Are real-ear measurements (REM) accurate when using the modified pressure with stored equalization (MPSE) method?

Area of Science:

• Audiology
• Hearing Instrument Science
• Acoustics

Background:

• Real-ear measurements (REM) are standard for verifying hearing aid fittings.
• The modified pressure with stored equalization (MPSE) method is recommended for open, non-occluding hearing instruments.
• MPSE lacks a reference microphone, making it vulnerable to signal level changes caused by patient movement.

Purpose of the Study:

• To quantify potential errors in MPSE real-ear measurements due to head and torso movement.
• To assess the clinical significance of these errors in hearing instrument fitting verification.

Main Methods:

• Real-ear unaided response (REUR) was measured before and after fitting a non-functioning hearing aid in the opposite ear.
• Twenty young adults participated in the study.
• Measurements were taken at 0-degree and 45-degree azimuths to evaluate loudspeaker-to-client angles.

Main Results:

• Mean differences in measurements were under 1 dB across frequencies for both azimuths.
• Standard deviations from the mean differences were typically below 1.5 dB.
• The MPSE method demonstrated minimal susceptibility to clinically significant errors.

Conclusions:

• The MPSE method is a reliable technique for verifying hearing instrument fittings, even with potential patient movement.
• The study suggests that MPSE does not introduce clinically significant errors in real-ear measurements for the tested population.
• Audiologists can confidently use the MPSE method for open, non-occluding hearing instruments.