Testing the safety of non-invasive transcranial ultrasound stimulation in people with essential tremor
| ISRCTN | ISRCTN17201632 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN17201632 |
| Integrated Research Application System (IRAS) | 365666 |
| Central Portfolio Management System (CPMS) | 74798 |
| Sponsor | NeuroHarmonics Ltd |
| Funders | NeuroHarmonics Ltd, UK Research and Innovation |
- Submission date
- 26/08/2026
- Registration date
- 26/08/2026
- Last edited
- 26/08/2026
- Recruitment status
- Not yet recruiting
- Overall study status
- Ongoing
- Condition category
- Nervous System Diseases
Plain English summary of protocol
Background and study aims
Essential tremor is the most common movement disorder, causing involuntary shaking, most often of the hands, that can significantly affect daily life. Medication and surgery help many people, but a substantial proportion do not get adequate relief or cannot tolerate side effects. Transcranial ultrasound stimulation (TUS) uses low-intensity focused sound waves, delivered through the intact skull, to temporarily alter brain cell activity. It is non-invasive, and unlike established focused ultrasound treatments it does not destroy brain tissue. This study investigates whether TUS delivered by a helmet-shaped device called Meridian can safely target the ventral intermediate nucleus of the thalamus, a deep brain structure involved in controlling tremor, and whether stimulation produces any measurable change in tremor. This is a first-in-patient study; it is not designed to provide lasting tremor relief, and any effects are expected to be temporary.
Who can participate?
Men and women aged 18 to 80 years with essential tremor affecting both hands for at least 3 years, whose tremor medications have not worked adequately, have caused unacceptable side effects, or who prefer not to take them.
What does the study involve?
Participants attend a screening visit including a brain MRI scan, a single stimulation session lasting approximately 2.5 to 3 hours, and a telephone follow-up call the next day. During the stimulation session, participants sit in a chair wearing the Meridian device while small motion sensors on the hands measure tremor. Stimulation is delivered in four periods; one of the four is an inactive (sham) period, included so that any tremor changes can be attributed to the stimulation itself. Tremor is then monitored for up to 60 minutes.
What are the possible benefits and risks of participating?
Participants are not expected to receive any direct health benefit, but the results may help develop new non-invasive treatments for essential tremor. TUS has been used in research studies involving over 700 people with no serious adverse events reported. Possible side effects are mostly mild and short-lived, including headache, scalp discomfort or tingling, clicking or buzzing sounds during stimulation, and temporary changes in tremor. The MRI scan and device fitting may cause mild discomfort or claustrophobia.
Where is the study run from?
National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Foundation Trust (UCLH), London, UK
When is the study starting and how long is it expected to run for?
September 2026 to April 2027
Who is funding the study?
NeuroHarmonics Ltd and UK Research and Innovation (UKRI)
Who is the main contact?
Dr Anna Latorre, a.latorre@ucl.ac.uk
Contact information
Public, Scientific, Principal investigator
Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Queen Square
London
WC1N 3BG
United Kingdom
| Phone | +44 20 3448 8066 |
|---|---|
| a.latorre@ucl.ac.uk |
Study information
| Primary study design | Interventional |
|---|---|
| Allocation | Randomized controlled trial |
| Masking | Blinded (masking used) |
| Control | Placebo |
| Assignment | Single |
| Purpose | Device feasibility |
| Scientific title | Safety and Target Engagement of Transcranial Ultrasound Stimulation of the Ventral Intermediate Nucleus for Essential Tremor: A First-in-Patient Proof-of-Concept Study |
| Study acronym | VIM-TUS-ET |
| Study objectives | 1. To evaluate the safety and tolerability of transcranial ultrasound stimulation (TUS) targeting the ventral intermediate nucleus (VIM) of the thalamus in patients with essential tremor 2. To assess preliminary evidence of target engagement by evaluating whether TUS of the VIM produces measurable changes in tremor power compared with baseline and with sham stimulation |
| Ethics approval(s) |
Approved 30/06/2026, West of Scotland REC 3 (West of Scotland Research Ethics Service) (Admin Building, Level 2, Gartnavel Royal Hospital, 1055 Great Western Road, Glasgow, G12 0XH, United Kingdom; +44 141 211 3600; ggc.wosrec3@nhs.scot), ref: 26/WS/0096 |
| Health condition(s) or problem(s) studied | Essential tremor |
