NEUROPSYCHOLOGIC DEVELOPMENT IN EARLY TREATED CONGENITAL HYPOTHYROIDISM - ANALYSIS OF LITERATURE DATA

The aim of this study was to determine the neuropsychologic developmen t in patients with congenital (primary) hypothyroidism (CH) detected b y screening and treated from early age. Seven studies were evaluated, including 675 CH patients and 570 controls. Criteria for inclusion of the studies were: 1) age of patients and controls greater than or equa l to 5 y; 2) control group well defined in the original article. A met a-analysis of the data on the intellectual development was performed. All analyzed studies show a trend toward lower intelligence quotient ( IQ) and-as far as investigated-poorer motor skills in CH patients comp ared with controls. Pooling of data showed a significant deficit of th e mean IQ of 6.3 (95% confidence interval: 4.7-7.8). The most importan t independent risk factor for the eventual outcome appears to be the s everity of CH (defined by initial thyroxine at the moment of diagnosis and by skeletal maturation); treatment variables do not seem to have an important effect the cognitive development. We conclude that CH, de spite early detection and treatment, results in an IQ deficit; the sev erity of CH seems to be the most important individual risk factor. Our second conclusion is that although biomedical risk factors were well investigated, the individual weight of these factors is yet largely un known. This may be due to the variability of definitions and test tool s, especially for the investigation of motor skills, that have been us ed.