Robotics and Neurostimulation in Stroke Recovery

Research has shown that robotics and non-invasive brain stimulation both can improve recovery from central nervous system damage. Can that recovery be enhanced by combining the two techniques? In this MossRehab Conversation, Dylan Edwards, PhD, discusses his research into both areas and what he is learning from using them together. Dr. Edwards recently joined the Moss Rehabilitation Research Institute as director. Previously, he worked at Burke Neurological Institute, where he was the director of the Non-Invasive Brain Stimulation Laboratory and director of the Restorative Neurology Clinic.

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Welcome to a MossRehab conversation, part of a continuing series of discussions with pioneers in physical medicine and rehabilitation from one of America's top US news-ranked rehab facilities. In this episode, MossRehab's Director of Digital Strategy Larry Blumenthal talks with Dylan Edwards, PhD, the recently named director of the Moss Rehabilitation Research Institute. Dr Edwards joined MRRI from Burke Neurological Institute in White Plains, NY. His research focuses on using technology including transcranial magnetic stimulation and robotics to improve recovery in stroke, spinal cord injury and other neurological conditions.

Welcome Dr Edwards. Your early training was in physical therapy. I'm curious if you plan at that point was to become a physical therapist and, if not, how you morphed from there into research?

I was interested in research as an undergraduate. I was studying exercise physiology and I was especially interested in the adaptive capacity of the brain, how it supports enhanced function like when we practice and learn new motor skills as an adult. And in this context I learned this emerging technique called transcranial magnetic stimulation. This was a method that could painlessly assess the connection between brain and muscle and it could evaluate brain reorganization associated with skill learning. I became really intrigued by new neurological conditions that could affect movement systems such as stroke and Parkinson's disease because of the pressing need for more effective treatments, but also as a model to help us understand brain function. Really I pursued studying physical therapy to understand dysfunctional movement symptoms and putative cause and treatment rationale and all the while I was continued research at the University of Western Australia.

I focused on the interaction of human sensory information and movement information. Technically speaking, that was a systems level physiology of sensory motor integration. And this is relevant because repetitive practice can improve function after stroke or partial spinal cord injury, for example, and requires voluntary movement attempts with feedback about performance. My PhD and other postdoctoral work built on this and ultimately lead to joint projects at MIT where there were expert scientists in rehabilitation robotics, and then Harvard University where there were expert scientists in transcranial magnetic stimulation and the clinical application at Cornell in New York that had a long history of excellence in clinical neuro rehabilitation.

Your early life and training occurred in Australia and then you made that move over to the United States. Did you find similar approaches, similar thinking here or where there's some obvious differences?

My initial impression when I moved to the United States was that the quality of work and both Australia and the United States is outstanding on the world stage and that the approach was very similar and indeed there are leaders in the field in both countries, so it was a natural fit.

You talked a little bit about how you've come to focus on the effects of both robotics and noninvasive brain stimulation on recovery from stroke, spinal cord and neurological conditions, but can you talk a little bit more about why you honed in on that area of study?

Central nervous system damage can result from different causes such as stroke or spinal cord injury. Damage of a normally functioning nervous system can lead to sudden and lasting impact or in the case of cerebral palsy damage early in life can alter normal development and have lasting effects. But in each of these cases where there is partial movement function preserved there is the opportunity to build on the existing capacity. Rehabilitation robotics can finely assess movement function, but also assist with intensive motor practice and therefore an appealing tool for promoting voluntary movement function. Noninvasive brain stimulation can shed light on the underlying basis of all motor function and is therefore a useful tool to probe the mechanism and inter-individual variants in response. Noninvasive brain stimulation can also induce transient changes in brain function and that can plausibly be leveraged to supplement behavioral therapies, although today this method shows conflicting results.

You've been doing research specifically with robotics. I'm curious what you've been learning from that.

For improving arm function in patients with a residual deficit intensive robotic assisted therapy is effective. But although it's endorsed clinically, at the individual level the outcome is difficult to predict. So to increase the certainty of outcome would be useful in determining how to allocate resources and the appropriate course of action in patient treatment. One way to address this would be the identification of robust biomarkers of recovery. For example, features of performance in a robot may be predictive of how well individual subjects might respond to a course of intensive training.

Let's move to the brain stimulation work. You've spent a lot of time and done a lot of research, including transcranial magnetic brain stimulation. Talk a little bit about the research that you've done and then what you've been learning.

Noninvasive stimulation in general, is an appealing tool to provide a quantitative assessment of the pathway from the brain to the affected limbs and also of the sensory pathway from the limb back to the brain. And both of these are known to be important for a recovery outcome, but they're not effectively built into predictive models to understand how somebody might recover spontaneously early after injury or in the long-term chronic phase of injury when we participate in an intervention. The long range goal of this would be to have robust markers of recovery in both the early phase after the injury, also the chronic phase after injury. When we have sensitive and robust markers of recovery we can improve the outcome prediction and also lead to more efficient clinical trials.

A lot of your work is not looking at robotics or brain stimulation by themselves, by. You've got a lot of interest in looking at that in combination as you work with treating patients. So why that approach and how does that work?

This is true. The combinatorial approach is important. Intensive movement practice is one of the best known methods of enhancing motor function in neurological patients. Yet it's far from optimal. It requires a large time investment and the gain is often relatively modest, even though the result can be clinically meaningful and sustained. A combinatorial approach of say supplementary brain stimulation or pharmacological intervention with the intensive practice might serve to lead to more substantial gains.

