MILD IODINE DEFICIENCY DURING FETAL NEONATAL LIFE AND NEUROPSYCHOLOGICAL IMPAIRMENT IN TUSCANY

The neuropsychological performance of schoolchildren living in areas w ith present and past iodine deficiency in Tuscany was investigated. Ch ildren were submitted to: a) block design subtest of the Wechsler Inte lligence Scale for Children-Revised (WISC-R) and a modified version of the WISC-R coding subtest which evaluate the general neuropsychologic al and cognitive performance, independently from familiar cultural bac kground; b) simple reaction time (RT) session which evaluates the effi ciency of the whole information processing and nervous transmission me chanisms. Neuropsychological performance was tested in 107 children li ving in Borgo a Mozzano, an area of mild iodine deficiency (IDA) with a median urinary iodine excretion (UIE) of 64 mu g/L (mean+/-SD: 80.1/-57). One hundred and six sex and age-matched children living in Mari na di Pisa, an iodine sufficient coastal village of Tuscany (ISA) with a median UIE of 142 mu g/L (mean+/-SD: 173+/-95) were used as control s. Tests for neuropsychological performance were performed in 57 child ren living in the village of Vagli, an area with past iodine deficienc y (PIDA): 30 children born before iodine prophylaxis (Group 1), when t he median UIE was 32 mu g/L (mean+/-SD: 47+/-22), 27 children born aft er the institution of iodine prophylaxis (Group 2), when the median UI E was 109 mu g/L (mean+/-SD:130+/-73). Sex and age-matched ISA-childre n were used as controls for each group. RTs were significantly delayed (p<0.05) in IDA than in ISA children, while block design and coding s ubtests showed no significant difference. PIDA children of Group 1, bu t not those of Group 2 showed significantly delayed RTs when compared to controls, block design and coding tests being unaffected. In conclu sion, our data indicate that: i) mild iodine deficiency may impair the rate of motor response to perceptive stimuli, as assessed by measurem ent of reaction time, in the absence of general cognitive impairment; ii) the effects of exposure to iodine deficiency during fetal/neonatal life, in spite of correction in the early childhood, may persist long er. Our findings also suggest that the measurement of simple RTs is a sensitive test to detect subtle neurological damages in mild iodine de ficiency.