Optimization of VIM Targeting in Essential Tremor Surgery (Opti-VIM)

Deep brain stimulation (DBS) for essential tremor is based on the intermedius ventralis nucleus of the thalamus (VIM) stimulation. This structure is however very difficult to target, as it remains invisible on imaging. The current procedure based on awake surgery with clinical and electrophysiological testings has several limitations that lead us to develop a probabilistic model to locate precisely the target. This study aims to show that asleep DBS surgery based on this new targeting method leads to at least the same clinical results than the classical procedure.

Study Overview

• Status: Completed
• Conditions: Essential Tremor
• Intervention / Treatment: Procedure: Opti-VIM targeting in DBS surgery

Detailed Description

The intermedius ventralis nucleus of the thalamus (VIM), which represents the target for deep brain stimulation (DBS) in essential tremor, still remains invisible on 1,5 tesla MRI (the only magnetic field available for stereotactic surgery). The target coordinates currently used are based on stereotactic atlases or mean coordinates from retrospective series. They are so imprecise that intra-operative clinical testing and micro-electrode recordings are mandatory to locate the exact position of the VIM. This procedure is long lasting, requires that the patient is awake, and increases the risk of intracerebral haemorrhage and nosocomial infections. Furthermore, some patients are not improved despite a DBS lead implanted in the electrophysiologically and clinically defined target. To overcome these limitations, investigators developed a probabilistic model based on data extracted from imaging of patients with particularly good outcomes after DBS surgery. This machine-learning model allows calculating to coordinates of the VIM according to the position of radio-anatomical landmarks with a mean precision of 1,65mm.

The aim of this study is to validate this new targeting method on a prospective cohort of patients. DBS surgery will be performed under general anaesthesia, without intra-operative clinical and electrophysiological testing, with a surgical robot and under CT-scan guidance (O-Arm ©).

Neurostimulation device programming will be performed as usual. Patients' tremor and quality of life will be evaluated pre and post-operatively at 3 months, according to the Fahn-Tolosa-Marin (FTM) scale and with an accelerometry recording (for tremor) and with the mPDQ-39 scale for quality of life. Surgical complications and side effects related to neurostimulation will be gathered all along the follow-up.

• Study Type: Interventional
• Enrollment (Actual): 22
• Phase: Not Applicable

Contacts and Locations

Study Locations

• France
  • Bordeaux, France, 33076
    • CHU de Bordeaux
  • Bron, France, 69500
    • Hospices Civils de Lyon

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 75 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Severe essential tremor despite the optimal medical management
• Age between 18 and 75 years
• Normal MRI scan
• Mattis Dementia Rating Scale (MDRS) score ≥ 130
• Affiliation to the social security
• Signed informed consent

Exclusion Criteria:

• Depression (Beck Depression Inventory scale > 20)
• Contra-indication to surgery or general anesthesia
• Cerebral atrophy on MRI scan
• Pregnant or breastfeeding women

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Severe essential tremor treated by DBS	Procedure: Opti-VIM targeting in DBS surgery; DBS surgery will be performed under general anaesthesia, without intra-operative clinical and electrophysiological testing, with a surgical robot and under CT-scan guidance (O-Arm ©). The VIM coordinates will be calculated with the probabilistic model that have been developed.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change of Fahn-Tolosa-Marin (FTM) scale score	Scale global range : min=0 / max=160 Higher values represent worse tremor	Before and 3 month after DBS surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Accelerometry recordings : spectral analysis	Accelerometry recordings at the pre-inclusion visit and at 3 months after surgery in ON and OFF-stimulation conditions with spectral analysis.	Before and 3 month after DBS surgery
Accelerometry recordings : calculation of the total accelerometry power	Accelerometry recordings at the pre-inclusion visit and at 3 months after surgery in ON and OFF-stimulation conditions with calculation of the total accelerometry power.	Before and 3 month after DBS surgery
Surgical complications	Onset of infection, hematoma or seizure	Up to 3 month after DBS surgery
Device complications and dysfunction	rupture or displacement of electrode, pain at the stimulation box implantation site or along the subcutaneous cable if they require further intervention, infection.	Up to 3 month after DBS surgery
Neurostimulation-related side effects	Onset of dysarthria and ataxia assessed by the items 1 to 4 of the Scale for Assessment and Rating of Ataxia (SARA), ataxia assessed by a posturometry analysis, paresthesia, muscular contractions	Up to 3 month after DBS surgery
Quality of life: change of modified Parkinson's Disease Questionnaire-39 (mPDQ-39) scale score	Adaptation of Parkinson's Disease Questionnaire-39 to essential tremor Scale global range : min=0 / max=156 Higher values represent worse Quality of life	Before and 3 month after DBS surgery
Coordinates of active contacts	Coordinates of active contacts (i.e; the contact with the best effect on tremor without side effects) These coordinates (x, y, z) are obtained by merging the images of the 3-month postoperative scanner with the images of the preoperative MRI.	3 month after DBS surgery

Collaborators and Investigators

• Sponsor: University Hospital, Bordeaux
• Investigators: Study Chair: Antoine BENARD, MD, USMR CHU de Bordeaux

Publications and helpful links

General Publications

• Engelhardt J, Simon E, Zemzemi N, Dallies-Labourdette C, Courtin E, Sitta R, Benard A, Branchard O, Goillandeau M, Laurencin C, Gervais-Bernard H, Caire C, Thobois S, Tourdias T, Munsch F, Guehl D, Cuny E. Enhancing Asleep Deep Brain Stimulation Targeting for Essential Tremor Using Machine Learning: The OPTIVIM Phase 2 Study. Neurosurgery. 2025 Dec 5. doi: 10.1227/neu.0000000000003870. Online ahead of print.

Study record dates

Study Major Dates

• Study Start (Actual): March 18, 2019
• Primary Completion (Actual): August 29, 2023
• Study Completion (Actual): August 29, 2023

Study Registration Dates

• First Submitted: November 26, 2018
• First Submitted That Met QC Criteria: November 29, 2018
• First Posted (Actual): November 30, 2018

Study Record Updates

• Last Update Posted (Actual): June 2, 2026
• Last Update Submitted That Met QC Criteria: May 29, 2026
• Last Verified: February 1, 2025

More Information

Terms related to this study

• Keywords: Essential Tremor; Deep brain stimulation; Ventro-intermediate nucleus of the thalamus; Targeting; Asleep surgery
• Additional Relevant MeSH Terms: Central Nervous System Diseases; Nervous System Diseases; Movement Disorders; Essential Tremor
• Other Study ID Numbers: CHUBX 2018/32; 2018-A02754-51 (Registry Identifier: ANSM)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No