Feasibility Study for the Use of Low-magnitude, High Frequency Mechanical Stimulation of Bone in Persons With Spinal Cord Injury (SCI)
Condition: Spinal Cord Injuries
MeSH terms: Spinal Cord Injuries
Study type: Observational

Summary: 
      In persons with SCI, because of inherent considerations, the use of mechanical stimulation
      has not been studied to determine improvement in bone mass. To achieve maximum transmission
      of the vibration from a vibrating plate to the lower body, the legs must be extended and the
      feet firmly placed against the surface plate of the device. Thus, these logistical
      considerations must be addressed to perform this mechanical intervention in persons with SCI.
      In those with complete or almost complete motor injury, there is lack of musculoskeletal
      function below the level of the lesion, which would prevent rigid straight leg extension and
      pressing one's feet against a surface, regardless of the angle of tilt that would permit
      adequate transmission of impulse in an able-bodied individual (preliminary data). However, in
      one subject with SCI, there was measurable, albeit low level, transmission of vibration with
      increasing angles of tilt (preliminary data). Because of the ability to transmit some signal
      in an individual with complete SCI, the possibility exists that with forms or mechanical
      support/manipulation, greater signal transmission may be possible. The study will be able to
      determine the best angle to transmit mechanical vibration through the lower body of SCI
      patients.
    

Detailed description: 
      Experiments will be performed in 12 persons with SCI and 10 healthy able-bodied to optimize
      the methodology for transmission of the mechanical impulse to the lower extremities in
      persons with SCI. This will entail the following combinations:

        1. positional modification (sitting, lying or standing if tolerable);

        2. bracing the knee to prevent flexion/extension;

        3. bracing the legs above and/or below the knee;

        4. supporting the ankle;

        5. tilting the surface (tilt table) to a maximum angle of 45 degrees;

        6. Standing with the assistance of a standing frame if subject can tolerate standing for 5
           minute time periods.

        7. increasing the magnitude of the plate acceleration (0.2-0.6g); and

        8. mechanically pressing the legs (ankle and knee joints relatively fixed in position by an
           orthotic device) against the plate by a spring-loaded method (it is envisioned that a
           padded belt-like article will be worn around the waist and would be attached with bungee
           cords (or springs) to each side of the vibrating plate; the maximum force delivered
           would be equal to 50 lbs or one-third of total body weight, whichever is less).

      An accelerometer for the measurement of impulse generation will be placed on the surface of
      the vibrating plate between the feet; a second will be placed on the shin about 4 inches
      below the knee (attached with double sided tape and athletic bandage wrap); a third
      accelerometer will be placed in the mouth as a bite-bar. Measurements would be acquired with
      combinations of body position, joint/leg fixation, magnitude of plate acceleration ("g"
      force), and mechanical force pressing the feet against the plate to determine the optimal
      transmission of impulse.

      This study will determine the optimal of the methodology for using the vibrating plate to
      transmit an impulse in persons with chronic SCI, with the anticipation of its application to
      increase bone mass in individuals with acute or chronic SCI. It is anticipated that each
      session will be between 30 and 120 minutes. An individual may voluntarily participate in as
      many as 5 sessions. The knowledge gained from the first sets of studies will obviate the need
      to perform less effective methods of mechanical signal transmission in subsequent studies. It
      is anticipated that once the most effective, as well as clinically applicable, form of
      mechanical stimulation is identified, it will be performed in most of the subjects. This
      preliminary study will also provide the information required to determine practical aspects
      of the length of each session and number of sessions per week in a future intervention trial.

      Since this research may have adverse effects on an unborn child and should not be done during
      pregnancy, we will administer a pregnancy test when appropriate. Subjects will be asked to
      avoid becoming pregnant and use contraceptives, take precautions against becoming pregnant.
    

Observational model: Case-Control
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        Ten ambulatory able-bodied and Twelve non-ambulatory subjects with SCI will be enrolled to
        participate
      
Keywords: Vibrating plate; Mechanical Stimulation; Osteoporosis