The Influence of RECD Transducer When Deriving Real-Ear Sound Pressure Level

Abstract

The accuracy of the derived real-ear response obtained using an RECD, measured with an ER-3A insert earphone, is very good when an HA1 is used for the coupler component of the RECD. The accuracy diminishes somewhat with the HA2 coupler, especially for undamped hearing instruments. The accuracy of the derived real-ear response is very good when the RECD is measured using the hearing instrument and the HA1 or the HA2 coupler.

Comparison of Psychophysical and Physical Measurements of Real Ear to Coupler Differences

“…, the test-retest reliability was very high, and no session effect was obtained. The test-retest reliability is in good agreement with the literature (Scollie et al 1998;Munro & Davis 2003;Munro & Millward 2006). The standard deviation is greater than 1 dB at lower and higher frequencies most probably due to the problem of air leakage at low frequencies and standing waves at high frequencies.…”

“…Length of earmold tubing and transducer impedance influence the RECD (Bagatto et al 2005). Munro and Millward (2006) found differences between the RECD measured with an ER-3A insert phone and with different hearing aids. In addition, it was shown by Munro and Howlin (2010) that the difference in RECD between the left and the right ears is small in adults, school-age children, and preschool children that use hearing aids with customized earmolds.…”

Using the Real-Ear-to-Coupler Difference within the American Academy of Audiology Pediatric Amplification Guideline: Protocols for Applying and Predicting Earmold RECDs

“…However, as earmold tubing length increases, accuracy in predicting real-ear SPL from BTE fittings decreases especially when an HA2 coupler is used (Munro and Hatton, 2000;Munro, 2004;Bagatto et al, 2005;Munro and Toal, 2005;Bech, 2007). For the frequency range 250 to 8000 Hz, and with clinically applicable earmold tubing lengths, the inaccuracies are lesser for small ears (,5 dB) and greater for larger ears (7-10 dB), with potential inaccuracies .10 dB when the earmold tubing length is .45 mm and/or the earhook is unfiltered (Munro and Millward, 2006;Bagatto et al, 2005;Gustafson et al, 2013). Coupling the personal earmold to the HA1 coupler also reduces inaccuracies (Munro and Hatton, 2000;Munro 2004;Bagatto et al, 2005), although using putty to connect soft silicone earmolds to metal couplers can be unstable in the test box and may create infection control concerns (Sturgulewski et al, 2006;Ahmad et al, 2007).…”

Venting Corrections Improve the Accuracy of Coupler-Based Simulated Real-Ear Verification for Use with Adult Hearing Aid Fittings

“…The application of S-REM for vented fittings, and for fittings in the adult population, has been less of a focus in the literature, and the inability of S-REM to account for venting is acknowledged within pediatric protocols (AAA, 2013;Bagatto, 2016). Several studies have examined or applied S-REM in adult ears with most fittings predicted within 5 dB (Bagatto et al, 2005;Munro & Hatton, 2000;Munro & Millward, 2006). These studies indicate that highimpedance transducers (Bagatto et al, 2005;Munro & Toal, 2005) and HA-1 coupler reference (Munro & Millward, 2006) provide improved accuracy, which relates to current recommendations to use a high-impedance transducer and a standardized HA-1 reference for the measurement of the RECD (American National Standards Institute, R2018).…”