StrokeNCT06048159
Transcranial Alternating Current Stimulation (tACS) for the Recovery of Phonological Short-Term Memory in Patients With Aphasia After Stroke
A study testing HD-tACS in people with Stroke and Aphasia, run by Medical College of Wisconsin at 1 site in United States.
Trial summary
This study will assess the effects of transcranial alternating current stimulation (tACS) on language recovery after stroke. Read more about this study
- Who is it for?
- Ages 18 years and older
- What is being tested?
- HD-tACS
- Type of treatment
- Medical device
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 120 participants
- Where
- 1 siteUnited States
- Study dates
- 6 Nov 2023to Jan 2033
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Diagnosed with left hemisphere stroke/aphasia
- Consent date >= 1 month after stroke onset
- Fluent in English
- 18 years of age or older
Who cannot join
- Severe cognitive, auditory or visual impairments that would preclude cognitive and language testing
- Presence of major untreated or unstable psychiatric disease
- A chronic medical condition that is not treated or is unstable
- The presence of cardiac stimulators or pacemakers
- Contraindications to MRI or tACS, e.g. patients with metallic implants, and/or history of skull fractures, pregnancy, skin diseases
- History of ongoing or unmanaged seizures
- History of dyslexia or other developmental learning disabilities
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Medical College of Wisconsin
Milwaukee, Wisconsin, 53226
Sidney E Schoenrock, MA, 414-955-7579, sschoenrock@mcw.edu
Priyanka Shah-Basak, PhD, 414-955-5752, prishah@mcw.edu
About this study
Official title: TACS for the Recovery of Phonological STM After Stroke
This study will assess the effects of transcranial alternating current stimulation (tACS) on language recovery after stroke.
Read the detailed description
Aphasia is a debilitating disorder, typically resulting from damage to the left hemisphere, that can impair a range of communication abilities, including language production and comprehension, reading, and writing. Approximately 180,000 new cases of aphasia are identified per year, and approximately 1 million or 1 in 250 are living with aphasia in the United States. Treatments are limited and provide modest benefits at best. The current emphasis in aphasia rehabilitation is to formulate intensive speech and language therapies and augment therapeutic benefits, potentially with brain stimulation concurrent with therapies.
The current study will investigate the efficacy of high-definition tACS (HD-tACS) to help restore neural oscillatory activity in stroke survivors with aphasia. TACS differs from trancranial direct current stimulation (tDCS), a widely used brain stimulation paradigm, in that sinusoidal or alternating currents are delivered rather than direct currents. TACS is shown to manipulate ongoing oscillatory brain activity and also to modulate synchronization (or connectivity) between targeted brain areas. This feature of tACS is quite attractive, given the new body of evidence suggesting that language impairments stem from diminished brain connectivity and ensuing disruptions in the language network due to stroke.
The study will employ high-definition tACS (HD-tACS) in a parallel, double-blinded, sham-controlled design combined with language therapy targeting phonological short-term memory (STM) function in stroke survivors with aphasia. Magnetoencephalography (MEG) and fMRI BOLD data collection will occur to determine tACS parameters and to evaluate stimulation-induced neural changes, respectively. The investigators plan to recruit 120 stroke survivors with aphasia in a 2-group tACS study design.
- Being tested
- HD-tACS, Sham HD-tACS
- Medical subject headings
- Stroke, Aphasia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
HD-tACSDevice
High definition tACS will be applied during speech therapy.
Sham HD-tACSDevice
Sham high definition tACS will be applied during speech therapy.
| Study group | Role | What they receive |
|---|---|---|
| High Definition tACS with Short-term Memory Focused Speech Therapy | Experimental | High-Definition-tACS will be delivered via a battery operated alternating current stimulator (Soterix) using two 3x1 center-surround montages.The current is turned on and increased in a ramplike fashion over approximately 30 seconds. Participants will undergo tACS stimulation for 20-minutes with 2 milliampere (mA) peak-to-peak intensity. Stimulation will be maintained no longer than 20 minutes. This will be paired with short-term memory focused speech therapy. Receives: Device: HD-tACS |
| Sham-High Definition tACS with Short-term Memory Focused Speech Therapy | Sham comparator | High-Definition-tACS will be delivered via a battery operated alternating current stimulator (Soterix) using two 3x1 center-surround montages. The current is turned on and increased in a ramplike fashion for 10 to 30 seconds and then ramped down. In this way, the participants experience the same initial sensations (mild tingling) as the active tACS groups. This will be paired with short-term memory focused speech therapy. Receives: Device: Sham HD-tACS |
What is being measured
The primary outcome is the main question the study is designed to answer.
Accuracy on a phonological STM task
Accuracy changes in a delayed sample-to-match task assessing phonological STM after tACS.
