The effects of early lead exposure on auditory function in rhesus monkeys.
Thirty-one female rhesus monkeys were randomly assigned to three lead exposure conditions (none, birth to 1 year, and birth to 2 years). Blood lead levels were maintained at 35-40 microg/dl beginning shortly after birth and continuing for 1 or 2 years postnatally. Auditory function was assessed in these monkeys at least 1 year after exposure to lead. The outcome measures included tympanometry to assess middle ear function, otoacoustic emissions (OAEs) to assess cochlear function, and auditory brainstem-evoked responses (ABRs) to assess the auditory nerve and brainstem pathways. There were no significant differences among the three experimental groups for any of the tympanometric variables measured suggesting no effect of lead exposure on middle ear function. Suprathreshold and threshold distortion product OAEs (DPOAEs) were comparable among the three groups. Finally, the auditory-evoked response at levels from the auditory nerve to the cerebral cortex did not significantly differ as a function of lead exposure. The lead exposure in this study had little effect on auditory function.
Lasky
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Center for Clinical Research and Evidence-Based Medicine, University of Texas-Houston Medical School, 6431 Fannin Street, MSB 2.106, Houston, TX 77030-1503, USA. robert.e.lasky@uth.tmc.edu
Luck
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Torre
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Laughlin
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D000158:Acoustic Impedance Tests; D000284:Administration, Oral; D000818:Animals; D001309:Auditory Threshold / Q000187:drug effects*; D005072:Evoked Potentials, Auditory / Q000187:drug effects*; D005260:Female; D007854:Lead / Q000097:blood / Q000633:toxicity*; D008253:Macaca mulatta; D008297:Male; D011247:Pregnancy
D007854:Lead