Changes in Cognitive Functions of Pupils under Conditions of Iodine Deficiency

Clinical and physiological examination of 38 children which latent hypothyroidism (the main group) and 176 apparently healthy persons of intact region (the control group) at the age from 8 to 17 years living in endemic region was carried out. To determine the functional state of the thyroid gland in blood serum the content of total triiodothyronine (Т3), total and free thyroxin (Т4, fТ4), thyroid-stimulating hormone (TSH) of adenohypophysis were determined as well as urinary iodine level was examined. The cognitive functions were characterized by the indices of attention as the result of correction test and rate of sensomotor reactions which were evaluated using modified Schulte tables. It was detected that in all children with latent hypothyroidism regardless of age work accuracy rate decreased, attention span increased slowly, fatigue developed early and rate of information analysis significantly reduced already within the first 5 minutes in comparison with analogical data in healthy children. When being tested children of the control group made fewer mistakes, the tempo of doing tasks remained higher for 5 minutes. There was a correlation between the indices of correction test, sensomotor reactions and data of thyroid status of pupils.