Morphometric and functional MRI changes in essential tremor with and without resting tremor

Area of Science:

• Neuroscience
• Neurology
• Medical Imaging

Background:

• The underlying causes of essential tremor (ET) remain unclear, with ongoing debate regarding circuit dysfunction versus degenerative changes.
• The association between ET and Parkinson's Disease (PD), including the presence of resting tremor in some ET patients, is controversial.

Purpose of the Study:

• To investigate morphological and functional brain changes in essential tremor (ET).
• To identify differences between ET patients with resting tremor (ET+R) and without resting tremor (ET-R).

Main Methods:

• 32 ET patients (18 ET+R, 14 ET-R) and 12 healthy controls (HC) underwent 3T-MRI.
• Voxel-Based Morphometry (VBM) and functional MRI (fMRI) during a writing task were performed.

Main Results:

• No significant gray or white matter atrophy was found in ET patients compared to HC, or between ET+R and ET-R groups.
• Healthy controls exhibited higher BOLD response in the cerebellum and cerebello-thalamo-cortical circuit compared to ET patients.
• ET-R patients showed greater activation in areas including the precentral gyrus, frontal and parietal lobes, cerebellum, and globus pallidus compared to ET+R patients.

Conclusions:

• Cerebello-thalamo-cortical network dysfunction is associated with essential tremor, independent of morphometric changes.
• Globus pallidus dysfunction in ET+R patients suggests a potential role in resting tremor, mirroring findings in Parkinson's disease.