{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,11]],"date-time":"2026-07-11T16:54:39Z","timestamp":1783788879062,"version":"3.55.0"},"reference-count":37,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,3,26]],"date-time":"2026-03-26T00:00:00Z","timestamp":1774483200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Robot. AI"],"abstract":"<jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>Despite strong evidence that repetitive home-based rehabilitation improves functional recovery after stroke, current delivery models still show gaps in continuity of care and patient engagement. AI-driven Embodied Conversational Agents (ECAs) could provide personalized home support through natural-language guidance on prescribed exercises, reinforcement of neuroplasticity, clarification of therapeutic principles, and motivational support. However, clinical deployment remains challenging. Many robotic platforms lack real-time interaction capabilities such as speech processing, gesture execution, and attention tracking, while Large Language Models (LLMs) may produce factual errors or inconsistent responses. Early development is also constrained by limited access to real users due to practical and ethical considerations.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>To address these challenges, we propose a Design-Based Research methodology for human\u2013AI co-design and evaluation of ECAs (co-AI DBR), where generative AI facilitates iterative cycles of design, testing, and refinement. Co-AI DBR combines synthetic patient generation with real-code execution to simulate, emulate, and evaluate the ECA platform and its LLM-based conversational pipeline. To validate the method in a post-stroke rehabilitation context, a virtual ECA was first tested with synthetic patients to assess technical implementation and accuracy of LLM responses. A pilot deployment using the Furhat robot as an ECA was then conducted with patient relatives and rehabilitation professionals to evaluate the voice interface and augmented communication.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>LLM responses to questions from real participants showed higher lexical diversity (MTLD \u2248 134 vs. 93.9) and lower repetition (Yule\u2019s K \u2248 66.8 vs. 115.4) than responses to synthetically generated questions. Responses remained factually consistent, with no contradictions and complete gender invariance, although slightly lower hapax rates were observed (88.8% vs. 99.4%). Usability scores were higher among relatives (M = 86.67) than professionals (M = 72.50), while Intrinsic Motivation Inventory scores indicated similarly high motivation in both groups (M = 6.32 vs. 6.12).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Discussion<\/jats:title>\n                    <jats:p>The results suggest that co-AI DBR can support early design and evaluation of ECAs when direct patient testing is limited. By combining synthetic patient generation with real-code execution, generative AI supports iterative knowledge building during the prototyping and refinement of LLM-based ECAs. This methodology enables the practical development of ECA to support home-based post-stroke rehabilitation.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/frobt.2026.1758391","type":"journal-article","created":{"date-parts":[[2026,3,26]],"date-time":"2026-03-26T10:09:50Z","timestamp":1774519790000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":1,"title":["Human\u2013AI co-research on design and evaluation of Embodied Conversational Agent in rehabilitation contexts"],"prefix":"10.3389","volume":"13","author":[{"given":"Anna","family":"Lekova","sequence":"first","affiliation":[{"name":"Bulgarian Academy of Sciences, Institute of Robotics","place":["Sofia, Bulgaria"]},{"name":"Centre of Competence: Intelligent Mechatronic, Eco- and Energy-Saving Systems and Technologies, Lab C5.3 Robotics and Mechatronics","place":["Sofia, Bulgaria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Paulina","family":"Tsvetkova","sequence":"additional","affiliation":[{"name":"Bulgarian Academy of Sciences, Institute of Robotics","place":["Sofia, Bulgaria"]},{"name":"University of Library Studies and Information Technologies, Faculty of Information Science","place":["Sofia, Bulgaria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tsvetelin","family":"Stefanov","sequence":"additional","affiliation":[{"name":"Bulgarian Academy of Sciences, Institute of Robotics","place":["Sofia, Bulgaria"]},{"name":"University of Library Studies and Information Technologies, Faculty of Information Science","place":["Sofia, Bulgaria"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,3,26]]},"reference":[{"key":"B1","doi-asserted-by":"crossref","DOI":"10.1109\/ICHI.2013.13","article-title":"On-Demand virtual health counselor for delivering behavior-change health interventions","volume-title":"2013 IEEE international conference on healthcare informatics","author":"Amini","year":"2013"},{"key":"B2","first-page":"1137","volume-title":"ConSiDERS-The-Human evaluation framework: rethinking human evaluation for generative large language models","author":"Aparna","year":"2024"},{"key":"B3","doi-asserted-by":"publisher","DOI":"10.48550\/arxiv.2410.00260","author":"Arannil","year":"2024","journal-title":"arXiv Cornell UnivDoPAMine: domain-Specific pre-training adaptation from seed-guided data mining"},{"key":"B4","first-page":"4","article-title":"SUS-A quick and dirty usability scale","volume":"189","author":"Brooke","year":"1996","journal-title":"Usability Eval. Industry"},{"key":"B5","doi-asserted-by":"publisher","first-page":"1877","DOI":"10.48550\/arXiv.2005.14165","article-title":"Language models are few-shot learners","volume":"33","author":"Brown","year":"2020","journal-title":"Adv. Neural Inf. Process. Syst."