tACS for Aphasia After Stroke

Overseen By Sidney Schoenrock, MA

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Medical College of Wisconsin

Disqualifiers: Severe cognitive, psychiatric, cardiac, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 2

Duration: 2-3 weeks

50 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial examines how transcranial alternating current stimulation (tACS) might aid in recovering language skills after a stroke. tACS uses gentle electrical currents to stimulate the brain, and the study will test two frequencies, 10-Hz and 40-Hz, to determine which is most effective. Individuals who have experienced a stroke and face language problems, known as aphasia, may qualify, particularly if they are fluent in English and have no major untreated health issues. As an unphased trial, this study provides a unique opportunity to contribute to scientific understanding and potentially benefit from an innovative treatment.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications. It is best to discuss this with the trial coordinators or your doctor.

What prior data suggests that this method is safe for language recovery after stroke?

Research has shown that transcranial alternating current stimulation (tACS) can aid recovery after a stroke. One study found that tACS improved movement, speech, and attention. Although specific safety details for tACS in humans are not provided, similar non-invasive brain stimulation methods have demonstrated safety. Studies on tACS report no major safety issues or side effects, indicating it is generally well-tolerated. Researchers are investigating both 10-Hz and 40-Hz versions of tACS. The trial phase is "Not Applicable," suggesting it is in the early stages. While safety is still under study, early results from similar research are promising. Always consult a healthcare provider for personal advice. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about tACS for aphasia after stroke because it offers a non-invasive and targeted approach to brain stimulation. Unlike traditional speech therapy, which focuses on language exercises, tACS uses electrical currents to directly stimulate brain areas involved in language processing. This innovative method can be precisely localized, potentially enhancing specific brain functions related to speech and language. By adjusting the frequency of the stimulation, tACS may optimize brain activity and improve language recovery, offering hope for faster and more effective results compared to conventional therapies.

What evidence suggests that tACS is effective for language recovery after stroke?

This trial will compare different frequencies of transcranial alternating current stimulation (tACS) to help people regain language skills after a stroke. Studies have shown that 10-Hz tACS, one of the frequencies tested in this trial, might improve language abilities, but more evidence is needed to confirm its benefits. Meanwhile, 40-Hz tACS, another frequency under study, has been associated with better overall recovery, including language skills. Both types of tACS aim to restore brain activity related to language. While early results are promising, further research will clarify its full potential for helping people with aphasia (language difficulties) after a stroke. ^{2 4 6 7 8}

Who Is on the Research Team?

Priyanka Shah-Basak, PhD

Principal Investigator

Medical College of Wisconsin

Are You a Good Fit for This Trial?

This trial is for adults who have had a stroke and are experiencing language difficulties (aphasia), as well as healthy adults without neurological issues. Participants must be fluent in English, at least 18 years old, and right-handed if they've had a stroke. They can't join if they have severe sensory impairments, untreated psychiatric diseases, unstable medical conditions, metal implants in the skull, or history of seizures or dyslexia.

Inclusion Criteria

I am fluent in English.

Healthy Controls: Fluent in English

I have never had a neurological or psychiatric disorder.

Exclusion Criteria

I have a history of seizures.

You have conditions that make it unsafe for you to have an MRI or tACS.

You have a serious untreated or unstable mental health condition.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

1-2 weeks

1 visit (in-person)

Treatment

Participants undergo HD-tACS at 10 Hz or 40 Hz, or sham-tACS, combined with language tasks and EEG monitoring

2-3 weeks

Multiple visits (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment

1 week

1 visit (in-person)

What Are the Treatments Tested in This Trial?

Interventions

• tACS 10-Hz
• tACS 40-Hz
• tACS sham

Trial Overview

The study is testing three types of transcranial alternating current stimulation (tACS): one with a frequency of 10-Hz, another with 40-Hz, and a sham (placebo) treatment to see how they affect language recovery after stroke and general language functions.

How Is the Trial Designed?

Group I: tACS 10 Hz low frequency Experimental Treatment 1 Intervention

All participants in a within-subject design will receive high-Definition-tACS, delivered via a battery operated alternating current stimulator (Soterix) using two 3x1 center-surround montages. Targets of stimulation will be localized based on the 10-10 International EEG system with center electrodes placed at a frontal and a temporoparietal site. The current is turned on and increased in a ramplike fashion over approximately 30 seconds. Participants will undergo tACS with frequencies ranging from 4-40Hz for 20-minutes with 2 milliampere (mA) peak-to-peak intensity. For sham stimulation, tACS is turned off after the first 30 seconds.

Who Is Running the Clinical Trial?

Medical College of Wisconsin

Lead Sponsor

Trials

645

Recruited

1,180,000+

Published Research Related to This Trial

In a study of 37 stroke patients, speech therapy combined with transcranial direct current stimulation (tDCS) significantly improved language function, with an average increase in aphasia quotient (AQ%) of 14.94% after treatment.

Patients with less severe, fluent types of aphasia who started treatment within 30 days of their stroke showed the best responses, and those with hemorrhagic strokes had a higher likelihood of improvement compared to those with infarctions.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The Factors Associated with Good Responses to Speech Therapy Combined with Transcranial Direct Current Stimulation in Post-stroke Aphasic Patients. Jung, IY., Lim, JY., Kang, EK., et al.[2021]

Low-frequency repetitive transcranial magnetic stimulation (LF-rTMS) combined with speech and language therapy (SLT) significantly improves language abilities in patients with poststroke aphasia, as shown in a meta-analysis of 18 studies involving 536 participants.

