(2) bilateral hearing loss (3) hearing loss of 25 dBA at 4,000 Hz in two consecutive audiograms (4) no significant medical history affecting hearing. Severity of NIHL was based on the World Health Organization grading
(2) Gehoorverlies bilaterale (3) Gehoorverlies van 25 dBA by 4000 Hz in Twee agtereenvolgende oudiogramme (4) geen beduidende invloed Verhoor Mediese Geskiedenis. Erns van NIHL is gebaseer op die World Health Organization gradering.