From Exposure to Internalization: Dual-Stream Calibration for In-context Clinical Reasoning
Authors: Chuang Zhao, Hongke Zhao, Xiaofang Zhou, Xiaomeng Li
Organizations: Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Hong Kong, SAR, China · College of Management and Economics, Laboratory of Computation and Analytics of Complex Management Systems (CACMS), Tianjin University, Tianjin 30072, China · Department of Computer Science and Engineering, The Hong Kong University of Science and Technology, Hong Kong, SAR, China
Contextual clinical reasoning demands robust inference grounded in complex, heterogeneous clinical records. While state-of-the-art fine-tuning, in-context learning (ICL), and retrieval-augmented generation (RAG) enable knowledge exposure, they often fall short of genuine contextual internalization: dynamically adjusting a model's internal representations to the subtle nuances of individual cases at inference time. To address this, we propose Dual-Stream Calibration (DSC), a test-time training framework that transcends superficial knowledge exposure to achieve deep internalization during inference. DSC facilitates input internalization by synergistically aligning two calibration streams. Unlike passive context exposure, the Semantic Calibration Stream enforces a deliberative reflection on core evidence, internalizing semantic anchors by minimizing entropy to stabilize generative trajectories. Simultaneously, the Structural Calibration Stream assimilates latent inferential dependencies through an iterative meta-learning objective. By training on specialized support sets at test-time, this stream enables the model to bridge the gap between external evidence and internal logic, synthesizing fragmented data into a coherent response. Our approach shifts the reasoning paradigm from passive attention-based matching to an active refinement of the latent inferential space. Validated against thirteen clinical datasets, DSC demonstrates superiority across three distinct task paradigms, consistently outstripping state-of-the-art baselines ranging from training-dependent models to test-time learning frameworks.
Figures & tables
Fig. 1: Motivations. Fig. 1(a) presents the ROUGE-L scores of various models evaluated on auxiliary QA pairs per sample. These QA pairs are generated from the eLife dataset’s context using DeepSeek-V3 [ 6 ] and subsequently provided as input for model evaluation. Qwen [ 7 ] and Lingshu [ 8 ] denote different LLM backbones. Fig. 1(b) depicts the predictive entropy fluctuations during the generative process. Fig. 1(c) evaluates model resilience (ROUGE-L) to contextual order on the eLife dataset, where the order of in-context demonstrations is randomly perturbed.
Fig. 2: Key difference between ICL, RAG, TTL-based baselines, and the proposed DSC. Our core innovation introduces a dual-calibration framework that enforces semantic understanding and structure robustness, transforming passive information retrieval into active contextual internalization.
Fig. 3: Overview of our DSC framework. The overall architecture of DSC is presented in (a), which outlines the comprehensive test-time training pipeline, while (b) provides a granular decomposition of our core dual-stream mechanism. DSC leverages two parallel streams to simultaneously refine the input from both semantic and structural dimensions. The Semantic Calibration Stream implements dynamic entropy detection and elimination. This process first localizes high-uncertainty tokens via long-short window entropy analysis and subsequently optimizes the model using dual objectives: an entropy loss to resolve ambiguity and a high-fidelity loss to preserve critical information, resulting in a semantically certain input representation. The Structure Calibration Stream runs in parallel to reconstruct the vital inferential links bridging the context and the clinical query. It employs an iterative, alternating framework where specialized support sets and meta-queries are dynamically synthesized for meta-optimization. Finally, (c) illustrates the test-time inference phase, where the model executes the final predictions using the parameters optimized specifically for the given query. θ∗ denotes the LLM parameters integrated with δ .
Methods
MedQA
PubMedQA
MedMCQA
MedBullets
MMLU
MMLU-Pro
MedExQA
Qwen2.5-7B [ 7 ]
0.160
0.160
0.240
0.045
0.127
0.260
0.090
Deepseek-R1-7B [ 6 ]
0.180
0.230
0.260
0.134
0.260
0.100
0.210
Lingshu-7B [ 8 ]
0.190
0.170
0.260
0.157
0.273
0.210
0.210
SFT [ 9 ]
0.210
0.180
0.080
0.184
0.260
0.180
0.160
GRPO [ 11 ]
0.230
0.240
0.230
0.134
0.150
0.180
0.180
ICL [ 17 ]
0.230
0.190
0.200
0.168
0.219
0.250
0.150
TABLE II: Performance comparison: Examination QA (HARD VERSION [ 33 ] ). The pipeline integrates Qwen2.5-7B [ 7 ] (LLM backbone), with further variations explored in Section V-B .