The treatment is safe, with no reported adverse events, and the most effective LF-rTMS protocol was found to be 20 minutes per session at 90% of the resting motor threshold, administered 5 days a week for 2 weeks.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Low-Frequency Repetitive Transcranial Magnetic Stimulation in Patients With Poststroke Aphasia: Systematic Review and Meta-Analysis of Its Effect Upon Communication. Yao, L., Zhao, H., Shen, C., et al.[2021]

A systematic review of 25 studies involving 471 participants found that Transcranial Direct Current Stimulation (tDCS) did not improve overall functional communication in stroke patients, indicating limited efficacy for this primary outcome.

However, anodal tDCS, especially when applied over the left inferior frontal gyrus, showed a significant improvement in noun naming performance, suggesting it may be a promising targeted treatment for specific language deficits after stroke.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Transcranial direct current stimulation (tDCS) for improving aphasia after stroke: a systematic review with network meta-analysis of randomized controlled trials. Elsner, B., Kugler, J., Mehrholz, J.[2020]

Transcranial direct current stimulation (tDCS) shows promise as an adjunct treatment for improving speech-language deficits in patients with chronic post-stroke aphasia and primary progressive aphasia, by enhancing cortical excitability in language areas.

Current research emphasizes the need for more studies to connect improvements in neuropsychological test performance with real-world functional communication outcomes, as most existing studies focus on impairment rather than practical communication skills.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Transcranial direct current stimulation in post stroke aphasia and primary progressive aphasia: Current knowledge and future clinical applications. Sebastian, R., Tsapkini, K., Tippett, DC.[2019]

A systematic review of 21 trials involving 421 participants found no evidence that transcranial direct current stimulation (tDCS) improves functional communication in people with aphasia after stroke, indicating low effectiveness for this purpose.

However, there is moderate evidence that tDCS may enhance noun naming accuracy, suggesting it could have some benefits in specific language tasks, although it did not show similar effects for verb naming.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Transcranial direct current stimulation (tDCS) for improving aphasia in adults with aphasia after stroke. Elsner, B., Kugler, J., Pohl, M., et al.[2023]

Low-frequency transcranial magnetic stimulation (LF-rTMS) is the most effective non-invasive brain stimulation method for reducing global severity of post-stroke aphasia, based on a meta-analysis of 69 randomized controlled trials involving 1670 patients.

For specific language tasks, dual-transcranial direct-current stimulation (dual-tDCS) is superior for improving naming and repetition, while both anodal-tDCS and dual-tDCS are more effective than LF-rTMS for enhancing spontaneous speech.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Comparative efficacy of non-invasive brain stimulation for post-stroke aphasia: A network meta-analysis and meta-regression of moderators. Ding, X., Zhang, S., Huang, W., et al.[2022]

Cathodal transcranial direct current stimulation (tDCS) applied to the right inferior frontal gyrus significantly improved picture naming speed in 24 healthy subjects, suggesting a potential enhancement in language function.

The improvement in naming speed was linked to increased anatomical connectivity between the right Broca's area and the supplementary motor area, indicating that the effects of tDCS may depend on the brain's structural and functional connections.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Connectivity between right inferior frontal gyrus and supplementary motor area predicts after-effects of right frontal cathodal tDCS on picture naming speed. Rosso, C., Valabregue, R., Arbizu, C., et al.[2016]

Transcranial direct-current stimulation (tDCS) significantly improved articulatory accuracy in patients with aphasia after stroke, indicating its potential effectiveness in enhancing speech production.

While tDCS showed qualitative improvements in naming and syllable repetition tasks, these results were not statistically significant, suggesting that further research is needed to fully understand its impact.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effect of Anodal tDCS on Articulatory Accuracy, Word Production, and Syllable Repetition in Subjects with Aphasia: A Crossover, Double-Blinded, Sham-Controlled Trial. Vila-Nova, C., Lucena, PH., Lucena, R., et al.[2021]

Transcranial direct current stimulation (tDCS) combined with language training showed improved verb production in a 43-year-old male with fluent-anomic aphasia after a stroke, suggesting enhanced language recovery.

The study indicates that using tDCS over Broca's area during language therapy may effectively support brain plasticity and improve language skills in individuals with aphasia.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Translational treatment of aphasia combining neuromodulation and behavioral intervention for lexical retrieval: implications from a single case study. Galletta, EE., Vogel-Eyny, A.[2020]

Citations

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Previous studies have provided evidence supporting the efficacy of low-frequency rTMS in improving language outcomes in post-stroke aphasia.

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Overall, theta tACS has significant potential for treating aphasia after stroke, although further research is needed to convict its efficacy.

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One study reported the efficacy of tACS on aphasia recovery (24), whereas one study evaluated the effect of tACS on hemispatial neglect (25). A ...

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tACS for Aphasia After Stroke

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clinicaltrials.gov/study/NCT04375722

Transcranial Alternating Current Stimulation (tACS) in ...

The current study will investigate the efficacy of high-definition tACS (HD-tACS) to help restore neural oscillatory activity in aphasia. TACS differs from ...

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pmc.ncbi.nlm.nih.gov/articles/PMC10805992/

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Our findings suggest that tACS improves functional recovery in patients with stroke. The application of tACS was associated with improved overall functional ...

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frontiersin.org

frontiersin.org/journals/neurology/articles/10.3389/fneur.2025.1614586/full

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This study shows that rTMS can safely and effectively improve speech function in patients with post-stroke aphasia (PSA), particularly in auditory comprehension ...

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neurology.org

neurology.org/doi/abs/10.1212/WNL.0000000000212378

Tuning the Brain for Language: Exploring tACS as a ...

This ongoing study is investigating if tACS delivered in the alpha frequency band improves word retrieval abilities in healthy older adults.