Evidence map›Paper›PMID 41899903›Full record

ArticleBioengineering (Basel, Switzerland)2026

Transcranial Alternating Current Stimulation as an Adjuvant for Nonfluent Aphasia: A Proof-of-Concept Study.

Lynsey M Keator, Lisa Johnson, Roger Newman-Norlund, Kyler Spell, Samaneh Nemati, Leigh Ann Spell, Dirk B den Ouden, Christopher Rorden, Julius Fridriksson

Abstract read
In one paragraph

Article in Bioengineering (Basel, Switzerland), 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 4 papers.

0numbers the graph read from it
0cells of the map it votes in
4citing 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.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

4 citing papers in PubMed.

  1. Review
  2. Article
  3. Review
  4. Reversing the Ruin: Rehabilitation, Recovery, and Restoration After Stroke.Current neurology and neuroscience reports · 2022
    Review
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

9 authors.

Lynsey M KeatorDepartment of Speech-Language Pathology, College of Rehabilitation Sciences, Thomas Jefferson University, 130 South 9th Street, Philadelphia, PA 19107, USA.ORCID 0000-0002-9064-6950
Lisa JohnsonDepartment of Communication Sciences and Disorders, University of South Carolina, 915 Green Street, Columbia, SC 29201, USA.
Roger Newman-NorlundDepartment of Psychology, University of South Carolina, 915 Green Street, Columbia, SC 29201, USA.
Kyler SpellDepartment of Communication Sciences and Disorders, University of South Carolina, 915 Green Street, Columbia, SC 29201, USA.
Samaneh NematiDepartment of Communication Sciences and Disorders, University of South Carolina, 915 Green Street, Columbia, SC 29201, USA.
Leigh Ann SpellSpeech-Language Pathology Program, School of Health Sciences, Columbia College, 1301 Columbia College Drive, Columbia, SC 29203, USA.
Dirk B den OudenCommunication Sciences and Disorders, Crean College of Health and Behavioral Sciences, Chapman University, 9401 Jeronimo Road, Irvine, CA 92618, USA.ORCID 0000-0001-6971-7606
Christopher RordenDepartment of Psychology, University of South Carolina, 915 Green Street, Columbia, SC 29201, USA.
Julius FridrikssonDepartment of Communication Sciences and Disorders, University of South Carolina, 915 Green Street, Columbia, SC 29201, USA.

Funding

Telerehab for Aphasia (TERRA)P50DC014664 · NIDCD · UNIVERSITY OF SOUTH CAROLINA AT COLUMBIA · PI HICKOK, GREGORY · 2016 to 2025
$25.0M
American Speech-Language-Hearing Foundation New Century Scholars Doctoral Scholarship ($10,000)Council of Academic Programs in Communication Sciences and Disorders Ph.D. Scholarship ($20,000)NIDCD NIH HHS P50 DC014664University of South Carolina Vice President of Research Graduate School SPARC Award ($5,000)
6 · The paper itself

Abstract

Effective rehabilitation tools are essential for improving language outcomes in chronic aphasia. Speech entrainment is a behavioral treatment that has shown promise in enhancing speech output in nonfluent aphasia, potentially by acting as an external mechanism to synchronize anterior and posterior language regions in the left hemisphere. Transcranial alternating current stimulation has been hypothesized to enhance functional connectivity between brain regions by amplifying endogenous oscillations. This proof-of-concept study explored whether high-definition tACS (HD-tACS) could improve speech fluency in nonfluent aphasia when paired with speech entrainment. In a double-blind, pseudorandomized study, 1 mA of HD-tACS at 7 Hz was applied to anterior and posterior left-hemisphere regions of individuals with nonfluent aphasia (N = 13). Stimulation was applied under three conditions: in-phase, anti-phase, and sham, and paired speech entrainment. Three outcome measures were examined: (1) number of words produced; (2) number of errors, and (3) 'entrainment' to the speech entrainment model. Group-level analyses for two of the three outcome measures reveal statistically significant differences between the experimental conditions. In-phase alternating current stimulation yielded more words and better entrainment to the audiovisual model than the sham condition. This study provides promising evidence that HD-tACS could improve speech production in individuals with nonfluent aphasia. These results contribute to growing evidence supporting the therapeutic potential of non-invasive brain stimulation approaches as an adjuvant to traditional behavioral speech-language therapy in stroke survivors.

Indexed as

nonfluent aphasianoninvasive brain stimulationspeech-language therapytranscranial alternating current stimulation (tACS)

Identifiers

PMID41899903
PMCPMC13023654

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Registered trials

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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.