Middle-ear stiffness increases cause low-frequency hearing loss

Evidence

Otosclerosis is a condition in which the ossicular bones are resorbed and replaced by a spongy, vascularized bone. In the later stages of the disease, the bony growths lead to fixation of the stapes footplate to the oval window. In the early stages, the disease is considered to be stiffness based from an acoustics standpoint. That is, the disease increases the stiffness of the middle ear system, which leads to a decreased ability to transmit low-frequency sound. Because the low-frequency gain of the middle-ear frequency-transfer function is diminished, a lowfrequency hearing loss will result. Any change in frequency transmission of the ear will map into a matched elevation in threshold of the MAP/MAF function. — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 263

Categorization

• DEFINE: Concise clinical definition of otosclerosis and the acoustic mechanism (stiffness-based) behind its early-stage hearing loss.