Sensorineural hearing loss
- increase in thresholds and/or loss of ability to transduce specific frequencies due to damage to the cochlea, auditory nerve or cochlear nucleus
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i.e., anything between the middle ear and the bilateral outputs of the cochlear nucleus
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most commonly used to refer to hair cell damage, and even more specifically, stereocilia damage
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the base (high frequency region) of the cochlea is the most sensitive to damage
common causes include:
- noise
- noise damage is not simply a function of intensity - length of exposure as well as the frequency spectrum are also important - brief, high frequency sounds (e.g., gunshots) have the most potential for damage
- genetic defects, especially damage to the system responsible for generating the endocochlear potential
- ototoxic drugs, including
- aminoglycoside antibiotics (e.g., gentamicin, amikacin) which cause stereocilia damage
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loop diuretics (e.g., furosemide) which block the Na+/K+/2Cl- transporter responsible for the generation of the endocochlear potential
- noise
- sensorineural hearing loss affects both airbourne and bone-conducted stimuli, therefore both curves exhibit a threshold shift in the affected frequency range on the audiogram