Grant: Operating Grant

The purpose of the project is to determine the best method for strengthening residual connections from the brain to the spinal cord in patients with central nervous system (CNS) damage resulting from conditions such as stroke, incomplete spinal cord injury and secondary progressive multiple sclerosis (MS). Currently, voluntary activity in physical therapy is used to strengthen muscles. We and others have noted that electrical stimulation for 10-30 minutes can strengthen connections from the brain, although the increase only lasts for a short time (30-60 min). We have also studied the effect of long-term stimulation on people who use a stimulator, WalkAide. We developed the stimulator, which is now available world-wide to treat the condition of foot drop that occurs after a number of CNS conditions. Use of electrical stimulation over a period of months leads to a persistent strengthening of connections from the brain and increases the ability to voluntarily contract the stimulated muscle. Other methods have also been suggested to strengthen the weakened connections including the traditional method of voluntary exercise and a technique known as paired associative stimulation (PAS). In PAS a peripheral nerve is stimulated prior to a magnetic stimulus pulse applied over the motor area of the brain. The interval between the two stimuli is adjusted so that sensory signals from the nerve can reach the motor area of the brain just before it is activated. This study will determine whether use of electrical nerve stimulation and magnetic brain stimulation alone or in combination with each other and exercise offer the best method for strengthening cortico-spinal connections in able-bodied subjects and subjects with disabilities, but who retain some residual connections following CNS damage. The second project will build and test better systems combining stimulation with novel braces for people with more serious injuries (paraplegia).