A3S@C-DAC at #SMM4H-HeaRD 2026: Reasoning Meets Evidence: LLMs for Interpretable Insomnia Detection with Evidence Extraction in Clinical Notes
Summary
A3S@C-DAC's systems for the SMM4H-HeaRD 2026 shared task address insomnia detection from clinical narratives, focusing on accurate classification and interpretable evidence extraction. The team utilized MIMIC-III notes, which were annotated with rule-based insomnia criteria and supporting evidence spans. Two primary approaches were explored: parameter-efficient fine-tuning (PEFT) of lightweight models using QLoRA and LoRA, and few-shot prompting of large language models (LLMs) for combined reasoning and evidence extraction. Their top-performing system achieved an F1-score of 0.7333 for binary classification and a micro-F1 of 0.6535 for multi-label rule prediction. Evidence extraction reached up to 0.5192 partial-match F1. The findings indicate that lightweight fine-tuned models excel in classification, while larger models demonstrate superior reasoning capabilities but struggle with precise evidence span localization, highlighting a critical need in clinically interpretable NLP.
Key takeaway
For NLP Engineers developing interpretable clinical systems, you should consider a hybrid approach. Fine-tune lightweight models using PEFT techniques like QLoRA or LoRA for robust classification, as they demonstrated superior performance (F1-score of 0.7333). Simultaneously, integrate larger language models for their stronger reasoning capabilities, but be prepared to address their current limitations in precise evidence span localization (up to 0.5192 partial-match F1). This strategy can balance classification accuracy with the need for clinically grounded, interpretable evidence.
Key insights
Lightweight fine-tuned models classify insomnia better, while LLMs reason stronger but struggle with precise evidence span localization.
Principles
- Interpretable clinical NLP requires both classification and evidence.
- PEFT can enable lightweight models to outperform larger LLMs.
- LLMs excel at reasoning but need better span localization.
Method
Systems used parameter-efficient fine-tuning (QLoRA, LoRA) on lightweight models and few-shot prompting of LLMs for joint reasoning and evidence extraction from MIMIC-III notes.
In practice
- Fine-tune lightweight models for classification tasks.
- Use LLMs for complex reasoning in clinical notes.
- Annotate clinical notes with rule-based criteria and evidence.
Topics
- Insomnia Detection
- Clinical NLP
- Large Language Models
- Parameter-Efficient Fine-Tuning
- Evidence Extraction
- MIMIC-III
Best for: AI Scientist, Research Scientist, NLP Engineer
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Editorial summary, takeaway, and curation by AIssential. Original article published by Paper Index on ACL Anthology.