Hearing Instrument Selection & Fitting Flashcards

What is the primary purpose of a real-ear measurement (REM) during hearing aid fitting?

Answer: To verify the hearing aid output matches the prescriptive target in the patient's ear canal

Real-ear measurement (REM) verifies that the hearing aid's acoustic output, measured in the patient's actual ear canal, matches the prescriptive gain target (e.g., NAL-NL2 or DSL v5), accounting for individual ear canal acoustics.

Which hearing aid style is most appropriate for a patient with severe-to-profound hearing loss who also has significant dexterity limitations?

Answer: Behind-the-ear (BTE) with earmold

BTE hearing aids with earmolds are easier to handle due to their larger size, and can accommodate the high-power amplification needed for severe-to-profound hearing loss.

The NAL-NL2 prescriptive formula is designed to maximize which outcome?

Answer: Speech intelligibility while maintaining acceptable loudness

NAL-NL2 (National Acoustic Laboratories Non-Linear 2) prescribes gain to maximize speech intelligibility while keeping overall loudness at an acceptable level, accounting for loudness normalization.

What is occlusion effect in hearing aid fitting, and when is it most problematic?

Answer: The boomy, hollow sound of the patient's own voice when the ear canal is blocked

Occlusion effect is the perception of one's own voice sounding hollow or boomy when the ear canal is occluded by an earmold or hearing aid shell, trapping low-frequency bone-conducted sound energy.

When selecting a hearing aid for a patient with single-sided deafness (SSD), which device type routes sound from the deaf side to the hearing ear?

Answer: CROS or BiCROS hearing aid

CROS (Contralateral Routing of Signals) transmits sound picked up by a microphone on the deaf side wirelessly to a hearing aid on the hearing ear, restoring awareness of sounds from the deaf side.

What is the purpose of a vent in a custom earmold?

Answer: To reduce occlusion effect and allow low-frequency sound to escape

Vents are channels built into earmolds that allow low-frequency sound to pass in and out of the ear canal, reducing the occlusion effect and providing a more natural sound quality.