Motor Recovery Following a Spinal Cord Injury (February 2021 – No 04)

February 2021 Edition (04)

Will I walk again? Improving rehabilitation outcomes by stimulating the nervous system

An interview summary with Dorothy Barthélemy

Dorothy Barthélemy, pht. M.Sc., Ph.D.

Associate Professor, School of Rehabilitation, Université de Montréal
Researcher, Research Centre, Hôpital du Sacré-Coeur de Montréal, CIUSSS du Nord-de-l’Île-de-Montréal
Researcher, CRIR–Institut universitaire sur la réadaptation en déficience physique de Montréal, Gingras pavilion,
CIUSSS du Centre-Sud-de-l’Île-de-Montréal


Neuromobility Lab


What research projects would you like to share with me today?

I would like to talk about three projects that concern locomotor recovery in patients with incomplete spinal cord injury. The first aims at improving assessment of sensorimotor capacities after injury. The second involves the use of novel stimulation paradigms to enhance neuroplasticity and promote motor recovery. The third concerns the development of an innovative dual-training protocol to improve balance function.

What is spinal cord injury?

The spinal cord and the brain make up the central nervous system. The spinal cord receives signals from the body and conveys signals for motor functions. People who suffer from spinal cord injuries have decreased sensory and motor capacities below the level of the lesion. This causes a handicap. Depending on the injury, people can have difficulty in feeling sensations, moving, walking, reaching for a glass, etc.

In Canada, over 86,000 people live with spinal cord injury.
An injury to the spinal cord interrupts communication between the brain and the body and causes total or partial paralysis of the limbs and trunk. The extent of paralysis depends on the location of the lesion in the spine and its severity. No two injuries are the same.
Injuries resulting in paraplegia are located lower in the spine, causing paralysis of the lower limbs, while a higher lesion at the level of the cervical vertebrae (the neck) results in quadriplegia, which is complete or partial paralysis of all four limbs.
As the spinal cord controls the operation of upper and lower limbs, victims of spinal cord injuries often have to use a wheelchair.
For many, spinal cord injury results in loss of independence, poverty and social isolation.
Spinal cord injuries are often the result of accidents: car accidents, falls, diving accidents, or work accidents. They can also result from non-traumatic causes such as spinal degeneration due to aging.

Sources : Moelle épinière et motricité Québec and Praxis Spinal Cord Institute. Rick Hansen Spinal Cord Injury Registry – A look at traumatic spinal cord injury in Canada in 2018. Vancouver, BC: Praxis; 2020.

Why do you study spinal cord injuries?

One of my main research interests is improving assessment of spinal cord injury impairments early on after the lesion, even before rehabilitation starts. This more precise assessment could lead to the design of treatment protocols to optimize recovery.

Clinicians working with spinal cord injury patients face several challenges. First, the full extent of paralysis patients will sustain is difficult to predict and can only be known towards the end of therapy. The reason for this is that we lack good indicators to tell us what damage has been done to the spinal cord early on after the lesion. Second, there is less time allocated for therapy due to constraints on the healthcare system. This means that improvements need to happen, and they need to happen relatively fast!  As soon as the rate of recovery slows down or stops (reaching a plateau), the treatment then focuses on helping patients compensate with different technical aids and with body parts that were not impaired by the lesion. This is essential so that patients can resume daily activities, but less emphasis is then placed on functional recovery. As it is not rare that some patients recover movement weeks or months after therapy, a lingering question is often: could we have done more to enable earlier recovery of movement? It would be useful to have objective and clear indicators regarding when to stop treatment aimed at regaining function and move on to a compensation approach.

Another challenge for clinicians is that spinal cord injury varies greatly among patients.  The spinal cord is complex: numerous pathways bring information from muscle and skin to the brain, while other pathways bring information from the brain to the muscles for movement production. Lesions can occur anywhere on the spinal cord. They can interrupt all or just one of these pathways and partially severe others.

Can you tell which spinal cord pathways are damaged?

