Brainstem auditory evoked potentials in individuals exposed to long-term low concentrations of toluene

Abstract

Brainstem auditory evoked potentials (BAEPs) were examined in 49 workers employed in a printing press, who were occupationally exposed to low concentrations of toluene for an average of 20.3 years, and in 59 subjects in a control group. In the group of exposed workers, a significant decrease was found in all wave amplitudes examined, a significant prolongation of PI wave latency, and an increased interval of interpeak latencies (P3–P5), indicating that the extramedullary and high medullary part of the auditory pathway are biologically most frequently affected by chronic exposure to low concentrations of toluene. The level of exposure to toluene in both groups was evaluated by defining the concentration of toluene in peripheral blood and the concentration of hippuric acid and ortho‐cresol in urine. © 1996 Wiley‐Liss, Inc.

Auditory system dysfunction in Brazilian gasoline station workers

“…Therefore, the ABR findings obtained in the present study suggest that the workers exposed to gasoline have auditory nerve dysfunction, as well as central auditory nervous system dysfunction involving brainstem. Dysfunction involving the auditory pathway in brainstem was also reported in a study of gasoline station workers as well as in workers exposed to solvents (Abbate et al 1993;Vrca et al 1996;Prasher et al 2005;Gopal 2008;Ju arez-P erez et al 2014;Fuente, McPherson and Cardemil 2013).…”

“…Significantly longer ABR latencies for workers exposed to solvents have been observed (Abbate et al 1993;Vrca et al 1996;Fuente, McPherson, and Cardemil 2013;Ju arez-P erez et al 2014) but not always for the same waves. The mean latencies of waves I, III and V (Abbate et al 1993;Vrca et al 1996), I-III, III-V and I-V IPL (Abbate et al 1993), and III-IV IPL (Vrca et al 1996) were significantly longer for the exposed group than for the CG. In other studies, the exposed group showed longer latencies than the CG in all ABR waves and IPL except for wave I latency (Fuente, McPherson, and ABR waves I, III and V are generated in the distal portion of the auditory nerve, cochlear nucleus, and in the lateral lemniscus, respectively (Moller 2013), and that prolonged III-V, or I-V IPLs are signs of brainstem involvement (Musiek, Shinn, and Jirsa 2007).…”

“…The effects of toluene on the peripheral and central auditory systems have been observed in several animal studies and among workers exposed simultaneously to noise (Abbate et al 1993;Morata et al 1993, Morata, Engel et al 1997Vrca et al 1996).…”

Self-reported hearing performance in workers exposed to solvents

“…11,23 Fuente et al have shown that workers exposed to a mixture of solvents (toluene, xylene and methyl ethyl ketone) may acquire central auditory dysfunction, as measured through a set of behavioral central auditory processing tests. 11 Other studies have found central auditory effects associated with solvent exposure (mainly toluene) through the use of electrophysiological measures such as the auditory brainstem response 1,27 and the P300 response. 18,26 In summary, solvents not only adversely affect the sensory organ of the auditory system (cochlea), as noise does, but also affect the central auditory structures.…”

Occupational Chemical-Induced Hearing Loss

“…Workers exposed to toluene obtained statistically significant higher absolute latencies and inter-peak latencies (IPL) between waves of the ABR (I-III IPL; I-V IPL; III-V IPL) than a non-exposed group of workers matched for gender and age (Abbate et al, 1993). Additional evidence of toluene-induced central auditory dysfunction in humans using ABR was shown by Vrca et al (1996). Workers exposed to low concentrations of toluene obtained a significant decrease in all wave amplitudes of auditory evoked potentials.…”