Grey matter abnormalities in untreated hyperthyroidism: a voxel-based morphometry study using the DARTEL approach

Area of Science:

• Neuroscience
• Endocrinology
• Radiology

Background:

• Hyperthyroidism often presents with neuropsychiatric symptoms like irritability and memory loss.
• Functional neuroimaging shows altered brain metabolism in hyperthyroidism.
• Regional cortical morphological changes linked to neurological deficits remain understudied.

Purpose of the Study:

• To investigate the pathophysiology of hyperthyroid-associated neural dysfunction.
• To compare grey matter volume (GMV) in adult hyperthyroid patients versus healthy controls.
• To utilize voxel-based morphometry (VBM) for assessing regional cortical differences.

Main Methods:

• Acquired high-resolution 3D T1-weighted MRI scans from 51 hyperthyroid patients and 51 controls.
• Performed VBM analysis using SPM8.
• Assessed correlations between regional GMV, serum free thyroid hormone (TH) levels, and disease duration via multiple regression.

Main Results:

• Hyperthyroid patients showed reduced GMV in the hippocampus, parahippocampal gyrus, calcarine, lingual gyrus, and left temporal pole.
• Increased GMV was observed in the bilateral supplementary motor area in hyperthyroid patients.
• Negative correlations found between GMV and serum free triiodothyronine (FT3), free thyroxine (FT4), and disease duration.

Conclusions:

• Hyperthyroid patients exhibit reduced GMV in brain regions critical for memory, attention, emotion, vision, and motor planning.
• Chronic elevation of thyroid hormones (TH) appears to induce abnormalities in the adult cortex.
• These findings link thyroid dysfunction to specific structural brain changes and neurological deficits.