arXiv:2608.21207cs.LGcs.AI2026-08

针对临床生理信号缺失设计分阶段修正的新型插补方法。

Curriculum-Aware Interpolate-then-Refine: Learned Physiological Time-Series Imputation under Realistic Missingness

  • 先粗插值再多轮精细化修正,模拟医生逐步调优过程。
  • 在真实缺失场景下,比现有方法误差低9%至19%。
  • 特别适合处理极端值附近或长间隔缺失,临床实用性强。

生理时间序列(如动脉血压、血糖)的插补对解决临床数据中普遍存在的缺失问题至关重要。然而,当前主流插补方法表现不佳:一项近期基准测试发现,简单线性插值在具有真实缺失模式的临床信号上优于所有学习型插补器。我们指出,这源于生理缺失的两个特性:缺失可能发生在信号处于临床极端而非典型状态时,且缺失长度可跨越数量级。为此,我们提出课程感知的“插值-修正”框架(CAIR),采用两阶段流程:先用双向GRU生成粗略基线曲线,再通过Transformer连续三轮修正以逼近生理合理性,整个过程在广泛、信号无关的随机缺失课程下联合训练。我们在按缺失长度与缺失机制(MCAR、MAR、NMAR)分层评估下进行测试,CAIR在连续血糖监测(AI-READI)和重症监护动脉压(MIMIC-III)数据集上对每种机制均表现最优。其相对于最强基线的提升随难度增加而扩大,从MCAR下的9%增至基于值依赖的缺失(value-dependent dropout)下的19%。此外,我们发现重建误差低并不等于临床价值高:误差与CAIR相当的插补器无法保持临床关注指标,而能恢复这些指标的模型精度远低于CAIR,唯独CAIR在误差与临床指标保留两方面均居前列。

原文摘要 · Abstract (English)

Imputing physiological time series (arterial blood pressure, blood glucose, etc.) is essential for addressing the missingness that pervades clinical data. Yet modern imputation methods perform poorly in this domain: a recent benchmark found that simple linear interpolation outperformed every learned imputer on real-world clinical signals with realistic gaps. We show that this reflects two properties of physiological missingness that generic imputers ignore: gaps may occur when the signal is clinically extreme rather than typical, and gap lengths can easily span orders of magnitude. To this end, we introduce Curriculum-Aware Interpolate-then-Refine (CAIR), a two-stage framework for physiological time-series imputation. Our key motivation is to learn a coarse base curve and then repeatedly correct it toward physiological realism, rather than predict a gap in a single pass. Consequently, CAIR couples a bidirectional-GRU interpolator with a Transformer refiner that corrects its own estimate over three successive passes, trained jointly under a broad, signal-agnostic random-gap curriculum. We evaluate imputers stratified by gap length and missingness mechanism (MCAR, MAR, NMAR) rather than by a single average, and CAIR is the most accurate under every mechanism on continuous glucose monitoring (AI-READI) and arterial pressure in intensive care (MIMIC-III). Its margin over the strongest baseline grows with difficulty, from 9% under MCAR to 19% under value-dependent dropout, where generic learned imputers are weakest. We further show low reconstruction error alone does not recover the burden metrics clinicians act on: interpolants matching CAIR's error fail to preserve those metrics, imputers that recover them are far less accurate, and CAIR alone ranks among the best on both axes.

时间序列插补临床数据生理信号多阶段修正

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