Essential tremor severity and anatomical changes in brain areas controlling movement sequencing

Area of Science:

• Neuroscience
• Neurology
• Neuroimaging

Background:

• Essential tremor (ET) is a common neurological disorder.
• The cerebello-thalamo-cortical network is implicated in ET pathogenesis.
• The precise origins of tremorgenic activity in ET remain unclear.

Purpose of the Study:

• To investigate the association between tremor severity and anatomical brain changes in ET patients.
• To analyze cortical thickness and neurophysiological correlates of tremor in ET.

Main Methods:

• Structural brain MRI (3T) and cortical thickness analysis were performed on 13 ET patients.
• High-density surface electromyography (hdEMG) and inertial measurement units (IMUs) quantified tremor severity.
• Advanced computational tools identified motor unit discharge patterns and synchronization.

Main Results:

• Increased motor unit synchronization, indicative of more severe tremor, was significantly associated with widespread cortical atrophy.
• Specific atrophic regions included the medial orbitofrontal cortex, cingulate gyrus, paracentral lobule, and lingual gyrus.
• Reduced volumes were observed in the supramarginal gyrus, thalamus, and amygdala.

Conclusions:

• ET tremor may arise from involuntary activation of motor sequencing programs.
• Widespread brain structural changes are linked to tremor severity in ET.
• Findings highlight the role of the cerebello-thalamo-cortical network and associated areas in ET.