Originally posted by: CarlKillerMiller
I've always wondered: is the damage caused to the ear during concerts and other sustained periods of loud noise permanent, or is it "healed" over time?
The temporary threshold shift (TTS) that occurs initially during and temporarily after noise exposure is believed to be caused by stress to the
stereocilia, inhibitance of potassium channels in the
organ of corti, or a combination of the two and possibly more factors.
The restoration of arrangement in the stereocilia; including clumping, parallel arrangement and order in general, as well as the return of potassium flow will largely restore the temporary threshold shift.
It's comparable to your hair blowing in the wind, much like the cochlear fluid vibrates the hair cells in the ear. If the wind (noise) is very strong, the hair will become disorganized but after a while return to it's original position. However unlike the hair on your head, the hair in your ear does not grow back. Sufficient stress on these cells will cause them to couple together irreversibly and/or detach from their ganglion neurons. Once the hairs have been destroyed, the ganglions will degenerate by
apoptosis, further complicating the possibility of restored sensitivity.
So to answer your question, the ear will 'heal', but only partially. A bit of permanent damage is done each time and it adds up.