Occurs when the cochlea's ability to convert a certain frequency to electrical signals is lost because of hair cell damage.

Occurs when the cochlea's ability to convert a certain frequency to electrical signals is lost because of hair cell damage.

• A. Temporary Threshold Shift
• B. Auditory fatigue
• C. Noise-induced hearing loss
• D. Permanent Threshold Shift

Answer: (D)

The key idea is how hearing sensitivity changes when hair cells lose their ability to transduce sound into electrical signals. When the cochlear hair cells are damaged in a way that cannot recover, the affected frequencies require a louder sound to be heard, and this loss of sensitivity is permanent. That is what defines a permanent threshold shift: irreversible damage to the transduction mechanism at certain frequencies, so the hearing threshold for those frequencies remains elevated. Temporary threshold shift, by contrast, comes from reversible hair cell stress; hearing thresholds recover after a rest period. Auditory fatigue refers to short-term performance decline from sustained use, not a lasting shift in thresholds. Noise-induced hearing loss is a broader term that can describe permanent or temporary effects, but the scenario specifically points to irreversible hair cell damage and a lasting threshold elevation, which lines up with a permanent threshold shift.

The key idea is how hearing sensitivity changes when hair cells lose their ability to transduce sound into electrical signals. When the cochlear hair cells are damaged in a way that cannot recover, the affected frequencies require a louder sound to be heard, and this loss of sensitivity is permanent. That is what defines a permanent threshold shift: irreversible damage to the transduction mechanism at certain frequencies, so the hearing threshold for those frequencies remains elevated.

Temporary threshold shift, by contrast, comes from reversible hair cell stress; hearing thresholds recover after a rest period. Auditory fatigue refers to short-term performance decline from sustained use, not a lasting shift in thresholds. Noise-induced hearing loss is a broader term that can describe permanent or temporary effects, but the scenario specifically points to irreversible hair cell damage and a lasting threshold elevation, which lines up with a permanent threshold shift.