Most people who survive a cerebrovascular accident (CVA) suffer impaired motor skills. UCL researchers may have found a way to boost their ability to relearn them.
Like all our organs, our brain is supplied blood by arteries. If one of them ruptures or is blocked, neurons in the area it supplies are deprived of blood and die. This is a cerebrovascular accident (CVA), also known as a stroke. Every year in Belgium 19,000 people suffer a CVA, 9,000 of whom die. Most survivors endure permanent damage: impaired motor skills (hemiplegia, weakened limbs, loss of coordination, etc.), language or vision impairments, etc. ‘In the acute phase, right after the CVA, up to 85% of patients have motor skill impairments’, says Prof. Yves Vandermeeren, a neurologist at CHU UCL Namur (Mont-Godinne) University Hospital and a researcher at the UCL Institute of NeuroScience (IoNS). ‘For about half of these patients, after a few months these impairments become chronic. This makes CVA the number one cause of disability in Western countries.’
How does the brain recover from a CVA?
The brain can spontaneously recover some lost motor skills. A personalised programme of neurorehabilitation (physiotherapy, ergotherapy, etc.) can also improve them. But the process has its limits. Neither spontaneous recovery nor rehabilitation resuscitates dead neurons, nor does it ‘grow’ new ones. However, the brain has options. ‘Its activity is simultaneously chemical and electrical’, says Prof. Vandermeeren. ‘After a CVA, electrical information no longer travels normally in or around the destroyed cerebral area. So the brain sets up new neuronal circuits. They’re often less effective than the original area, but they help recover a more or less significant degree of lost function. In fact, electrical information is like a motorist. Normally, to drive from Brussels to Namur, he takes the quickest route: the E411 motorway. If that’s impossible, he can take the N4 or minor roads. It’ll take longer, but he’ll get there!’
Neuromodulation: principle and limits
The motorist can’t build a new road. However, he can improve his car’s performance so that it goes faster on secondary roads. That’s the principle of neuromodulation. Transcranial direct-current stimulation (tDCS), one type of neuromodulation, consists of sending a weak electric current into the brain via two electrodes attached to the patient’s skull. This improves brain activity. ‘The downside: owing to the brain’s internal mechanisms that regulate its electrical activity,’ Prof. Vandermeeren explains, ‘after 30 to 60 minutes the positive effect of tDCS tends to diminish…and finally disappears. So we thought of coupling neuromodulation with a motor learning task to see if tDCS would improve the patient’s motor learning ability and long-term motor skills memory.’
Two double-blind clinical studies have been conducted, involving some 40 patients suffering from hemiplegia in one arm. Jackpot: ‘Not only were the results better than with tDCS alone, they also lasted longer! A week after the sessions, patients’ motor skills were tested and they improved 40 to 50%...compared to 4% and 12% in placebo groups.1 It’s as if, during the session, the tDCS helped the brain select and permanently “mark” the best neural pathway.’
These promising results open the way to other areas that will surely be subject to clinical studies:
- Does using tDCS during physiotherapy and/or ergotherapy sessions improve patient progress?
- The first two studies helped some patients improve their performance in other rehabilitation exercises. Even better, approximately 20% of them reported motor skill improvement in other limbs (arm(s), leg(s)) after participating in the study.
- In 2016, Prof. Vandermeeren’s team will combine tDCS with REAplan, a robot developed at UCL,2 which aids the patient’s movement during exercises. The goal: to determine whether this approach further improves results.
‘We’re still at the experimental stage’, says Prof. Vandermeeren. ‘But if the system works for post-CVA rehabilitation, maybe it’ll work for other pathologies (arteriosclerosis, Parkinson’s, etc.). The future will tell!’
(1) Results of the first study (2012) were determined via simple rehabilitation tests. For the second study (published in December 2014 in the journal Brain), in addition to determining motor skill memory, brain reorganisation was evaluated by functional MRI. (2) REAplan is the fruit of collaboration between Louvain Bionics Center of Interdisciplinary Expertise and Axinesis, a UCL spin-off (www.axinesis.com).
A glance at Yves Vandermeeren's bio
1994 Doctorate in Medicine (UCL)
2003 Doctoral Thesis in Biomedical Sciences – Neurosciences (UCL)
2005 Neurologist’s Certificate
2005-2007 Post-doctoral Training at the National Institutes of Health (US)
Since 2012 Associate Head of Clinic, Neurology Department, CHU Mont-Godinne Namur (UCL)
2013 Winner of Prix F. DepelchinSince
2014 Member of Louvain Bionics (UCL) and founding member of Société belge de neurorevalidation (bSNR)
Since 2015 Professor, UCL
Prof. Vandermeeren’s research is or has been financed mainly by the FNRS, the Fondation Albert Frère and the Fondation Mont-Godinne.