Measured: Upon the completion of therapy cycle (a cycle consists of 10 intervention days) and 10 weeks post
fMRI measures of language network activation after tACS
Activation in the language network regions involved in phonological STM will be assessed before and after tACS
Measured: Upon the completion of therapy cycle (a cycle consists of 10 intervention days) and 10 weeks post
Secondary outcomes (1)
Functional Communication Outcome
Improvements in using language in daily life or functional communication as assessed by patient reported measure of Communication Effectiveness Index (CETI)
Measured: Upon the completion of therapy cycle (a cycle consists of 10 intervention days) and 10 weeks post
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Sep 2023
- Study start6 Nov 2023
- Primary completionJan 2033 (estimated)
- Study completionJan 2033 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (52)Papers the sponsor has linked to this study.
- Other trials for StrokeStudies of the same condition, open and under way.
- More trials run by Medical College of WisconsinThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Care provider, Outcomes assessor
- Enrolment
- 120 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Medical College of Wisconsin
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Priyanka Shah-Basak, PhD, Medical College of Wisconsin
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06048159
- Sponsor's protocol ID
- PRO00046360
- Other IDs
- PRO00046360
- Status last verified
- Jul 2026
- First submitted
- 18 Aug 2023
- Last updated
- 10 Jul 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- No
Publications
Pedersen PM, Jorgensen HS, Nakayama H, Raaschou HO, Olsen TS. Aphasia in acute stroke: incidence, determinants, and recovery. Ann Neurol. 1995 Oct;38(4):659-66. doi: 10.1002/ana.410380416.
PubMed 7574464Engelter ST, Gostynski M, Papa S, Frei M, Born C, Ajdacic-Gross V, Gutzwiller F, Lyrer PA. Epidemiology of aphasia attributable to first ischemic stroke: incidence, severity, fluency, etiology, and thrombolysis. Stroke. 2006 Jun;37(6):1379-84. doi: 10.1161/01.STR.0000221815.64093.8c. Epub 2006 May 11.
PubMed 16690899Shah-Basak PP, Norise C, Garcia G, Torres J, Faseyitan O, Hamilton RH. Individualized treatment with transcranial direct current stimulation in patients with chronic non-fluent aphasia due to stroke. Front Hum Neurosci. 2015 Apr 21;9:201. doi: 10.3389/fnhum.2015.00201. eCollection 2015.
PubMed 25954178Shah-Basak PP, Wurzman R, Purcell JB, Gervits F, Hamilton R. Fields or flows? A comparative metaanalysis of transcranial magnetic and direct current stimulation to treat post-stroke aphasia. Restor Neurol Neurosci. 2016 May 2;34(4):537-58. doi: 10.3233/RNN-150616.
PubMed 27163249Boyle M. Semantic feature analysis treatment for anomia in two fluent aphasia syndromes. Am J Speech Lang Pathol. 2004 Aug;13(3):236-49. doi: 10.1044/1058-0360(2004/025).
PubMed 15339233Leonard, C., Rochon, E., & Laird, L. (2008). Treating naming impairments in aphasia: Findings from a phonological components analysis treatment. Aphasiology, 22, 923-947. https://doi.org/10.1080/02687030701831474
Paulesu E, Frith CD, Frackowiak RS. The neural correlates of the verbal component of working memory. Nature. 1993 Mar 25;362(6418):342-5. doi: 10.1038/362342a0.
PubMed 8455719Buchsbaum BR, Olsen RK, Koch P, Berman KF. Human dorsal and ventral auditory streams subserve rehearsal-based and echoic processes during verbal working memory. Neuron. 2005 Nov 23;48(4):687-97. doi: 10.1016/j.neuron.2005.09.029.
PubMed 16301183Buchsbaum BR, Baldo J, Okada K, Berman KF, Dronkers N, D'Esposito M, Hickok G. Conduction aphasia, sensory-motor integration, and phonological short-term memory - an aggregate analysis of lesion and fMRI data. Brain Lang. 2011 Dec;119(3):119-28. doi: 10.1016/j.bandl.2010.12.001. Epub 2011 Jan 21.
PubMed 21256582Antal A, Paulus W. Transcranial alternating current stimulation (tACS). Front Hum Neurosci. 2013 Jun 28;7:317. doi: 10.3389/fnhum.2013.00317. Print 2013.
PubMed 23825454Helfrich RF, Schneider TR, Rach S, Trautmann-Lengsfeld SA, Engel AK, Herrmann CS. Entrainment of brain oscillations by transcranial alternating current stimulation. Curr Biol. 2014 Feb 3;24(3):333-9. doi: 10.1016/j.cub.2013.12.041. Epub 2014 Jan 23.
PubMed 24461998Violante IR, Li LM, Carmichael DW, Lorenz R, Leech R, Hampshire A, Rothwell JC, Sharp DJ. Externally induced frontoparietal synchronization modulates network dynamics and enhances working memory performance. Elife. 2017 Mar 14;6:e22001. doi: 10.7554/eLife.22001.
