Restorative Neuromodulation for Lower Extremity Functions
Condition: Spinal Cord Injuries; Stroke; Paralysis
MeSH terms: Spinal Cord Injuries; Paralysis
Study type: Interventional

Summary: 
      The overall objective of the proposed study is to restore lower-extremity functions of
      paraplegic individuals. Paralysis following Stroke or spinal cord injury (SCI) result harsh
      sufferings including lifelong dependence on wheelchairs and thus often life threatening
      conditions such as pressure sore resulted from the immobility. Recently, electrical
      stimulation targeting the lumbosacral spinal cord has shown activation of spinal circuits
      that control standing and walking functions; while body-weight supported locomotor training
      has shown overall health improvement of the paraplegic patients through activity dependent
      rehabilitation. In the current project we aim to combine the trans-spinal electrical
      stimulation and locomotor training in an efficient, cost-effective and simplified manner for
      functional rehabilitation. In this proposed study, Stroke and SCI paraplegics will be
      regularly trained to stand and walk on a body-weight support system with the aid of
      lower-limb orthoses and trans-spinal electrical stimulation. In progressive weeks the
      orthotic support of the lower-limb would be slowly lifted off and only the stimulation
      therapy will be delivered during the locomotor training. Repetitive training with this
      combination therapy, the spinal pathways would likely reorganize and would promote long-term
      rehabilitation of the lower-extremity. After successful demonstration of this in our
      laboratory settings, we aim to transform this technology for community use.
    

Detailed description: 
      Spinal cord is composed of specialized neural networks, capable of executing different
      functions. Although the command for lower-limb functions such as standing and walking is
      primarily delivered from the brain, it was found that the spinal cord circuits not only
      execute it but also maintain the task and control the dynamics with proper feedback
      mechanisms with it's reflex circuitry. Simple bipedal standing and walking requires
      spatiotemporal coordination of muscles, limb joints, balance etc., their adaptation and
      control in gravity. For human, these physiological activities are well choreographed by sets
      of neural networks. In combination with afferent proprioceptive inputs, these network
      circuits work with the motor periphery to generate a series of motor acts during each task.
      Normally, the activity of these spinal networks are regulated supraspinally and by peripheral
      sensory inputs. In case of the loss of supraspinal inputs, resultant of a Stroke or spinal
      cord injury (SCI), motor tasks maybe enabled by directly activating these specialized spinal
      cord networks via external stimuli. Recent studies have demonstrated that neuromodulation via
      spinal cord stimulation can effectively restore lower-extremity functions in patients with
      chronic neurological injuries.

      Traumatic injury to the central nervous system (CNS) such as SCI is devastating events
      leaving patients with impairment of motor, sensory and autonomic functions. Mainstay for the
      treatment is still limited to rehabilitation by physical therapy and training. In few
      patients, however, neuroplasticity and repair mechanisms are considered to contribute to
      recovery of paresis in the acute stage of the injury and stops in the chronic stage. But,
      recent groundbreaking studies have shown that the recovery can be further amplified in the
      chronic stage by the novel treatment of trans-spinal electrical stimulation. However, the
      rehabilitation related to this recovery is not very significant, and thus it is a challenge
      to be convinced with the efficacy of this new therapy. A combination therapy of trans-spinal
      electrical stimulation along with body-weight would promote better recovery and benefit the
      patients more. The current study will further assist the researchers to design such
      combinational therapeutic intervention for neurologically impaired patients to stimulate to
      walk again. Successful translation of this novel technology would facilitate the paraplegic
      community to become more healthy, independent and happy.
    

Intervention name(s): trans-spinal Electrical Stimulation (tsES)
Intervention type(s): Device
Intervention description(s): The trans-spinal pulsed-current stimulation utilizes non-invasive russian stimulation using a research grade stimulator and direct-current stimulation utilizes non-invasive constant stimulation using a medical grade stimulator. Both pulsed- and direct-current stimulation will be achieved with cutaneous cathode electrodes attached to the dorsal aspect of the back overlying at and bellow thoracic vertebrae and anode electrodes placed over the iliac crests or lower abdomen. Spinal motor evoked potentials will be induced by trans-spinal pulsed-current stimulation (parameters, 1 Hz with a 1 millisecond pulse width and monophasic waveform) to determine recruitment profiles of proximal and distal motor pools with increasing stimulation intensity ranging from 10-200 milliampere. Stimulation parameters for the therapeutic stimulation will be ranged from 5-50 Hz and 20-200 milliampere. For direct-current stimulation, the stimulation current will be kept constant at 2-2.5 milliampere.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Treatment