THE PROCESS & TECHNOLOGY OF COCHLEAR IMPLANTATION

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Dennis McLaughlin
5 years ago
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1 DURBAN COCHLEAR IMPLANT PROGRAMME Dr. Garth Skinner, ENT Surgeon; Dr. Zieciak, ENT Surgeon; Maxine Dobeyn, Audiologist Kara Hoffman, Audiologist Debbie Hardcastle, Speech/Language Therapist (Sherwood) Livingstone School Ingrid Robertson, Tersia Fox, Linda Johnstone Lisa Lee & Julie Cardona speech therapists THE PROCESS & TECHNOLOGY OF COCHLEAR IMPLANTATION BRIEF OVERVIEW OF THE PROCESS OF IMPLANTATION Enrollment into the programme; Audiological assessments; ENT examination; Radiology; Communication & (re) habilitation assessment; Expectations & informed consent; Surgery; MAPping; Follow-ups and (re) habilitation FINAL STEPS IN THE PROCESS Team meeting to review the data collected in order to make a final decision as to whether the patient is a candidate; Meningitis vaccination; Funding to be finalized; Realistic expectations to be set; Informed consent to be obtained; Book surgery & perform the surgery; Intra-operative testing; Post operative x-rays x & monitoring of patient; Programming of the device, with consistent follow-up and rehabilitation FACTORS TO CONSIDER FOR CANDIDACY Degree of hearing loss Benefit from hearing aids Duration of deafness & the age of implantation Communication mode Radiological and medical considerations Family (and patient) expectations; support system Educational support & placement Finance

DEGREE OF HEARING LOSS DURATION OF DEAFNESS Normal hearing Mild HL Moderate HL Severe HL OHC loss: Hearing aid fitting FDA criteria for cochlear implantation have changed over the last 20 years, and

2 DEGREE OF HEARING LOSS DURATION OF DEAFNESS Normal hearing Mild HL Moderate HL Severe HL OHC loss: Hearing aid fitting FDA criteria for cochlear implantation have changed over the last 20 years, and now includes the following: AGE Adults Children (12 months) now even as young as 6 months Profound HL IHC loss: Cochlear implantation ONSET OF HL Adults & Children pre-and post-lingual DEGREE OF HL Severe-profound AUDIOLOGICAL GUIDELINES Consider CI if: Unaided scores: HTL s s at 1, 2, & 4 khz are 75 dbhl or worse in the better hearing ear; HTL s s at 1, 2 & 4 khz are 90 dbhl or worse in the worse ear; Aided thresholds of 55dBHL or more at 2000 Hz 50% open-set sentence recognition in the ear to be implanted and 60% in the best-aided condition CRITICAL PERIODS Pediatricians & ENT s s need to be aware of the critical period for the development of spoken language, so that prompt referrals and intervention may be performed; Neuroplasticity is greatest in the first 3 years of life, and research suggests a phonological critical period from months of life; Early implantation bypasses the period of reorganization of the brain, and therefore will have more auditory capacity; IDENTIFICATION OF NEWBORN HL SHOULD BE CONSIDERED A NEURODEVELOPMENTAL EMERGENCY! Those implanted young are 5 times more likely to be mainstreamed, which leads to higher standards of education, better communication on models and improved speech intelligibility; Implantation at no older than 3.6 years of age for pre-lingually deafened babies DURATION OF DEAFNESS: OLDER CHILDREN, ADOLESCENTS & ADULTS Early auditory experience; Consistent HA use; Spoken language as mode of communication RADIOLOGICAL & MEDICAL GUIDELINES Considerations: Auditory nerve remains present; Surgical procedure with minimal risk for the patient; Otological examination; CT & MRI scans (inner ear & brain anatomy); Neurological & psychological examination; Health assessment; Congenital abnormalities; Meningitis / otosclerosis; Middle ear pathology

