Determination of hearing loss and disability assessment from pure tone audiometry and speech audiometry in occupational noise-induced hearing loss

BACKGROUND: Occupational hearing loss is the most accepted occupational disease. The assessment should be conducted in accordance with the "K?nigsteiner Merkblatt" which appeared in the fourth completely revised edition in 1996. Determination of degree of disability is mainly based on speech audiometry. Adapted complete word understanding is most important. In special cases only sinus-tone audiometry is used for the assessment. Knowledge about common and uncommon schedules is important for the assessment. METHODS AND PATIENTS: The results of 200 audio metrical examinations in case of professional hearing loss have been evaluated with eight different schedules. Four of these schedules for determination of hearing loss are based on sinus tone audiometry. Boenninghaus and R?ser's schedule uses speech audiometry under consideration of simple and adapted complete word understanding. Lehnhardt's schedule uses sinus-tone and speech audiometry for determination of degree of disability. Further on it is shown that the complete word understanding is the most important parameter for the quantitative determination of permanent noise induced hearing loss. It is even possible to determine the degree of disablement only using the complete word understanding. For all cases, the eight schedules were used to calculate the average hearing loss and the average degree of disability. Further on it was shown in how many cases-according to each schedule-a degree of disability of less than 10%, 10 to 15%, 20%, and more than 20% was calculated. RESULTS AND CONCLUSION: Comparing these eight schedules, it was shown that the use of adaptec complete word understanding increases the number of cases with 10% and 20% degree of disability. Using R?ser's schedule of 1980, the number of minimal handicap increases. With the new "K?nigsteiner Merkblatt" a 10% degree of disability is reached more easily than it was previously.