Susceptibility to tinnitus revealed at 2 kHz range by bilateral lower DPOAEs in normal hearing subjects with noise exposure.
We investigated potential markers of susceptibility to tinnitus in a group of normal hearing young pilots aged 25-35 years and with 8 +/- 5 years of aircraft noise exposure. 316 pilots were interviewed about their tinnitus status and were tested for hearing thresholds (audiograms) and distortion products otoacoustic emissions (DPOAE-grams). There was no subject with permanent tinnitus. 23% reported having occasionally perceived tinnitus after flight missions and 77% reported never having experienced tinnitus after flight missions. General discomfort in the ears to noise was higher in the occasional tinnitus group (15 vs. 6%). The major finding was that difference of susceptibility to tinnitus in normal hearing subjects exposed to noise on a daily basis seemed to be clearly related to lower DPOAEs, bilaterally, in the 1500- to 2800-kHz range. However, no difference could be observed between groups on audiograms at the 2-kHz frequency range. This study provided evidence of outer hair cell dysfunctions in normal hearing subjects exposed to noise and susceptible to tinnitus. Hypersensitivity to noise and decreased DPOAEs in a non-noise-specific frequency range support the idea of another alteration mechanism than noise itself. This point was discussed in the light of recent publications.
Job
Agnès
A
Centre de Recherches du Service de Santé des Armées, La Tronche, France. agnes.job@laposte.net
Raynal
Marc
M
Kossowski
Michel
M
D000328:Adult; D000401:Aircraft; D001301:Audiometry, Pure-Tone; D001309:Auditory Threshold; D005260:Female; D006801:Humans; D008297:Male; D009623:Noise, Occupational / Q000009:adverse effects*; D009784:Occupational Diseases / Q000175:diagnosis* / Q000453:epidemiology*; D016273:Occupational Exposure; D017084:Otoacoustic Emissions, Spontaneous; D011237:Predictive Value of Tests; D015995:Prevalence; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014012:Tinnitus / Q000175:diagnosis* / Q000453:epidemiology*