},{"key":"B6","doi-asserted-by":"publisher","first-page":"e1","DOI":"10.2196\/rehab.3151","article-title":"THERAPIST: towards an autonomous socially interactive robot for motor and neurorehabilitation therapies for children","volume":"1","author":"Calderita","year":"2014","journal-title":"JMIR Rehabilitation Assistive Technol."},{"key":"B7","doi-asserted-by":"publisher","first-page":"204","DOI":"10.3390\/bioengineering12020204","article-title":"Exploring the impact of socially assistive robots in rehabilitation scenarios","volume":"12","author":"Carnevale","year":"2025","journal-title":"Bioengineering"},{"key":"B8","doi-asserted-by":"publisher","first-page":"165","DOI":"10.1007\/s13748-025-00363-2","article-title":"The potential of large language models for social robots in special education","volume":"14","author":"Evdokia","year":"2025","journal-title":"Prog. Artif. Intell."},{"key":"B9","first-page":"126","volume-title":"Personalized human robot interaction in the unique context of rehabilitation","author":"Feingold-Polak","year":"2021"},{"key":"B10","doi-asserted-by":"publisher","first-page":"174749302091514","DOI":"10.1177\/1747493020915144","article-title":"Taking charge after stroke: a randomized controlled trial of a person-centered, self-directed rehabilitation intervention","volume":"15","author":"Fu","year":"2020","journal-title":"Int. J. Stroke"},{"key":"B11","doi-asserted-by":"publisher","first-page":"17","DOI":"10.1007\/s11910-025-01403-z","article-title":"Supporting long-term meaningful outcomes in stroke rehabilitation","volume":"25","author":"Fu","year":"2025","journal-title":"Curr. Neurology Neurosci. Rep."},{"key":"B12","doi-asserted-by":"publisher","first-page":"8","DOI":"10.2307\/1517697","article-title":"The number and distribution of hapax legomena in biblical Hebrew","volume":"30","author":"Greenspahn","year":"1980","journal-title":"Vetus Testam."},{"key":"B13","doi-asserted-by":"publisher","first-page":"3589","DOI":"10.18653\/v1\/2024","article-title":"The curious decline of linguistic diversity: training language models on synthetic text","volume":"228","author":"Guo","year":"2024","journal-title":"Findings-Naacl"},{"key":"B14","doi-asserted-by":"publisher","first-page":"e69908","DOI":"10.2196\/69908","article-title":"Use of socially assistive robots in physiotherapy: scoping review","volume":"12","author":"He","year":"2025","journal-title":"JMIR Rehabilitation Assistive Technol."},{"key":"B16","doi-asserted-by":"publisher","first-page":"1560214","DOI":"10.3389\/frobt.2025.1560214","article-title":"Ethical considerations in the use of social robots for supporting mental health and wellbeing in older adults in long-term care","volume":"12","author":"Hung","year":"2025","journal-title":"Front. Robotics AI"},{"key":"B17","doi-asserted-by":"publisher","first-page":"89","DOI":"10.1007\/978-3-031-53445-4_8","article-title":"Risk assessment for digital twins applied in systems medicine","volume":"1136","author":"Iliu\u021b\u0103","year":"2024","journal-title":"Stud. Comput. Intell."},{"key":"B18","doi-asserted-by":"publisher","first-page":"e38525","DOI":"10.2196\/38525","article-title":"Design and evaluation challenges of conversational agents in health care and well-being: selective review study","volume":"24","author":"Kocaballi","year":"2022","journal-title":"J. Med. Internet Res."},{"key":"B19","doi-asserted-by":"crossref","DOI":"10.18653\/v1\/2020.emnlp-main.750","article-title":"Evaluating the factual consistency of abstractive text summarization","volume-title":"Proceedings of the 2020 conference on empirical methods in natural language processing (EMNLP)","author":"Kryscinski","year":"2020"},{"key":"B20","doi-asserted-by":"publisher","first-page":"3","DOI":"10.1097\/01.npt.0000260568.31746.34","article-title":"Counting repetitions: an observational study of outpatient therapy for people with hemiparesis post-stroke","volume":"31","author":"Lang","year":"2007","journal-title":"J. Neurologic Phys. Ther."},{"key":"B21","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1145\/3462256","article-title":"Emerging roles for social robots in rehabilitation","volume":"10","author":"Langer","year":"2021","journal-title":"ACM Trans. Human-Robot Interact."