Evidence map›Paper›PMID 41928799›Full record

ArticleResearch square2026

Stable speech BCI performance during slow progression of ALS: A longitudinal ECoG study.

Ziwei Ouyang, Kalan Walmsley, Shiyu Luo, Donna Tippett, Kimberley Wyse-Sookoo, Matthew Fifer, Mariska J Vansteensel, Miguel Angrick, Nick Ramsey, Nathan E Crone

Registry-linked trialAbstract readPreprint
In one paragraph

Article in Research square, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT03567213 (Investigation on the Cortical Communication), which is not on this map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

NCT03567213 narecruitingnot on this map

Investigation on the Cortical Communication (CortiCom) System

TypeinterventionalSponsorJohns Hopkins UniversityRan2021 to 2030Enrolled3ConditionsTetraplegia, Locked-in Syndrome, Brainstem Stroke, Amyotrophic Lateral SclerosisArmsSurgical implantation of CortiCom system
3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

10 authors.

Ziwei OuyangJohns Hopkins University.
Kalan WalmsleyÉcole Polytechnique Fédérale de Lausanne.
Shiyu LuoJohns Hopkins University.
Donna TippettJohns Hopkins University School of Medicine.
Kimberley Wyse-SookooJohns Hopkins University.
Matthew FiferJohns Hopkins University Applied Physics Laboratory.
Mariska J VansteenselUniversity Medical Center Utrecht.
Miguel AngrickJohns Hopkins University School of Medicine.
Nick RamseyUniversity Medical Center Utrecht.
Nathan E CroneJohns Hopkins University School of Medicine.

Funding

Investigation of the Cortical Communication (CORTICOM) SystemUH3NS114439 · NINDS · JOHNS HOPKINS UNIVERSITY · PI CRONE, NATHAN E, RAMSEY, NICOLAS FRANCISCUS · 2020 to 2025
$6.6M
NINDS NIH HHS UH3 NS114439
6 · The paper itself

Abstract

Background: Electrocorticographic (ECoG) speech brain-computer interfaces (BCIs) show promise for restoring communication in amyotrophic lateral sclerosis (ALS), but the long-term stability of speech-related neural signals and decoding performance during disease progression remains unclear. We tracked signal characteristics and decoding over 25 months in a participant with ALS to determine how high-gamma (HG, 70-170 Hz) activity changes over time and whether these changes affect offline speech decoding. Methods: We implanted two 8×8 subdural ECoG grids over left sensorimotor cortex (SMC) in a participant with slowly progressive bulbar variant ALS. Across 25 months, the participant performed an overt syllable-repetition task (12 consonant-vowel tokens) during simultaneous ECoG and audio recording. We quantified HG activation ratio (ActR), spectral signal-to-noise ratio (SNR; HG/HF, where HF = 300-499 Hz), and peak z-scored HG responses. Speech acoustics were evaluated using first/second formants (F1/F2) and the triangular vowel space area (tVSA). Offline EEGNet-based decoders were assessed in two stages: models trained on post-implant months 1-6 were tested on months 7-25, while models trained on stabilized data (months 7-11) were tested on the remaining period (months 12-25). Electrode-level saliency assessed spatial contributions to decoding. Results: Acoustic analyses showed a significant reduction in tVSA over two years (-44.6 Hz Conclusions: Speech-related HG features exhibited an initial unstable period followed by a long-term gradual SNR reduction, potentially reflecting disease progression. Models trained after signal stabilization generalized robustly to data recorded over a year later. These findings confirm that despite reduced absolute HG power and mild acoustic degradation of speech, cortical features remain stable enough to support durable ECoG speech BCIs without frequent recalibration. These findings will motivate future adaptive calibration algorithms that account for slow signal changes while leveraging stable spatial representations in ventral SMC. ClinicalTrialsgov Identifier: NCT03567213.

Identifiers

PMID41928799
PMCPMC13042181

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Registered trials

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.