Real Ear Measurement Why, how, where, and when

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Real Ear Measurement Why, how, where, and when?

• MHAS Training Team
• with thanks to
• Pauline Smith

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Three basic principles

• Use manufacturers agreed target, NAL NL1 is
  preferred
• Verify using REIG in all patients
• Adjust programming of aid if there is a gross
  difference between target gain and insertion gain

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Why REM?

• Where theres a target curve
• It is based on the average ear or a metal ear in
  a plastic man (KEMAR)
• It might be different in a real ear with a real
  earmould

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GP
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DW
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within target range before REIG
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So, protocol states

• Check whether the real ear curve is like the
  target curve
• at the fitting appointment,
• on all patients

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How?

• 1. Tube calibration
• each time you change a tube
• each patient
• hold tube in front of ref mic
• 2. Check calibration
• REUR should give a flat line with tube and mic
  in same position

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How?

• 3. Position the patient so ear is
• 45? to speaker
• 0.5m from speaker
• level with centre of speaker
• 4. Otoscopy proceed with caution if
• perf, grommet, mastoid cavity, glue ear,
  discharge, wax covers1/3 area...

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How?

• 5. Insert probe tube
• 1.1mm tube with black marker
• set marker to 27mm
• black marker at tragus
• check with otoscope

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How?

• 6. Measure REUR, no hearing aid in
• 7. Measure REOR, aid in but switched OFF
• 8. Measure REIR, aid in and switched ON

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REIR

• Aid set for everyday use
• Select NAL NL1
• Remember that Genie adaptation manager 1,2 or 3
  will give less gain than NAL NL1

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REIR

• Select 65dB for target
• Select stimulus of modulated SN at 65dB

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Using the REMs

• How much should I modify the click and fit
  settings
• based on REM?
• based on patient responses?

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Tolerances guidelines

• Where a fitting rationale contains an acoustical
  target,
• /- 5dB at frequencies 250 - 2k Hz
• /- 8dB at 3k and 4k Hz
• slope /- 5dB per octave

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If there is a difference

• Investigate gross differences
• faulty hearing aid, faulty programming
• unusual shapes or sizes of ear canals
• difficulties with earmoulds
• Always listen to what the patient says
• Consider modifying the programme

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9. Modify the programming

• Run 2 modules on Aurical at the same time
• Set up REIG to run continuously
• Adjust the settings in Genie and monitor the
  changes on the REIG curve

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10. Check high level output

• OPTIONAL
• Use 90dB warble tone to check patient response,
  ULL not exceeded
• More important if programming of aid has changed
  after REMs

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Where?

• In a quiet room
• Speaker should not be at the back of a table
• Avoid flat reflecting surfaces of possible

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Background noise

• The room must not be too noisy, particularly for
  measurement at 55dB
• BS states that the signal must be gt10dB above
  ambient noise in all frequency bands

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When?

• At the initial fitting appointment
• To verify the fitting
• At later appointments if necessary
• if changes made to the programming
• if new mould / patient not happy