Real-Ear to Coupler Difference in Patients with Ear Drum Perforation

Abstract

The aim of this study is to investigate the effects of ear drum perforation on real-ear to coupler difference (RECD) in adults. RECD was measured using a probe tube microphone system in 22 patients with ear drum perforations. Twenty-two normal subjects served as controls. For normal subjects, RECD was in good agreement with the values reported in the literature. For the perforated ears, the RECD was up to 8 dB smaller in the frequency range from 0.5 to 1 kHz. There was no significant difference at frequencies below 0.25 kHz and above 1 kHz. A much larger intersubject variability was found in the experimental group. The mean intersubject standard deviation was 4.4 dB in the experimental group as contrasted with 2.2 dB in the control group. Neither the equivalent ear canal volume nor the perforation size appeared to be correlated with the degree of RECD reduction over lower frequencies. These results strongly suggest the need for individual RECD measurements, rather than using the average normal RECD, to appropriately compensate for the reduced transmission of lower-frequency sounds in fitting hearing aids for patients with ear drum perforations.

A computer program to calculate the size of tympanic membrane perforations

“…Clinically, the perforation size is one of the most important prognostic factors for tympanoplasty 1 . For those patients who choose hearing aids instead of surgery as a way of aural rehabilitation, the size of the perforation also affects the results of real ear measurements 2,3 . A number of studies have found that the size of tympanic membrane perforation is closely related to the middle ear sound transmission 4–6 .…”

Applying the reference values of real-ear-to-coupler-difference for deaf and hard-of-hearing children in Taiwan: Cautions and considerations

“…Our measurements followed this procedure; however, the measured RECDs for frequencies of 0.25 kHz−3 kHz were still significantly larger than the reference values. In addition, higher RECDs at low frequencies were also reported by Liu and Lin [17]. Although they reported that the RECDs between adults and children were not significantly different, the RECDs were greater for children at all frequencies.…”

“…The use of individually measured RECDs becomes crucial in cases where children might be inappropriately fitted based on general reference values. Whenever feasible, incorporating individual RECD measurements during the HA fitting and selection process is essential [17,26]. Existing research also advocates for the use of fit-to-target methods and RECD measurements to optimize hearing aid output and enhance auditory outcomes [27].…”

A Study of Hearing Aid Fitting Characteristics in Patients with Eardrum Perforation

“…국내에서 만성적인 고막천공이 약 2%의 높은 출현율을 보이는 것으로 보고되고 있다 (Kim et al, 1993 (Mueller et al, 1992), 연령, 외이도 길이와 형태, 중이 임피던스, 이어몰드의 음향적 특성 등 다양한 변수에 의해 영향을 받는다 (Westwood et al, 1995). 고막천공으로 인한 청력손실은 주파수에 따라 달라 저 주파수에서 가장 크고, 천공의 크기가 클수록 손실이 크며, 중이강 용적에 반비례한다 (Mehta et al, 2006;Voss et al, 2001 (Liu & Lin, 1999;Martin et al, 2001).…”

“…고막천공으로 인한 저주파수에서의 RECD의 큰 차이에 대 한 이유로 Martin et al (1997) (Liu & Lin, 1999, 2000Martin et al, 2001 (Liu & Lin, 1999), 또 다른 연구 (Martin et al, 2001…”