Tinnitus attracts large interest among researchers all over the world due to its negative psychological side-effects. Researchers from the National Acoustic Laboratory (NAL) tested life-time noise exposure and its influence on the tinnitus experience in 1435 young Australians from various regions. The participants were aged from 11 to 35 years old. The cumulative life-time noise exposure was evaluated using a method developed by NAL from ISO 1999:2013 based on the full audiological case history of the participants.
The tinnitus experience was assessed on the basis of only two general questions about ever having tinnitus, which was understood as a perception of buzzing, ringing or any other sounds in ears or head, and its duration. All participants also underwent full audiological assessment including otoscopy, pure tone audiometry, tympanomery and otoacoustic emissions (DPOAEs and TEOAEs) tests. Results did not reveal significant correlation between noise exposure and hearing thresholds levels (HTL) or OAEs. Tinnitus was not always associated with perception of changes in hearing. Eighty percent of participants reporting changes in their hearing and 57% of participants not perceiving changes in their hearing experienced some tinnitus. However, this result refers to any experience of tinnitus. Thirty-six participants of those reporting tinnitus experienced a constant form of it and interestingly, 61% of this number were males. Overall, a significant increase in the frequency of the tinnitus experience with increased cumulative noise exposure was observed. More research is required to fully explore the topic. However, this is another study confirming that noise can have negative impacts on hearing much before any changes in PTA can be observed.