title: Effects of pulse width variations in pallidal stimulation for primary generalized dystonia.
abstract: BACKGROUND
  Various pulse widths (from 60-450 mus) have been used for bilateral pallidal stimulation in generalized dystonia but, to date, no comparison of this parameter's effects is available.
  
  
  OBJECTIVE
  To provide an analysis of the differential effects of bilateral short, medium and long stimulus pulse width (PW) on clinical improvement in primary generalized dystonia.
  
  
  METHODS
  The most effective therapeutic stimulation parameters were recorded in 22 patients using bilateral pallidal stimulation. Six months after surgery, the effects of bilateral pallidal short (60-90 micros), medium (120-150 micros) and long (450 micros) PWs were studied in 20 of those patients. The effect of the stimulation was assessed by reviewing videotaped sessions by an observer blinded to treatment status (Burke-Fahn-Marsden movement score). Patients were tested on separate days, in random order, for the stimulation conditions (acute effect with the stimulation condition lasting 10 hours). The same contact was used for each stimulation condition. All the electrodes were set at 130 Hz (monopolar stimulation) and the intensity was set individually 10% below the side effect threshold.
  
  
  RESULTS
  Median PWs of 60 (short), 120 (medium) and 450 micros (long) were compared,with a mean intensity of 4.46, 3.45 and 2.47 V, respectively. This study failed to demonstrate any significant difference in the movement scale dystonia mean scores depending on PW.
  
  
  CONCLUSIONS
  According to our findings, short duration stimulus PWs are as effective as longer ones during a 10 hour period of observation. Confirmation of this finding for chronic use could be of importance in saving stimulator energy. Moreover, the use of smaller stimulus pulse widths are said to reduce charge injection and increase the therapeutic window between therapeutic effects and side effects.
authors.affiliation: Neurology and Neurosurgery, CHU Grenoble, 38043 Grenoble, France. LVercueil@chu-grenoble.fr
authors.forename: Laurent
authors.initials: L
authors.lastname: Vercueil
authors.forename: Jean Luc
authors.initials: JL
authors.lastname: Houeto
authors.forename: Pierre
authors.initials: P
authors.lastname: Krystkowiak
authors.forename: Christelle
authors.initials: C
authors.lastname: Lagrange
authors.forename: François
authors.initials: F
authors.lastname: Cassim
authors.forename: Abdelhamid
authors.initials: A
authors.lastname: Benazzouz
authors.forename: Bernard
authors.initials: B
authors.lastname: Pidoux
authors.forename: Alain
authors.initials: A
authors.lastname: Destée
authors.forename: Yves
authors.initials: Y
authors.lastname: Agid
authors.forename: Philippe
authors.initials: P
authors.lastname: Cornu
authors.forename: Serge
authors.initials: S
authors.lastname: Blond
authors.forename: Alim Louis
authors.initials: AL
authors.lastname: Benabid
authors.forename: Pierre
authors.initials: P
authors.lastname: Pollak
authors.forename: Marie
authors.initials: M
authors.lastname: Vidailhet
mesh_terms: D046690:Deep Brain Stimulation / Q000379:methods*; D004307:Dose-Response Relationship, Radiation; D004311:Double-Blind Method; D004421:Dystonia / Q000628:therapy*; D005500:Follow-Up Studies; D005917:Globus Pallidus / Q000502:physiology*; D006801:Humans; D011446:Prospective Studies; D013997:Time Factors