Audiology: Amplification, Rehabilitation, and Habilitation
This domain tests hearing aid selection, fitting, verification, validation, and rehabilitation across the lifespan. Questions often ask you to choose technology, set targets, interpret real-ear measures, or plan auditory training and counseling.
Core rules
- Prescription targets such as NAL-NL2 or DSL are starting points; real-ear measurement (REM) or speech mapping verifies gain against targets.
- Compression manages dynamic range and recruitment. Fast attack/release affects audibility of consonants; too much gain at high frequencies increases feedback risk.
- Open fittings reduce occlusion for sloping high-frequency loss but limit low-frequency gain. Custom earmolds suit severe loss or pediatric patients needing retention and feedback control.
- Validation uses patient-reported outcomes such as APHAB, COSI, or IOI-HA and functional tasks, not only coupler gain.
- Cochlear implantation is considered for severe-to-profound sensorineural loss with limited benefit from amplification; candidacy requires audiologic, medical, and rehabilitative evaluation.
Worked example
A 70-year-old has bilateral sloping high-frequency sensorineural loss, word recognition 80% at 65 dB HL, and reports difficulty in noise. A receiver-in-canal aid with an open dome, NAL-NL2 targets, and noise reduction is fitted. REM shows 8 dB under target at 3–4 kHz. Reasoning: increase high-frequency gain cautiously and recheck feedback; open domes reduce occlusion but may leak low-frequency sound. Validation with COSI and aided speech-in-noise testing confirms benefit.
Traps
Do not assume manufacturer settings equal verification. Do not overamplify low frequencies in a sloping loss. Do not use adult prescription targets unchanged for young children. Do not recommend a cochlear implant for mild or moderate loss without other indications.