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.