It is important to study if synergistic effects occur also at lower levels of exposure. Data analyses are under way. The project is run by the National Institute for Working Life. The risk to obtain damaged hearing by a certain noise is highly individual. Attempts to find predictive factors for noise induced hearing loss, NIHL, have so far been without success.
New possibilities are now available by measuring the micromechanics of the inner ear.
The aim of the project is to find a measurement procedure suitable for judgment of susceptibility to NIHL before a hearing loss has appeared. Measurements of the degree of non-linearity of the inner ears of various individuals are being used. Tympanometry will be performed as a check. Various types of data, including provocation data, obtained before the noise exposition with possible changes during the noise exposure, will be compared. Recently, new hearing aids with more flexible signal processing possibilities have been introduced.