, M. (2004). Binaural benefits for adults who use hearing aids and cochlear implants in opposite ear. Ear and Hearing, 25 (1), 9-21. </li></ul><ul><li>Ching, T.Y.C., Psarros, C., Hill, M., Dillon, H.,& Incerti, P. (2001). Should children who use cochlear implants wear hearing aids in the opposite ear? Ear and Hearing, 22 (5), 365-380. </li></ul><ul><li>Contradica. (2007, November 26). Cochlear implant activation – captioned [Video file]. From </li></ul><ul><li>Dillier, N. (2010). Illustration of the setup for intracochlear recordings of electrically evoked compound action potentials (NRT, Neural Response Telemetry). From </li></ul>
  45. 45. References <ul><li>Kim, H.J. (1993). Congenital inner ear malformations. Retrieved from Baylor College of Medicine’s website </li></ul><ul><li>Knutson, J.F., Johnson, A., & Murray, K.T. (2006) Social and emotional characteristics of adults seeking a cochlear implant and their spouses. British Journal of Health Psychology, 11 (2), 279-292. </li></ul><ul><li>Lane, H, & Bahan, B. (1998). Ethics of cochlear implantation in young children: A review and reply from a Deaf-World perspective. Otolaryngology and Head Neck Surgery, 119 , 297-313. </li></ul><ul><li>Litovsky, R.Y., Johnstone, P.M., & Godar, S.P. (2006). Benefits of bilateral cochlear implants and/or hearing aids in children . International Journal of Audiology, 45 (S1), 78-91. </li></ul><ul><li>Litovsky, R.Y., Parkinson, A., Arcaroli, J., Peters, R., Lake, J., Johnstone, P, & Gonquiang, Y. (2004). Bilateral cochlear implants in adults and children. Archives of Otolaryngology Head and Neck Surgery, 130 (5), 648-655. </li></ul><ul><li>MedLine Plus. (2008). CT scan. Retrieved from </li></ul><ul><li>MedLine Plus. (2008). Head MRI. Retrieved from </li></ul>
  46. 46. References <ul><li>National Institute on Deafness and Other Communication Disorders (NIDCD). (2009). Cochlear implants. From </li></ul><ul><li>Niparko, J. (2009). Cochlear implants . Baltimore, MD: Lippincott, Williams, and Wilkins. </li></ul><ul><li>Nussbaum, D. (2003). Cochlear implants: Navigating a forest of information … one tree at a time. From Gallaudet University Laurent Clerc National Deaf Education Center’s website </li></ul><ul><li>Science Daily. (2009). Low frequency hearing linked to shape of cochlea. Retrieved from </li></ul><ul><li>Tbhbc. (2009, April 14). Cochlear implant surgery part 1 (without sound) [Video file]. From </li></ul><ul><li> </li></ul><ul><li>Tbhbc. (2009, April 14). Cochlear implant surgery part 2 (without sound) [Video file]. From </li></ul><ul><li> </li></ul><ul><li>The Hearing House. Glossary of terms. From </li></ul>
  47. 47. References <ul><li>Tyler, R.S., Gantz, B.J., Rubenstein, J.T., Wilson, B.S., Parkinson, A.J., Wolaver, A., Preece, J.P., Witt, S., & Lowder, M.W. (2002). Three-month results with bilateral cochlear implants. Ear and Hearing, 23 (1), 80S-89S. </li></ul><ul><li>University of Maryland Medical Center (UMMC). (2010). Maryland hearing and balance center: Cochlear implant program . Retrieved from </li></ul><ul><li>U.S. Food and Drug Administration (FDA). (2009). Medical devices: Cochlear implants. Retrieved from </li></ul><ul><li>Van Der Veer Institute for Parkinson’s and Brain Research. (2007). Magnetic resonance Imaging at 3 tesla – The first in New England. Retrieved from </li></ul>