Transcranial Alternating Current Stimulation (tACS) for the Recovery of Phonological Short-Term Memory in Patients With Aphasia After Stroke

May 8, 2025 updated by: Priyanka Shah-Basak, PhD, Medical College of Wisconsin

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.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

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 Type

Interventional

Enrollment (Estimated)

120

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

  • Name: Priyanka Shah-Basak, PhD
  • Phone Number: 414-955-5752
  • Email: prishah@mcw.edu

Study Locations

  • United States
    • Wisconsin
      • Milwaukee, Wisconsin, United States, 53226
        • Recruiting
        • Medical College of Wisconsin
        • Contact:
        • Contact:
          • Priyanka Shah-Basak, PhD
          • Phone Number: 414-955-5752
          • Email: prishah@mcw.edu

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Diagnosed with left hemisphere stroke/aphasia
  • Consent date >= 1 month after stroke onset
  • Fluent in English
  • 18 years of age or older

Exclusion Criteria:

  • 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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: High Definition tACS with Short-term Memory Focused Speech Therapy
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.
Device: HD-tACS
High definition tACS will be applied during speech therapy.
Sham Comparator: Sham-High Definition tACS with Short-term Memory Focused Speech Therapy
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.
Device: Sham HD-tACS
Sham high definition tACS will be applied during speech therapy.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
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.
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
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
Upon the completion of therapy cycle (a cycle consists of 10 intervention days) and 10 weeks post

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Functional Communication Outcome
Time Frame: Upon the completion of therapy cycle (a cycle consists of 10 intervention days) and 10 weeks post
Improvements in using language in daily life or functional communication as assessed by patient reported measure of Communication Effectiveness Index (CETI)
Upon the completion of therapy cycle (a cycle consists of 10 intervention days) and 10 weeks post

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Medical College of Wisconsin

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

November 6, 2023

Primary Completion (Estimated)

January 1, 2033

Study Completion (Estimated)

January 1, 2033

Study Registration Dates

First Submitted

August 18, 2023

First Submitted That Met QC Criteria

September 15, 2023

First Posted (Actual)

September 21, 2023

Study Record Updates

Last Update Posted (Actual)

May 14, 2025

Last Update Submitted That Met QC Criteria

May 8, 2025

Last Verified

May 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • PRO00046360 (Other Identifier: Medical College of Wisconsin)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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