Measurement of postural equilibrium has been employed as an indirect i
ndicator of functional status of the nervous systems of 109 children (
mean age: 5.8 +/- 0.78 years) from the Cincinnati Lead Program Project
. The geometric mean blood lead for the first five years of life (PbB0
5) was 11.9 +/- 1.5 mug/dL. Postural sway associated with upright bala
nce was noninvasively quantitated with a microprocessor-based force pl
atform and four tasks performed for 30 sec each by the subjects. A cov
ariate-adjusted multiple regression analysis showed statistically sign
ificant associations between PbB05 and the postural sway for the task
requiring primarily vestibular and/or proprioceptive systems input, im
plying potential functional impairment. These findings raised several
new issues which are addressed here: (1) A dynamic task has been devel
oped to further test the effect of perturbing those afferents' functio
nal capabilities. (2) A method has been developed to quantitate the st
ability boundary of each subject to better characterize the limits of
functionally-safe postural sway. (3) There is a need to perform the po
stural sway in a shorter duration than 30 sec so that children younger
than five years of age can be tested for early identification of Pb-i
nduced functional impairment of postural equilibrium. (C) 1993 Intox P
ress, Inc.