@article{SteigerwaldMuellerJohannesetal.2016,
  author    = {Steigerwald, Frank and M{\"u}ller, Lorenz and Johannes, Silvia and Matthies, Cordula and Volkmann, Jens},
  title     = {Directional deep brain stimulation of the subthalamic nucleus: a pilot study using a novel neurostimulation device},
  series = {Movement Disorders},
  volume    = {31},
  journal   = {Movement Disorders},
  number    = {8},
  doi       = {10.1002/mds.26669},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-187683},
  pages     = {1240-1243},
  year      = {2016},
  abstract  = {Introduction A novel neurostimulation system allows steering current in horizontal directions by combining segmented leads and multiple independent current control. The aim of this study was to evaluate directional DBS effects on parkinsonian motor features and adverse effects of subthalamic neurostimulation. Methods Seven PD patients implanted with the novel directional DBS system for bilateral subthalamic DBS underwent an extended monopolar review session during the first postoperative week, in which current thresholds were determined for rigidity control and stimulation-induced adverse effects using either directional or ring-mode settings. Results Effect or adverse effect thresholds were modified by directional settings for each of the 14 STN leads. Magnitude of change varied markedly between leads, as did orientation of optimal horizontal current steering. Conclusion Directional current steering through chronically implanted segmented electrodes is feasible, alters adverse effect and efficacy thresholds in a highly individual manner, and expands the therapeutic window in a monopolar review as compared to ring-mode DBS.},
  language  = {en}
}
@article{CanessaPozziArnulfoetal.2016,
  author    = {Canessa, Andrea and Pozzi, Nicol{\`o} G. and Arnulfo, Gabriele and Brumberg, Joachim and Reich, Martin M. and Pezzoli, Gianni and Ghilardi, Maria F. and Matthies, Cordula and Steigerwald, Frank and Volkmann, Jens and Isaias, Ioannis U.},
  title     = {Striatal Dopaminergic Innervation Regulates Subthalamic Beta-Oscillations and Cortical-Subcortical Coupling during Movements: Preliminary Evidence in Subjects with Parkinson's Disease},
  series = {Frontiers in Human Neuroscience},
  volume    = {10},
  journal   = {Frontiers in Human Neuroscience},
  number    = {611},
  doi       = {10.3389/fnhum.2016.00611},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-164061},
  year      = {2016},
  abstract  = {Activation of the basal ganglia has been shown during the preparation and execution of movement. However, the functional interaction of cortical and subcortical brain areas during movement and the relative contribution of dopaminergic striatal innervation remains unclear. We recorded local field potential (LFP) activity from the subthalamic nucleus (STN) and high-density electroencephalography (EEG) signals in four patients with Parkinson's disease (PD) off dopaminergic medication during a multi-joint motor task performed with their dominant and non-dominant hand. Recordings were performed by means of a fully-implantable deep brain stimulation (DBS) device at 4 months after surgery. Three patients also performed a single-photon computed tomography (SPECT) with [123I]N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl)nortropane (FP-CIT) to assess striatal dopaminergic innervation. Unilateral movement execution led to event-related desynchronization (ERD) followed by a rebound after movement termination event-related synchronization (ERS) of oscillatory beta activity in the STN and primary sensorimotor cortex of both hemispheres. Dopamine deficiency directly influenced movement-related beta-modulation, with greater beta-suppression in the most dopamine-depleted hemisphere for both ipsi- and contralateral hand movements. Cortical-subcortical, but not interhemispheric subcortical coherencies were modulated by movement and influenced by striatal dopaminergic innervation, being stronger in the most dopamine-depleted hemisphere. The data are consistent with a role of dopamine in shielding subcortical structures from an excessive cortical entrapment and cross-hemispheric coupling, thus allowing fine-tuning of movement.},
  language  = {en}
}