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Probe Tube Microphone Measurements (Basics and Definitions) Greg Nassar MCHAS Team

Probe Tube Microphone Measurements (Basics and Definitions) Greg Nassar MCHAS Team University of Manchester. Prescriptive Targets. Probe Tube Microphone Measures. Best Fit within Fitting Software. 2cc Coupler. Individual ear canal size. Individual ear canal acoustics. Kemar.

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Probe Tube Microphone Measurements (Basics and Definitions) Greg Nassar MCHAS Team

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  1. Probe Tube Microphone Measurements (Basics and Definitions) Greg Nassar MCHAS Team University of Manchester

  2. Prescriptive Targets Probe Tube Microphone Measures Best Fit within Fitting Software 2cc Coupler Individual ear canal size Individual ear canal acoustics Kemar Targets Based on Pure Tones Targets based on Speech Different Input levels

  3. Probe tube Measurement microphone Reference microphone Supporting wire

  4. Umbo Light Reflex Probe Tube

  5. ULL HTL

  6. Real Ear Unaided Response

  7. Clinical measurement of Real Ear Unaided Response (REUR)

  8. REUR The SPL as a function of frequency in the unoccluded ear canal. Is expressed as either SPL or gain in dB relative to the stimulus level. Real Ear Unaided Response

  9. REUR The SPL as a function of frequency in the unoccluded ear canal. Is expressed as either SPL or gain in dB relative to the stimulus level. Real Ear Unaided Response

  10. REUR The SPL as a function of frequency in the unoccluded ear canal. Is expressed as either SPL or gain in dB relative to the stimulus level. Real Ear Aided Response • REAR • The SPL as a function of frequency in the ear canal with the hearing aid in place and turned on. • Also known as in situ response and is normally displayed as dB SPL Real Ear Unaided Response

  11. REUR The SPL as a function of frequency in the unoccluded ear canal. Is expressed as either SPL or gain in dB relative to the stimulus level. Real Ear Aided Response REAR The SPL as a function of frequency in the ear canal with the hearing aid in place and turned on. Also known as in situ response and is normally displayed as dB SPL Real Ear Unaided Response

  12. REUR The SPL as a function of frequency in the unoccluded ear canal. Is expressed as either SPL or gain in dB relative to the stimulus level. Real Ear Aided Response REAR The SPL as a function of frequency in the ear canal with the hearing aid in place and turned on. Also known as in situ response and is normally displayed as dB SPL Insertion Gain Real Ear Unaided Response

  13. Clinical measurement of real ear aided response (REAR)

  14. Real Ear Unaided Response

  15. Real Ear Unaided Response

  16. Open Ear Gain

  17. Insertion Gain Open Ear Gain

  18. Insertion Gain Target Insertion Gain Open Ear Gain

  19. In adults the REIR is the measure of choice in verifying the electroacoustic characteristics of the chosen hearing aid meet the prescribed gain and desired frequency response. Insertion Gain Target Insertion Gain The difference in dB as a function of frequency between the REUR and the REAR (REIR=REAR-REUR). The real ear insertion gain is the value in dB of the REIR at a specific frequency Open Ear Gain

  20. PTM’s on Children REAR should be used rather than REIR. The REAR will prescribe the same gain at the eardrum for a given hearing loss, regardless of ear canal size and shape. This ensures target speech levels at the child’s eardrum will meet the requirements of the hearing impaired ear despite changes in resonant frequencies of the child’s ear canal over the first few years of life.

  21. RESR Is the SPL as a function of frequency in the ear canal with the hearing aid in place and turned on. The measurement is obtained with the stimulus level sufficiently intense as to operate the hearing aid at its’ maximum output level. ULL RECD Is the difference in dB as a function of frequency between the outputs of a hearing aid measured in the real ear versus a 2cc coupler. Using these measurements the real ear performance of the hearing aid can be predicted. HTL

  22. Key Points to Take Away! REIGtarget based upon the average adult ear canal resonance Not appropriate to ear canal with different acoustic properties to average adult ear REAR target based upon the desired SPL at the eardrum This is always the same for a given hearing threshold (dB SPL) regardless of the size of the ear canal….. However the output of the hearing aid still needs to be corrected for differing ear canal sizes

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