Characteristics of noise induced hearing loss in gold miners : research

The characteristics of Noise Induced Hearing Loss (NIHL) in gold miners of different ages and occupation types were examined and the incidence of tinnitus, vertigo/balance problems and nausea were determined. The results indicate that as a group these subjects had symmetrical bilateral, mild hearing loss in the frequencies below 2000 Hz deteriorating to a moderate sloping hearing loss in the frequencies above 2000 Hz, and the loss did not demonstrate the expected "notch" at 4000 Hz that is usually found in NIHL. The average deterioration in the pure tone thresholds of gold miners was 3.5 dB at 500 Hz, 2.75 dB at 1000 Hz, 15.37 dB at 2000 Hz, 19.12 dB at 3000 Hz, 20.87 dB at 4000 Hz and 14.16 dB at 6000 Hz for every ten years of age. The pattern of hearing loss varies for the different occupation types with machine operators being the most severely affected. The majority of tinnitus sufferers were in the age range 30-60 years and 57.8 % were in the under 60 years old category, while in the over 60 years category the incidence was 4.8%. The incidence of vertigo and nausea was found to be 27% in this population. The results of this study will equip the audiologist to deal more effectively with diagnostic testing, successful hearing aid fitting and aural rehabilitation in this population. The study highlights the need for greater awareness and the imparting of detailed information to gold miners about the impact of noise on their hearing. Die kenmerke van geraas-geinduseerde gehoorverlies is bepaal vir 'n groep goudmyners van verskillende ouderdomme en tydperke van diens. Variante wat ondersoek is, is gehoordrempels, voorkoms van tinnitus, Vertigo / balans-steurnisse en voorkoms van naarheid. Die resultate toon dat hierdie populasie oor die algemeen 'n bilaterale simmetriese gehoorverlies het, wat in die frekwensies onder 2000 Hz gering is maar daarna verswak tot 'n gemiddelde verlies in die frekwensies bo 2000 Hz. Die oudiogram bevat nie die keep by 4000 Hz wat kenmerkend van geraas-geinduseerde gehoorverlies is nie. Die gemiddelde jaarlikse afname in gehoorvermoe vir myners was 3.5 dB by 500 Hz, 2.75 dB by 1000 Hz, 15.37 dB by 2000 Hz, 19.12 dB by 3000 Hz, 20.87 dB by 4000 Hz en 14.16 dB by 6000 Hz vir elke tien jaar van ouderdom. Die patroon van die oudiogram het verskil vir die verskeie werksoorte, en masjien-operateurs se gehoor was die meeste aangetas. Die meerderheid tinnitus-lyers kom voor in die ouderdomsgroep 30-60 jaar. In die ouderdoms-groep onder