Same Brain, Different Prediction: How Preprocessing Choices Undermine EEG Decoding Reliability

Fuente: arXiv
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Main Authors: Hou, Dengzhe, Wu, Zihao, Jiang, Lingyu, Li, Zirui, Lin, Fangzhou, Yamada, Kazunori D.
Format: Preprint
Published: 2026
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author Hou, Dengzhe
Wu, Zihao
Jiang, Lingyu
Li, Zirui
Lin, Fangzhou
Yamada, Kazunori D.
author_facet Hou, Dengzhe
Wu, Zihao
Jiang, Lingyu
Li, Zirui
Lin, Fangzhou
Yamada, Kazunori D.
contents Electroencephalography (EEG) is a cornerstone of brain-computer interfaces and clinical neuroscience, yet deep learning models are typically trained and evaluated under a single, unreported preprocessing pipeline. We formalize preprocessing choices as a counterfactual intervention space and show that EEG predictions are surprisingly unstable under this space: across six datasets spanning four paradigms, up to 42% of trial-level predictions flip when only the preprocessing changes, a variability that standard uncertainty methods do not explicitly quantify because they condition on a fixed preprocessing pipeline. We provide three tools to make this instability measurable, decomposable, and reducible. First, a Walsh-Hadamard decomposition of the 2^7 pipeline space reveals that sensitivity is near-additive in practice under the binary intervention design, enabling efficient step-by-step optimization. Second, we introduce Preprocessing Uncertainty (PU), a per-trial diagnostic that captures a dimension of instability complementary to model-based confidence. Third, we study Normalized Adaptive PGI (NA-PGI), a graph-structured regularizer that exploits the compositional structure of preprocessing interventions as one mitigation strategy with clear scope conditions.
format Preprint
id arxiv_https___arxiv_org_abs_2605_07212
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Same Brain, Different Prediction: How Preprocessing Choices Undermine EEG Decoding Reliability
Hou, Dengzhe
Wu, Zihao
Jiang, Lingyu
Li, Zirui
Lin, Fangzhou
Yamada, Kazunori D.
Machine Learning
Artificial Intelligence
Human-Computer Interaction
Neural and Evolutionary Computing
Signal Processing
Electroencephalography (EEG) is a cornerstone of brain-computer interfaces and clinical neuroscience, yet deep learning models are typically trained and evaluated under a single, unreported preprocessing pipeline. We formalize preprocessing choices as a counterfactual intervention space and show that EEG predictions are surprisingly unstable under this space: across six datasets spanning four paradigms, up to 42% of trial-level predictions flip when only the preprocessing changes, a variability that standard uncertainty methods do not explicitly quantify because they condition on a fixed preprocessing pipeline. We provide three tools to make this instability measurable, decomposable, and reducible. First, a Walsh-Hadamard decomposition of the 2^7 pipeline space reveals that sensitivity is near-additive in practice under the binary intervention design, enabling efficient step-by-step optimization. Second, we introduce Preprocessing Uncertainty (PU), a per-trial diagnostic that captures a dimension of instability complementary to model-based confidence. Third, we study Normalized Adaptive PGI (NA-PGI), a graph-structured regularizer that exploits the compositional structure of preprocessing interventions as one mitigation strategy with clear scope conditions.
title Same Brain, Different Prediction: How Preprocessing Choices Undermine EEG Decoding Reliability
topic Machine Learning
Artificial Intelligence
Human-Computer Interaction
Neural and Evolutionary Computing
Signal Processing
url https://arxiv.org/abs/2605.07212