MediSketch: Test-Time Scaling for Multimodal Patient Education

Zhipeng Tang, Benlu Wang, Zhenyu Zhang, Wuao Liu, Pengda Xiang, Juncheng Huang, Chin Siang Ong, Hong yu, Zonghai Yao


Abstract
Patient education is a major NLP application, but current evaluation largely focuses on text-only assistance. In radiology, this overlooks an important part of clinical communication: patients often need both a plain-language explanation and a visual aid showing where to look and what it refers to. We introduce MediSketch, a multimodal patient-education task in which an agent must produce an image–text bundle: an educational image and a grounded plain-language explanation. We instantiate this setting with a clinician-curated radiology testbed, a structured multimodal rubric, and a rubric-following judge that evaluates bundle quality rather than text-only correctness. Under a matched image-generation budget, we compare three test-time scaling strategies: parallel sampling, sequential revision, and hybrid search. Across five backbone models, the no-scaling baseline remains weak, while naive parallel search often provides little gain despite using the full budget. Hybrid performs best on 4 of 5 backbones, suggesting that test-time compute works best when exploration and revision are combined. Further analysis identifies weak multimodal self-critique as a major bottleneck: many models stop revising too early and overestimate the quality of their own image–text outputs. MediSketch exposes both an evaluation gap in multimodal patient education and a concrete failure mode in test-time scaling.
Anthology ID:
2026.findings-emnlp.2280
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
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SIGDAT
Publisher:
Association for Computational Linguistics
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Pages:
48808–48859
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URL:
https://aclanthology.org/2026.findings-emnlp.2280/
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Cite (ACL):
Zhipeng Tang, Benlu Wang, Zhenyu Zhang, Wuao Liu, Pengda Xiang, Juncheng Huang, Chin Siang Ong, Hong yu, and Zonghai Yao. 2026. MediSketch: Test-Time Scaling for Multimodal Patient Education. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 48808–48859, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
MediSketch: Test-Time Scaling for Multimodal Patient Education (Tang et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.2280.pdf