Local muscle vibration in early subacute stroke: preliminary results on upper-limb spasticity and spinal excitability from the randomized placebo controlled IMPROVE study

Local muscle vibration in early subacute stroke: preliminary results on upper-limb spasticity and spinal excitability from the randomized placebo controlled IMPROVE study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Local muscle vibration in early subacute stroke: preliminary results on upper-limb spasticity and spinal excitability from the randomized placebo controlled IMPROVE study Sophie JULLIAND, Charalambos PAPAXANTHIS, Laure CUNNAC, Anne MOCK, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9310646/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 5 You are reading this latest preprint version Abstract Background : Post-stroke spasticity frequently emerges during the early subacute phase and may interfere with motor recovery. Local muscle vibration (LMV) has shown potential to reduce spasticity in chronic stroke populations, but its effects when applied during the early phase of recovery, when neuroplasticity is heightened, remain unclear. This study aimed to investigate whether a 6-week LMV intervention initiated during the early subacute phase post-stroke can modulate the development of upper-limb spasticity and improve sensorimotor recovery in a population at risk. Methods : In this randomized, placebo-controlled trial, stroke patients (median: 29 days post-stroke) received either LMV applied to wrist and elbow flexors (INT group) or a sham intervention (SHAM group) for 6 weeks. Spasticity was assessed across 20 upper-limb muscles using the Modified Ashworth Scale (MAS), with wrist and elbow flexors as primary targets. Motor recovery was evaluated using the Fugl-Meyer Assessment for the upper extremity (FMA-UE). Spinal and peripheral excitabilities (H-reflex and Mmax) was assessed as a secondary neurophysiological outcome. Results : 42 patients were included (21 per group). After 6 weeks, wrist flexors spasticity increased in the SHAM group but remained stable in the INT group, resulting in a significant Group*Time interaction. No significant interaction was observed at the elbow flexors or for global upper-limb spasticity, although similar trends were noted. Motor recovery improved significantly over time in both groups, with greater gains in the INT group (significant Group*Time interaction on FMA-UE scores). Changes in spasticity were moderately correlated with motor improvement. No significant between-group differences were observed for spinal excitability measures. Conclusions : LMV applied during the early subacute phase after stroke appears to mitigate the progression of wrist flexors spasticity and enhance upper-limb motor recovery. These findings suggest that early peripheral neuromodulation may influence the trajectory of post-stroke spasticity and promote more favorable functional outcomes during a critical window of neuroplasticity. Further studies with larger samples are needed to confirm these results and clarify the underlying mechanisms. Trial registration : NCT05315726 Stroke rehabilitation Spasticity prevention Upper-limb recovery Local muscle vibration Early intervention Randomized controlled trial Spinal excitability Full Text Additional Declarations No competing interests reported. Supplementary Files SJulliandetalSupplementalsJNER.docx Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 18 Apr, 2026 Reviewers invited by journal 13 Apr, 2026 Editor assigned by journal 06 Apr, 2026 Submission checks completed at journal 06 Apr, 2026 First submitted to journal 03 Apr, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9310646","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":625422329,"identity":"a98dcb85-ddcd-49d5-8dff-ee2c9277abc1","order_by":0,"name":"Sophie 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Rehabilitation","twitterHandle":"@BioMedCentral","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Stroke rehabilitation, Spasticity prevention, Upper-limb recovery, Local muscle vibration, Early intervention, Randomized controlled trial, Spinal excitability","lastPublishedDoi":"10.21203/rs.3.rs-9310646/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9310646/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cem\u003eBackground\u003c/em\u003e: Post-stroke spasticity frequently emerges during the early subacute phase and may interfere with motor recovery. Local muscle vibration (LMV) has shown potential to reduce spasticity in chronic stroke populations, but its effects when applied during the early phase of recovery, when neuroplasticity is heightened, remain unclear.\u003c/p\u003e\n\u003cp\u003eThis study aimed to investigate whether a 6-week LMV intervention initiated during the early subacute phase post-stroke can modulate the development of upper-limb spasticity and improve sensorimotor recovery in a population at risk.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eMethods\u003c/em\u003e: In this randomized, placebo-controlled trial, stroke patients (median: 29 days post-stroke) received either LMV applied to wrist and elbow flexors (INT group) or a sham intervention (SHAM group) for 6 weeks. Spasticity was assessed across 20 upper-limb muscles using the Modified Ashworth Scale (MAS), with wrist and elbow flexors as primary targets. Motor recovery was evaluated using the Fugl-Meyer Assessment for the upper extremity (FMA-UE). Spinal and peripheral excitabilities (H-reflex and Mmax) was assessed as a secondary neurophysiological outcome.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eResults\u003c/em\u003e: 42 patients were included (21 per group). After 6 weeks, wrist flexors spasticity increased in the SHAM group but remained stable in the INT group, resulting in a significant \u003cem\u003eGroup*Time\u003c/em\u003e interaction. No significant interaction was observed at the elbow flexors or for global upper-limb spasticity, although similar trends were noted. Motor recovery improved significantly over time in both groups, with greater gains in the INT group (significant \u003cem\u003eGroup*Time\u003c/em\u003e interaction on FMA-UE scores). Changes in spasticity were moderately correlated with motor improvement. No significant between-group differences were observed for spinal excitability measures.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eConclusions\u003c/em\u003e: LMV applied during the early subacute phase after stroke appears to mitigate the progression of wrist flexors spasticity and enhance upper-limb motor recovery. These findings suggest that early peripheral neuromodulation may influence the trajectory of post-stroke spasticity and promote more favorable functional outcomes during a critical window of neuroplasticity. Further studies with larger samples are needed to confirm these results and clarify the underlying mechanisms.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eTrial registration\u003c/em\u003e: NCT05315726\u003c/p\u003e","manuscriptTitle":"Local muscle vibration in early subacute stroke: preliminary results on upper-limb spasticity and spinal excitability from the randomized placebo controlled IMPROVE study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-20 22:33:24","doi":"10.21203/rs.3.rs-9310646/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"77970993311351017809165393769722112007","date":"2026-04-18T12:10:07+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-04-13T12:07:03+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-04-06T07:37:33+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-04-06T07:37:29+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of NeuroEngineering and Rehabilitation","date":"2026-04-03T08:19:30+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-neuroengineering-and-rehabilitation","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jner","sideBox":"Learn more about [Journal of NeuroEngineering and Rehabilitation](http://jneuroengrehab.biomedcentral.com/)","snPcode":"12984","submissionUrl":"https://submission.nature.com/new-submission/12984/3","title":"Journal of NeuroEngineering and Rehabilitation","twitterHandle":"@BioMedCentral","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"b64f506e-9139-4851-8609-277a31f100e8","owner":[],"postedDate":"April 20th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-04-20T22:33:24+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-20 22:33:24","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9310646","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9310646","identity":"rs-9310646","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}