Effects of noise associated with pesticides in the hearing and vestibular systems of endemic disease control agents

Abstract

Occupational hearing loss is primarily attributed to noise-related exposure. However, certain chemicals may damage central and peripheral hearing system, as well as the vestibular system, or even potentialize noise effects. Thus, the current study aimed to assess the effect of the concomitant exposure to noise and chemicals on peripheral and central hearing systems, as well as on the vestibular system of endemic disease control agents. The sample comprised 58 participants, males, divided in two groups. The experimental group (EG) comprised 40 agents, between 48 and 72 years of age, exposed to the noise of motorized knapsack sprayers (107 dB SPL), and vehicle-mounted, ultra-low volume aerosol generators (75 to 110 dB SPL), as well as to pesticides (organophosphates and pyrethroids). The control group (CG) comprised 18 participants, without exposure to pesticides and/or noise, paired according to age range and gender. The participants from both groups underwent conventional pure-tone audiometry and high-frequency audiometry, evoked otoacoustic emissions, immitance testing, suppression effect of the evoked otoacoustic emissions, brainstem evoked response audiometry, and dichotic digits test (DDT). Vestibular assessment was only carried out in the experimental group (EG). Results showed no difference between the groups in the findings of the pure-tone audiometry, and suppression effect of the evoked otoacoustic emissions. Difference was evidenced between the groups in the acoustic reflex testing, in the tympanometry, in the brainstem evoked response audiometry, and in the dichotic digits test, with worse results among the EG. In the vestibular assessment, there was prevalence of altered tests among EG in 36.4% of the cases, more evidence for the peripheral deficitary vestibular dysfunction. Concluding, simultaneous noise and pesticide exposure impaired the hearing system in the vestibular system of endemic disease control agents