title: Modulation of attentional processing by deep brain stimulation of the pedunculopontine nucleus region in patients with parkinsonian disorders.
abstract: OBJECTIVE
  Low-frequency electrical stimulation of the pedunculopontine nucleus (PPN) is a therapeutic approach aiming to improve motor symptoms such as freezing of gate and postural instability in parkinsonian disorders. Because the PPN is a component of the reticular activating system, we tested whether PPN stimulation directly affects attention and consciousness.
  
  
  METHODS
  Eight patients with parkinsonian disorders and implanted with electrodes in the bilateral PPN underwent computerized assessment of attention. Performance in 3 standard reaction time (RT) tasks was assessed at 5 different stimulation frequencies in 5 consecutive sessions.
  
  
  RESULTS
  Stimulation of the PPN at low (8 Hz) and therapeutic (20 Hz) frequencies led to a significant improvement of performance in a simple RT task. Patients' RTs were significantly faster at stimulation frequencies of 8 Hz and 20 Hz relative to no stimulation. Stimulation did not affect patients' performance in more complex attentional tasks.
  
  
  CONCLUSIONS
  Low-frequent stimulation of PPN improves basal attentional processing in patients with parkinsonian disorders, leading to an improved tonic alertness. As successful performance in this task requires the intrinsic ability to build up and keep a certain level of attention, this might be interpreted as attentional augmentation related to stimulation features. Stimulation had no effect on more complex attentional processing. Our results suggest an influence of the PPN on certain aspects of attention, supporting attentional augmentation as one possible mechanism to improve motor action and gait in patients with parkinsonian disorders.
authors: Department of Neurology, Otto-von-Guericke University.
authors: Julia
authors: J
authors: Fischer
authors: Department of Neurology, Otto-von-Guericke University.
authors: Kati
authors: K
authors: Schwiecker
authors: Department of Neurology, Otto-von-Guericke University.
authors: Verena
authors: V
authors: Bittner
authors: Department of Neurology, Otto-von-Guericke University.
authors: Hans-Jochen
authors: HJ
authors: Heinze
authors: Department of Stereotactic Neurosurgery, Otto-von- Guericke University.
authors: Jürgen
authors: J
authors: Voges
authors: Department of Neurology, Otto-von-Guericke University.
authors: Imke
authors: I
authors: Galazky
authors: Department of Neurology, Otto-von-Guericke University.
authors: Tino
authors: T
authors: Zaehle
mesh_terms: D000368:Aged; D001288:Attention; D003243:Consciousness; D046690:Deep Brain Stimulation; D004567:Electrodes, Implanted; D005260:Female; D020233:Gait Disorders, Neurologic / Q000209:etiology / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D020734:Parkinsonian Disorders / Q000523:psychology* / Q000628:therapy*; D045042:Pedunculopontine Tegmental Nucleus; D011597:Psychomotor Performance; D011930:Reaction Time; D016896:Treatment Outcome