Rehabilitating Corticospinal Control of Walking
Condition: Stroke
MeSH terms: Stroke
Study type: Interventional

Summary: 
      The VHA estimates that over 15,000 Veterans incur a stroke each year. As the population of
      older Veterans grows, stroke will become an increasingly important problem to the VHA.
      Recovery of walking function is the most common goal of stroke survivors. The proposed study
      will test whether training with accurate walking tasks to engage the damaged supraspinal
      motor pathways is more effective than training with steady state walking. The investigators
      expect that training accurate tasks will be more effective, thereby improving walking
      function of Veteran stroke survivors and reducing the burden of care placed on families and
      on the VHA. Furthermore, this rehabilitation approach can be accomplished at comparable cost
      to existing rehabilitation approaches, which is important given that the VHA invests $88
      million per year toward outpatient care, including physical rehabilitation, in the first six
      months after stroke. This research also has implications for rehabilitation of other
      neurologically injured populations, including traumatic brain injury and incomplete spinal
      cord injury.
    

Detailed description: 
      Current approaches for rehabilitation of walking following stroke do not sufficiently restore
      mobility function. For instance, fewer than 50% of individuals with stroke-induced walking
      dysfunction recover the ability to walk independently in the community. New breakthroughs in
      rehabilitation are needed that will target the motor impairments responsible for poor walking
      function in individuals post-stroke. Functional recovery can occur in response to
      task-specific neuroplasticity of damaged brain circuitry. The corticospinal tract is an
      important target for neuroplasticity because it plays an important role for control of
      walking in humans. Research has shown that, compared to steady state walking, accurate gait
      modification (ACC) tasks are a potent behavioral stimulus for activating the corticospinal
      tract. Therefore, the investigators propose that training with ACC tasks (e.g., obstacle
      crossing/avoidance, accurate foot placement, etc.) may be superior to training with steady
      state walking (SS) for eliciting corticospinal neuroplasticity and recovery of walking
      function. Most rehabilitation paradigms have previously focused on SS training. This is
      largely because therapists consider it premature to progress to ACC tasks when persistent
      deficits of steady state walking still remain. However, this reasoning might be
      counter-productive, because training only steady state walking may not sufficiently stimulate
      neuro-plasticity of the damaged corticospinal pathway. In contrast, ACC training is
      specifically designed to stimulate corticospinal neuroplasticity. Importantly, since ACC
      training targets a central mechanism, its benefits are expected to generalize across walking
      conditions. Furthermore, it is expected to benefit most stroke survivors who possess at least
      a minimal residual capability to activate the corticospinal tract. ACC training also provides
      an opportunity to practice tasks that are analogous to challenges encountered in the home and
      community environments. Accordingly, there is strong mechanistic and practical rationale for
      ACC training.

      A number of earlier studies have cumulatively established exciting preliminary evidence
      showing that walking function is enhanced by training with ACC tasks. However, no prior study
      has been specifically designed and sufficiently powered to determine the extent to which the
      "accurate gait modification" ingredient is crucial for recovery of walking function. Also not
      known is the extent to which ACC training reduces the neural impairments underlying poor
      walking function. The central hypothesis of this study is that ACC training will be superior
      to SS training for increasing walking function and for reducing underlying neural control of
      the paretic leg in adults with post-stroke hemiparesis. Each intervention will involve twelve
      weeks of training, 3 days per week (36 sessions total), and will emphasize the motor learning
      principles of high intensity, repetition and task-specificity. Assessments will be conducted
      immediately pre-intervention, immediately post-intervention and at a follow-up session 3
      months later. Walking function will be measured in the lab and in the "real world". Neural
      impairment measures will include electromyography-based measures of inter-muscular
      coordination and corticospinal drive.

      The investigators expect that the benefits of ACC training will justify larger randomized
      controlled trials to optimize the use of ACC training, including timing relative to stroke,
      combination with other therapeutic approaches, and identifying individuals who are most
      likely to benefit from this approach. This research is expected to enhance walking function
      in stroke survivors, including for the 15,000 Veterans who suffer a stroke each year.
    

Intervention name(s): ACC training; SS training
Intervention type(s): Behavioral; Behavioral
Intervention description(s): Rehabilitation of walking using accurate (ACC) walking tasks, such as stepping on targets, over obstacles, etc.; Rehabilitation of walking using typical steady state (SS) walking. Conducted overground and on treadmill. 36 sessions of training conducted over the course of 12 weeks. Each session lasts about 1 hour.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment
Keywords: Rehabilitation; Walking; Motor skills disorders; Electromyography