Cerebello-thalamo-cortical Coupling in Essential Tremor

Study Overview
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Brief Summary
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Essential tremor (ET) is a frequent and disabling disorder with progressive worsening of postural tremor of the upper limbs that impairs most of the manual activities of every day life (feeding, drinking, etc.). Although the pathophysiology of essential tremor (ET) is not fully elucidated, tremor is associated with abnormal activity within different brain regions, in particular the thalamus and the cerebellum. Deep brain stimulation (DBS) of the ventral intermediate nucleus of the thalamus (VIM-Thal) reverses the symptoms of tremor but is an invasive procedure. Transcranial stimulation of the cerebellum may represent a non-invasive therapeutic option for ET patients. Here, the investigators propose to test the efficacy of cerebellar stimulation in 15 ET patients previously operated for DBS of the thalamus. To further understand how this treatment provokes tremor reduction, the investigators will analyse the brain neuronal activity in 13 others ET patients candidate to thalamic DBS by using combined electrophysiological recordings of the thalamus (with the electrodes implanted), the cerebellum and the cortex with magnetoencephalography.

Official Title
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Cerebello-thalamo-cortical Coupling in Essential Tremor: Effects of High Frequency tACS of the Cerebellum

Conditions
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Essential Tremor

Intervention / Treatment
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* Device: tACS of the cerebellum


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: age below 75 years diagnosis of essential tremor according to the criteria of the Tremor Investigation Group and the Consensus statement of the Movement Disorder Society Group (ref) health insurance signed informed written consent Exclusion Criteria: other neurological disorders medications that interact with or influence brain excitability significant brain lesions detected in MRI

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: LFP-MEG recording with tACS of the cerebellum<br>To explore how cerebellar stimulation (using tACS) will alter oscillations and coupling along the CTC pathway, relating these changes in brain activity to clinical improvement. | Device: tACS of the cerebellum<br>* tACS of the cerebellum<br>|
| Active Comparator: tACS of the cerebellum vs VIM-DBS<br>To evaluate the differential effects of non invasive high-frequency stimulation tACS of the cerebellum, as compared to high-frequency stimulation of the thalamus (using DBS of the VIM). | Device: tACS of the cerebellum<br>* tACS of the cerebellum<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The neuronal activity in the cerebello-thalamo-cortical pathway | LFP, MEG and EMG activity recordings | 1 day |