Bilateral Pallidal Stimulation in Patients With Advanced Parkinson's Disease-LATESTIM

Exclusion Criteria

• •* Mattis dementia rating scale \<130 points
• •* postural instability of \>1 in the item of MDS-UPDRS III \[item #12\] "on" medication
• •* less than 30% improvement of axial score in the acute levodopa challenge test \[axial score =sum of items 3.1, 3.9, 3.10, 3.12, 3.13 of the MDS UPDRS III\]
• •* age \> 70 years
• •* Mattis dementia rating scale \<134 points
• •* gait freezing "on" medication
• •* dysarthria of \> 2 in the item of the MDS-UPDRS III \[item #3.1\]
• •* less than 50% improvement of axial score in the acute levodopa challenge test \[axial score = sum of items 3.1, 3.9, 3.10, 3.12, 3.13 of the MDS UPDRS III\]
• •* Starkstein apathy score of ≥14
• •Complete baseline PDQ-39-SI and patient diary available
• •written informed consent
• •Age \> 85 years
• •surgical or medical contraindications
• •abnormalities on brain MRI that preclude the implantation of electrodes into the GPi
• •contraindication for 3T MRI (baseline imaging)
• •severe medical illness that is likely to hamper the benefit of DBS
• •severe personality disorder that may interfere with optimization of DBS
• •dementia according to DSM-V and MMSE \< 20
• •ongoing psychosis (except pseudohallucinations)
• •ongoing major depression (BDI-II \> 23) or depression of any severity with suicidal ideation