Disturbances of thyroid function are often accompanied by cognitive and affective disorders. Assessment of cognitive status in the patients with subclinical hypothyroidism represents a possibility for early diagnostics of cognitive impairment and timely introduction of necessary pharmacotherapy treatment. The aim of this study was to quantify whether there are P3 event related potential (ERP) deviations as electrophysiological markers of cognitive activity in patients with subclinical hypothyroidism. P300 potentials were examined in thirty patients with subclinical hypothyroidism and in 30 healthy subjects of the control group. P300 was recorded using the classic auditory oddball paradigm, with 20% of target and 80% of non-target stimuli. The results analysis showed a significantly longer latency P300 and reduced amplitude P300 in subjects with subclinical hypothyroidism compared to euthyroid subjects. There is also a statistically significant negative correlation between the results of a mini mental state examination and the P300 latency at Fz electrode (r= -0.47, p <0.01) and Cz electrode (r= -0.43, p =0.017). P300 ERP is important in the evaluation of patients with subclinical hypothyroidism, due to the sensitivity in the detection cognitive disorders.
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