Methods
Cochrane
eLife
PLOS
Metrics
ROUGE-1
ROUGE-L
SARI
ROUGE-1
ROUGE-L
SARI
ROUGE-1
ROUGE-L
SARI
Qwen2.5-7B [ 7 ]
0.397
0.372
0.384
0.350
0.322
0.433
0.370
0.348
0.394
Deepseek-R1-7B [ 6 ]
0.400
0.369
0.383
0.368
0.349
0.437
0.410
0.372
0.367
Lingshu-7B [ 8 ]
0.385
0.357
0.383
0.312
0.291
0.428
0.357
0.329
0.384
SFT [ 9 ]
0.435
0.400
0.382
0.423
0.409
0.405
0.415
0.371
0.396
GRPO [ 11 ]
0.410
0.380
0.389
0.405
0.382
0.443
0.409
0.387
0.397
TABLE III: Performance comparison: Lay Summarization. In this task, we follow [ 24 ] .
TABLE V: Ablation Study. -NC ablates the retrieved context C ; -NSW/-NLW ablate the short/long entropy windows detection using fixed threshold, respectively; -NR ablates the Lrcf regularization term; -NS ablates the entire Semantic Calibration Stream; and -NST ablates the Structure Calibration Stream.
Fig. 4: Comparison under diverse retrievers. We employ the popular BMRETRIEVER [ 64 ] , E5 [ 62 ] , and MedCPT [ 42 ] . We compare retrieval-dependent baselines, including ICL, i-MedRAG, and TTT.
Fig. 5: Comparison under diverse LLMs. We employ Qwen2.5-1.5B [ 7 ] , Lingshu-7B [ 8 ] , and Qwen3-14B [ 60 ] . We select ICL, SFT, i-MedRAG, and TTT as representative baselines. We additionally incorporate TAGS for MedQA and AgentSimp for eLife due to their competitive performance.
Fig. 6: Comparison under diverse uncertainty estimation. Following [ 43 ] , we employ Entropy, Perplexity, and Energy. TTL-based baselines are included.
Fig. 7: Online vs. Offline test-time optimization. Online methods tailor the model to each test query individually prior to inference, whereas offline methods conduct a one-time optimization on the entire test set before evaluating queries sequentially. TTL-based baselines are included.
Fig. 8: OOD examination. (a) cross-dataset scenario. (b) cross-task scenario. For both scenarios, we use one domain as the pre-training / Index domain and then directly assess performance on the test set of the other domain.
Methods
MATH Reasoning
Knowledge QA-ReClor
AMC-ACC ↑
LogiQA-ACC ↑
ACC ↑
ROUGE-L ↑
SARI ↑
Qwen25-7B [ 7 ]
0.450
0.443
0.234
0.269
0.482
Linshu-7B [ 9 ]
0.040
0.388
0.205
0.259
0.479
ICL [ 17 ]
0.520
0.451
0.248
0.270
0.485
SFT [ 9 ]
0.500
0.488
0.246
0.227
0.466
Ensemble [ 61 ]
0.440
0.484
0.214
0.156
0.405
TABLE VI: Other Scenarios.
Fig. 9: Time complexity. To demonstrate practicality and fairness, for Fig. 9(a) and 9(b) , we test the inference time for the eLife dataset on a machine equipped with one A800 GPU.
Fig. 10: Case studies. Fig. 10(a) identifies critical tokens as those belonging to U (red) and certain tokens as those with X∖U (blue). Fig. 10(b) illustrates the transition in predictive entropy during generation with and without entropy control. Fig. 10(c) displays the answering accuracy on auxiliary QA pairs (generated by DeepseekV3) derived from the context, comparing performance before and after the tuning process on eLife.
Fig. 11: Illustrative examples. The upper panel displays our response, while the lower panel shows the response generated by TTT. For visual clarity, we use placeholders for the questions and few-shot examples.
Fig. 12: Hyper-parameter tests. Here, we take eLife as an example.