NAL-NL1, the first procedure from the National Acoustic Laboratories (NAL) for prescribing nonlinear gain, was a purely theoretically derived formula aimed at maximizing speech intelligibility for any input level of speech while keeping the overall loudness of speech at or below normal loudness. The formula was obtained through an optimization process in which speech intelligibility and loudnes...

Several hearing aid prescription procedures specify frequency gain functions in terms of the desired levels of amplified speech. The most direct method for verifying hearing aid fittings based on these procedures requires a measurement of amplified speech in the ear canal. This paper describes the evaluation of a probe microphone measurement procedure designed to measure amplified speech to ver...

Both the overall aging of the population and its exposure to higher noise levels have increased the tendency to hearing loss and the importance of improved hearing aids for speech perception. This article reviews improvements in conventional electroacoustic hearing aids, as well as recently developed alternative classes of speech-perception aids, including surgically implanted cochlear stimulat...

BACKGROUND Some patients have to stop using their air-conduction hearing aid(s) because it causes or exacerbates chronic otitis. Then, a solution is the use of a bone-conduction hearing aid such as the percutaneous bone-anchored hearing aid (BAHA). OBJECTIVE To compare patients' performance with their previous air-conduction hearing aid(s) and their BAHA using audiometric tests and a question...