MEGConformer: Conformer-Based MEG Decoder for Robust Speech and Phoneme Classification

Fuente: arXiv
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Main Authors: de Zuazo, Xabier, Saratxaga, Ibon, Navas, Eva
Format: Preprint
Published: 2025
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_version_ 1866918329890897920
author de Zuazo, Xabier
Saratxaga, Ibon
Navas, Eva
author_facet de Zuazo, Xabier
Saratxaga, Ibon
Navas, Eva
contents Decoding speech-related information from non-invasive MEG is a key step toward scalable brain-computer interfaces. We present compact Conformer-based decoders on the LibriBrain 2025 PNPL benchmark for two core tasks: Speech Detection and Phoneme Classification. Our approach adapts a compact Conformer to raw 306-channel MEG signals, with a lightweight convolutional projection layer and task-specific heads. For Speech Detection, a MEG-oriented SpecAugment provided a first exploration of MEG-specific augmentation. For Phoneme Classification, we used inverse-square-root class weighting and a dynamic grouping loader to handle 100-sample averaged examples. In addition, a simple instance-level normalization proved critical to mitigate distribution shifts on the holdout split. Using the official Standard track splits and F1-macro for model selection, our best systems achieved 88.9% (Speech) and 65.8% (Phoneme) on the leaderboard, winning the Phoneme Classification Standard track. For further implementation details, the technical documentation, source code, and checkpoints are available at https://github.com/neural2speech/libribrain-experiments.
format Preprint
id arxiv_https___arxiv_org_abs_2512_01443
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle MEGConformer: Conformer-Based MEG Decoder for Robust Speech and Phoneme Classification
de Zuazo, Xabier
Saratxaga, Ibon
Navas, Eva
Computation and Language
Machine Learning
Neural and Evolutionary Computing
Sound
68T07 (Primary), 92C55, 62H30 (Secondary)
I.2.6; I.5.1; J.3
Decoding speech-related information from non-invasive MEG is a key step toward scalable brain-computer interfaces. We present compact Conformer-based decoders on the LibriBrain 2025 PNPL benchmark for two core tasks: Speech Detection and Phoneme Classification. Our approach adapts a compact Conformer to raw 306-channel MEG signals, with a lightweight convolutional projection layer and task-specific heads. For Speech Detection, a MEG-oriented SpecAugment provided a first exploration of MEG-specific augmentation. For Phoneme Classification, we used inverse-square-root class weighting and a dynamic grouping loader to handle 100-sample averaged examples. In addition, a simple instance-level normalization proved critical to mitigate distribution shifts on the holdout split. Using the official Standard track splits and F1-macro for model selection, our best systems achieved 88.9% (Speech) and 65.8% (Phoneme) on the leaderboard, winning the Phoneme Classification Standard track. For further implementation details, the technical documentation, source code, and checkpoints are available at https://github.com/neural2speech/libribrain-experiments.
title MEGConformer: Conformer-Based MEG Decoder for Robust Speech and Phoneme Classification
topic Computation and Language
Machine Learning
Neural and Evolutionary Computing
Sound
68T07 (Primary), 92C55, 62H30 (Secondary)
I.2.6; I.5.1; J.3
url https://arxiv.org/abs/2512.01443