Efficacy of Segmental Muscle Vibration on Pain Modulation in Patients with Primary Cervical Dystonia Treated with Botulinum Type-A Toxin: A Protocol for a Randomized Controlled Trial

Primary cervical dystonia (PCD), or spasmodic torticollis, is a focal dystonia characterized by involuntary and often painful muscle contractions, leading to abnormal cervical movements and postures. While botulinum toxin injections are the first-line treatment, additional therapies, such as segmental muscle vibration (SMV), remain underexplored. SMV, a non-invasive neuromodulation technique, may enhance motor cortex excitability and promote neuroplasticity, offering potential benefits in PCD management. This single-center triple-blinded randomized controlled trial evaluates SMV's efficacy in reducing dystonic pain and improving quality of life in PCD patients undergoing standardized rehabilitation after botulinum toxin treatment. Participants with a pain level of ≥3 on the Numerical Rating Scale will be randomized into two groups. The experimental group will receive 80 Hz SMV during a 10-session rehabilitation program, while the control group will undergo sham SMV. Both groups will follow identical physiotherapy and occupational therapy protocols. The primary outcomes include changes in pain intensity and function, assessed at baseline, mid-treatment, and post-treatment using validated scales. The secondary outcomes will evaluate quality of life and patient satisfaction. This study hypothesizes that SMV will significantly reduce dystonic pain and enhance quality of life, supporting its integration into multidisciplinary rehabilitation for dystonic disorders. Trial registration number: NCT06748846.