Pallidal Stimulation and Gilles de la Tourette Syndrome (STIC)

• To evaluate the therapeutic effect of the high frequency bilateral stimulation of GPI in severe forms and invalidating MGT, in a protocol randomized as a double blind man in parallel groups. [ Time Frame: during the 44 months ] [ Designated as safety issue: Yes ]
  
• The assumption tested is that of the frank improvement (> 60% on scale YGTSS) of the symptoms of the MGT by the bilateral stimulation of GPI in its former part. [ Time Frame: at the end of 44 months ] [ Designated as safety issue: Yes ]
  

• To evaluate time necessary to obtaining the maximum effect and its evolution after this one (maintenance or not of the effect in the course of time) [ Time Frame: during the study ] [ Designated as safety issue: Yes ]
  
• To study the effects of the stimulation of GPI in its former part, on the driving tics simple and complex, vocal, the self-mutilations, and the psychopathology of which time, emotions and impulsiveness [ Time Frame: during the 44 months ] [ Designated as safety issue: Yes ]
  
• To evaluate the repercussion of this technique on the sociological-professional handicap, operation and the adaptation [ Time Frame: during the 44 months ] [ Designated as safety issue: No ]
  
• To seek determinants before intervention of the effectiveness of stimulation (determining neurological, psychiatric, neuropsychological, functional) [ Time Frame: during the 44 months ] [ Designated as safety issue: Yes ]
  
• To establish correlations between the localization of the studs of stimulation (retiming atlas/IRM) and the symptoms [ Time Frame: during the 44 months ] [ Designated as safety issue: Yes ]
  
• To determine the modifications of cerebral activation induced by the bilateral stimulation of GPI at the time of the improvement of the neurological symptoms (study in Mtoe). [ Time Frame: during the 44 months ] [ Designated as safety issue: Yes ]
  

It acts of a randomized study, in parallel, double group blind, multi-centric relating to 14 patients.

The interest of this multicentric study, which will be carried out in centers specialized in the field of major cerebral stimulation with for each one a multidisciplinary team, is to carry out a homogeneous protocol which should make it possible to give a clear response in term of effectiveness for this treatment in this pathology.

The evaluation will be:

1. neurological (YGTSS, video scale of the tics);
2. psychiatric, with in particular of the specific psychopathological evaluations centered on mood;
3. neuropsychological, centered on impulsiveness;
4. functional calculus evaluating total operation and the social adaptation;
5. neurophysiological (recording of the neuronal activities).

Calculations of the number of subjects necessary showed, by laying down the principal objective at an improvement of at least 60 % of the score of the YGTSS under treatment, which 14 subjects will make it possible to show a significant difference with the procedure placebo.

Study in Tomography by Emission of Positrons (Mtoe) carried out on 8 of the 14 operated patients having had at least 3 months of stimulation, in comparison on 8 pilot subjects (paired for the sex and the age), should make it possible to determine, at the time of the improvement of the driving symptoms, modifications of cerebral activation induced by the high frequency stimulation of GPI among patients.

The association of this study to the comparison of the improvement of the neurological symptoms with the precise localization of the therapeutic stud of the electrode reformatted on the post-operative TDM (8), carried out for all the patients, should make it possible to specify the anatomy-physiological bases to specify the anatomy-physiological bases of the MGT The duration of the study will be 14 month for each patient, that is to say one 2 months preoperative period intended for inclusion; one 3 months post-operative period without stimulation; one period randomized with stimulation either "one" (3 months), or "off" (3 months), then an open study for all the patients with stimulation "one" for one 6 months duration.

It is envisaged to include 14 patients reached of the MGT (of which 8 will take part in study Mtoe) and 8 subjects controls for study Mtoe is 22 subjects.