Thalamic Structural Connectivity Alterations in Essential Tremor Associated with REM Sleep Behaviour Disorder

Area of Science:

• Neuroscience
• Neurology
• Medical Imaging

Background:

• REM sleep behavior disorder (RBD) is a rare parasomnia linked to Essential Tremor (ET).
• Thalamic structural alterations are implicated in idiopathic and Parkinson's disease-related RBD.
• This study investigates thalamic changes in ET patients with and without RBD.

Purpose of the Study:

• To investigate thalamic structural connectivity in Essential Tremor patients with and without REM sleep behavior disorder.
• To identify specific thalamic regions associated with the ET-RBD phenotype.

Main Methods:

• MRI data from 96 participants (41 ET, 10 ET-RBD, 45 controls) were analyzed.
• Grey matter volumes of 28 thalamic regions were estimated using the AAL3 template.
• Graph theoretical analysis, including centrality measures and clustering coefficients, was applied to assess structural connectivity.

Main Results:

• ET-RBD patients exhibited increased local strength and weighted clustering coefficient in the Geniculate Body and increased Betweenness centrality in the Right Pulvinar Inferior Nucleus.
• Compared to controls, ET-RBD patients showed increased strength and weighted clustering coefficient in the Left Lateral Geniculate Body and Right Medial Geniculate Body.
• These alterations were statistically significant (p < 0.05 FDR-corrected).

Conclusions:

• The presence of RBD in ET is associated with altered thalamic structural connectivity.
• Findings support the thalamus' pathophysiologic role in RBD within the ET phenotype.
• Specific thalamic nuclei, including geniculate and pulvinar nuclei, are implicated in ET-RBD pathophysiology.