In an innovative approach, a full body suit with multiple electrodes for provision off electrical stimulation has been developed by a Swedish Med-tech company. Based on theoretical background and clinical experience, this study will explore the potential value of the EXOPULSE Mollii suit-method in the management of post stroke shoulder pain. The overall aim of this study is to test and further develop the Mollii-suit for its ability to reduce hemiplegic shoulder pain. The specific aims are 1) to compare the effect of different stimulation modes for shoulder pain reduction 2) to explore which patients will respond best to these.

One challenging complication to stroke is the development of hemiplegic shoulder pain, which is reported in approximately 30% of the stroke population. Treatment strategies recommended in the Swedish National Guidelines for Stroke Care (NBHW) include use of assistive devices for arm support and treatment with transcutaneous electric nerve stimulation (TENS), which may impact on both pain and muscle tone. In an innovative approach, a full body suit with multiple electrodes for provision off electrical stimulation has been developed by a small Swedish med-tech company. The suit ( EXOPULSE Mollii suit) is currently used for treatment of disabling spasticity and to improve motor function in persons living with effects of central nervous system disease or injury. The theoretical background of the EXOPULSE Mollii-method primarily refers to the concept of reciprocal inhibition, i.e. that sensory input from a muscle may inhibit the activation of an antagonistic muscle. Thus, the application of EXOPULSE Mollii aims at stimulating a muscle, e.g. the anterior tibial muscle of the lower leg in order to reduce reflex mediated over-activity, i.e. spasticity, in calf muscles by inducing reciprocal inhibition. Studies on the effects on spasticity and perceived usability of the suit in a stroke population have recently been completed by our study group at the Department of Rehabilitation Medicine Stockholm at Danderyd Hospital (dnr 2017/935-31) and preliminary analyses indicate that spasticity may be reduced by use of the suit.

Based on the theoretical and practical background outlined above, this study will explore the potential value of the Mollii-method in the management of post stroke shoulder pain. The overall aim of this study is to test and further develop the Mollii-suit for its ability to reduce hemiplegic shoulder pain. The specific aims are 1) to compare the effect of different stimulation modes for shoulder pain reduction 2) to explore which patients will respond best to these.

Inclusion Criteria:

• Eligible participants will have suffered a stroke > 6 months earlier and are living with hemiplegia affecting the right or the left side of the body including the upper extremity. They will have developed hemiplegic shoulder pain within the first 6 months after stroke onset. Moreover, eligible study participants will be able to understand instructions as well as written and oral study information and can express informed consent. Furthermore, study participants need to pass the AbilityQ test (Turner-Stokes 2003) that assesses the cognitive ability to fill in a rating scale for pain.

Exclusion Criteria:

• Exclusion criteria comprise any other disorder with an impact on sensorimotor function, any other severe concomitant disease (such as cancer, cardiovascular, inflammatory or psychiatric disease), uncontrolled epilepsy or blood pressure, major surgery during the last year, any implanted medical devices, pregnancy, BMI>35.

Patients with ongoing pharmacological treatment for spasticity or pain may be included only if the medication is stable since at least 3 months. Patients, who have been subject to intramuscular treatment for spasticity may participate only if the time since last treatment is 3 months or more and if it is anticipated that next treatment will not be given during the study period.

The outcome assessor will be blinded to the type of intervention provided at each session.