Thyroid dysfunction and cognitive function: a review

Recently, the incidence of thyroid diseases has been on the rise. While standardized diagnosis and treatment generally yield excellent prognoses, the association between thyroid disorders and cognitive function remains a topic of significant interest. Cognitive function includes memory, language, visuospatial ability and executive function. Cognitive dysfunction refers to the impairment of one or more of the above, including mild cognitive impairment (MCI) and dementia. More and more studies have shown that thyroid disease is associated with cognitive dysfunction. Clinically, some patients present with noticeable symptoms such as memory loss and inattention, which severely impede their daily social functioning. There is a consensus on the view that thyroid hormone deficiency during the neonatal or embryonic period can cause disorders in the central nervous system, resulting in severe cognitive impairment such as persons with congenital hypothyroidism, but there is disagreement on the relationship between adult thyroid diseases, including clinical hyperthyroidism, hypothyroidism, subclinical hyperthyroidism, subclinical hypothyroidism and cognitive dysfunction. The inconsistencies in research conclusions are attributed to complex factors. Differences in age stratification constitute an important confounding factor for thyroid-related cognitive impairment; various neuropsychological assessment tools show obvious discrepancies in the sensitivity of detecting cognitive damage, which can directly affect the evaluation of research outcomes. Meanwhile, methodological heterogeneity among studies is also a key inducement for the inconsistent findings on the association between clinical thyroid dysfunction and cognitive function in adults. Therefore, this article mainly reviews the relationship and research progress between thyroid function and cognitive dysfunction in adults. From this review, we conclude that obvious thyroid dysfunction is obviously related to cognitive function, mainly focusing on attention and memory. Treatment would improve cognition to some extent, but wouldn't fully restore it. The relationship between subclinical thyroid dysfunction and cognitive function is still of important significantly.