ABSTRACT
The aim of this study is to explore the combined effect of occupational exposure to noise and lead on the hearing process of the exposed workers. Twenty-four exposed workers [48 ears] from two printing facilities at Cairo University and twenty controls [40 ears], not occupationally exposed to noise or lead, were included in this study. All studied personnel were subjected to medical and occupational history, clinical and ENT examination, blood lead level determination and audiological assessment including: pure tone hearing thresholds, otoacoustic emissions [OAE] and auditory brain-stem response [ABR]. The work environments were tested for noise levels which were found to be 88 and 92 dB A, respectively. Statistically significant differences were detected between the exposed group and the controls as regards the hearing thresholds at frequencies 4 and 8 KHz and the OAE, The ABR revealed significant prolongation of the absolute latencies of waves 1 and 3 with increased [1 -3] interpeak latency in the exposed group. The 5/ 1 amplitude ratio was also smaller in the exposed compared to the controls. The blood lead level was significantly higher in the exposed in comparison to the controls [p < 0.001]