Effectiveness of Focal Muscle Vibrations in Improving Sensorimotor Performance, Mobility and Strength in Spinal Cord Injury Population: A Systematic Review

Introduction The pathophysiology of spinal cord injury (SCI) is still not completely understood. Current SCI rehabilitation strategies remain ineffective. Focal muscle vibrations (FMVs), through afferent nerve stimulation, modulate peripheral and central pathways and have potential as a complementary and easy to administer rehabilitation tool in treating SCI populations, however the exact effectiveness of FMVs remains unknown. Methods This study is a systematic review on the use of FMVs in SCIs. Sensorimotor function, and mobility and strength were the main outcomes considered. Science Direct, PubMed, Cochrane library, PEDro, Google Scholar and Springer databases were searched for original studies until June 2023. The PEDro scale was used to assess the methodological quality of the studies. Results Twenty-three studies were included. Nine studies using FMV in the upper limb and fourteen in the lower limb. The analysis includes 422 SCI patients and 132 non-disabled participants, with a focus on male, chronic SCI cases, and a prevalence in North American studies. Conclusion Our findings suggest potential benefits of FMV on sensory perception, motor function, mobility, and strength in both upper and lower limbs of SCI patients. However, there is acute need for further research to optimize the application of FMV through its vibration parameters, location, duration and understanding its long-term effects. Due to the lack larger sample sizes and longitudinal studies, any conclusions derived here and within these studies should be interpreted with caution. #### WHAT IS ALREADY KNOWN ON THIS TOPIC WHAT IS ALREADY KNOWN ON THIS TOPIC Focal muscle vibrations (FMVs) are known to modulate central and peripheral pathways by a the afferent nerves and have been shown to improve neuro-muscular performance in healthy, stroke and spinal cord injury (SCI) populations. #### WHAT THIS STUDY ADDS WHAT THIS STUDY ADDS This study synthesises the current evidence to assess the effects of FMVs on the sensorimotor function and the rehabilitation of SCI subjects. Our study also highlights the limitations of current evidence. #### HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY The evidence presented and discussed here offers valuable insights into the effectiveness of FMV in SCI rehabilitation, its usefulness in improving functional movements, presents insights into the underlying neural mechanisms, and offers recommendations for both clinical applications and future research. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement ANP has been funded by Royal Academy of Engineering (RAEng)-Leverhulme Trust Fellowship and RAEng Industrial Fellowship. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present work are contained in the manuscript