[Structural changes in the auditory field in relation to age].

Using a category scale we measured the loudness of narrow band noises experienced in 3 age groups (15-23, 33-45, and 60-75 years old). The narrow band noises had center frequencies between .125 and 8 kHz with sound pressure levels of 60, 75, and 90 dB each. We found the well-known high-frequency loss. However, we also found a hypersensitivity at middle frequencies correlated with high-frequency loss. The presumable causes of this hypersensitivity and its consequences for hearing aid fitting will be discussed.