Short-Term Memory Impairment in Different Ranges of Thyroid Stimulating Hormone in Patients with Subclinical Hypothyroidism

Introduction: Subclinical hypothyroidism (SCH) is one of the main causes of cognitive impairments. Despite being euthyroid or having Levothyroxine (LT-4), patients have memory impairments. The current study has investigated impairments in short-term memory in SCH across different ranges of thyroid-stimulating hormone (TSH). Methods: This study included four groups: Group 1 Healthy individuals; Group 2 recently diagnosed patients with SCH (≥2.5mIU/L); Group 3: patients with elevated TSH levels≥4.0mIU/L (having L-T4 treatment); and Group 4: euthyroids (TSH levels<4.0mIU/L), ongoing LT-4 treatment. The Cambridge Neuropsychological Test Automated Battery was administered, and delayed matching of the sample task was performed for short-term memory. (please add more details about statistical analysis, and all methods used for this study). Results: Group 4 performed better than another two groups of patients, however group 3 showed better performance than group 2 (TSH levels≥2.5mIU/L). Despite receiving LT-4, group 3 and 4 did not have better processing speed compared to newly diagnosed patients. Conclusion: Patients who were receiving LT-4 treatment showed better performance in shortterm memory function than those who were recently diagnosed with SCH.