Dual-Site Transcranial Magnetic Stimulation of the Supplementary Motor Area and Cerebellum for the Treatment of Essential Tremor.

Summary

Essential tremor is a common movement disorder that causes involuntary shaking, mainly during voluntary actions such as writing or holding objects. Recent research suggests that essential tremor is not caused by a single brain area, but by abnormal activity within a network that includes the cerebellum and motor areas of the brain. However, most non-invasive brain stimulation studies to date have targeted only one brain region and have shown inconsistent clinical benefits.

This randomized, double-blind, placebo-controlled clinical trial aims to evaluate the effects of a dual-site transcranial magnetic stimulation (rTMS) protocol targeting the supplementary motor area (SMA) and the cerebellum in patients with essential tremor that does not respond adequately to standard medications. The study is based on previous pilot data showing meaningful tremor reduction using combined stimulation of these two brain regions.

Participants will receive five sessions of rTMS, consisting of low-frequency stimulation over the SMA followed by high-frequency stimulation over the cerebellum. The main hypothesis is that this combined approach will lead to an immediate and sustained improvement in action tremor of the dominant upper limb, measured up to four weeks after treatment. Secondary outcomes include quality of life, safety, side effects, and changes in brain excitability associated with tremor improvement.

Conditions

• Essential Tremor

Interventions

DEVICE

Dual-site repetitive transcranial magnetic stimulation (rTMS) of the supplementary motor area and cerebellum

This intervention consists of a sequential dual-site repetitive transcranial magnetic stimulation (rTMS) protocol targeting two interconnected nodes of the tremor network. Low-frequency stimulation (1 Hz) is first applied over the supplementary motor area at 110% of the resting motor threshold to modulate cortical motor drive, followed by high-frequency stimulation (10 Hz) over the cerebellar cortex at 90% of the resting motor threshold to modulate abnormal cerebellar output. Stimulation is delivered over five consecutive daily sessions using standardized anatomical localization and identical session duration across participants. Sham Intervention The sham intervention replicates the anatomical targeting, sequence, session duration, and acoustic characteristics of the active dual-site rTMS protocol without delivering an effective magnetic field. An inactive coil is positioned over the same supplementary motor area and cerebellar cortex

DEVICE

Transcranial Magnetic Stimulation Sham

The sham intervention replicates the anatomical targeting, sequence, session duration, and acoustic characteristics of the active dual-site rTMS protocol without delivering an effective magnetic field. An inactive coil is positioned over the same supplementary motor area and cerebellar targets, while sound simulation is used to mimic active stimulation, ensuring maintenance of blinding and comparability with the active intervention.

Sponsors & Collaborators

• São Paulo State University

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

TRIPLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2026-01-15

Primary Completion

2026-10-31

Completion

2027-01-31

Countries

• Brazil

Study Locations