Question
Are there modified strategies for inserting the probe tube into a young infant's ear for measuring the real-ear portion of the RECD?
Answer
Strategies for measuring RECDs on toddlers may not work for young infants. Infants are usually being cradled in the caregiver's arms or in a stroller or car seat. Access to the ear is a challenge due to this positioning and the close proximity of the ear to the shoulder. A strategy that involves connecting the probe tube to a small eartip or personal earmold using plastic wrap or soft surgical tape (see Figure 1 & 2) has been evaluated and shown to be feasible in young infants (Bagatto et al., 2002).
Figure 1. The probe tube connected to the earmold using clear wrap.
The probe tube should extend approximately 2 to 4 mm beyond the sound bore. Unfortunately, the plastic wrap used for protecting hearing aids from moisture (Moisture Guard) is no longer available. Therefore, soft surgical or first aid tape cut in very thin strips is recommended. Soft surgical tape should be used as opposed to regular tape as this may cause a sharp edge when applied.
Figure 2. Insertion depth guideline when probe tube is inserted independently.
If inserting the probe tube separately from the eartip is preferable, the insertion depth guideline determined in the Bagatto et al. (2002) study is 10 mm from the opening of the ear canal.
References:
Bagatto, M., Moodie, S., (2007, October 8). Learning the Art to Apply the Science: Common Questions Related to Pediatric Hearing Instrument Fitting. Audiology Online, Article 1886. Accessed from the Article Archives from www.audiologyonline.com/
Bagatto, M.P., Scollie, S.D., Seewald, R.C., Moodie, K.S., & Hoover, B.M. (2002). Real-ear-to-coupler difference predictions as a function of age for two coupling procedures. Journal of the American Academy of Audiology, 13, 407-415.
This Ask The Expert Question was taken from an article previous published on Audiology Online entitled, "Learning the Art to Apply the Science: Common Questions Related to Pediatric Hearing Instrument Fitting". See Bagatto and Moodie (2007) for additional information.
Marlene Bagatto, Au.D., is a Research Associate and Sheila T. F. Moodie, M.Cl.Sc., is a Research Audiologist at the National Centre for Audiology at the University of Western Ontario in London, Ontario, Canada.
