Distortion Products Otoacoustic Emissions as Markers of Tinnitus Persistence after Acute Acoustic Trauma
Abstract
It is a common thought in the physicians military community that persistence of tinnitus after acute acoustic trauma (AAT) essentially depends on severity of hearing thresholds shifts. Nevertheless it has never been demonstrated scientifically. Here we have looked for predictive factors of tinnitus duration after AAT by using hearing thresholds and distortion product otoacoustic emissions ( DPOAEs). DPOAEs are otoacoustic emissions that revealed the functional state of the active cochlear mechanical processes. Young military adults under 25 years old, without history of tinnitus and hospitalized for an AAT were followed-up for 15 days. Examination during which the tinnitus state was recorded were carried out at three periods of time : 24 5 hours, 72 hours and 15 days after the trauma. Two groups were defined according to their tinnitus duration after AAT (Group 1 < 72 hours and Group 2 > 72 hours). At 24 hours after AAT, hearing levels in the high frequency range did not differ significantly (p=0.250) between the short-lasting tinnitus group (Group 1) and the long-lasting tinnitus group (Group 2). In contrast, 24 hours after AAT, groups differed for DPOAEs, significantly (p=0.016). When statistical analyses took into account the severity of the acoustic trauma (Hearing levels held constant), DPOAEs were even more significantly different between the long and short-lasting groups (p=0.007).This result is mainly in favour of an outer hair cell (OHC) dysfunction in persistent tinnitus. Here we show that even moderated acoustic trauma could generated persistent tinnitus and was associated with poorer hearing thresholds recovery 15 days after AAT. DPOAEs may be useful predictors at 24 hours after the trauma, but also certainly before any deleterious acoustic event. Prospective studies are in progress. They could be interesting markers for subsequent pharmacological studies.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 2005
- Accession Number
- ADA454715
Entities
People
- Brossard Nicolas
- Job Agnes
- Nottet Jean-bertrand
- Suc Benoit