title: Therapeutic intraspinal microstimulation improves forelimb function after cervical contusion injury.
abstract: OBJECTIVE
  Intraspinal microstimulation (ISMS) is a promising method for activating the spinal cord distal to an injury. The objectives of this study were to examine the ability of chronically implanted stimulating wires within the cervical spinal cord to (1) directly produce forelimb movements, and (2) assess whether ISMS stimulation could improve subsequent volitional control of paretic extremities following injury.
  
  
  METHODS
  We developed a technique for implanting intraspinal stimulating electrodes within the cervical spinal cord segments C6-T1 of Long-Evans rats. Beginning 4 weeks after a severe cervical contusion injury at C4-C5, animals in the treatment condition received therapeutic ISMS 7 hours/day, 5 days/week for the following 12 weeks.
  
  
  RESULTS
  Over 12 weeks of therapeutic ISMS, stimulus-evoked forelimb movements were relatively stable. We also explored whether therapeutic ISMS promoted recovery of forelimb reaching movements. Animals receiving daily therapeutic ISMS performed significantly better than unstimulated animals during behavioural tests conducted without stimulation. Quantitative video analysis of forelimb movements showed that stimulated animals performed better in the movements reinforced by stimulation, including extending the elbow to advance the forelimb and opening the digits. While threshold current to elicit forelimb movement gradually increased over time, no differences were observed between chronically stimulated and unstimulated electrodes suggesting that no additional tissue damage was produced by the electrical stimulation.
  
  
  CONCLUSIONS
  The results indicate that therapeutic intraspinal stimulation delivered via chronic microwire implants within the cervical spinal cord confers benefits extending beyond the period of stimulation, suggesting future strategies for neural devices to promote sustained recovery after injury.
authors.affiliation: Department of Rehabilitation Medicine, University of Washington, Seattle, WA, USA.
authors.forename: M R
authors.initials: MR
authors.lastname: Kasten
authors.forename: M D
authors.initials: MD
authors.lastname: Sunshine
authors.forename: E S
authors.initials: ES
authors.lastname: Secrist
authors.forename: P J
authors.initials: PJ
authors.lastname: Horner
authors.forename: C T
authors.initials: CT
authors.lastname: Moritz
mesh_terms: D000818:Animals; D002574:Cervical Vertebrae; D004567:Electrodes, Implanted; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D005552:Forelimb / Q000503:physiopathology*; D009069:Movement Disorders / Q000175:diagnosis / Q000503:physiopathology* / Q000534:rehabilitation*; D051381:Rats; D020318:Rats, Long-Evans; D020127:Recovery of Function; D013119:Spinal Cord Injuries / Q000175:diagnosis / Q000503:physiopathology* / Q000534:rehabilitation*; D062187:Spinal Cord Stimulation / Q000295:instrumentation* / Q000379:methods; D016896:Treatment Outcome