Lead effects on neurobehavioral development in the neonatal rhesus monkey (Macaca mulatta)

Effects of lead exposure on behavioral development during the first month o f postnatal life were examined in rhesus monkeys using a multi-item assessm ent scale developed for the evaluation of neonatal rhesus monkeys. Lead was administered daily beginning at day 8 postpartum at levels that produced b lood lead levels of about 20 mu g/dl by week 4 (n = 48); controls were trea ted identically but given vehicle only (n = 24). All monkeys were tested on ce a week for the first 4 weeks postpartum The first principal component ex plained a substantial portion of the variance and was relatively consistent across ages for both groups. Analyses of the individual items and of both conceptually derived and empirically defined summary scores yielded no sign ificant effects of lead. Furthermore, there were no systematic relationship s between blood lead level and performance on the test. Correlation coeffic ients indicated more similarity across age for control monkeys than for lea d-exposed monkeys suggesting that continuity of development, as measured by this test, was disrupted by lead. The relationship between outcome on thes e early assessments and later behavior will be explored in subsequent studi es of these monkeys. (C) 1999 Elsevier Science Inc. All rights reserved.