},{"key":"B22","doi-asserted-by":"publisher","first-page":"1505024","DOI":"10.3389\/fpsyt.2024.1505024","article-title":"Artificial intelligence conversational agents in mental health: patients see potential, but prefer humans in the loop","volume":"15","author":"Lee","year":"2025","journal-title":"Front. Psychiatry"},{"key":"B23","doi-asserted-by":"publisher","first-page":"786","DOI":"10.1177\/17474930251340286","article-title":"Do self-management interventions improve self-efficacy and health-related quality of life after stroke? A systematic review","volume":"20","author":"Lynch","year":"2025","journal-title":"Int. J. Stroke"},{"key":"B24","doi-asserted-by":"crossref","DOI":"10.1057\/9780230511804","volume-title":"Lexical diversity and language development","author":"Malvern","year":"2004"},{"key":"B25","doi-asserted-by":"publisher","first-page":"381","DOI":"10.3758\/brm.42.2.381","article-title":"MTLD, vocd-D, and HD-D: a validation study of sophisticated approaches to lexical diversity assessment","volume":"42","author":"McCarthy","year":"2010","journal-title":"Behav. Res. Methods"},{"key":"B26","doi-asserted-by":"publisher","DOI":"10.48550\/arXiv.2305.15852","article-title":"Self-contradictory hallucinations of large language models: evaluation, detection and mitigation","author":"M\u00fcndler","year":"2023","journal-title":"arXiv.Org"},{"key":"B27","doi-asserted-by":"publisher","first-page":"5356","DOI":"10.18653\/v1\/2021.acl-long.416","article-title":"StereoSet: measuring stereotypical bias in pretrained language models","author":"Nadeem","year":"2021"},{"key":"B28","doi-asserted-by":"publisher","first-page":"79","DOI":"10.1186\/s12984-025-01605-z","article-title":"Systematic review of AI\/ML applications in multi-domain robotic rehabilitation: trends, gaps, and future directions","volume":"22","author":"Nicora","year":"2025","journal-title":"J. NeuroEngineering Rehabilitation"},{"key":"B29","article-title":"TRUE: re-Evaluating factual consistency evaluation","volume-title":"Proceedings of the 2022 conference of the north American chapter of the association for computational linguistics: human language technologies","author":"Or","year":"2022"},{"key":"B30","doi-asserted-by":"crossref","DOI":"10.18653\/v1\/W18-5814","volume-title":"On hapax legomena and morphological productivity","author":"Pierrehumbert","year":"2018"},{"key":"B31","doi-asserted-by":"publisher","first-page":"6377","DOI":"10.3390\/app15116377","article-title":"Designing social robots with LLMs for engaging human interaction","volume":"15","author":"Pinto-Bernal","year":"2025","journal-title":"Appl. Sci."},{"key":"B32","doi-asserted-by":"publisher","first-page":"120","DOI":"10.3390\/robotics12050120","article-title":"The Co-Design of an embodied conversational agent to help stroke survivors manage their recovery","volume":"12","author":"Richards","year":"2023","journal-title":"Robotics"},{"key":"B33","unstructured":"Precision at scale: domain-specific datasets On-Demand\n          \n          \n            \n              Rodr\u00edguez-de-Vera\n              J. M.\n            \n            \n              Estepa\n              I. G.\n            \n            \n              Saras\u00faa\n              I.\n            \n            \n              Nagarajan\n              B.\n            \n            \n              Radeva\n              P.\n            \n          \n          \n          2024"},{"key":"B34","doi-asserted-by":"publisher","first-page":"91","DOI":"10.1017\/s1351324902212851","article-title":"Christopher D. Manning and hinrich schutze. Foundations of statistical natural language processing","volume":"8","author":"Siddharthan","year":"2002","journal-title":"Nat. Lang. Eng."},{"key":"B35","first-page":"718","volume-title":"Effects of embodiment and personality in LLM-based conversational agents","author":"Sonlu","year":"2025"},{"key":"B36","doi-asserted-by":"publisher","first-page":"206","DOI":"10.3390\/ai6090206","article-title":"Unlocking the potential of the prompt engineering paradigm in software engineering: a systematic literature review","volume":"6","author":"Syahputri","year":"2025","journal-title":"AI"},{"key":"B37","doi-asserted-by":"publisher","first-page":"e98","DOI":"10.1161\/STR.0000000000000098","article-title":"Guidelines for adult stroke rehabilitation and recovery: a guideline for healthcare professionals from the American heart association\/american stroke association","volume":"47","author":"Winstein","year":"2016","journal-title":"Stroke"},{"key":"B39","doi-asserted-by":"publisher","first-page":"100505","DOI":"10.1016\/j.asw.2020.100505","article-title":"Investigating minimum text lengths for lexical diversity indices","volume":"47","author":"Zenker","year":"2021","journal-title":"Assess. Writ."}],"container-title":["Frontiers in Robotics and AI"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/frobt.2026.1758391\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,3,26]],"date-time":"2026-03-26T10:09:53Z","timestamp":1774519793000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/frobt.2026.1758391\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,3,26]]},"references-count":37,"alternative-id":["10.3389\/frobt.2026.1758391"],"URL":"https:\/\/doi.org\/10.3389\/frobt.2026.1758391","relation":{},"ISSN":["2296-9144"],"issn-type":[{"value":"2296-9144","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,3,26]]},"article-number":"1758391"}}