Patients with untreated adult-onset overt hypothyroidism appear to manifest reductions in right hippocampal volume compared with age-matched healthy controls, according to recent findings.
In the study, researchers evaluated 11 adults with untreated hypothyroidism aged 27 to 55 years and nine healthy control patients aged 26 to 54 years. The hypothyroid and healthy patients had similar levels of education. Elevated levels of thyrotropin and decreased concentrations of free thyroxine were used to diagnose hypothyroidism.
The researchers performed high-resolution magnetization prepared rapid acquisition with gradient echo scans on all patients, and segmentation and volumetric evaluation of the left and right hippocampus was conducted using functional MRI imaging of the brain-integrated registration and segmentation tool.
Through these analyses, the researchers found that the hypothyroid patients had significantly lower right hippocampal volumes vs. those of control patients (hypothyroid group: 3,897 ± 141 mm3; control group: 4,435 ± 158 mm3; P=.023)
According to the researchers, ﬁndings are a preliminary indication that the adult human brain incurs structural deficits as a result of untreated hypothyroidism. They added that further study is needed to determine the long-term cognitive effects of hypothyroidism.
“Our previous behavioral studies, along with the present findings, enhance our understanding of hippocampal changes associated with hypothyroidism,” the researchers wrote. “Although the numbers in the present study were small, the findings support previous studies that have reported neuronal alterations in hypothyroidism.”
Disclosure: The researchers report no relevant financial disclosures.