Severe Disabling Tremor Clinical Trial
Official title:
Evaluation of the Predictors of Clinical and Radiological Response to Gamma-Knife Radiosurgery in the Treatment of Intermediate Ventral Nucleus of the Thalamus (VIM) Thalamotomy Tremor.
Gamma-Knife radiosurgery of the VIM for patients presenting with severe drug-resistant tremor
is now current practice as an alternative to Deep Brain Stimulation (DBS) of the VIM.
Now, around 100 patients are treated annually in our unit (essential tremor or Parkinson
tremor).
Clinical and radiological follow-up is demonstrating that 80% of these patients are
presenting with a homogenous response complete or subtotal, the disappearance of the tremor
mean delay of 6 months after radiosurgery. In neuroradiological responses on the MRI, is
appearing roughly at the same time local contrast enhancement surrounding highty to signal no
associated with clinical side effects.
In 15 to 20% of the patients, the clinical effets is not obtained and in the vast majority no
MRI response or minimal MRI response is observed on images suggesting that these failures are
related to specific resistance to radiosurgery of this subgroup.
In roughly 5% of the patients, at the contrary, hyper response is observe on the MRI rating
clinically with side effects (hemiparesis or proprioceptive ataxia or dysarthria, hands
problems….). The adverse effects are generally reversible either in whole or in part with the
resorption of the perilesionnel oedema.
It would be extremely helpfull to be able to identify in advance these 2 groups of hyper and
hypo respondeurs.
The capacity to identify in advance these patients at risk to hypo or hyper response would
allow us to either contre-indicate radiosurgery or modify radiosurgery technicaly at the time
of dose planing.
Sequently, these predictions would allow us to tailor individually mission management and
information leading to improvment of the efficacy and tolerance of this kind of intervention.
The parameters suspected to be likely to influence the response are :
- genetics
- co-morbidities (diabetis, vascular…)
- Main aspect of the brain (severe atrophy, vascular, micro-infacts…)
- Chronobiological (timing during the day of the radiosurgical procedure)
- Associated medication (potential radioprotector or radiosensitizer effect of some drugs)
- Radiobiological (dose rate…)
The goal of this study is to collect all of these informations out of genetical one in the
cohort of 700 patients having benefited ou will benefit from radiosurgery in the situation
for essential tremor and parkinson disease. It will be test the predictive value of these
parameters and the capacity to predict hyper or hypo response.
The work on the genetic material will take place in the second stage in the frame of a new
different resarch project.
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