Evaluation of real-ear to coupler difference (RECD) Values and Test-Retest Reliability in 0.4 cc and 2 cc Coupler Measurements in Young Adults

Objectives: The aim of this study was to obtain normative data and examine test-retest reliabilities in HA-2 2cc and 0.4 cc coupler RECD measurements in the young adult Turkish population.Materials and Methods: In this study, 36 participants (17 females, 19 males), aged between 20 and 26 years (mean age = 21.80, SD = 1.27), with normal otoscopic findings, normal bilateral hearing, and no history of outer or middle ear surgery, were evaluated. HA-2 2cc and 0.4 cc RECD measurements, as well as retest measurements, were conducted on both ears of the participants by using insert phones and foam tip.Results: A statistically significant positive correlation was observed between the HA-2 2 cc and 0.4 cc RECD test–retest measurements. For the 2 cc RECD test–retest results, reliability was found to be moderate at 125 Hz and 10 kHz, excellent at 3 kHz, and good at the other frequencies. For the 0.4 cc RECD test–retest results, reliability was moderate at 1 kHz, 1.5 kHz, 2 kHz, and 10 kHz, and good at the other frequencies. No interaural differences were found in the RECD values obtained with either coupler. A significant difference between male and female participants was observed only at 250 Hz for the 2 cc RECD test results, and at 125 Hz and 250 Hz for the 0.4 cc RECD test results. Across all frequencies, the 2 cc RECD values were higher than the 0.4 cc RECD values.Conclusion: HA-2 2 cc and 0.4 cc RECD measurements by using insert phones and foam tip are repeatable and clinically reliable methods in young adults.