Eligibility Criteria

Inclusion Criteria

- Patients with hemiparesis and shoulder pain due to first stroke (ischemic or hemorrhagic) admitted in a rehabilitative department to carry out a standard post-acute rehabilitative program
- Pain score of 45 or greater on a 0-100 mm pain visual analog scale (VAS; 0 = no pain, 100 = worst possible pain)
- Duration of HSP for at least one month
- Pain refractoriness to conventional treatment i.e. common analgesics (such as paracetamol and NSAIDs), slings, strapping and handling of the arm, functional electrical stimulation of shoulder muscles

Exclusion Criteria

- Significant spasticity in the upper shoulder joint, defined as a score of 2 or more at the modified Ashworth scale
- History of shoulder pain or shoulder diseases.
- History of neurological diseases (i.e. Parkinson disease, dystonia).
- History of botulinum toxin treatment