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IMPLANTABLE HEARING DEVICES, Type 2 - Attach using magnet, Type 1,…

- - - - Hearing cannot be aided by the other implantable devices
        
        During the tumour removal surgery,
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        During tumor resection, the surgeons may
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- - - - First, a speech processor with a microphone collects and digitizes sound. Then, it sends sound to a transmitter, which sends signals to a receiver under the skin
      - Electrodes threaded into the cochlea are connected to the receiver. Electrical impulses are sent through the electrodes directly to the auditory nerve, bypassing the damaged cells of the inner ear.
        
        MECHANISM
      - An implanted receiver under the skin takes signals from the transmitter and delivers them to electrodes that have been surgically inserted in the cochlea.
  - - - For pre-lingual children, the child should be implanted before 2 years of age.
      - No age restriction for:
        
        Crossover candidates
        
        Post-lingual children & adults
      - No minimum & maximum age of referral for CI candidates.
    - - Functional auditory nerves.
      - Prior use of optimally fitted HA.
      - Normal hearing or mild-to-moderate hearing loss in the contralateral ear.
      - Little/ no benefit from acoustic HA.
      - Severe-to-profound SNHL in the affected ear.
      - Adequate motivation and expectations.
    - - Candidates should demonstrate appropriate preverbal, cognition, and social communication skills.
      - Candidate does not or show only minimal improvement in auditory/ speech and language skills despite consistent usage of HAs.
    - - No AB gap > 15 dB.
      - Speech recognition scores in the best aided condition using HINT in quiet < 60%.
      - Stable air conduction thresholds.
      - Aided hearing thresholds at 1000 Hz and above fall at least at the lower border of the speech spectrum in the better ear after being optimally fitted.
      - Severe-to-profound high-frequency hearing loss.
    - - Candidates/ families should commit to a continuous auditory learning & assessment program offered by the team.
      - Candidates/ families need to have appropriate & realistic expectations and understand the potential and limitations of a CI.
    - - PEDIATRICS
        
        3FA at 500, 1000, 2000 Hz for both ears > 70 dB HL.
        
        Aided hearing thresholds at ≥ 1000 Hz fall at least at the lower border of the speech spectrum in the better ear that has been optimally fitted.
        
        Severe-to-profound SNHL bilaterally.
      - ADULTS
        
        Using oral communication mode.
        
        Little/ no benefit from HAs.
        
        Severe-to-profound SNHL bilaterally.
      - In ANSD cases, those with moderate hearing loss can also be considered for CI provided the candidate is showing limited functional benefits from the HAs.
  - - - agenesia of cochlea
      - chronic otitis media and mastoiditis
    - - uncontrolled epilepsy
      - inappropriate medical conditions
      - not being available for postoperative rehab
- - - - .
  - - - Conductive hearing loss
      - Sensorineural Hearing Loss
      - Mixed Hearing Loss
  - - - Offer amplification without an ear mould in the ear.
      - Some report a more natural sound than conventional hearing aids
      - No obstruction of the ear canal - advantage for people who are prone to ear infections.
      - Last a lifetime
      - Reduced or no feedback - microphone of the audio processor is farther away from the pinna
      - Improve speech intelligibility in noise and quiet
    - - Complication
        https://onlinelibrary.wiley.com/doi/full/10.1002/lary.27513
        
        Medical
        
        Infection
        
        Wire extrusion in the outer ear canal
        
        Pain complaints
        
        Floating Mass Transducer (FMT) displacement
        
        Technical
        
        Device failure
        
        Progressive hearing loss
  - - - Audio processor
  - - - The audio processor converts sound waves to electrical signals.
        
        The signals are then transmitted through your skin to the implant.
        
        The implant then transmits the signals to a tiny part called a transducer - which is attached to one of the bones in the middle ear or attached near to the membrane window of the cochlea
        
        The transducer converts the signals into mechanical vibrations that stimulate movement of your middle ear structures - It works by directly moving the bones of the middle ear, or by vibrating the membrane window of the cochlea.
        
        The vibrations transmit the acoustic information to your inner ear and then to your brain, where it is interpreted as sound.
- - - - Microtia
      - Atresia
    - - If patients use earmolds, the fluid can enter the tubing and block it
      - If they use custom made HA, the fluid can enter the system
    - - Has difficulty hearing people on their deaf side & understanding speech background noise
      - Gets benefits from BAHA
        
        As it eliminates the head shadow effect by bringing the sound to the good ear
        
        As it helps in situations which involve background noise.
    - - BC threshold is 45 dBHL and below (500-3000Hz)
      - Unaided speech discrimination scores is 60% and above
  - - - Titanium implant
        
        Is surgically placed at the mastoid of the temporal bone, amalgamates naturally with the bone
        
        Needs to wait 2-6 months before placing the abutment
      - Abutment
        
        Is placed, extending through the skin
      - Sound processor
        
        Attached to the abutment at the external part
  - - - The sound vibration will be delivered directly through the bone to the inner ear or cochlea.
        
        It will be connected into the electrical impulses by hair cells in the cochlea. This allows the impulses to travel to the brain and perceive the sound naturally.
  - - - Better sound quality as there is no damping when sound is being transmitted via skin
      - Use of titanium abutment reduces the risk of skin infection
      - Ear canal is not occluded by ear molds, preventing humidity build up and skin irritation (more comfortable)
      - Surgery is performed with local anesthesia
      - No pressure against the skin and skull
      - Benefit for those with external canal absence
      - Allows for pre-operative surgery by using headband or test rod
      - Uses the same advanced technology used in premium hearing instruments
    - - Expensive (including the transducer replacement as it can only lasts up to 5 years)
      - Age limitation (minimum age for BAHA is 5 years old)
      - Surgery needed
      - Surgery in pediatric population required extra care