3 SUMMARY OF SELECTION CRITERIA SURGERY Bilateral severe-profound SNHL Little or no benefit for speech perception from conventional amplification The duration of the hearing loss in terms of critical periods for language development (children) and auditory deprivation (adults) No medical or radiological contraindications Available educational support Realistic expectations & commitment from family and partners VACCINATION Prior to implantation, the patient will receive a Meningitis vaccination by their ENT surgeon. Vaccination regimen: All pts receive 23-valent vaccine (Pneumovax) Children under 2: heptavalent vaccine (Prevenar) 23 valent (Pneumovax) For more information regarding the vaccination, it is recommended to consult with the implanting surgeon. SURGICAL STEPS IN CI The audiologist is not involved directly in the surgery, and therefore these steps will only be briefly looked at, however for more information regarding the surgery, it is best to consult with the implanting surgeon. The following steps are involved in the implantation: General anaesthetic (2-3 3 hours) Plan positioning of implant Incision Cortical mastoidectomy Posterior tympanotomy Bed for implant in skull bone Channel from bed to cortical mastoidectomy Cochleostomy Insertion of electrode & sealing with fascia (Positioning of ground electrode) Securing of implant Testing of device Closure of wound Radiological check C.I TECHNOLOGY Nucleus Freedom CI uses 22 electrodes to do the job of thousands of hair cells; A CI system attempts to emulate acoustic hearing, by using sequential, pulsatile stimulation, where pulses are presented on one electrode in rapid succession; Sound is conveyed in the normal ear using spectral (place) and temporal (time) resolution, and a CI attempts to provide the implantee with both those characteristics of sound in order to hear as close to normal as possible SPECTRAL: CI is able to provide spectral information by having multiple electrodes, located at different sites in the cochlea (tonotopic arrangement); Apical electrodes: low frequency, Basal electrodes: High frequency TEMPORAL: Temporal information is conveyed by varying the amount of charge in the pulse delivered to one channel

SOUND PROCESSOR The sound processor is the device that is external, and processes the sound being transmitted to the electrodes

determines the quietest sounds that are detected by the sound processor; The automatic gain control ensures optimal sensitivity to

the ambient noise floor MAPPING Recipient Control Unilateral & Bilateral Program Volume Sensitivity Telecoil Monitoring &

Sound on Remote Assistant The process of measuring and controlling the amount of electrical current delivered to the cochlea The

for making these programmes comfortable for patients to listen in their everyday environments This may be performed behaviourally

especially the first f 6 months after implantation, until the MAP is stable; In South Africa, all MAPping audiologists have to be

4 SOUND PROCESSOR The sound processor is the device that is external, and processes the sound being transmitted to the electrodes internally; It is responsible for optimizing the acoustic signal prior to sound coding; It consists of a sensitivity control which determines the quietest sounds that are detected by the sound processor; The automatic gain control ensures optimal sensitivity to normal sounds without resulting in distortion of loud sounds; Autosensitivity control changes sensitivity automatically based on the ambient noise floor MAPPING Recipient Control Unilateral & Bilateral Program Volume Sensitivity Telecoil Monitoring & Troubleshooting Bi-Directional Confidence Status Alerts Troubleshoot Coil Sense Advanced Flexibility Processor Settings Custom Sound on Remote Assistant The process of measuring and controlling the amount of electrical current delivered to the cochlea The aim is to optimize the information provided for a particular patient, and the audiologist is responsible for this programming and for making these programmes comfortable for patients to listen in their everyday environments This may be performed behaviourally or automatically depending on the age of the patient, and their capabilities; MAPping is performed regularly with implantees, especially the first f 6 months after implantation, until the MAP is stable; In South Africa, all MAPping audiologists have to be additionally licensed through the University of Stellenbosch and Tygerberg CI programme and registered with SACIG, and a member of an implanting team.

