Haptic interaction with a human partner for ankle training in chronic stroke: a pilot study

Haptic interaction with a human partner for ankle training in chronic stroke: a pilot 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 Haptic interaction with a human partner for ankle training in chronic stroke: a pilot study Matthew Short, Laura Bandini, Daniel Ludvig, Lorenzo Vianello, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7376392/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 18 Dec, 2025 Read the published version in Journal of NeuroEngineering and Rehabilitation → Version 1 posted 10 You are reading this latest preprint version Abstract Background: Sensorimotor impairments following stroke frequently result in diminished voluntary control of the ankle, contributing to deficits in balance and gait. Robotic training paradigms targeting ankle motor control often use an assist-as-needed strategy, where compliant guidance is provided to assist movements towards a target trajectory. However, interaction with "perfect" reference trajectories may overly constrain movements during training and has been shown to limit learning in many upper-limb contexts; alternatives to robotic assistance have rarely been explored for post-stroke ankle training. Inspired by human-robot-human interaction studies, we investigated whether physical interaction with a therapist-termed human interaction-offers advantages over traditional trajectory guidance regarding short-term learning. Methods: In a within-subject design, nine individuals with chronic stroke (61.6 +/- 14.3 years) performed a 1-DoF visuomotor tracking task while wearing ankle robots designed to train dorsiflexion and plantarflexion movements. Two robotic training methods were evaluated in separate visits: (1) compliant connection to a sinusoidal target trajectory (i.e., trajectory guidance) and (2) compliant connection to a physical therapist who tracked the same target trajectory (i.e., human interaction). In each visit, tracking performance (i.e., errors, movement smoothness) and muscle activation were evaluated during and immediately after training. Results: Both strategies improved tracking accuracy and movement smoothness during training, however there were trends of better tracking performance with trajectory guidance compared to human interaction. In particular, random error was more significantly suppressed during trajectory guidance training. Importantly, we observed that human interaction led to a trend of improvements in unassisted tracking performance and significantly higher dorsiflexor activation immediately after training. Conclusion: Our results suggest that human interaction has the potential to facilitate improved learning during ankle training in chronic stroke participants, likely by providing assistance without over-constraining an individual's movement smoothness or variability. Training while physically interacting with a partner may serve as an effective alternative to conventional robot-guided therapy for post-stroke ankle rehabilitation, though further studies are needed to assess the generalization of this approach regarding long-term retention and functional improvements. Registry: clinicaltrials.gov, TRN: NCT04578665, Registration date: 8 October 2020. Chronic stroke rehabilitation robotics ankle human-human physical interaction Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 18 Dec, 2025 Read the published version in Journal of NeuroEngineering and Rehabilitation → Version 1 posted Editorial decision: Revision requested 18 Oct, 2025 Reviews received at journal 18 Oct, 2025 Reviewers agreed at journal 30 Sep, 2025 Reviews received at journal 21 Sep, 2025 Reviewers agreed at journal 26 Aug, 2025 Reviewers agreed at journal 25 Aug, 2025 Reviewers invited by journal 20 Aug, 2025 Editor assigned by journal 18 Aug, 2025 Submission checks completed at journal 18 Aug, 2025 First submitted to journal 14 Aug, 2025 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. 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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-7376392","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":501876850,"identity":"bda303e5-1216-41e2-ab86-8c2f5947126c","order_by":0,"name":"Matthew 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Rehabilitation","twitterHandle":"@BioMedCentral","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Chronic stroke, rehabilitation robotics, ankle, human-human physical interaction","lastPublishedDoi":"10.21203/rs.3.rs-7376392/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7376392/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Background: Sensorimotor impairments following stroke frequently result in diminished voluntary control of the ankle, contributing to deficits in balance and gait. Robotic training paradigms targeting ankle motor control often use an assist-as-needed strategy, where compliant guidance is provided to assist movements towards a target trajectory. However, interaction with \"perfect\" reference trajectories may overly constrain movements during training and has been shown to limit learning in many upper-limb contexts; alternatives to robotic assistance have rarely been explored for post-stroke ankle training. Inspired by human-robot-human interaction studies, we investigated whether physical interaction with a therapist-termed human interaction-offers advantages over traditional trajectory guidance regarding short-term learning.\n\nMethods: In a within-subject design, nine individuals with chronic stroke (61.6 +/- 14.3 years) performed a 1-DoF visuomotor tracking task while wearing ankle robots designed to train dorsiflexion and plantarflexion movements. Two robotic training methods were evaluated in separate visits: (1) compliant connection to a sinusoidal target trajectory (i.e., trajectory guidance) and (2) compliant connection to a physical therapist who tracked the same target trajectory (i.e., human interaction). In each visit, tracking performance (i.e., errors, movement smoothness) and muscle activation were evaluated during and immediately after training.\n\nResults: Both strategies improved tracking accuracy and movement smoothness during training, however there were trends of better tracking performance with trajectory guidance compared to human interaction. In particular, random error was more significantly suppressed during trajectory guidance training. Importantly, we observed that human interaction led to a trend of improvements in unassisted tracking performance and significantly higher dorsiflexor activation immediately after training.\n\nConclusion: Our results suggest that human interaction has the potential to facilitate improved learning during ankle training in chronic stroke participants, likely by providing assistance without over-constraining an individual's movement smoothness or variability. Training while physically interacting with a partner may serve as an effective alternative to conventional robot-guided therapy for post-stroke ankle rehabilitation, though further studies are needed to assess the generalization of this approach regarding long-term retention and functional improvements.\n\nRegistry: clinicaltrials.gov, TRN: NCT04578665, Registration date: 8 October 2020.","manuscriptTitle":"Haptic interaction with a human partner for ankle training in chronic stroke: a pilot study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-20 11:06:22","doi":"10.21203/rs.3.rs-7376392/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-10-18T04:17:48+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-18T04:06:49+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"141018860081845298418746925770980417587","date":"2025-09-30T04:46:58+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-21T23:19:23+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"303085883516455221797602516883114001145","date":"2025-08-26T16:43:57+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"182366522257906449406694306169488258280","date":"2025-08-25T11:41:42+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-08-20T23:32:03+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-08-18T10:07:55+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-08-18T10:06:58+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of NeuroEngineering and Rehabilitation","date":"2025-08-14T18:42:43+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":"854585c6-f0b1-46fd-b086-c47720afe369","owner":[],"postedDate":"August 20th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-12-22T16:04:24+00:00","versionOfRecord":{"articleIdentity":"rs-7376392","link":"https://doi.org/10.1186/s12984-025-01840-4","journal":{"identity":"journal-of-neuroengineering-and-rehabilitation","isVorOnly":false,"title":"Journal of NeuroEngineering and Rehabilitation"},"publishedOn":"2025-12-18 15:57:36","publishedOnDateReadable":"December 18th, 2025"},"versionCreatedAt":"2025-08-20 11:06:22","video":"","vorDoi":"10.1186/s12984-025-01840-4","vorDoiUrl":"https://doi.org/10.1186/s12984-025-01840-4","workflowStages":[]},"version":"v1","identity":"rs-7376392","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7376392","identity":"rs-7376392","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}