Outwitting the brain when it causes pain



Those affected by paralysis say that phantom pain is often far more limiting than a wheelchair. 

Over 50% of paraplegic patients suffer from phantom pain: they ache in their paralyzed limbs even though they no longer feel them. Researchers know that the problem is actually occurring in the brain, which has registered persistent pain and imprinted it in its circuitry. Those affected by paralysis say that phantom pain is often far more limiting than a wheelchair! According to Catherine Mercier, professor in the Department of Rehabilitation at Université Laval and researcher at the Centre for Interdisciplinary Research in Rehabilitation and Social Integration, this soreness must be considered before and during rehabilitation since it impedes the outcome of sufferers' physical training. She is currently leading a research program to understand the root of the pain and determine ways to reprogram the brain that is causing it. 

Using transcranial magnetic stimulation, Professor Mercier relies on a magnetic field to activate the neurons in the areas of the brain involved in movement and thus trigger involuntary muscle contractions that can then be recorded. Her approach makes it possible to assess how pain impacts the motor system. With electroencephalography and electrodes, she is also able to evaluate electrical activity in the brain and its reaction when a painful stimulus is applied in a controlled laboratory setting. 

The researcher is also focused on virtual reality. For example, she may ask paraplegic patients to imagine themselves walking as an avatar. The method is meant to outwit the brain by feeding it false visual and sensory feedback and making it believe that the person's legs are still functional. The gray matter presumes that the body's balance has been restored and stops sending alert signals as pain.

Catherine Mercier believes that brain stimulation and virtual reality could serve as a complement to medication to relieve pain and support maximum motor recovery.