Vibro-tactile stimulation as a non-invasive neuromodulation method to treat motor symptoms in focal dystonia: a systematic review

Background Superficial vibrotactile stimulation (VTS) is a non-invasive form of neuromodulation targeting tactile and proprioceptive mechanoreceptors known to influence reflexive and voluntary motor behavior and conscious proprioception. Objectives Systematically review empirical evidence on the behavioral, biomechanical and neurophysiological effects of VTS in focal dystonia and evaluate its suitability and potential as a clinical intervention in patients with focal dystonia. Methods PUBMED, MEDLINE, CINAHL, and Cochrane Library databases were searched up to September 6, 2025. Included were studies that investigated underlying neurophysiological mechanisms of VTS and the behavioral effects in patients with dystonia. A total of 24 eligible studies were reviewed. Results The review of empirical data indicated that VTS of dystonic regions is typically fast acting and can lead to symptoms reduction within minutes. Results show than VTS can 1) induce head righting and reduce pain in cervical dystonia, 2) improve voice quality and reduce speech effort in laryngeal dystonia, 3) normalize muscle activation in upper limb and cervical dystonia. Based on objective behavioral and biomechanical measures as well as subjective effect ratings by patients, between 57% and 85% of participants responded to VTS by reducing the frequency and magnitude of symptoms. Temporal post-treatment VTS effects varied widely, with short applications (4 s −15 min) decaying within minutes and longer applications (20–45 min) showing effects for hours or days. Major observable electrophysiological responses to VTS included 1) a reduction in EMG activity of vibrated muscle and its synergists, and increased activity of antagonistic muscles, 2) reduction of excessive neuronal synchronization over somatosensory-motor cortex, 3) and altered motor-evoked potentials of vibrated muscles, their synergists and antagonists. Conclusion The reviewed empirical evidence indicates that VTS can reduce unwanted muscle spasms in various forms of focal dystonia. At present, there is no knowledge of optimal daily or weekly dosage. Initial evidence indicates that at-home application of VTS over months is feasible, but there is only inconclusive evidence about the long-term effects of VTS on FD symptoms and what differentiates responders from non-responders to VTS.