[State of the hearing function and cerebral hemodynamics in agricultural machine operators]

The hearing function and cerebral hemodynamics were investigated in 96 agricultural machine operators, 14.6% and 23.2% of whom presented complaints about noise in the ear and hearing impairment, respectively. Hearing impairment was diagnosed in 90.6% in terms of tonal thresholds and in 63.3% in terms of speech intelligibility. Threshold increase was often observed at a frequency of 6 kHz. The number of operators with enhanced tone of cerebral vessels, especially in the vertebral area, grew with their work record. As the enhanced tone spread over both cerebral blood flow systems, the number of cases of injury of the sound-receiving apparatus increased.