Early otosclerosis adds stiffness and thus selectively reduces low-frequency hearing
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. For example, a decrease in sound transmission of 10 dB from 250 to 1000 Hz due to otosclerosis will elevate MAP/ MAF thresholds between 250 and 1000 Hz by a corresponding 10 dB. — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 263
When thresholds are plotted in this way, we observe that this early-stage otosclerosis is associated with hearing loss only in the low frequencies and no loss above 2 kHz. On the other hand, late-state otosclerosis is associated with a similar amount of hearing loss in dB across the frequency range. — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 279
Categorization
- corroborated: 3 independent passages support this claim — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 263; Jennifer Lentz, Psychoacoustics- Perception of Normal…, 279
- XREF: connects to: Otosclerosis stiffens ossicle movement and attenuates transmitted sound; Eustachian tube blockage causes pain and low-frequency hearing loss