Open Hearing Aid Fittings for Small Children

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Answer

The audiological management of an infant or young child with normal hearing through 2000 Hz is definitely a challenge. Open canal (OC) fittings that are coupled to miniature BTEs are a consideration, but may be problematic because they may not have DAI and/or safety features. Coupling an open earmold to a standard BTE that has these important characteristics is another option, provided some additional considerations are taken into account.

Firstly, OC fittings require verification of the electroacoustic characteristics of the hearing aid to ensure the appropriateness of the electroacoustic fitting. For practical reasons, verification of hearing aids for infants and young children is typically performed by using real-ear-to-coupler difference (RECD) measurements and a coupler-based (or simulated) real-ear verification protocol. A limitation of this protocol with OC fittings is that the effects of the open earmold will not be fully accounted for. 'Actual' real-ear measurements are required to obtain a more accurate picture of the acoustic properties of the open earmold. This method can be a challenge for infants and young children who cannot sit still or quiet during traditional real-ear verification procedures.

Another aspect to consider is the potential for acoustic feedback with an open earmold. While feedback management systems provide a way to reduce unwanted acoustic feedback, one must ensure that audibility of the high frequencies is not compromised. After all, this is the frequency region where amplification is required.

One final piece to bear in mind is the retention of the open earmold in the patient's tiny ear canal. For infants and active toddlers, an open earmold may not provide enough stability in the ear canal to remain in place during routine activities. There may be a higher risk of loss or damage to the hearing aid. In addition, if the aid does not stay in place reliably, a consistently audible signal is not being provided to the child.

It is therefore important to consider the above issues when contemplating an OC fitting for an infant or young child. If a child is able to tolerate traditional real-ear verification procedures so that an appropriate electroacoustic fitting can be achieved without feedback and earmold retention is reliable, then an OC fitting would be a strategy to consider for a young patient with a high frequency hearing loss.

Marlene Bagatto, Au.D. is a Research Associate at the National Centre for Audiology at the University of Western Ontario in London, Ontario, Canada. She can be contacted via email at bagatto@nca.uwo.ca.