Spatial Working Memory Impairment in Subclinical Hypothyroidism: An fMRI Study.

Yin, Jing-Jing; Liao, Ling-Min; Luo, Dong-Xue; Xu, Ke; Ma, Shu-Hua; Wang, Zhao-Xin; Le, Hong-Bo; Huang, Ran-Ran; Cai, Ze-Long; Zhang, Jiong

Objective: Using a block-designed BOLD-fMRI to explore the neural basis of spatial working memory impairment in patients with subclinical hypothyroidism (SCH) performing an n-back task. Methods: Sixteen patients with SCH before and after being treated with levothyroxine (LT4) for 6 months and 16 matched euthyroid subjects were scanned by fMRI under the n-back task. Results: The fMRI scan found that a neural network consisting of bilateral dorsolateral prefrontal cortex (DLPFC), bilateral premotor area (PreMA), supplementary motor area/anterior cingulate cortex, bilateral parietal lobe (PA) and right caudate nucleus/thalamus was activated, with right hemisphere dominance. In euthyroid subjects, all these regions of interest (ROIs) showed load effect; however, only left DLPFC, left PA, bilateral PreMA and right caudate nucleus/thalamus showed the same effect in Pre-SCH patients. Furthermore, activation intensities of most ROIs (especially DLPFC and right PA) for Pre-SCH patients were lower than those in the euthyroid subjects (F 0.062). Importantly, after a 6-month treatment with LT4, the load effect in SCH patients appeared the same as in the euthyroid subjects in all the ROIs (F >13.176, p 4 replacement therapy can improve the memory impairment and reverse the altered neural activity network. Copyright © 2012 S. Karger AG, Basel

HYPOTHYROIDISM; SHORT-term memory; FRONTAL lobe; CEREBRAL cortex; FUNCTIONAL magnetic resonance imaging

Neuroendocrinology, 2013, Vol 97, Issue 3, p260

0028-3835

Academic Journal

10.1159/000343201