Eas n hp zee


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Eas n hp zee

  1. 1. Electric Acoustic Stimulationand Hearing Preservation :Atraumatic SurgicalTechniques and OutcomeDr Zeeshan Ahmad Department of ENT,M.S.(ENT,PGY1) NMCH,Patna. 18-10-2012
  2. 2. Cochlear Implant History#Pre-1960’s - beginning studies of electrical stimulation on humans#1960’s - active research of electrical stimulation in human ears#1970’s - first wearable implants designed for long-term stimulation#1980’s - commercial development of the cochlear implant device began
  3. 3. #1985…continued - United States Food & Drug Administration (FDA) granted the first approval for implantation in adults #1990 - FDA granted approval for cochlear implants in children #1999 - Electric Acoustic stimulation first described by C. Von Ilberg & J Kiefer of Frankfurt University. Same year first EAS implant was done.
  4. 4. Somethingbeyond“JUST COCHLEARIMPLANT”
  5. 5. From CI to EAS : BasisFeasibility to preservepreoperative low frequencyhearing when performing CIin the Scala Tympani(ST)gave rise to the concept ofELECTRIC ACOUSTICSTIMULATION.
  6. 6. An EASSystem(Externalcomponents)
  7. 7. ELECTRIC STIMULATION: A cochlear implant converts everyday sounds into coded electrical pulses. These pulses stimulate the auditory nerve. The brain interprets these signals as sound. Mid and high frequency sounds are picked up by the microphone of theDUET 2 Audio Processor and are converted into a special code.
  8. 8. ELECTRICSTIMULATION: This code is sent to the coil and is transmitted across the skin. The implant interprets the code and sends electrical pulses to the electrodes in the cochlea. The auditory nerve relays these signals to the brain
  9. 9. ACOUSTIC STIMULATION: Acoustic amplification turns up the volume on the sounds that the cochlea is still able to hear. For EAS, only the low frequencies are amplified. Low frequency sounds are picked up by the microphone and are digitally processed. Sounds are amplified by the loudspeaker located in the ear hook and are relayed via the ear mould to the ear canal.
  10. 10. ACOUSTIC STIMULATION: Sounds reach the undamaged areas of the cochlea responsible for processing low-frequency sound. The auditory nerve sends the signals to the brain.
  11. 11. The importance of highfrequency hearing Our brain relies extensively on high frequency sounds to clearly decipher and understand spoken words, especially at a distance or in noisy places. High frequencies deliver the additional vital details of sound – making the sounds you hear richer, fuller and crisper in every way. Hearing high frequency sounds clearly can enrich your awareness and enhance your experience.
  12. 12. High frequency hearing loss Did you know that many words begin and end with high frequency sounds? That explains why, when you lose high frequency hearing, words seem to merge together and become indistinguishable from one to the next. In addition to human speech, your environment is full of many other high frequency sounds, without which you can’t get a complete sense of a situation.
  13. 13. Let’s see a typical audiogramfor an individual with highfrequency hearing loss.Someone with severe to profound highThe red line shows a persons hearingfrequency hearing loss would strugglethe of toThe closer the line is to the bottom hear atprofile - how much sound they canhear the sounds above the hearing loss.audiogram, the greater red linedifferent frequencies.(speech, birdsong, music, telephone
  14. 14. Indications and Criteria forEAS(a)Audiological criteria ◦ below 1.5 kHz – No or moderate HL ◦ above 1.5 kHz – Severe to profound SNHL
  15. 15. Indications and Criteria forEAS(b)Speech recognition• The patients monosyllable word score should be ≤ 60% at 65dB SPL in the best aided condition.
  16. 16. Indications and Criteria forEAS(c)Additional criteria No progressive hearing loss(10/2, 15/1 in 1yr) No autoimmune inner-ear disease No hearing loss as a result of meningitis, otosclerosis or ossification No malformation or obstruction of the cochlea Maximum air–bone gap 15dB HL No external ear contraindications to
  17. 17. SURGERY :-The EAS surgeries are aimed atpreserving the anatomical structures andpreserving the cochlear function. Stepsare as follows:- Pre-incision measures ◦ Antibiotic prophylaxis ◦ Systemic corticosteroids Posterior tympanotomy ◦ A standard mastoidectomy is done ◦ Anatomy identified
  18. 18. SURGERY :- Endosteum or Round Window exposure at the Cochleostomy site ◦ Currently, RW approach is mostly used Topical steroid application ◦ Dexamethasone 1mg/ml or Triamcinolone 40 mg/ml ◦ Allowed for minimum 30 minutes
  19. 19. SURGERY :- Placing the Implant ◦ Subperiosteal pocket created ◦ Well for Implant created ◦ Bone dust and blood removed ◦ New gloves ◦ Subcutaneous fat autografts taken ◦ Implant inserted into the implant well ◦ Electrode array is coated with Hyaluronic acid and Steroid
  20. 20. SURGERY :- Inserting the Electrode Array ◦ Electrode tip is placed in the opening(RW or Cochleostomy) and introduced into the Scala Tympani supero-posterior to antero-inferior ◦ Slowly to prevent intracochlear pressure build-up ◦ Inserion is stopped when predefined length is reached or resistance is felt ◦ tip touching the ST Modiolar wall avoided ◦ Opening closed with previously taken antibiotic soaked Fat Autografts.
  21. 21. SURGERY :- Securing the Electrode and Closing the Retroauricular Incision in Three Layers ◦ Care is taken that Ossicular Chain is not touching with any component
  22. 22. Electrode design for HP For hearing preservation the Electrodes are designed to create least trauma to intracochlear structures ◦ Thinner caliber 0.25mm at tip and 0.8mm at entry site ◦ More flexible Tip regions ◦ Tailoring the insertion depth
  23. 23. Outcome of EAS HEARING PRESERVATION ◦ The success of EAS Implant depends upon the RLFH(Residual Low Frequency Hearing). ◦ The cochlear hybrid implant using 6mm and 10mm elctrodes resulted in long term hearing preservation in 75% of subjects. ◦ Studies using Med-El elctrodes showed a successful HP in 12/18 subjects with complete hearing loss in 3/18 subjects.
  24. 24. Outcome of EAS SPEECH PERCEPTION with EAS ◦ EAS significantly improves speech perception in quiet and in noise compared to acoustic hearing only. ◦ In a study by Gstoettner et al EAS treatment yielded an improvement in speech perception in quiet from 24% preoperatively to 71% after 12 months.
  25. 25. Outcome of EAS Music appreciation and Subjective benefit with EAS ◦ EAS users perform better on melody and instrument recognition than CI users. ◦ Subjective benefit of EAS was assessed with APHAB(Abbreviated Profile of Hearing Aid Benefit). ◦ Observed with EAS fitting and improved gradually with experience.
  26. 26. THANK YOUexplore the video coming