Cognitive Skills Adversely Affected by Thyroid Dysfunction

Patients with subclinical hypothyroidism scored worse on tests of processing speed than patients with normal thyroid function.

Thyroid dysfunction in children may adversely affect cognitive skills — specifically processing speed — according to the results of a study presented at the 2017 annual meeting of the Endocrine Society, April 1-4, 2017 in Orlando, Florida.

Previous studies have demonstrated the ill effects of overt hypothyroidism on cognition in children, but the impact of subclinical hypothyroidism is not known.

In the current study, researchers led by Rashmi Jain, MD, of Drexel University College of Medicine in Philadelphia, Pennsylvania, evaluated cognitive function in pediatric patients (mean age 11.9+3.3) with primary hypothyroidism (n=5), subclinical hypothyroidism (n=18), and normal thyroid function (n=7). Primary disease was defined as low free thyroxine (T4)/total T4 and high thyroid stimulating hormone (TSH), subclinical disease was defined as normal free T4/total T4 and TSH above normal but <15 mIU/L, and normal function was defined as normal free T4/total T4 and normal TSH.

Cognitive function was assessed using the Flanker Inhibitory Control and Attention Test (attention), the List Sorting Test (working memory), and the Pattern Comparison Test (processing speed).

Analysis revealed a significant negative correlation between TSH and scores on the Pattern Comparison test for processing speed (r= −0.454; P =.015), with the primary disease group scoring the lowest (80.9±25.13), the normal group scoring the highest (92±16.73), and the subclinical group recording an intermediate score (88.67±16.83). The differences in the Pattern Comparison test scores between the groups, while not significant, suggest that processing speed may be more sensitive to changes in thyroid function than other cognitive skills.

The investigators noted that larger studies are needed to confirm these findings. If validated, the findings could impact clinical care.


Jain R, Grant M, De Luca F. Cognitive effects of subclinical hypothyroidism in children. Presented at: ENDO 2017. April 1-4, 2017; Orlando, Florida. Abstract SUN 027.