Presently we cannot tell which spinal cord pathways are damaged. Clinicians use two methods to categorize spinal cord injuries. The first involves where the lesion is located in the spinal cord. The section where the lesion is located determines the type of injury. For instance, injury in the lumbar area, or lower back, generally affects hip and leg movement, but not the upper body. The second criteria concerns the extent of the lesion, whether the injury is complete or incomplete. Clinicians use the ASIA Impairment Scale from the American Spinal cord Injury Association to determine this. However, these two methods do not provide information on which pathways have been interrupted or cut.

A complete spinal cord injurymeans that all feeling (sensory) and ability to control movement (motor) are lost below the area injured.
An incomplete spinal cord injury means there is some some motor or sensory function below the affected area. The ability to move and the amount of feeling varies from person to person.


During the past ten years, my research focused on quantifying the damage lesions cause to spinal cord pathways and their effect on movement. Results from previous studies we performed with people that had a spinal injury for at least one year indicate a clear correlation between the location of the lesion on the spinal cord, the pathways that have been damaged, and its impact on function. This work also underlined the potential for neuroplasticity below the lesion.

How does your research assess the role neuroplasticity plays on the recovery of spinal neural pathways after spinal cord injury?

First, let us start with a definition of neuroplasticity.

Neuroplasticity is the ability of the nervous system to change its activity in response to intrinsic or extrinsic stimuli by reorganizing its structure, functions, or connections. More specifically in relation to lesions of the brain or spinal cord, neuroplasticity refers to the capacity of the nervous system for adaptation or regeneration after trauma.
Ref.: http://medical-dictionary. Thefreedictionary .com /neuroplasticity;

We know that for different pathologies there is a period after the lesion when neuroplasticity is optimal. For instance, studies show that for stroke, it is three months. For spinal cord injuries, this period probably exists but has yet to be defined.

An innovative aspect of my research is the use of electrophysiological tests to assess neuroplasticity. Most often, these tests are used to see if connections between the brain and the spinal cord are still present, and if there are any changes in their function.

Electrophysiological tests involve placing electrodes on the skin or on the head to measure electrical signals produced in the human body through the firing of neurons. Various types of tests are used in physical rehabilitation research including the electroencephalogram (EEG) to measure the firing of neurons in the brain; the Transcranial magnetic stimulation (TMS) to measure connections between the brain and muscles; and the electromyogram (EMG) to measure muscular activity.

One goal of the project is to get information on the state of these connections early on from patients with spinal cord injury.  Electrophysiological measurements are taken at different periods after injury, starting at one month, then at three and six months – up to one year. I should mention that for many patients the first measurements are taken at their bedside using mobile equipment; not in our CRIR Neuromobility Lab.  Being able to conduct mobile tests is an important advancement since patients are often unable to move right after a spinal cord injury. Therefore, we can get data from all patients and even before rehabilitation treatment starts.

These measurements, taken at different times, provide information on what pathways have been the most interrupted and what deficits the patient is most likely to have. This gives us a more precise diagnosis and a prognosis of what to expect for the patient recovery.

Have you had any results that would be of interest to clinicians and patients?

From our preliminary data, one of the most predictive measure for patient recovery following spinal cord injury is the sensory function taken at one month. We used a new approach called Electrical perceptual threshold.

The electrical perceptual threshold (EPT) exam measures the sensory threshold or minimally detectable electrical stimulus intensity applied to the skin.

An increasing number of research labs around the world are experimenting with this method.  It allows for a much higher resolution of results regarding sensitivity range and intensity. We are currently submitting our preliminary results on this technique. My research team and I are continuing our studies in this area.

What kind of impact do you think your research can have on clinical practice?

We have a way to determine which spinal cord pathways are most impaired. Each pathway has a specific purpose. Some enable balance control, others sensory function, and still others voluntary movement. Knowing which pathway the lesion severed gives us a good idea of what deficits patients are likely to sustain in the longer term.