So you're saying that this combination is what's most effective rather than doing each one in isolation?

Yes. The idea is that the repetitive practice leads to meaningful change, but as scientists, we're not happy with the degree of change. It seems like a heavy time investment and for a relatively modest effect, even though it can be very meaningful to individual patients, so were trying to push the envelope for seeing more substantial gains by looking at the addition of supplementary treatments that might augment the effect of the practice. Noninvasive brain stimulation is one method, but also there might be promise with drugs such as fluoxetine or Prozac that people have interest in at the moment and it's showing reasonable results in motor recovery.

You've talked in the past about the importance of taking risks and thinking outside of the box in research. I'm wondering how that approach has played in your work.

The idea of taking risks and thinking differently than others is because of the need to drastically change rehabilitation approaches because we're not happy with current practice. There's still considerable disability in the community and we need to think really quite differently about ways to resolve that disability by targeting impairments and function with therapies that are very effective. And to do that, we really need to not follow what others are doing - to certainly build on historic incremental advances - but think quite radically about how and why new approaches might work. This in part can be done by going back to theory and having strong rationale for treatments.

Given your advocacy for doing research a little differently and thinking differently, I'm still wondering if when you look back on recent years, are there some areas of research that you're really excited about that you think show us some great promise?

There's some great advances in medical science and fascinating developments in the early medical management and neuro protective strategies in parallel with increased understanding of the biology of neurological injury and disease that can act to minimize the damage of the brain. The field of rehabilitation neuroscience is expanding, takes advantage of sophisticated technology such as neural imaging in combination with careful clinical profiling using these validated tools to understand the biology of the symptoms and the spontaneous and intervention-related recovery. The diversity of approaches spanning applied and basic sciences is encouraging and is moving the field closer to resolving disability in neurological patients. One exciting development in rehabilitation science is data sharing, the potential for data collected at one site to be compiled with that collected by other groups or analyzed in new ways and thus maximizing the benefit of investment in collection and broadening the impact and advancing science in a more efficient and powerful manner.

Let's talk about your decision to become director of the Moss Rehabilitation Research Institute. What attracted you to the institution?

It's an honor to assume the role of director of this prestigious Moss Rehabilitation Research Institute. MRRI has an impressive past and a bright future. The research areas are highly relevant to current and future predictive needs and rehabilitation medicine. The staff here have impressive reputations, productivity, extramural competitive funding. The Einstein Healthcare Network and MossRehab demonstrate a strong commitment to the institute recognizing the importance of research. The integration with MossRehab hospital ranked by US News and World report as a top rehabilitation hospital for multiple years running. In particular, MossRehab leadership and clinical staff embrace and are part of medical practice advancement and technology advancement. MRRI has steady and consistent markers of success, most notably important peer reviewed scientific publications in addition to grants and other awards, leadership roles in professional and academic organizations, journal editorial responsibilities. In part, this is reflective of the high caliber staff attracted to work at the institute historically and to this day and in part by institution founding principles, balanced and effective leadership that promotes a scholarly environment and structured and a critical appraisal of research ideas and data interpretation and with appropriate nurturing and support. The Philadelphia area is also a rich intellectual environment and has geographic strategic position on the East Coast with a number of benefits such as collaboration and attracting top researchers and clinicians. What makes the institute however is the people, and it's inspiring to see the collegial yet high paced interaction here. The length of employment attests to ongoing success and workplace fulfillment of staff. The vibrancy flows over to not only scientific and clinical peers, but also patients and the broader community. These features make MRRI an enviable environment to work and attracted me here.

MRRI has always had a focus on research that can be directly translated to patient care. Will that focus continue?

Yes. The translational aspect of our research has always been important and I plan to continue that and accelerate new ways for clinicians and scientists to have regular, small but meaningful facetime and thinking together and understanding each other's needs to advance clinical science.

Any other plans that you have for the institute at this point?

The outstanding team of the scientists, the administrative and support staff are collectively responsible for ongoing institute activity. My first priority is to ensure that the environment and the resources continue to foster the current high productivity and intellectual curiosity to keep the institute on the cutting edge of rehabilitation science. I plan to work with institute scientists and MossRehab leadership and clinicians to build scientist-clinician interaction in a natural yet effective way that challenges theoretically based studies to have clinical relevance and clinical studies to be rigidly scientific in approach and lead to definitive outcomes that advance the field. This concept is not new and indeed MRRI made significant ground here. I'm looking forward to facilitate this interaction building on my past experience and existing methods to lead to fruitful interaction with a tractable projects. Working with institute staff and advisors we will review and if necessary, adapt the strategic direction of MRRI to remain current and competitive in the most significant areas of rehabilitation medicine - building on historic strengths and existing successful programs and ensure that depth of understanding is above breadth of topic areas in institute priority.

In addition to all of that, we assume that you are going to continue your own research.

I plan to continue my own research. I think as a director I need to be part of the momentum of the institute to not only contribute to advancing science, to be at the leading edge means is you need to maintain a current understanding and part of this is to be addressing contemporary questions. I plan to have a group that will continue this line of work, including interaction with the hospital and external collaborators and I'm looking forward to that.

Thank you Dr Edwards for spending some time with us.

Thank you very much, Larry. It's a pleasure to be here, and I appreciate your time.

You've been listening to a MossRehab Conversation with Dr. Dylan Edwards, talking with director of digital strategy. Larry Blumenthal about his research to date and his goals in his new position as director of the Moss Rehabilitation Research Institute. I'm Bill Fantini. Thanks for listening.