Probabilistic Targeting of the VIM

After having included the most improved patients by DBS among those implanted in Bordeaux Hospital University, and having defined the most active plots on tremor by its prospective grading on Fahn-Tolosa-Marin (FTM) scale and accelerometry, coordinates of active plots and landmarks will be calculated on post-operative imaging. Association between landmarks and active plots coordinates will be modelled with machine-learning algorithms. The aim is to retrieve the position of the VIM on the basis of the landmarks coordinates.

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Key information

Conditions

Essential Tremor Central Nervous System Diseases Deep Brain Stimulation Movement Disorders Nervous System Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Bordeaux University Hospital

Bordeaux, 33076, France

About this study

The intermedius ventralis nucleus of the thalamus (VIM), which represents the target for deep brain stimulation (DBS) in essential tremor, still remains invisible to imaging in spite of the development of new MR sequences. The coordinates currently used in the classical (ACPC) system are so imprecise that per-operative electrophysiology is mandatory to locate the exact position of this target. Micro-electrode recordings (MER) however improve hemorrhagic risk and may be poorly tolerated by patients operated on 7 to 8 hours under local anaesthesia. Based on litterature review, no one tried to retrieve the position of the VIM from anatomical landmarks coordinates in the era of MRI. The patients operated will be clinically tested to define those very well improved by the stimulation. Stimulation efficacy will be assessed by comparing the clinical evaluation (FTM scale) with and without stimulation, and the four contacts of each electrode will be tested clinically, with an accelerometer and an electromyography to determine which one is the most active on tremor. Coordinates of the anatomical landmarks will be calculated on the pre-operative MRI and those of the active plots on the fusion between post-operative CT-scan and pre-operative MRI. These coordinates will be analysed by machine-learning algorithms to create a model predicting the position of the active contacts from the coordinates of the landmarks.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

patient older than 18 years
who underwent a DBS surgery targeting the VIM at Bordeaux University Hospital
in the strict indication of the essential tremor
with an excellent post-operative result defined by a complete withdrawal of medication, a stability of the stimulation effects without any setting adjustments since at least 3 months and an improvement of more than 66% on the FTM scale between OFF and ON-stimulation assessments.

Exclusion criteria

patients who underwent a DBS surgery targeting the VIM for different indications (Parkinson's disease for instance), patients with a poor post-operative efficacy

Treatment and study plan

Coordinates of active plots and VIM landmarks calculation

Other

Stimulation efficacy will be assessed by comparing, according to usual care, the clinical evaluation (FTM scale) with and without stimulation, and the four contacts of each electrode will be tested clinically, with an accelerometer and an electromyography to determine which one is the most active on tremor. Coordinates of the anatomical landmarks will be calculated on the pre-operative MRI and those of the active plots on the fusion between post-operative CT-scan and pre-operative MRI.

Primary outcomes

Euclidian distance between the predicted target and the center of the active contact of the DBS lead

Time frame: 6 month after DBS surgery

Euclidian distance in milimeter measured on the fusion between post-operative CT-scan and pre-operative MRI.

Sponsors and collaborators

Lead sponsor

University Hospital, Bordeaux

Other

Collaborators

Institut National de Recherche en Informatique et en Automatique

Registry information

Official study title

Probabilistic Determination of the Ventro-intermediate Nucleus of the Thalamus (VIM) Coordinates From Radio-anatomical Landmarks on 1.5 Tesla MRI

Acronym: PROBA-VIM

Important dates

Study start: 2018
Primary completion: 2018
Study completion: 2018
First posted: Oct 4, 2018
Registry last updated: Sep 21, 2021

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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Completed