title: The influence of deep brain stimulation intensity and duration on symptoms evolution in an OFF stimulation dystonia study.
abstract: BACKGROUND
  Deep brain stimulation (DBS) of the internal globus pallidus (GPi) is an established therapy for primary generalized dystonia. However, the evolution of dystonia symptoms after DBS discontinuation after years of therapy has only rarely been reported. We therefore longitudinally studied the main physiological measurements known to be impaired in dystonia, with DBS ON and then again after termination of DBS, after at least five years of continuous DBS.
  
  
  OBJECTIVE
  We studied whether dystonia evolution after DBS discontinuation in patients benefiting from long-term GPi DBS is different from that observed in earlier stages of the therapy.
  
  
  METHODS
  In eleven DYT1 patients treated with bilateral GPi DBS for at least 5 years, dystonia was assessed ON-DBS, immediately after switch-off (OFF-DBS1) and 48 h after DBS termination (OFF-DBS2). We studied the influence of DBS intensity on dystonia when DBS was discontinued.
  
  
  RESULTS
  On average a significant difference in symptoms was measured only between ON-DBS and OFF-DBS1 conditions. Importantly, none of the patients returned to their preoperative dystonia severity, even 48 h after discontinuation. The amount of clinical deterioration in the OFF conditions positively correlated with higher stimulation current in the chronic ON-DBS condition.
  
  
  CONCLUSIONS
  The duration of DBS application influences symptom evolution after DBS termination. DBS intensity seems to have a prominent role on evolution of dystonic symptoms when DBS is discontinued. In conclusion, DBS induces changing modulation of the motor network with less worsening of symptoms after long term stimulation, when DBS is stopped.
authors.affiliation: CHRU Montpellier, Hôpital Gui de Chauliac, Service de Neurochirurgie, Montpellier F-34000, France. a-cif@chu-montpellier.fr
authors.forename: Laura
authors.initials: L
authors.lastname: Cif
authors.forename: Diane
authors.initials: D
authors.lastname: Ruge
authors.forename: Victoria
authors.initials: V
authors.lastname: Gonzalez
authors.forename: Patricia
authors.initials: P
authors.lastname: Limousin
authors.forename: Xavier
authors.initials: X
authors.lastname: Vasques
authors.forename: Marwan I
authors.initials: MI
authors.lastname: Hariz
authors.forename: John
authors.initials: J
authors.lastname: Rothwell
authors.forename: Philippe
authors.initials: P
authors.lastname: Coubes
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D046690:Deep Brain Stimulation / Q000379:methods*; D004421:Dystonia / Q000503:physiopathology / Q000601:surgery / Q000628:therapy*; D020821:Dystonic Disorders / Q000503:physiopathology / Q000601:surgery / Q000628:therapy*; D005260:Female; D005917:Globus Pallidus / Q000503:physiopathology* / Q000601:surgery; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D016896:Treatment Outcome
keywords: Deep brain stimulation duration; Dystonia evolution; Intensity and arrest