Grant: CIHR New Investigator

Shoulder pain is common and associated with substantial functional limitations. Rotator cuff (RC) disorders accounts for 50% to 85% of all shoulder complaints. Regardless of intervention, clinical trials suggest that the long-term outcome is negative for more than 30% of patients with RC disorders. The overarching aim of my research program is thus to improve the outcome of interventions for this population. To reach this aim, the present proposal includes 3 projects needed to fill some knowledge gaps. Individuals with RC disorder present movement deficits that lead to the compression of RC tendons and pain. In Project 1, the reasons they start moving differently will be investigate by exposing healthy individuals to experimental pain or fatigue and see how it influences shoulder movements. This project will improve our understanding on the development of movement deficits associated with RC disorders. One way of improving the outcome of interventions is to optimize shoulder movement by relearning a normal movement using training. However should pain be avoided during training? Project 2 will look at how well healthy individuals (experimental pain) and individuals with RC disorders learn and retain what they have learned if they are in pain. Subjects will be exposed to a force field applied to the upper limb, and will have to adapt to retrieve a normal movement. If pain interferes with learning, it would suggest that the same intervention would be less effective in the presence of pain. Transcranial direct current stimulation (tDCS; low current delivered to the brain) has been shown to enhance learning associated with training. Project 3 will investigate the effects of combining tDCS and training to improve rehabilitation outcomes. Individuals with RC disorders will be randomly assigned to one of two intervention groups: training with tDCS or same training with sham tDCS. This project will determine if tDCS should be used in this population to improve the outcome.