HOW “REAL” ARE REAL EAR MEASUREMENTS FOR OPEN-FIT INSTRUMENTS? 

Appleby R, Groth J, Kulkarni S.

GN Resound

Real ear measurements (REM) can be used to verify that hearing instruments are meeting the patient’s needs as well as the hearing aid manufacturer’s prescriptive targets.  Recent trends in hearing aid dispensing have shown an increase in the number of patients purchasing open-fit hearing instruments.   There are not currently any industry standards for REM testing.  How do different calibration methods and equipment affect the REM results obtained with open hearing instruments? 

This study was designed to evaluate how different calibration methods and/or equipment can affect REIG measurements with open-fit hearing instruments.  

REIG measurements were performed on 10 subjects, using ReSound Be hearing instruments (open-fit with a remote microphone) programmed for a symmetrical high frequency hearing loss.   Feedback cancellation was enabled on the hearing instruments and all other algorithms were disabled.   REIG measures were evaluated using two different calibration methods and  pieces of commercially available REM equipment.

Results revealed no significant difference when comparing averaged data for REIG measures performed with two different calibration methods (concurrent equalization (MPSE) and stored equalization (MPSE).   However, a significant difference was noted when comparing averaged data for REIG measures obtained using two different REM systems(Verifit Audioscan and GN Otometrics Aurical).  The results of this study will be discussed in more detail and recommendations will be made for conducting real ear measurements with open hearing instruments.

E-mail: rappleby@gnresound.com