At the 6-month follow-up, the postoperative bone-conduction deterioration persisted in 4 of these patients (16%), and they were deemed to have had a permanent threshold shift
But if permanent threshold shift
occurs, hearing loss may become irreversible.
Future studies of NIHL associated with stock car racing may include audiologic testing of fans, drivers, and track employees to demonstrate any related temporary or permanent threshold shifts
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).
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.