title: Effects of transcutaneous spinal direct current stimulation in idiopathic restless legs patients.
abstract: BACKGROUND
  Transcutaneous spinal direct current stimulation (tsDCS) is a new non-invasive technique to modulate spinal cord activity. The pathophysiological concept of primary RLS proposes increased spinal excitability.
  
  
  OBJECTIVE
  This pilot study used tsDCS to reduce pathologically enhanced spinal excitability in RLS patients and to thereby ameliorate clinical symptoms.
  
  
  METHODS
  20 patients with idiopathic RLS and 14 healthy subjects participated in this double-blinded, placebo-controlled study. All participants received one session of cathodal, anodal and sham stimulation of the thoracic spinal cord for 15 min (2.5 mA) each, in randomized order during their symptomatic phase in the evening. The soleus Hoffmann-reflex with Hmax/Mmax-ratio and seven different H2/H1-ratios (of two H-reflex responses to double stimuli) were measured. The RLS symptoms were assessed by a visual analogue scale (VAS). All parameters were measured before and twice after tsDCS.
  
  
  RESULTS
  RLS patients showed increased H2/H1-ratios during their symptomatic phase in the evening. Application of anodal stimulation led to a decreased H2/H1-ratio for 0.2 and 0.3 s interstimulus intervals in patients. Furthermore, application of anodal and cathodal stimulation led to a reduction in restless legs symptoms on the VAS, whereas application of sham stimulation had no effects on either the VAS or on the H2/H1-ratio in patients. VAS changes did not correlate with changes of H2/H1-ratios.
  
  
  CONCLUSIONS
  This is the first tsDCS study in idiopathic RLS, which resulted in short-lasting clinical improvement. Furthermore, our results support the pathophysiological concept of spinal cord hyperexcitability in primary RLS and provide the basis for a new non-pharmacological treatment tool.
authors.affiliation: Department of Clinical Neurophysiology, University Medical Center, Göttingen, Germany.
authors.forename: A C
authors.initials: AC
authors.lastname: Heide
authors.affiliation: Department of Neurology, University of Munich, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Winkler
authors.affiliation: Department of Medical Statistics, Georg August University, Göttingen, Germany.
authors.forename: H J
authors.initials: HJ
authors.lastname: Helms
authors.affiliation: Department of Clinical Neurophysiology, University Medical Center, Göttingen, Germany.
authors.forename: M A
authors.initials: MA
authors.lastname: Nitsche
authors.affiliation: Department of Clinical Neurophysiology, University Medical Center, Göttingen, Germany; Paracelsus-Elena Hospital, Kassel, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Trenkwalder
authors.affiliation: Department of Clinical Neurophysiology, University Medical Center, Göttingen, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Paulus
authors.affiliation: Department of Clinical Neurophysiology, University Medical Center, Göttingen, Germany; Paracelsus Hospital Osnabrück, Germany. Electronic address: cbachma@gwdg.de.
authors.forename: C G
authors.initials: CG
authors.lastname: Bachmann
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D012148:Restless Legs Syndrome / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy*; D013116:Spinal Cord / Q000503:physiopathology*; D004561:Transcutaneous Electric Nerve Stimulation / Q000379:methods*; D016896:Treatment Outcome; D055815:Young Adult
keywords: H-reflex; Restless legs syndrome; Spinal cord hyperexcitability; Transcutaneous spinal direct current stimulation