HAC Earmold Selection & Hearing Aid Styles Flashcards

Which materials are most commonly used to fabricate custom hearing aid earmolds?

Answer: Acrylic (hard) or silicone (soft)

Custom earmolds are typically made from hard acrylic or soft silicone, with the choice based on retention requirements, comfort preferences, and acoustic needs.

Why is an ear impression taken before fabricating a custom hearing aid or earmold?

Answer: To capture the exact shape of the ear canal and concha so a precisely fitting shell or mold can be manufactured

An ear impression creates a physical replica of the ear canal and concha, which is used as the model for manufacturing a custom-fit earmold or hearing aid shell.

What is an open-fit dome in a RIC or slim-tube BTE hearing aid?

Answer: A small non-occluding tip that leaves much of the ear canal open, minimizing the occlusion effect

An open-fit dome leaves the ear canal largely unoccluded, reducing the occlusion effect and making it suitable for patients with normal or near-normal low-frequency hearing.

Which earmold style provides the most retention and acoustic seal, making it suitable for severe-to-profound hearing loss?

Answer: Full shell (concha fill) earmold

A full shell earmold fills the entire concha bowl, providing maximum surface contact for retention and a secure acoustic seal essential for high-power fittings.

What does a CROS hearing aid system do?

Answer: Routes sound picked up at a non-aidable ear to a hearing aid worn on the better ear for unilateral hearing loss

A CROS (Contralateral Routing of Signal) system transmits sound from the poorer ear's microphone wirelessly to a receiver worn on the better ear.

How does a longer canal portion of an earmold affect feedback susceptibility?

Answer: It reduces feedback by providing a deeper, tighter acoustic seal in the canal

A longer canal portion creates a better acoustic seal deeper in the ear canal, reducing the likelihood that amplified sound will leak back to the microphone and cause feedback.