Subclinical neurophysiological effects of lead: A review on peripheral, central, and autonomic nervous system effects in lead workers.
BACKGROUND
The peripheral nerve conduction velocity (NCV), distribution of nerve conduction velocities (DCV), somatosensory, visual, and brainstem auditory evoked potentials (SEP, VEP, and BAEP, respectively), event-related potential (P300), computerized static posturography with spectral analysis (postural balance), and electrocardiographic R-R interval variability (CV(RR)) with spectral analysis appear to be promising techniques for assessing subclinical effects of lead on the peripheral, central and autonomic nervous systems. This article presents an overview of research addressing subclinical neurophysiological effects of lead in workers exposed to lead.


METHODS
We reviewed 102 articles to examine the effects and dose-effects relationships of lead on peripheral, central, and autonomic nervous system function together with reversibility of the effects, interaction between lead and other metals, and relative sensitivity and specificity of each technique. Background and methodology were also reviewed.


CONCLUSIONS
Available data suggest that, on a group basis, the reduction in the NCV, together with the effects on the P300 latency, postural balance, and CV(RR), occurs at a mean blood lead concentration (BPb) as low as 30-40 microg/dL; the effects on the latencies of the short-latency SEP, VEP, and BAEP, as well as the DCV, start at a BPb as low as 40-50 microg/dL. Further cross-sectional and preferably prospective studies by using each of those methods are needed to establish more precise dose-effects (and response) relationships of lead.
Araki
S
S
Department of Public Health and Occupational Medicine, Graduate School of Medicine/Faculty of Medicine, The University of Tokyo, Japan.
Sato
H
H
Yokoyama
K
K
Murata
K
K
D001341:Autonomic Nervous System / Q000187:drug effects; D002490:Central Nervous System / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005071:Evoked Potentials / Q000187:drug effects*; D016057:Evoked Potentials, Auditory, Brain Stem / Q000187:drug effects; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects; D005074:Evoked Potentials, Visual / Q000187:drug effects; D006801:Humans; D007854:Lead / Q000009:adverse effects*; D009420:Nervous System / Q000187:drug effects*; D009431:Neural Conduction / Q000187:drug effects; D017933:Peripheral Nervous System / Q000187:drug effects
D007854:Lead