LightBeam: An Accurate and Memory-Efficient CTC Decoder for Speech Neuroprostheses

Fuente: arXiv
Enregistré dans:
Détails bibliographiques
Auteurs principaux: Feghhi, Ebrahim, Hu, Junlin, Hadidi, Nima, Kao, Jonathan C.
Format: Preprint
Publié: 2026
Sujets:
Accès en ligne:
Tags: Ajouter un tag
Pas de tags, Soyez le premier à ajouter un tag!
_version_ 1866912966221234176
author Feghhi, Ebrahim
Hu, Junlin
Hadidi, Nima
Kao, Jonathan C.
author_facet Feghhi, Ebrahim
Hu, Junlin
Hadidi, Nima
Kao, Jonathan C.
contents A promising pathway for restoring communication in patients with dysarthria and anarthria is speech neuroprostheses, which directly decode speech from cortical neural activity. Two benchmarks, Brain-to-Text '24 and '25, released intracranial recordings from patients with dysarthria along with a baseline algorithm trained with Connectionist Temporal Classification (CTC). Despite significant innovation on these benchmarks, all leading published prior work relies on a WFST-based CTC decoder that requires ${\sim}$320 GB of RAM. These memory requirements limit accessibility for both patients and researchers. Here, we propose LightBeam, a non-WFST based CTC decoder that requires only ${\sim}$10 GB of RAM and achieves state-of-the-art performance on both benchmarks. LightBeam achieves this by integrating an LLM into the beam-search process via delayed fusion, obviating the prior need for using a large N-gram LM. LightBeam is implemented in Python and is open-source.
format Preprint
id arxiv_https___arxiv_org_abs_2603_14002
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle LightBeam: An Accurate and Memory-Efficient CTC Decoder for Speech Neuroprostheses
Feghhi, Ebrahim
Hu, Junlin
Hadidi, Nima
Kao, Jonathan C.
Human-Computer Interaction
Sound
A promising pathway for restoring communication in patients with dysarthria and anarthria is speech neuroprostheses, which directly decode speech from cortical neural activity. Two benchmarks, Brain-to-Text '24 and '25, released intracranial recordings from patients with dysarthria along with a baseline algorithm trained with Connectionist Temporal Classification (CTC). Despite significant innovation on these benchmarks, all leading published prior work relies on a WFST-based CTC decoder that requires ${\sim}$320 GB of RAM. These memory requirements limit accessibility for both patients and researchers. Here, we propose LightBeam, a non-WFST based CTC decoder that requires only ${\sim}$10 GB of RAM and achieves state-of-the-art performance on both benchmarks. LightBeam achieves this by integrating an LLM into the beam-search process via delayed fusion, obviating the prior need for using a large N-gram LM. LightBeam is implemented in Python and is open-source.
title LightBeam: An Accurate and Memory-Efficient CTC Decoder for Speech Neuroprostheses
topic Human-Computer Interaction
Sound
url https://arxiv.org/abs/2603.14002