I work with physiatrists at Hôpital du Sacré-Cœur-de-Montréal and at the Institut universitaire sur la réadaptation en déficience physique de Montréal who are very interested in the outcome of this research.  Their patients often ask, “Will I recover?”  “Will I move again?”  “Will I walk again?” Right now, physiatrists are unable to answer these questions. Finding answers takes time. Our hope is that our research findings contribute additional and relevant information to support clinician – patient discussions about recovery and treatment.

What do you plan to do next in your research?

The next step involves using target therapies to optimize the plasticity in the central nervous system. In other words, to boost spinal cord pathways that were spared by the lesion to improve recovery. This will allow us to personalize treatment and is the focus of a second research project where we will be using a novel therapy called repetitive transcranial magnetic stimulation or rTMS.

Repetitive transcranial magnetic stimulation (rTMS), is a noninvasive form of brain stimulation in which a changing magnetic field is used to cause electric current at a specific area of the brain through electromagnetic induction. It can modulate brain cell activity.

Many patients who have somewhat recovered still have difficulty moving their legs. This difficulty points to damage in the pathway connecting the brain to the muscles, or the corticospinal pathway. This pathway is essential for locomotion and movement in healthy persons. rTMS can be used to enhance activity in the brain and in the partly interrupted pathways, alongside current clinical therapies, to improve recovery of movement. If we apply this treatment during the first months after the lesion, will this enhance recovery? Will we have bigger effects that will continue to carry on? We are looking for answers to these questions.

Who do you think will find your research of interest?

My research holds interest for researchers working on different aspects of spinal cord injury. It is also relevant for students involved in research who want to continue this type of investigation and push boundaries further. For clinical stream students, this research may provide a glimpse of what future therapies may hold.  Research results may also interest clinicians working with spinal cord injury since they complement existing knowledge and practice.

Moving on to your third project on developing balance training sessions for patients with spinal cord injury, can you describe what you are doing?

I am working with Dr. Charlotte Pion, a postdoctoral research fellow at my research lab, to design a new training paradigm to improve balance control. According to the literature, patients with incomplete spinal cord injuries are at high-risk for falls. This risk also applies to those who perform well on clinical balance tests. These patients lack the efficient postural reactions of healthy individuals. Healthy individuals are able to control, readjust and maintain balance in problematic situations. For instance, when walking in the dark or on uneven ground.

To quantify and improve strength and rapidity of these postural reactions, we designed a dual-training paradigm combining two approaches. The first, perturbation balance training, involves training balance by applying perturbation. Studies suggest that patients with different health conditions, including spinal injury, benefit from this emergent training.  Explosive strength training is the second approach used. It is designed to improve muscle reaction rapidity. Rapid reaction time is necessary to activate muscles in case of a fall. Hence, we are training a rapid response within a simulated situation involving falling.

Has combined training worked for patients?

We only had two patients that have received this training so far and they have both improved. However, I am not satisfied with just knowing that patients have improved! (Laughs.) Hence the innovative aspect of the project. We want to identify and measure what changes occur in the central nervous system that explain this improvement. Preliminary findings indicate that the training improves how the brain integrates sensory information from the legs. This means that the brain understands better and quicker that the environment is becoming unstable. The brain is then able to react by activating appropriate muscles more quickly. However, more participants are needed to confirm these changes!

You seem very motivated to do this type of research. Can you explain why?

I worked as a physiotherapist for three years while in graduate studies.  I applied best practice therapy to my patients as best as possible; some would respond really well and others not at all.  I wondered why. I wanted to know what explained this difference. These questions drove me to research. The three research projects I shared with you today are relevant for today’s clinical practice. Mind you, it will take some time before results can be applied in the clinic. Perhaps these finding can lead to the development of new tools that complement existing techniques that work well.  By providing answers to such fundamental questions, we can improve rehabilitation.

Who would be interested in receiving a copy of this interview?

Patients. When talking to patients to recruit them for our studies, they always want to know more about their lesion and are interested in cutting-edge research. Clinicians as well and of course other researchers. Hearing about our research may lead to future collaborations.

Interview and text: Spyridoula Xenocostas, Coordinator—Partnerships and Knowledge Mobilization, CRIR at: