Dbs lead model 3389

All enrolled participants underwent clinical examination and neuropsychological assessment prior to surgery. Clinical and neuropsychological assessments were repeated 14 AE 4.5 months postoperatively. The surgical procedure has been described previously (24) and involved DBS lead (model 3389, Medtronic Inc.) implantation in the ipsilateral VTA or bilaterally (if symptoms were side alternating) under local or general anesthesia. The most deep contact location of the quadripolar lead was determined on a 1.5T T2 axial stereotactic MRI at a level directly above the mammillary bodies, anteromedial to the hypointense red nucleus and posterolateral to the hypointense mammillothalamic tract (24) . In the weeks following surgery, open label programming was conducted to define optimal stimulation parameters. All devices were programmed with a frequency of 185 Hz and pulse width of 60 ms, gradually increasing the intensity up to 4.0 volts (V) on weekly intervals according to occurrence of side effects (diplopia, vertigo, oscillopsia, and ophthalmoplegia). Stimulation parameters are provided in Table 1.

The DBS electrodes (DBS lead model 3389, Medtronic Inc., USA) with a radius of 0.635 mm, a contact length of 1.5 mm and a contact separation of 0.5 mm were modelled in Comsol Multiphysics 5.2 (Comsol AB, Sweden) and placed in the positions indicated by the postoperative MRI relative to the above described conductivity matrix of the brain tissue.