title: Transmission of low-intensity vibration through the axial skeleton of persons with spinal cord injury as a potential intervention for preservation of bone quantity and quality.
abstract: OBJECTIVE
  Persons with spinal cord injury (SCI) develop marked bone loss from paralysis and immobilization. Low-intensity vibration (LIV) has shown to be associated with improvement in bone mineral density in post-menopausal women and children with cerebral palsy. We investigated the transmissibility of LIV through the axial skeleton of persons with SCI as an initial approach to determine whether LIV may be used as a clinical modality to preserve skeletal integrity.
  
  
  METHODS
  Transmission of a plantar-based LIV signal (0.27 +/- 0.11 g; 34 Hz) from the feet through the axial skeleton was evaluated as a function of tilt-table angle (15, 30, and 45 degrees) in seven non-ambulatory subjects with SCI and ten able-bodied controls. Three SCI and five control subjects were also tested at 0.44 +/- 0.18 g and 34 Hz. Transmission was measured using accelerometers affixed to a bite-bar to determine the percentage of LIV signal transmitted through the body.
  
  
  RESULTS
  The SCI group transmitted 25, 34, and 43% of the LIV signal, and the control group transmitted 28, 45, and 57% to the cranium at tilt angles of 15, 30, and 45 degrees, respectively. No significant differences were noted between groups at any of the three angles of tilt.
  
  
  CONCLUSIONS
  SCI and control groups demonstrated equivalent transmission of LIV, with greater signal transmission observed at steeper angles of tilt. This work supports the possibility of the utility of LIV as a means to deliver mechanical signals in a form of therapeutic intervention to prevent/reverse skeletal fragility in the SCI population.
authors.affiliation: Center of Excellence for the Medical Consequences of Spinal Cord Injury, VA Medical Center, Bronx, NY 10468, USA.
authors.forename: Pierre
authors.initials: P
authors.lastname: Asselin
authors.forename: Ann M
authors.initials: AM
authors.lastname: Spungen
authors.forename: Jesse W
authors.initials: JW
authors.lastname: Muir
authors.forename: Clinton T
authors.initials: CT
authors.lastname: Rubin
authors.forename: William A
authors.initials: WA
authors.lastname: Bauman
mesh_terms: D000208:Acute Disease; D000328:Adult; D001510:Bed Rest / Q000009:adverse effects; D001835:Body Weight; D015519:Bone Density; D002908:Chronic Disease; D005240:Feasibility Studies; D050723:Fractures, Bone / Q000517:prevention & control; D006801:Humans; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000517:prevention & control*; D011782:Quadriplegia / Q000628:therapy*; D013119:Spinal Cord Injuries / Q000628:therapy*; D018667:Tilt-Table Test; D016896:Treatment Outcome; D014732:Vibration / Q000627:therapeutic use*; D055815:Young Adult