Hearing Aid

Aka: Hearing Aid

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II. Background

  1. OTC Hearing Aids will be available in U.S. in 2023

III. Evaluation: Available Features When Purchasing a Hearing Aid

  1. Digital noise reduction (most modern Hearing Aids)
    1. Reduces Ambient common noises such as wind
  2. Tinnitus Masking (most modern Hearing Aids)
    1. External noise volume adjusted to mask the specific Tinnitus frequency
  3. Feedback Suppression
    1. Prevents squealing sound (microphone feedback)
  4. Directional Microphones
    1. Sound directly in front of patient is amplified, and sounds from other directions are reduced
  5. Automatic noise level adjustments
    1. Newer Hearing Aids adjust volumes to optimize speech understanding given Ambient noise
  6. Multiple Pre-Programmed Settings
    1. Audiologist can setup multiple different modes for specific listening needs and environments
  7. Rechargeable Batteries
    1. No need to replace batteries (every 1-2 weeks, ~30 per year) eases maintenance (esp. low dexterity, Vision)
  8. Smartphone Integration
    1. Newer Hearing Aids connect to smartphones to adjust volumes and listening profiles via manufacturer apps
  9. Wireless or Bluetooth Connectivity
    1. Newer Hearing Aids may connect to phones, computers, televisions either directly or via secondary device
  10. Telecoil (T-Coil)
    1. T-Coil compatible devices (phones) and facilities (e.g. Hearing loop theaters) improve sound quality

IV. Types: Location

  1. Hearing Aid behind the ear (mild to severe Hearing Loss)
    1. Classic Hearing Aid with the electronics in a small case behind the ear
    2. Sound tube exits the Hearing Aid and is placed inside the ear
    3. Largest Hearing Aids, but easier to use, with volume control and some are rechargeable
  2. Mini Hearing Aid external and receiver in ear canal (mild to severe Hearing Loss)
    1. Ear canal receiver connects via a thin wire to a small Hearing Aid behind the ear
    2. Typically rechargable devices with many added modern features, and less visible than behind the ear
    3. Manual dexterity needed to position, and susceptible to earwax clogging
  3. Hearing Aid completely In the ear canal (mild to moderate Hearing Loss)
    1. Custom made Hearing Aid that completely sits within the ear canal (Least externally visible Hearing Aid)
    2. Batteries are small, with short lives, difficult to handle, and not rechargeable
    3. Lack added features (e.g. volume control, directional microphone, T-Coil) and susceptible to earwax clogging
  4. Full Ear including bowl/concha (moderate to severe Hearing Loss)
    1. Largest devices that are the easiest to manipulate by those with decreased dexterity
    2. Hearing Aid fills the external bowl of the ear (antihelix, concha) and canal
      1. Available as full shells or half shells (fill only part of the ear bowl)

V. Types: Conventional Analog Hearing Aids

  1. Cost: ~$900 per ear
  2. Components
    1. Battery
    2. Microphone transduces sound into electrical energy
    3. Receiver changes electrical energy into sound
    4. Most Hearing Aids can adjust volume
      1. May be a problem with background noise
  3. Sub-Types
    1. Linear (Simple Hearing Aid)
      1. Amplifies loud and soft sounds equally
    2. Non-Linear
      1. Varied amplification for loud and soft sounds
      2. Decreased recruitment (increased loudness)

VI. Types: Programmable Hearing Aids

  1. Programmable by audiologist
    1. Sound levels adjustable for audibility and comfort
    2. Volume per frequency
    3. Intensity
    4. Microphone power output
    5. Compression Ratios
  2. Some available with multiple programs
    1. (e.g. telephone, music)

VII. Types: Digital Hearing Aids

  1. Cost: ~$2900 per ear
  2. Digital signal processor samples incoming signals
  3. Adjusts in different sound environments
    1. Can reduce background noise from non-speech source
    2. Enhances speech understanding
  4. Programmable by audiologist
    1. See Above

VIII. Management

  1. Hearing Aids amplify many sounds including background noise
    1. Expect a time to adjust to Hearing Aids, and tuning out background noise (e.g. footsteps)
    2. Proficiency with Hearing Aids requires a training period with frequent, continuous Hearing Aid use
    3. Start with less noisy
  2. General measures
    1. Ears should be dry before inserting Hearing Aids
    2. Turn off Hearing Aids when not in use
    3. Removing ear wax with cotton swabs is not needed and may cause ear Trauma
    4. Remove Hearing Aids when sleeping, bathing, swimming, applying hair care products or instilling ear medications
      1. Light rain and mild sweating is not typically a problem
    5. Clean Hearing Aids daily with a soft cloth
    6. Button Batteries
      1. May need changing as every week or more
      2. Button batteries are dangerous if swallowed (keep away from pets and young children)
  3. Ear Pruritus or Irritation
    1. Causes
      1. Over-cleaning (e.g. wax removal decreases ear canal protection)
      2. Dry Skin
      3. Mal-fitting Hearing Aid
      4. Reaction to Hearing Aid material (uncommon)
    2. Approach
      1. Expect irritation and itching to improve over time
      2. Consider Skin Lubricant (skin Moisturizer) application overnight while Hearing Aids are out of the ear
      3. Recheck with Hearing Aid specialist if persists

IX. Resources

  1. Hearing Aid Styles (Cleveland Clinic)
    1. https://my.clevelandclinic.org/health/articles/5122-hearing-aid-styles
  2. Best Hearing Aids (NCOA)
    1. https://www.ncoa.org/adviser/hearing-aids/best-hearing-aids/

X. References

  1. (2022) Presc Lett 29(9): 52
  2. Michels (2019) Am Fam Physician 100(2): 98-108 [PubMed]
  3. Unwin (2024) Am Fam Physician 109(3): 279-83 [PubMed]

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