FUNCTIONAL IMPLICATIONS OF POSTURAL DISEQUILIBRIUM DUE TO LEAD-EXPOSURE

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.