In hearing aids, what does the term "OSPL90" refer to?

The term "OSPL90" refers specifically to the maximum output sound pressure level of a hearing aid when it is providing full-on gain. This measurement reflects the maximum sound level that the device can produce, which is significant when assessing how well the hearing aid can amplify sounds for users with varying degrees of hearing loss.

Understanding OSPL90 is crucial for hearing aid dispensers and audiologists, as it helps ensure that hearing aids are set to provide adequate amplification without causing discomfort or damage to the user’s hearing. It is typically measured in decibels (dB) and indicates the hearing aid's capability to deliver sound at a loudness level that can be beneficial for the user while taking into account the risk of feedback or distortion at high output levels.

The other options relate to different aspects of hearing aid performance and measurement, but OSPL90 specifically pertains to the amplifier's ability to output sound at its maximum capacity under controlled test conditions.