BACKGROUND: Besides fluctuations, therapy refractory tremor is one of the main 
indications of deep brain stimulation (DBS) in patients with idiopathic 
Parkinson syndrome (IPS). Although thalamic DBS (ventral intermediate nucleus 
[Vim] of thalamus) has been shown to reduce tremor in 85-95% of patients, 
bradykinesia and rigidity often are not well controlled. The 
dentato-rubro-thalamic tract (DRT) that can directly be targeted with special 
diffusion tensor magnetic resonance imaging sequences has been shown as an 
efficient target for thalamic DBS. The subthalamic nucleus (STN) is typically 
chosen in younger patients as the target for dopamine-responsive motor symptoms. 
This study investigates a one-path thalamic (Vim/DRT) and subthalamic 
implantation of DBS electrodes and possibly a combined stimulation strategy for 
both target regions.
OBJECTIVE: This study investigates a one path thalamic (Vim/DRT) and subthalamic 
implantation of DBS electrodes and a possibly combined stimulation strategy for 
both target regions.
METHODS: This is a randomized, active-controlled, double-blinded (patient- and 
observer-blinded), monocentric trial with three treatments, three periods and 
six treatment sequences allocated according to a Williams design. Eighteen 
patients will undergo one-path thalamic (Vim/DRT) and STN implantation of DBS 
electrodes. After one month, a double-blinded and randomly-assigned stimulation 
of the thalamic target (Vim/DRT), the STN and a combined stimulation of both 
target regions will be performed for a period of three months each. The primary 
objective is to assess the quality of life obtained by the Parkinson's Disease 
Questionnaire (39 items) for each stimulation modality. Secondary objectives 
include tremor reduction (obtained by the Fahn-Tolosa-Marin tremor rating scale, 
video recordings, the Unified Parkinson's disease rating scale, and by tremor 
analysis), psychiatric assessment of patients, and to assess the safety of 
intervention.
RESULTS: At the moment, the recruitment is stopped and 12 patients have been 
randomized and treated. A futility analysis is being carried out by means of a 
conditional power analysis.
CONCLUSIONS: The approach of the OPINION trial planned to make, for the first 
time, a direct comparison of the different stimulation conditions (Vim/DRT, 
compared to STN, compared to Vim/DRT+STN) in a homogeneous patient population 
and, furthermore, will allow for intraindividual comparison of each condition 
with the "quality of life" outcome parameter. We hypothesize that the combined 
stimulation of the STN and the thalamic (Vim/DRT) target will be superior with 
respect to the patients' quality of life as compared to the singular stimulation 
of the individual target regions. If this holds true, this work might change the 
standardized treatment described in the previous section.
TRIAL REGISTRATION: ClinicalTrials.gov: NCT02288468; 
https://clinicaltrials.gov/ct2/show/NCT02288468 (Archived by WebCite at 
http://www.webcitation.org/6wlKnt2pJ); and German Clinical Trials Register: 
DRKS00007526; https://www.drks.de/drks_ 
web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00007526 (Archived by 
WebCite at http://www.webcitation.org/6wlKyXZZL).