On Ear / Real Ear Procedures

  1.  Calibrate the probe tube
  2. Otoscopy
  3. Check placement of the speaker
  4. Place the probe tube
    1. Measure the probe tube and mark
      1. Adult: 30mm males, 28mm females, kids 20-25mm
  5. Geometric
    1. Measure 5mm past tip of ear hold or hearing aid
    2. Closer to the TM the MORE accurate the high frequencies

RECD - Real Ear to Coupler Difference
  • ANSI Definition: Difference in dB as a function of frequency between the SPL at a specified measurement point in the ear canal and the SPL in a 2cc coupler for a specified input signal
    • usually a positive number
    • smaller heads = larger RECD
    • what if RECD is negative?
  • Know the levels of amplified sound delivered into the patient's ear canal
  • accounts for unique acoustic properties of the ear and earmold coupling (if the RECD is conducted with the earmold)
    • this helps avoid errors that can occur when using average values in the fitting process
  • hearing instrument response shaping can be performed in the hearing aid test chamber, under highly controlled acoustic conditions
  • the degree of cooperation and amount of time required from the patient in the fitting process is greatly reduced

REUR/REUG

REAR/REAG - Real Ear Aided Response / Gain
  • Difference in dB as a function of frequency between the SPL at a specified measurement point in the ear canal and the SPL at the field reference point for a specified sound field, with the hearing aid (and its acoustic coupling) in place and turned on
  • Why?
    • prescriptive methods specify REAR/REAG targets for a variety of input levels and thus require these measurements during the fitting process
    • used as a reference for calculation of real ear insertion gain (REIG)(i.e. REAG - REUG = REIG)
    • an individual's auditory characteristics are specified in dB SPL

REIG - Real Ear Insertion Gain
  • ANSI Definition: Difference in dB as a function of frequency between the REAG and the REUG obtained with the same measurement point and the same sound field conditions. Previously called real-ear insertion response
  • Why?
    • Determine whether a particular hearing aid setting has achieved a particular insertion gain prescriptive target
    • in the absence of a theoretical target, the calculation of REIG becomes rather meaningless

REOR/REOG

Probe microphone measures allow you to account for RECD and/or REUR
  • RECD makes sense whenever you are dealing with couplers and want to be exact and/or know that your patient is very different from a coupler
  • REUR makes sense when you need to have a reference for insertion gain or when all you have is sound field thresholds

Challenges for the Clinician
  • Measure SPL at the eardrum
  • Choose a valid, reliable outcome measure
  • Remember: feedback, occlusion problems and loudness comfort are still the top three reasons for individuals rejecting hearing aids
  • Batteries and moisture continue to be a problem for patients
  • Re-structure your time so customization is part of your activities
  • Embrace new developments while following an evidence based approach
  • Provide the rehabilitation that makes the person an active participant
  • Include hearing protection in everything you do!

Speech Mapping