ELECTROENCEPHALOGRAPHIC FINDINGS IN PATIE NTS TREATED WITH L-THYROXINE FOR HASHIMOTOS-THYROIDITIS

Electroencephalographic activity was recorded in a group of 21 girls a ged 6.5-21.3 years, affected by Hashimoto's thyroiditis who were treat ed with l-thyroxine for a mean period of 27.4 months (4-101). Mean dai ly dose of l-thyroxine at the time of investigation was 81.9 mu g/m(2) (range 65-119 mu g/m(2)). The control group consisted of 20 healthy g irls matched for age and pubertal stage. T3 (p < 0.05), T4 (p < 0.001) and fT4 (p < 0.001) serum levels of the patients were higher and that of TSH lower (p < 0.001) than controls. Analysis of electroencephalog raphic recordings of the patients showed higher alpha frequency (p < 0 .05), higher incidence (p < 0.01) and frequency (p < 0.01) of fast act ivity (p < 0.01), but no correlation was found between electroencephal ographic findings and thyroid hormone serum level, daily dose of l-thy roxine and length of treatment. Although the patients did not show any neurological signs, we suggest however a careful EEG monitoring of th ose subjects on high thyroxine dosage.