A 70-year-old patient with moderate-to-severe presbycusis (sloping high-frequency SNHL) requires hearing aid fitting. The 'gain' of a hearing aid is defined as:
- A The difference between the output sound pressure level and the input sound pressure level (dB) ✓
- B The maximum power output of the hearing aid in dB SPL
- C The frequency range over which the hearing aid amplifies sound
- D The ratio of signal-to-noise improvement in dB provided by directional microphones
Correct answer: A. The difference between the output sound pressure level and the input sound pressure level (dB)
Explanation
The gain of a hearing aid is defined as the difference (in dB) between the output sound pressure level (at the ear canal) and the input sound pressure level (presented to the microphone). For example, if the input is 60 dB SPL and the output is 90 dB SPL, the gain is 30 dB. This is distinguished from saturation sound pressure level (SSPL or OSPL90), which is the maximum output regardless of gain. Understanding gain is fundamental to hearing aid prescription and fitting.
Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.