Algorithms for Programming DBS Systems for ET

Overview

Deep brain stimulation (DBS) targeting the Vim thalamus (ventralis intermedius nucleus) is an FDA-approved neuromodulation therapy for treating postural and action tremor in individuals with essential tremor (ET). The success of this treatment, however, is highly dependent on the ability of clinicians to identify therapeutic stimulation settings through a laborious programming process. There is a strong and growing clinical need for new approaches to provide clinicians with more efficient guidance on how to titrate stimulation settings. This study will leverage subject-specific computational models that can predict neural activation of axonal pathways adjacent to the active electrode(s) and implicated in the therapeutic mechanisms of Vim-DBS to in turn guide clinicians with which stimulation settings are likely to be the most therapeutic on tremor.

Detailed description

Primary Endpoint/Event/Outcome:

Endpoint: Identify the neural pathways within the brain that are involved in the reduction of action and postural tremor using directional DBS leads and advanced computational optimization algorithms.

Event: Using anatomical segmentation of high-field 7-Tesla MRI and diffusion tensor imaging from 25 human ET subjects, the investigators will build prospective subject-specific, multi-compartment neuron models of the afferent and efferent projections from and to the sensorimotor thalamus. Using these models, the investigators will then apply a semi-automated algorithm that can efficiently identify stimulation settings that most selectively target one pathway over other adjacent pathways. Note that these stimulation settings will not exceed the FDA-approved safety limits that are already programmed into the implanted pulse generator. The optimization algorithm defined stimulation settings will then be tested in human ET subjects to compare the therapeutic efficacy and efficiency of DBS targeting the: interposed-receiving area of motor thalamus, dentate-receiving area of motor. Rendering of a 4-channel DBS lead implant in the VIM nucleus (ventralis intermedius nucleus) of thalamus for treating Essential Tremor.

thalamus, pre-lemniscal radiations (raprl) with medial and lateral divisions, and zona incerta, all of which have been implicated in the therapeutic mechanisms of DBS. This clinical evaluation will occur during routine clinical follow-up sessions in which the Essential Tremor Rating Assessment Scale (TETRAS) will serve as the primary form of qualification scoring of each setting tested.

Outcome: The investigators hypothesize that targeting the interposed-receiving region of motor thalamus and in particular the ascending cerebello-thalamic fibers to this region will result in the strongest and most energy-efficient suppression of action and postural tremor.

Interventions

• Device Vim-Deep Brain Stimulation
  This study consists of testing additional model-derived DBS settings during initial and regular follow-up clinical visits every 6 months for up to 2 years in which individuals with DBS implants are re-evaluated by a clinician to make sure that the stimulation settings employed during the previous clinical visit remain therapeutic. It is important to note that this study is post-surgical and all procedures (i.e. stimulation settings that will be tested in the clinic) are within the FDA-approved r

Primary outcome measures

• Therapeutic Windows [Time frame: 24-months]
• Objective Measures of Tremor [Time frame: 24-months]
• Quality of Life Questionnaire: QUEST [Time frame: 24-months]
• Quality of Life Questionnaire: TETRAS [Time frame: 24-months]

Eligibility criteria

Inclusion criteria

• diagnosis of ET
• medication-refractory tremor
• VIM-DBS implant (unilateral or bilateral)
• 7T MRI pre-operative scan under Dr. Harel's IRB (institutional review board) protocol (#1210M22183)
• Post-operative CT scan

Exclusion criteria

• history of musculoskeletal disorders that affect movement of the limbs
• other significant neurological disorder
• prior history of stereotactic neurosurgery (other than VIM-DBS surgery)
• pregnancy

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

N/A

Model

Single group

Masking

Open label

Primary purpose

Basic science

Study locations

United States · 1 center

• University of Minnesota — Minneapolis

Identifiers

NCT: NCT03984643 · CSENG-2018-27182

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