PubMed 28288700Herrmann CS, Rach S, Neuling T, Struber D. Transcranial alternating current stimulation: a review of the underlying mechanisms and modulation of cognitive processes. Front Hum Neurosci. 2013 Jun 14;7:279. doi: 10.3389/fnhum.2013.00279. eCollection 2013.
PubMed 23785325Benson, D. F., & Ardila, A. (1996). Aphasia: A Clinical Perspective. Oxford University Press.
Code C, Petheram B. Delivering for aphasia. Int J Speech Lang Pathol. 2011 Feb;13(1):3-10. doi: 10.3109/17549507.2010.520090.
PubMed 21329405
Study at a glance
From the registry record, last updated by the sponsor on 10 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- TACS for the Recovery of Phonological STM After Stroke
- ClinicalTrials.gov ID
- NCT06048159
- Acronym / sponsor ID
- PRO00046360
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 120 participants (estimated)
- Lead sponsor
- Medical College of WisconsinUniversity, hospital or other
- Study start
- 6 Nov 2023 (actual)
- Primary completion
- Jan 2033 (estimated)
- Study completion
- Jan 2033 (estimated)
- First posted
- 21 Sep 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study will assess the effects of transcranial alternating current stimulation (tACS) on language recovery after stroke.
Detailed description
Aphasia is a debilitating disorder, typically resulting from damage to the left hemisphere, that can impair a range of communication abilities, including language production and comprehension, reading, and writing. Approximately 180,000 new cases of aphasia are identified per year, and approximately 1 million or 1 in 250 are living with aphasia in the United States. Treatments are limited and provide modest benefits at best. The current emphasis in aphasia rehabilitation is to formulate intensive speech and language therapies and augment therapeutic benefits, potentially with brain stimulation concurrent with therapies.
The current study will investigate the efficacy of high-definition tACS (HD-tACS) to help restore neural oscillatory activity in stroke survivors with aphasia. TACS differs from trancranial direct current stimulation (tDCS), a widely used brain stimulation paradigm, in that sinusoidal or alternating currents are delivered rather than direct currents. TACS is shown to manipulate ongoing oscillatory brain activity and also to modulate synchronization (or connectivity) between targeted brain areas. This feature of tACS is quite attractive, given the new body of evidence suggesting that language impairments stem from diminished brain connectivity and ensuing disruptions in the language network due to stroke.
The study will employ high-definition tACS (HD-tACS) in a parallel, double-blinded, sham-controlled design combined with language therapy targeting phonological short-term memory (STM) function in stroke survivors with aphasia. Magnetoencephalography (MEG) and fMRI BOLD data collection will occur to determine tACS parameters and to evaluate stimulation-induced neural changes, respectively. The investigators plan to recruit 120 stroke survivors with aphasia in a 2-group tACS study design.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, care provider, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| High Definition tACS with Short-term Memory Focused Speech Therapy | Experimental | Device: HD-tACSHigh-Definition-tACS will be delivered via a battery operated alternating current stimulator (Soterix) using two 3x1 center-surround montages.The current is turned on and increased in a ramplike fashion over approximately 30 seconds. Participants will undergo tACS stimulation for 20-minutes with 2 milliampere (mA) peak-to-peak intensity. Stimulation will be maintained no longer than 20 minutes. This will be paired with short-term memory focused speech therapy. |
| Sham-High Definition tACS with Short-term Memory Focused Speech Therapy | Sham comparator | Device: Sham HD-tACSHigh-Definition-tACS will be delivered via a battery operated alternating current stimulator (Soterix) using two 3x1 center-surround montages. The current is turned on and increased in a ramplike fashion for 10 to 30 seconds and then ramped down. In this way, the participants experience the same initial sensations (mild tingling) as the active tACS groups. This will be paired with short-term memory focused speech therapy. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Diagnosed with left hemisphere stroke/aphasia
- Consent date >= 1 month after stroke onset
- Fluent in English
- 18 years of age or older
Key exclusion criteria (7 listed)
- Severe cognitive, auditory or visual impairments that would preclude cognitive and language testing
- Presence of major untreated or unstable psychiatric disease
- A chronic medical condition that is not treated or is unstable
- The presence of cardiac stimulators or pacemakers
- Contraindications to MRI or tACS, e.g. patients with metallic implants, and/or history of skull fractures, pregnancy, skin diseases
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| HD-tACSHigh definition tACS will be applied during speech therapy. | Device | High Definition tACS with Short-term Memory Focused Speech Therapy |
| Sham HD-tACSSham high definition tACS will be applied during speech therapy. | Device | Sham-High Definition tACS with Short-term Memory Focused Speech Therapy |
Primary outcome
Accuracy on a phonological STM task
Time frame: Upon the completion of therapy cycle (a cycle consists of 10 intervention days) and 10 weeks post
Accuracy changes in a delayed sample-to-match task assessing phonological STM after tACS.
fMRI measures of language network activation after tACS
Time frame: Upon the completion of therapy cycle (a cycle consists of 10 intervention days) and 10 weeks post
Activation in the language network regions involved in phonological STM will be assessed before and after tACS
1 secondary outcome
Functional Communication Outcome
Time frame: Upon the completion of therapy cycle (a cycle consists of 10 intervention days) and 10 weeks post
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 10 Jul 2026.
