Neurocognitive functions and some electrioencephalographic changes in preadolescent children with different degrees of primary hypothyroidism and mild iodine deficiency

Abstract

Neurologic and electrophysiologic changes in children with mild hypothyreosis and euthyroid goiter at the background of mild ID are not well understood at present. Our goal was to evaluate of some cognitive disturbances and alteration of some EEG parameters in preadolescent children at early stages of the development of primary hypothyreosis and euthyroid goiter. 55 somatically healthy preadolescent children, aged 8-12 years with the 1st degree of diffuse goiter underwent clinical and neurological investigation of cognitive functions: ”copy”, ”time to copy” and ”recognition” using Rey Complex Figure Test and recognition trial as well as Rochester fatigue Diary test; Motor Fatigue index, PASAT – 3 (second version) and lassitude was evaluated. Digital 21 channeled EEG study was also performed. Study groups were randomized to: children with overt mild hypothyreosis; children with subclinical hypothyreosis; euthyroid children; healthy controls. Mediana of UIE 64 was in the lower 3rd in the range for mild ID. Children of the study group more often had non-specififi c neurologic symptoms. All indices of neurocognitive dysfunction were more frequent in patients with overt hypothyreosis (P<0,001) and in lesser extent were present in subclinical hypothyreosis and euthyroid goiter, compared to controls. This was accompanied by the changes of EEG parameters. The pathologic visual version of EEG had 90% of children with overt hypothyreosis. In turned out that in prepubertal children is accompanied by cognitive disorders represented by Mild Cognitive Impairment; among neurologic subclinical signs of manifestation of ID the Fatigue test is of great sensitivity; even mild ID is characterized by specififi c changes of the frequency and amplitude of physiologic spectrum of EEG activity, mainly of aA; pathologic consequences of ID are manifested both in overt and subclinical hypothyroidism and in lesser extent in patients with euthyroid goiter.