Deep brain stimulation (DBS) of both ventral intermediate nucleus (VIM) and the posterior subthalamic area (PSA) has shown to be an effective treatment for essential tremor (ET). Characterizing the differences between both targets is necessary. The aim of the study is comparison of efficacy, safety, energy efficiency, neuropsychological status and quality of life of bilateral PSA-DBS vs bilateral VIM-DBS in the treatment of ET. The study hypothesis is that PSA-DBS is not inferior to VIM-DBS in terms of efficacy in controlling tremor, but has superior energy efficiency and safety.
Deep brain stimulation (DBS) of the ventral intermediate (VIM) nucleus of the thalamus is an effective treatment for disabling essential tremor (ET). In recent years, the posterior subthalamic area (PSA) has emerged as a potentially more effective target. There is a need for specific research into the clinical efficacy, efficiency, as well as the mid-term cognitive and quality-of-life outcomes of VIM-DBS and PSA-DBS. The aim of this study is: 1) to compare the efficacy and safety of bilateral PSA-DBS versus bilateral VIM-DBS in the treatment of ET. 2) to determine the impact of bilateral PSA-DBS versus bilateral VIM-DBS on quality of life, neuropsychological status, energy efficiency of the DBS system, and durability of the tremor-suppressing effect. The hypothesis is that PSA-DBS is not inferior to VIM-DBS in terms of efficacy in controlling tremor, but has superior energy efficiency and safety. To this end, a randomized, double-blind, crossover trial will be conducted, in which bilateral octopolar DBS leads will be implanted in a single-trajectory covering the VIM and PSA in patients with disabling and refractory ET. They will be randomly assigned to group 1 (PSA-VIM) or group 2 (VIM-PSA), undergoing stimulation on each target for 3 months. A blinded assessment will be carried out at the end of each period.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
11
Bilateral implantation of octopolar DBS leads covering VIM and PSA
Virgen de las Nieves University Hospital (Neurotraumatology and Rehabilitation Hospital)
Granada, Granada, Spain
Improvement in tremor assessed by Fahn-Tolosa-Marin Tremor Rating Scale (FTM-TRS) total score
Improvement from baseline to the end of the VIM-DBS vs PSA-DBS period, assessed as the FTM-TRS total score (0-144 points; higher scores indicate greater tremor severity).
Time frame: - Preoperative baseline, - 4 postoperative months (after the first 3-month stimulation period) and - 7 postoperative months (after the second 3-month stimulation period)
Stimulation efficiency assessed by stimulation amplitudes (mA)
Stimulation efficiency measured by stimulation amplitudes (mA). The greater the amplitude, the higher the energy consumption (lower theoretical energy efficiency)
Time frame: 4 postoperative months (after the first 3-month stimulation period) and 7 postoperative months (after the second 3-month stimulation period)
Stimulation efficiency measured by total electrical energy delivered (TEED)
TEED (μJ) = \[(I² · R · PW · f) 1e-6\], where DBS parameters are frequency (f, Hz), pulse width (PW, μsec), impedance (R, Ω) and current intensity (I, mA). The higher the TEED, the lower the energy efficiency.
Time frame: 4 postoperative months (after the first 3-month stimulation period) and 7 postoperative months (after the second 3-month stimulation period)
Quality of life (QoL) assessed using Visual Analog Scale (VAS)
Change from baseline to the end of the VIM-DBS vs PSA-DBS period assessed using VAS-QoL (1-10; higher scores indicate better QoL)
Time frame: - Preoperative baseline, - 4 postoperative months (after the first 3-month stimulation period) and - 7 postoperative months (after the second 3-month stimulation period)
Quality of life (QoL) assessed using the Quality of life in essential tremor questionnaire (QUEST)
Change from baseline to the end of the VIM-DBS vs PSA-DBS period assessed using the QUEST (1-120; higher scores indicate poor QoL)
Time frame: - Preoperative baseline, - 4 postoperative months (after the first 3-month stimulation period) and - 7 postoperative months (after the second 3-month stimulation period)
Number and type of stimulation-induced side effects
Type and frequency (absolute and relative) of stimulation-induced side effects in the VIM-DBS vs PSA-DBS period
Time frame: - 4 postoperative months (after the first 3-month stimulation period) and - 7 postoperative months (after the second 3-month stimulation period)
Overall cognitive assessment evaluated using the Dementia Rating Scale 2 (DRS-2)
Change in cognition from baseline to the end of the VIM-DBS vs PSA-DBS period assessed using the DRS-2 (1-144; higher scores indicate better cognitive performance)
Time frame: - Preoperative baseline, - 4 postoperative months (after the first 3-month stimulation period) and - 7 postoperative months (after the second 3-month stimulation period)
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