ABSTRACT
A study was performed to examine the effects of industrial exposures to lead and mercury on the brainstem auditory pathway by recording brainstem auditory evoked potentials (BAEPs). BAEPs were recorded from 22 workers exposed to lead, from eight exposed to mercury and from two control groups of age- and sex-matched subjects never exposed to neurotoxic substances. The time between BAEP peaks I and V were evaluated. The mean durations of exposure were 9.3 and 11.7 years for lead and mercury, respectively. Blood lead concentration (PbBc) on the morning of the test day was 47.5 micrograms/dl, whereas urinary mercury content at the end of the previous work day was 325 micrograms/g creatinine. Both mercury and lead exposed workers showed a significant prolongation of wave I-V time. In addition, the interwave time was longer in a lead subgroup with the greatest mean level of lead in blood. These results are consistent with other studies and show that BAEPs may provide a sensitive tool for detecting subclinical central neurotoxicity caused by lead and mercury.
Subject(s)
Evoked Potentials, Auditory, Brain Stem/drug effects , Lead/adverse effects , Mercury/adverse effects , Nervous System Diseases/chemically induced , Occupational Exposure , Acoustic Stimulation , Adult , Analysis of Variance , Evoked Potentials, Auditory, Brain Stem/physiology , Female , Humans , Male , Middle Aged , Reaction Time/physiologyABSTRACT
Brainstem Evoked Potentials (BAEPs) were recorded in 49 lead exposed workers, and in a control group of 49 age- and sex-matched subjects, never exposed to neurotoxic substances. The mean duration of lead exposure was 7.4 (SD 5.6) yr. Blood lead concentration was analyzed in the morning of the experimental day (PbBc); an averaged PbB level was based on the levels of the 3 previous years (PbBm). Interpeak latency differences (IPLD) I-V, I-III and III-V were considered. The mean PbBc level was 54.6 (SD 16.1) micrograms/dl while the mean PbBm level was 53.5 (SD 15.9) micrograms/dl. Lead exposed workers showed a significant prolongation of IPLDs. IPLD I-V was longer in the subgroup with PbBm greater than 50 micrograms/dl (4.06 vs 3.98, c.l. 95% 0.00-0.16). These results are consistent with literature data and show that BAEPs may be a sensitive detector of subclinical lead effects on brainstem auditory pathways.
