Aim: to evaluate attention, concentration, memory changes and executive function inpatients with hyperthyroidism compared with normal thyroid function patients.
Methods: a cross sectional study was conducted in 21 patients (14F, 7M) with symptoms of sweating, sleep disturbance, fine tremor, headache, palpitation, nervousness, forgetfulness and diarrhea. Neurological examination found that 2 patients had proximal paresis and periodic paralysis. Their thyroid functions (FT4 and TSHS) were done, 13 patients were hyperthyroid, 2 patients were subclinical hyperthyroid and 6 patients were euthyroid. Neuropsychological tests such as: Mini Mental State Examination (MMSE), Trail Making Test (TMT) A and B, Continuous Performance Test (CPT), Vigilance Complex Task (VCT), Digit Forward and Backward Repetition (DFR, DBR) were performed in all of those patients. The mean age of sample was 47,3 +/- 8,45 years old and all of them had minimal 6 years education background, no history of cerebro vascular disease, brain injury or tumour or infection, epilepsy, cerebral degeneration, and taking neuroleptics or antidepressants.
Results: using the Kendall correlation coefficients showed that FT4 had negative correlation with VCT, CPT, DFR, DBR and positive correlation with TMT A (time) and TMT B (time and error). Study T-test showed that high level of thyroid function had significant difference in TMT A (time), TMT B (time), DBR, DFR, VCT, CPT. Fischer exact gave statistically significant in VCT and fine tremor in hyperthyroid patients (RR VCT 5.60, 95% CI 0.93-33.68, RR fine tremor 0.50, 95% CI 0.28-0.88).
Conclusion: hyperthyroid patients had significant decrease on attention, concentration, verbal memory and executive function (working memory) compared with euthyroid patients.