- Background: PubMed 7574464Pedersen PM, Jorgensen HS, Nakayama H, Raaschou HO, Olsen TS. Aphasia in acute stroke: incidence, determinants, and recovery. Ann Neurol. 1995 Oct;38(4):659-66. doi: 10.1002/ana.410380416.
- Background: PubMed 16690899Engelter ST, Gostynski M, Papa S, Frei M, Born C, Ajdacic-Gross V, Gutzwiller F, Lyrer PA. Epidemiology of aphasia attributable to first ischemic stroke: incidence, severity, fluency, etiology, and thrombolysis. Stroke. 2006 Jun;37(6):1379-84. doi: 10.1161/01.STR.0000221815.64093.8c. Epub 2006 May 11.
- Background: PubMed 25954178Shah-Basak PP, Norise C, Garcia G, Torres J, Faseyitan O, Hamilton RH. Individualized treatment with transcranial direct current stimulation in patients with chronic non-fluent aphasia due to stroke. Front Hum Neurosci. 2015 Apr 21;9:201. doi: 10.3389/fnhum.2015.00201. eCollection 2015.
- Background: PubMed 27163249Shah-Basak PP, Wurzman R, Purcell JB, Gervits F, Hamilton R. Fields or flows? A comparative metaanalysis of transcranial magnetic and direct current stimulation to treat post-stroke aphasia. Restor Neurol Neurosci. 2016 May 2;34(4):537-58. doi: 10.3233/RNN-150616.
- Background: PubMed 15339233Boyle M. Semantic feature analysis treatment for anomia in two fluent aphasia syndromes. Am J Speech Lang Pathol. 2004 Aug;13(3):236-49. doi: 10.1044/1058-0360(2004/025).
- BackgroundLeonard, C., Rochon, E., & Laird, L. (2008). Treating naming impairments in aphasia: Findings from a phonological components analysis treatment. Aphasiology, 22, 923-947. https://doi.org/10.1080/02687030701831474
- Background: PubMed 8455719Paulesu E, Frith CD, Frackowiak RS. The neural correlates of the verbal component of working memory. Nature. 1993 Mar 25;362(6418):342-5. doi: 10.1038/362342a0.
- Background: PubMed 16301183Buchsbaum BR, Olsen RK, Koch P, Berman KF. Human dorsal and ventral auditory streams subserve rehearsal-based and echoic processes during verbal working memory. Neuron. 2005 Nov 23;48(4):687-97. doi: 10.1016/j.neuron.2005.09.029.
- Background: PubMed 21256582Buchsbaum BR, Baldo J, Okada K, Berman KF, Dronkers N, D'Esposito M, Hickok G. Conduction aphasia, sensory-motor integration, and phonological short-term memory - an aggregate analysis of lesion and fMRI data. Brain Lang. 2011 Dec;119(3):119-28. doi: 10.1016/j.bandl.2010.12.001. Epub 2011 Jan 21.
- Background: PubMed 23825454Antal A, Paulus W. Transcranial alternating current stimulation (tACS). Front Hum Neurosci. 2013 Jun 28;7:317. doi: 10.3389/fnhum.2013.00317. Print 2013.
- Background: PubMed 24461998Helfrich RF, Schneider TR, Rach S, Trautmann-Lengsfeld SA, Engel AK, Herrmann CS. Entrainment of brain oscillations by transcranial alternating current stimulation. Curr Biol. 2014 Feb 3;24(3):333-9. doi: 10.1016/j.cub.2013.12.041. Epub 2014 Jan 23.
- Background: PubMed 28288700Violante IR, Li LM, Carmichael DW, Lorenz R, Leech R, Hampshire A, Rothwell JC, Sharp DJ. Externally induced frontoparietal synchronization modulates network dynamics and enhances working memory performance. Elife. 2017 Mar 14;6:e22001. doi: 10.7554/eLife.22001.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing HD-tACS in people with Stroke and Aphasia, run by Medical College of Wisconsin at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 10 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Sidney E Schoenrock, MA (414-955-7579, sschoenrock@mcw.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Accuracy on a phonological STM task (time frame: Upon the completion of therapy cycle (a cycle consists of 10 intervention days) and 10 weeks post). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06048159, which also lists 52 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 10 Jul 2026.