| Intervention | Participants receive a single session of low-intensity transcranial ultrasound stimulation (TUS), delivered with the Meridian device and targeting the ventral intermediate nucleus (VIM) of the thalamus in one hemisphere (left or right, randomised 1:1 using a computer-generated sequence). The session comprises four stimulation conditions, one of which is a sham (control) condition; participants are not told which condition is the sham. Hand tremor is measured by accelerometers during the session and for up to 60 minutes afterwards. Participants attend a screening visit including a brain MRI scan (Visit 1), the stimulation session lasting approximately 2.5 to 3 hours (Visit 2), and a telephone follow-up approximately 24 hours later (Visit 3); total participation is approximately 2 to 4 weeks. |
| Intervention type | Device |
| Phase | Not Applicable |
| Drug / device / biological / vaccine name(s) | Meridian transcranial ultrasound stimulation system |
| Primary outcome measure(s) |
|
| Key secondary outcome measure(s) |
|
| Completion date | 21/04/2027 |
Eligibility
| Participant type(s) | |
|---|---|
| Age group | Mixed |
| Lower age limit | 18 Years |
| Upper age limit | 80 Years |
| Sex | All |
| Target sample size at registration | 10 |
| Key inclusion criteria | 1. Adults aged 18-80 years 2. Clinical diagnosis of essential tremor according to Movement Disorder Society consensus criteria 3. Tremor affecting both upper limbs, defined as TETRAS Performance Subscale item 4 (upper limb tremor) score >=1.5 in both upper limbs 4. Tremor duration of at least 3 years 5. Suboptimal response to, intolerance of, contraindication to, or preference not to use at least one first-line medication (propranolol, primidone) 6. Stable dose of tremor medication for at least 2 weeks prior to screening, or medication-naive 7. Able to maintain a postural hold position for tremor assessment (repeated blocks of 30 seconds) 8. Able to provide written informed consent, comply with study procedures, and communicate in English |
| Key exclusion criteria | 1. Any condition which results in significant movement of the head during a 30 second postural hold of the arms, including clinically apparent cervical dystonia, tics affecting the head, or head tremor (TETRAS Performance Subscale item 1 score >1) 2. Unable to achieve proper device fit due to head circumference exceeding 62 cm, or hair circumference exceeding 80 cm 3. Contraindications to MRI: 3.1. Metallic implants incompatible with MRI 3.2. Cardiac pacemaker or implantable cardioverter-defibrillator 3.3. Cochlear implants 3.4. Implanted medication infusion device (e.g., insulin pump, intrathecal pump) 3.5. Severe claustrophobia 3.6. Other standard MRI contraindications 4. Contraindications to transcranial ultrasound stimulation: 4.1. Previous cranial surgery or skull defects 4.2. Intracranial metallic implants, clips, or devices 4.3. History of epilepsy or unprovoked seizure 4.4. History of severe head trauma 4.5. History of unexplained syncope 4.6. Prior intracranial haemorrhage 4.7. Structural lesion at or near VIM target (tumour, cavernoma, AVM, large infarct) 4.8. Space-occupying lesion 4.9. Stroke (ischaemic or haemorrhagic in past 6 months) 4.10. MI (in past 6 months) and severe cardiac disease 4.11. Uncontrolled hypertension (systolic >180) 4.12. Current use of medications associated with a substantially increased seizure risk (clozapine or bupropion). Other medications with potential to lower seizure threshold will be reviewed at screening. Stable use of standard antidepressants and other psychotropic medications at usual therapeutic doses is permitted unless, in the opinion of the investigator, overall seizure risk is materially increased. 4.13. Electroconvulsive therapy (ECT) within the past 6 months 5. Pregnancy or breast-feeding 6. Previous surgical treatment for tremor (deep brain stimulation, thalamotomy, focused ultrasound ablation) 7. Other neurological conditions that could affect tremor assessment or confound results: Parkinson's disease; dystonia; multiple sclerosis; stroke affecting motor function; other movement disorders 8. Scalp condition that would prevent device placement (e.g., open wounds, severe dermatitis, psoriasis) 9. Recent scalp or cranial surgical procedure, biopsy, or hair transplant/follicle extraction within the past 6 months 10. Unable to tolerate sitting still for the duration of the intervention (approximately 120 minutes) 11. Participation in another interventional clinical trial within the past 30 days 12. Any condition that, in the opinion of the investigator, would make participation unsafe or compromise data quality |
| Date of first enrolment | 21/09/2026 |
| Date of final enrolment | 21/03/2027 |
Locations
Countries of recruitment
- United Kingdom
- England
Study participating centre
London
WC1N 3BG
England
Results and Publications
| Individual participant data (IPD) Intention to share | No |
|---|
Editorial Notes
26/08/2026: Trial's existence confirmed by West of Scotland REC 3.