5 (RE) HABILITATION / LEARNING TO LISTEN (AUDITORY VERBAL THERAPY & PRACTICE) The process of (re) associating meaning to sound and improving listening, communication, speech and language; Its purpose is to provide support in the areas of operating the device, monitoring hearing, familiarization with sounds, and social / emotional issues; It is ongoing, and therapists will feed back to the MAPping audiologist regarding concerns of the speech stimulus received by the patient. The application and management of technology, strategies, techniques and procedures to enable children who are hearing impaired to learn to listen and understand spoken language in order to communicate through speech. Therapy is diagnostic, with each session being an ongoing evaluation of the child s and parents progress Children learn to use their amplified hearing (hearing aids or cochlear implants) to listen to their own voices, the voices of others and the sounds of their environment in order to understand spoken communication and engage in meaningful conversations. AVP follows and encourages natural spoken language and speech development The parents and therapists help the child to integrate hearing, language and spontaneous speech into the child s personality. Through play and active involvement in everyday situations, listening can become a way of life (Pollack 1985; Estabrooks & Samson 1992; Estabrooks 1994). AVP and other listening spoken language interventions continue to be widely accepted because more children are acquiring, or have already acquired the ability to use spoken language. According to Warren Estabrooks (2006), the ability to interact more freely with other members of society, to obtain higher levels of academic education, to have a more extensive range of careers, to have greater security of employment and to have fewer limitations of the personal and social aspects of their lives. The various techniques, strategies & procedures used to help acquire a speech sound or to clarify a spoken message. Today, the ongoing pursuit of science and artful AVP continue to yield greater possibilities than ever before for children who are born with hearing impairment or who acquire hearing impairment in early childhood. These children and their parents are transforming a grey world of silence into a colourful world of sound (MacIver-Lux, 2005). To ensure the maximum development of spoken conversation through listening

In 2010, a group of 13 South African Speech Language Pathologists, Audiologists & Teachers of the Deaf were selected to receive a scholarship, sponsored by Cochlear.

Part of this commitment to the training, was a promise to train other professionals working with hearing impaired children with regards to the principles and practice, techniques and strategies of

6 In 2010, a group of 13 South African Speech Language Pathologists, Audiologists & Teachers of the Deaf were selected to receive a scholarship, sponsored by Cochlear. This scholarship required a year-long commitment to a training programme, provided by Warren Estabrooks and his team of AV consultants from WE Listen International Inc. Part of this commitment to the training, was a promise to train other professionals working with hearing impaired children with regards to the principles and practice, techniques and strategies of Auditory-Verbal Therapy marks the beginning of professional training in South Africa, and Durban has initiated its own training programme in order to improve services provided to children and their parents. Introducing: 1.Kara Hoffman Janet Smith Inc. & Associates 2.Debbie Hardcastle Sherwood Assessment & Therapy Centre 3.Julie Cardona Private Practice, Hillcrest 4.Ingrid Robertson and Linda Johnstone Livingstone Pre-Primary 5.An additional trainee, Tersia Fox (teacher at Livingstone) was included in 2012 rollout Estelle Roberts: Johannesburg Cochlear Implant Unit Kerry-Lee Galliard: Brenda Schmid: Pretoria Marguerite Monvoisin: private Dani Schlesinger: Chris Hani Baragwanith Hospital Shireen Govender: Kara Hoffman: Durban Programme Ilouise le Roux: Bloemfontein Jenny Bester: Carel du Toit Centre programme Robyn Dalton: TBH Cochlear Implant Unit Barbara Kellett: TBH Cochlear Implant Unit

7 as therapists, we need to... acknowledge parents as our primary clients learn how to engage with adult learners meaningfully practice skills of guiding and coaching provide hope and support ensure that our goals are relevant to the style of the family actively engage the parents observe participate practice empower our clients ensure they experience success Therapist need to be able to... understand the auditory potential of a child understand the science and always be able to explain the reasons behind what we do provide reasonable information and counselling so that a parent can affirm a sense of control as the primary case manager of their child engage with parents as primary clients guide and coach from the side follow normal developmental patterns in audition, speech, language, cognition, communication set clear, specific goals and share them chart progress provide guidance and assistance to other therapists

Cochlear Implants: The Role of the Early Intervention Specialist. Carissa Moeggenberg, MA, CCC-A February 25, 2008

Cochlear Implants: The Role of the Early Intervention Specialist Carissa Moeggenberg, MA, CCC-A February 25, 2008 Case Scenario 3 month old baby with a confirmed severe to profound HL 2 Counseling the