Skilled Motor Training and tDCS to Improve Leg Function After Spinal Cord Injury

Overview

The study investigates the effect of using transcranial direct current stimulation (tDCS) and skilled stepping training versus skilled stepping training with sham-tDCS in improving ankle and leg motor control in persons with ambulatory persons with spinal cord injury. Hypotheses H1: Participants will display greater improvement in stepping function following tDCS combined with training compared to sham-tDCS and training. H2: Participants will display greater gains in cortical excitability, as evidenced by lower cortico-motor threshold (MT) associated with the TA muscles following tDCS and training compared to following sham stimulation and training. H3: Participants in the tDCS+training group will show greater increases walking speed in a timed 10 meter walking trial. H4: Participants in the tDCS+training group will show be able to perform a greater number of toe-taps test.

An estimated 265,000 individuals live with the consequences of SCI in the United States alone. Individuals with motor incomplete spinal cord injury (MISCI) commonly experience loss or impairment of lower extremity function. There are a limited number of options for restoration of walking function in individuals with motor-incomplete spinal cord injury (MISCI) who exhibit some ability to stand and walk but may be impeded by impaired voluntary control of the lower limb particularly, the ankle. In persons with spinal cord injury, walking function is often limited by poor ability to lift and advance the legs. Lower extremity orthotic devices may be employed to stabilize the ankle joint and provide toe clearance during walking. However, these devices are cumbersome, and may be aesthetically unappealing. Newer evidence indicates that non-invasive approaches to brain stimulation may provide a way to improve voluntary control of the legs and ankles in persons with neurologic disorders. Purpose of this research study: The overall goal of this study is to develop functional rehabilitation strategies that facilitate optimal restoration of leg and ankle motor control in individuals with MISCI. Individuals with MISCI exhibit some motor function below the level of lesion and include American Spinal Injury Association Impairment Scale (AIS) classifications AIS C and AIS D. We propose to test non-invasive cortical stimulation in combination with lower-extremity functional motor training for its ability to assist in improving fine motor control of the lower limbs in individuals with MISCI. Studies have shown that non-invasive transcranial direct current stimulation (tDCS) can increase activity in specific cortical areas associated with motor learning, and therefore improve on the cortical and functional effects associated with motor practice training in individuals with SCI. If brain stimulation in combination with motor training is found to enhance improvements in control more effectively than motor training alone, this would provide a basis for further examining stimulation combined with lower limb joint therapy in individuals with spinal cord injury. Objectives: To Assess improvements in lower extremity motor control that are associated with bilateral tDCS and functional motor training or sham tDCS and functional motor training in individuals with motor incomplete spinal cord injury.