Histopathological differences between temporary and
permanent threshold shift. Hear Res.
The mean duration of drilling among the 4 patients with the
permanent threshold shift was 60.0 minutes (range: 45 to 75) (table 3).
But if
permanent threshold shift occurs, hearing loss may become irreversible.
In summary, slow underhand softball pitches most likely pose little to no risk to hearing, but batting practice with multiple impulse sound exposures could put an individual at risk of temporary to
permanent threshold shift with bat materials that produce high intensity sounds.
Permanent threshold shifts are a result of the swelling and deforming of outer hair cells and alterations in endoplasmic reticulum.
Prior acoustic insult, which does not result in
permanent threshold shifts, potentiates aminoglycoside ototoxicity.
Noise-induced
permanent threshold shifts affect 10 to 20 million people in the United States alone.
3) Maintain a log of all
permanent threshold shifts reported by the medical department representative (MDR).
(See if the volume on your car radio seems very high when you drive to work the day following significant noise exposure.) However, initial temporary threshold shifts in hearing acuity likely will be followed by a permanent change in acuity, described as
permanent threshold shifts.
For example, Attias et al conducted a double-blind, placebo-controlled study and found that a group of patients who had been given oral magnesium supplements displayed a significantly lower incidence of noise-induced
permanent threshold shifts than did the controls.