title: Twiddler (or Not) Syndrome: Questioning etiology for an uncommon form of hardware malfunction in deep brain stimulation.
abstract: BACKGROUND
  Hardware failure or malfunction after deep brain stimulation is an infrequent but costly occurrence with currently available systems.
  
  
  METHODS
  The authors present the case of a 65-year-old female patient with predominantly tremoric Parkinson's disease who, 4 months after bilateral subthalamic nucleus stimulation with very good clinical results, began to display signs of recurrent disease and an increasingly smaller response to stimulation. Radiological studies, changes in electrode impedance and surgical findings and results established the diagnosis of Twiddler syndrome. Close patient follow-up, lack of a psychiatric history and physical examination findings were, however, contrary to the previously described causative mechanism.
  
  
  CONCLUSIONS
  The clinical and radiological setup of Twiddler syndrome must be readily recognized. Its causative mechanism should remain under discussion, and intraoperative technical details may help to explain its occurrence.
authors.affiliation: Department of Neurosurgery, Hospital S. João, Porto - Portugal Faculty of Medicine, University of Porto, Portugal.
authors.forename: Pedro Alberto
authors.initials: PA
authors.lastname: Silva
authors.affiliation: Department of Neurosurgery, Hospital S. João, Porto - Portugal Faculty of Medicine, University of Porto, Portugal ; Department of Movement Disorders Unit, Hospital S. João, Porto - Portugal Faculty of Medicine, University of Porto, Portugal.
authors.forename: Clara
authors.initials: C
authors.lastname: Chamadoira
authors.affiliation: Department of Neurology, Hospital S. João, Porto - Portugal Faculty of Medicine, University of Porto, Portugal.
authors.forename: Henrique
authors.initials: H
authors.lastname: Costa
authors.affiliation: Department of Neurosurgery, Hospital S. João, Porto - Portugal Faculty of Medicine, University of Porto, Portugal ; Department of Movement Disorders Unit, Hospital S. João, Porto - Portugal Faculty of Medicine, University of Porto, Portugal.
authors.forename: Paulo
authors.initials: P
authors.lastname: Linhares
authors.affiliation: Department of Neurology, Hospital S. João, Porto - Portugal Faculty of Medicine, University of Porto, Portugal ; Department of Movement Disorders Unit, Hospital S. João, Porto - Portugal Faculty of Medicine, University of Porto, Portugal.
authors.forename: Maria José
authors.initials: MJ
authors.lastname: Rosas
authors.affiliation: Department of Neurosurgery, Hospital S. João, Porto - Portugal Faculty of Medicine, University of Porto, Portugal ; Department of Movement Disorders Unit, Hospital S. João, Porto - Portugal Faculty of Medicine, University of Porto, Portugal.
authors.forename: Rui
authors.initials: R
authors.lastname: Vaz
keywords: Deep brain stimulation; dysfunction; failure; hardware; surgery