Dynamic Thumb Proprioception: Quantification with a Novel Robotic Task

Dynamic Thumb Proprioception: Quantification with a Novel Robotic Task | 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 Dynamic Thumb Proprioception: Quantification with a Novel Robotic Task Luis Garcia-Fernandez, Andria J. Farrens, Christopher A. Johnson, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6917900/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 11 Jan, 2026 Read the published version in Experimental Brain Research → Version 1 posted You are reading this latest preprint version Abstract The thumb plays a crucial role in hand function, yet its proprioceptive abilities remain poorly understood. Here we quantified dynamic thumb localization ability in unimpaired participants, using a novel task in which a robot moved the thumb in a circle and participants pressed a button when they felt their thumb aligning with a target point on a screen. After pressing the button, they received visual error feedback in the form of a ball jumping toward the target. To characterize thumb localization ability, we varied thumb speed and rotation diameter, assessed the effect of a propriovisual rotational perturbation, and compared index finger performance. Following task familiarization, thumb localization error was ~ 25º and did not change significantly with speed or circle diameter. Reversing thumb rotation increased error followed by rapid error adaptation across the next 20 trials, as would be expected if individuals formed an internal model based on a body-centered (movement-aligned) frame of reference rather than a world-centered spatial frame. Localization error was larger for the thumb than the index finger error for the same task (p = 0.02) and was correlated with a different, robotic assessment of finger proprioception (ρ = 0.61, p = 0.001). These findings indicate that dynamic thumb localization is somewhat inaccurate, although it can leverage visual feedback within a body-centered reference frame, a form of passive, cross-sensory adaptation. Further, in unimpaired adults, the dynamic proprioceptive abilities of the thumb and index finger are related, with thumb proprioception ability being less accurate than the finger. thumb proprioception stroke rehabilitation sensorimotor assessment robotic evaluation hand function proprioceptive adaptation Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 11 Jan, 2026 Read the published version in Experimental Brain Research → Version 1 posted 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. 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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-6917900","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":475925346,"identity":"c26e9302-5316-465c-a31a-e70b21137c63","order_by":0,"name":"Luis Garcia-Fernandez","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAxElEQVRIiWNgGAWjYLCCBAa5+n4gfYCBgZloLcaMMxtI0sIA1LLhAJhBhBZ597MPPzyoMWA2vpH88ABDhXViAyEthmfSjSUSjhmwmd1IMzjAcCadCC0NaWwMCWx/eMxu5DAcYGw7TISW/mdALf8MJIxngLT8I0KLvATQlsQ2AwMDCZCWBiK0GEg8Y5ZI7DNIkDjzzOBAwrF0Y8K29KcxfvzxzSCBvz358YcPNdayhG05gMxLIKQcbAtBQ0fBKBgFo2AUAAC8uz7Ee+godQAAAABJRU5ErkJggg==","orcid":"","institution":"University of California, Irvine","correspondingAuthor":true,"prefix":"","firstName":"Luis","middleName":"","lastName":"Garcia-Fernandez","suffix":""},{"id":475925347,"identity":"0588137e-d7a5-45e2-92bc-8f0f971878a0","order_by":1,"name":"Andria J. 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Perry","email":"","orcid":"","institution":"University of Idaho","correspondingAuthor":false,"prefix":"","firstName":"Joel","middleName":"C.","lastName":"Perry","suffix":""},{"id":475925351,"identity":"b48abc63-2f69-431e-8ef2-a15b9df89e57","order_by":5,"name":"Eric T. Wolbrecht","email":"","orcid":"","institution":"University of Idaho","correspondingAuthor":false,"prefix":"","firstName":"Eric","middleName":"T.","lastName":"Wolbrecht","suffix":""},{"id":475925352,"identity":"28907f26-a4a2-4332-b1fc-28fafd622d30","order_by":6,"name":"David J. Reinkensmeyer","email":"","orcid":"","institution":"University of California, Irvine","correspondingAuthor":false,"prefix":"","firstName":"David","middleName":"J.","lastName":"Reinkensmeyer","suffix":""}],"badges":[],"createdAt":"2025-06-18 01:08:07","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6917900/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6917900/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00221-025-07211-8","type":"published","date":"2026-01-11T15:58:11+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":100070234,"identity":"5d121913-507e-40ac-b06b-d90034a9409a","added_by":"auto","created_at":"2026-01-12 16:17:08","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":723509,"visible":true,"origin":"","legend":"","description":"","filename":"EBRDynamicThumbProprioceptionQuantificationwithaNovelRoboticTask.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6917900/v1_covered_95b3c00d-4f19-43f2-81a7-5a9fe629a63a.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Dynamic Thumb Proprioception: Quantification with a Novel Robotic Task","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"thumb proprioception, stroke rehabilitation, sensorimotor assessment, robotic evaluation, hand function, proprioceptive adaptation","lastPublishedDoi":"10.21203/rs.3.rs-6917900/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6917900/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e \u003ca class=\"FNLink\" href=\"#Fn1\" id=\"#FNLinkFn1\"\u003e\u003c/a\u003e \u003csup\u003e \u003c/sup\u003eThe thumb plays a crucial role in hand function, yet its proprioceptive abilities remain poorly understood. Here we quantified dynamic thumb localization ability in unimpaired participants, using a novel task in which a robot moved the thumb in a circle and participants pressed a button when they felt their thumb aligning with a target point on a screen. After pressing the button, they received visual error feedback in the form of a ball jumping toward the target. To characterize thumb localization ability, we varied thumb speed and rotation diameter, assessed the effect of a propriovisual rotational perturbation, and compared index finger performance. Following task familiarization, thumb localization error was ~\u0026thinsp;25\u0026ordm; and did not change significantly with speed or circle diameter. Reversing thumb rotation increased error followed by rapid error adaptation across the next 20 trials, as would be expected if individuals formed an internal model based on a body-centered (movement-aligned) frame of reference rather than a world-centered spatial frame. Localization error was larger for the thumb than the index finger error for the same task (p\u0026thinsp;=\u0026thinsp;0.02) and was correlated with a different, robotic assessment of finger proprioception (ρ\u0026thinsp;=\u0026thinsp;0.61, p\u0026thinsp;=\u0026thinsp;0.001). These findings indicate that dynamic thumb localization is somewhat inaccurate, although it can leverage visual feedback within a body-centered reference frame, a form of passive, cross-sensory adaptation. Further, in unimpaired adults, the dynamic proprioceptive abilities of the thumb and index finger are related, with thumb proprioception ability being less accurate than the finger.\u003c/p\u003e","manuscriptTitle":"Dynamic Thumb Proprioception: Quantification with a Novel Robotic Task","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-25 15:53:30","doi":"10.21203/rs.3.rs-6917900/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"3e51c9ee-fc3e-4345-bd23-ec290604decf","owner":[],"postedDate":"June 25th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-01-12T16:12:32+00:00","versionOfRecord":{"articleIdentity":"rs-6917900","link":"https://doi.org/10.1007/s00221-025-07211-8","journal":{"identity":"experimental-brain-research","isVorOnly":false,"title":"Experimental Brain Research"},"publishedOn":"2026-01-11 15:58:11","publishedOnDateReadable":"January 11th, 2026"},"versionCreatedAt":"2025-06-25 15:53:30","video":"","vorDoi":"10.1007/s00221-025-07211-8","vorDoiUrl":"https://doi.org/10.1007/s00221-025-07211-8","workflowStages":[]},"version":"v1","identity":"rs-6917900","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6917900","identity":"rs-6917900","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}