Post on 31-May-2015
Cochlear Implantation Journey-candidacy to communication
DR SHEELU SRINIVASCONSULTANT ENT SURGEON
Cochlear Implant
• Bionic ear• Hearing is the only special sense which is
conquered • Electronic device when implanted provides
sense of sound• The cochlear implant is the most significant
technical advance in the treatment of hearing impairment since the development of the hearing aid around the turn of the century.
Cochlear Implants
Designed to restore some sense of hearing for:
• Children or adults who receive little or no benefit from hearing aids.
• Loss must be: (a) profound, (b) bilateral, and (c) sensorineural.
• Problem: Auditory nerve is intact, but hair cell transducers are not functioning.
Normal Ear
Deafness: Normally functioning hair cells not present; some atrophy of 8th N fibers.
What is the difference between CI & Hearing Aid?
• HA simply amplify sounds.CI on the other hand transforms speech sounds into electrical energy used to stimulate the surviving auditory nerve fibers in the inner ear.
• CI have internal & external parts & a surgical process is needed to place internal processor components
Candidacy
• Age: most important criteria• Maximum Benefit in speech & language: in
children born with bilateral sensorineural hearing loss is to be carried out before age of 3 years.
• Up to the age of 6 years good benefit• Above 6 years limited benefit
2 groups
Pre lingual• Lost hearing before
acquisition of speech• Implant before 3 years• CEREBRAL PLASTICITY
Post lingual• Lost hearing after
acquisition of speech• Implant as soon as
possible• Any age 6 months to 100
yrs
Newborn hearing screening• Two to four new-born's,
out of every 1,000, have hearing deficiency
• among the high-risk babies, the number of hearing-impaired is 5 to 14 per cent.
• High-riskers include those birth weight was less than 1.5 kg; jaundice, meningitis or
birth asphyxia; ventilation after birth; family history of hearing
loss
Do we need a test?• Initially, babies who are born with hearing loss do
not look or behave any differently from babies who are hearing.
• However, undetected and untreated hearing loss has serious consequences on the acquisition of language skills as well as cognition and emotional and social development.
• The first 6 months of a baby’s life are very crucial for the development of speech and language.
Results
• Given immediately• Either Pass/Refer• Even though child passes if he is a high
risker further assessment done• Up to 3 years ,every 6 months
Audiological assessment
• OAE-oto acoustic emission• ABR/BERA• Play Audiometry• Impedance audiometry
Audiological
Radiology absolute requirements
• Presence of cochlea(either normal or malformed)
• Presence of auditory nerve• Combination of CT/MRI is performed
Cochlear aplasia.
Absence of the cochlear nerve.
Speech & Language assessments
Psychological & IQ
Medical work up
• Pediatric• Syndromes-Usher’s• Ophthalmology• Neurology• Psychology• Immunization:
Prevenar(pneumococcal),Hib
Counseling/Expectations
• Factors affecting the performance of cochlear implantee
• Duration of deafness• Age of onset of deafness• Age at implantation• Duration of hearing aid use• Others: no. of surviving spiral ganglion cells,
electrode placemt,signal processing strategy
What is a cochlear implant system?
• Microphone• Sound processor: is a tiny computer that
takes the sound captured by the microphone and converts it into detailed digital information. This digital information is sent to the magnetic headpiece, transmitted to the implant, and then sent to the hearing nerve, which in turn sends electrical impulses to the brain, where they’re interpreted as sound.
Surgery
Risks & complications of surgery
• Injury to facial nerve• Meningitis• CSF leak• Skin infection• Flap hematoma• Extrusion of device• Tinnitus• Dizziness
Duration of AVT therapy & benefit in speech
• Compulsory therapy for 1 year• However speech benefits go on for 4 years
post implant• Involvement of family-most crucial
Why are we not implanting all eligible candidates?
• COST FACTOR• LATE PRESENTATION• COMMITMENT FOR AVT