Otosclerosis stiffens ossicle movement and attenuates transmitted sound

Evidence

The second function of the middle ear is to provide some protection for the hearing system from the effects of loud sounds, whether from external sources or the individual concerned. This occurs as a result of the action of two muscles in the middle ear: the tensor tympani and the stapedius muscle. These muscles contract automatically in response to sounds with levels greater than approximately 75 dB(SPL), and they have the effect of increasing the impedance of the middle ear by stiffening the ossicular chain. This reduces the efficiency with which vibrations are transmitted from the tympanic membrane to the inner ear and thus protects the inner ear to some extent from loud sounds. Approximately 12 to 14 dB of attenuation is provided by this protection mechanism, but this is for frequencies below 1 kHz only. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 541 (#complicates, via linked claim)

Categorization

• XREF: connects to: SOAE bouncing is not caused by middle-ear impedance changes; Early otosclerosis adds stiffness and thus selectively reduces low-frequency hearing — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 263; The ossicles convert air vibrations into mechanical movements that drive cochlear fluid (+3 more)

Related

• Middle-ear muscles automatically stiffen to block loud sounds (similarity 0.91)
• The middle ear both transmits sound and protects against loud noise (similarity 0.90)
• The middle ear amplifies sound pressure through three mechanical mechanisms (similarity 0.90)
• Early otosclerosis adds stiffness and thus selectively reduces low-frequency hearing (similarity 0.89)
• An acoustic reflex desensitizes the ear to protect cochlear hair cells (similarity 0.89)
• SOAE bouncing is not caused by middle-ear impedance changes (similarity 0.88)
• Middle-ear stiffness increases cause low-frequency hearing loss (similarity 0.88)
• The ossicles mechanically transform impedance to overcome fluid resistance (similarity 0.87)
• The ossicle-softer-ligament design protects ears by dumping intense-sound energy. (similarity 0.87)
• Middle ear stiffness reduces low-frequency gain while added mass reduces high-frequency gain (similarity 0.86)
• Eustachian tube blockage causes pain and low-frequency hearing loss (similarity 0.86)
• The ossicles convert air vibrations into mechanical movements that drive cochlear fluid (similarity 0.85)
• Sound becomes mechanical movement via the eardrum and ossicle chain (similarity 0.83)
• Middle ear impedance match is optimal near 1 kHz (similarity 0.82)
• Ossicular mass increases from otosclerosis cause high-frequency hearing loss (similarity 0.82)

Broader Connections

• The ossicles convert air vibrations into mechanical movements that drive cochlear fluid #expands (0.85)
• Middle-ear muscles automatically stiffen to block loud sounds #complicates (0.80) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 541
• An acoustic reflex desensitizes the ear to protect cochlear hair cells #complicates (0.75)