TRANSCRANIAL DIRECT CURRENT STIMULATION TO ENHANCE REHABILITATION IN INDIVIDUALS WITH ROTATOR CUFF TENDINOPATHY: A TRIPLE-BLIND RANDOMIZED CONTROL TRIAL

Fournier Belley A.¹, Mercier C.¹, Roy J.-S.¹

¹Laval University, Quebec, Canada

Background: Transcranial direct current stimulation (tDCS), an electrostimulation technique known to modulate the motor cortex excitability, has been shown to enhance the effects of rehabilitation in populations with neurological injuries. tDCS could similarly be effective in individuals with rotator cuff (RC) tendinopathy,
as this pathology is also associated with pain and motor control deficits. For the treatment of RC tendinopathy, sensorimotor training is effective to reduce pain, increase function and enhance motor control of the shoulder. The addition of tDCS during sensorimotor training could enhance motor learning associated with sensorimotor training and thus improve treatment outcome.

Purpose: To compare, in terms of symptoms, functional limitations and shoulder control, a group receiving a rehabilitation program centered on sensorimotor training combined with tDCS to a group receiving the same rehabilitation program combined with sham tDCS in individuals with RC tendinopathy.

Methods: Eighteen adults with RC tendinopathy took part in the 4 evaluation sessions (0, 3, 6, 12 weeks) and the 8 supervised physiotherapy treatments during a 6-week rehabilitation program of this triple-blind randomized control trial. They were either randomized to tDCS group (stimulations of 1.5 mV for 30 minutes; anodal tDCS) or sham tDCS group (stimulations activated for 15 seconds and then stopped). Outcome measures were symptoms and functional limitations (Disability of the Arm, Shoulder and Hand [DASH] and the Western Ontario Rotator Cuff [WORC] index), as well as acromiohumeral distance ([AHD] ultrasonographic measurement at 0° and 60° of elevation arm). The rehabilitation program included sensorimotor training, strengthening and education. tDCS was applied during sensorimotor training on the motor cortex contralateral to the side of pain. A 2-way ANOVA was used to analyse the effects of tDCS on the outcomes.

Results: Results show a statistically and clinically significant improvement in symptoms and functional limitations at 3, 6 and 12 weeks for both groups (Time effect p 0.001 for WORC and DASH; mean change at 12 weeks: 38.5 WORC points, 23.6 points DASH). However, no Group X Time interaction (p> 0.35) or Group effects were observed (p> 0.05). A statistically significant difference in the AHD at 60 ° elevation arm was demonstrated (Time effect p = 0.02), indicating an increase in the AHD at the end of the rehabilitation program. However, no between group difference was observed for the AHD (Time X Group interaction: p> 0.63; Group effect: p> 0.717).

Conclusion(s): Our results do not demonstrate any added effect when using the tDCS during a sensorimotor training in a population with RC tendinopathy. The results confirm the effectiveness of a rehabilitation program centered on sensorimotor training to improve symptoms, functional limitations and shoulder control.

Implications: As the effect of a rehabilitation program centered on sensorimotor training is already effective for the treatment of RC tendinopathy, the addition of tDCS may not further prime the plastic potential of the motor cortex during the training and lead to more important changes. Still, tDCS could be relevant for some specific patients and future studies will need to identify which ones are more likely to benefit from tDCS.

Funding acknowledgements: Supported by the Quebec Rehabilitation Research Network (REPAR) and the Ordre professionnel de la Physiothérapie du Québec.

Topic: Professional practice: other

Ethics approval: This study was approved by the Ethics Committee of the Institut de réadaptation en déficience physique de Québec, Quebec City

All authors, affiliations and abstracts have been published as submitted.