Evaluation of visual evoked potentials in patients with Hashimoto thyroiditis

Background and purpose – Our aim was to use visual evoked potentials (VEP) to evaluate changes in brain bioelectrical activity in Hashimoto thyroiditis patients with normal neurological examination and imaging findings and to correlate the evoked potential parameters with clinical data. Methods – The study included 75 clinically diagnosed Hashimoto thyroiditis patients and 45 healthy individuals who met the selection criteria. Demographic and clinical characteristics such as age, sex, disease duration, serum thyroid hormone levels, autoantibody titers, thyroid ultrasonography, brain magnetic resonance imaging, and levothyroxine dose used were recorded. VEP tests were performed in both groups. All participants provided informed consent. Results – Of the Hashimoto thyroiditis patients included in the study, 92% (n=69) were female, the mean age was 40.3±12.2 years, and the mean disease duration was 5.7±7.5 years (range: 0-40 years, median: 4 years). Euthyroid patients showed significantly longer P100 latency difference and higher N75/P100 amplitude than the control group (p=0.014 and 0.007, respectively). Elevated thyroid-stimulating hormone level was associated with longer N75 and P100 latencies. Conclusion – Our results demonstrated the presence of abnormal brain bioelectric activity in Hashimoto thyroiditis patients without active neurological findings. These effects increase with disease severity and duration and necessitate the development of early treatment strategies to halt the progressive autoimmune process.