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

NCT ID: NCT06048159

Last Updated: 2025-05-14

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: NA
• Total Enrollment: 120 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2023-11-06
• Study Completion Date: 2033-01-31

Brief Summary

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.

Conditions

Stroke; Aphasia

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: TRIPLE

Study Groups

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.

Group Type: EXPERIMENTAL

HD-tACS

Intervention Type: DEVICE

High definition tACS will be applied during speech therapy.

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.

Group Type: SHAM_COMPARATOR

Sham HD-tACS

Intervention Type: DEVICE

Sham high definition tACS will be applied during speech therapy.

Interventions

HD-tACS

High definition tACS will be applied during speech therapy.

Intervention Type: DEVICE

Sham HD-tACS

Sham high definition tACS will be applied during speech therapy.

Intervention Type: DEVICE

Eligibility Criteria

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

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Medical College of Wisconsin

OTHER

Sponsor Role: lead

Responsible Party

Priyanka Shah-Basak, PhD

Principal Investigator

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

Medical College of Wisconsin

Milwaukee, Wisconsin, United States

Site Status: RECRUITING

Countries

United States

Central Contacts

Sidney E Schoenrock, MA

Role: CONTACT

sschoenrock@mcw.edu

414-955-7579

Priyanka Shah-Basak, PhD

Role: CONTACT

prishah@mcw.edu

414-955-5752

Facility Contacts

Sidney E Schoenrock, MA

Role: primary

sschoenrock@mcw.edu

414-955-7579

Priyanka Shah-Basak, PhD

Role: backup

prishah@mcw.edu

414-955-5752

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Other Identifiers

PRO00046360

Identifier Type: OTHER

Identifier Source: secondary_id

PRO00046360

Identifier Type: -

Identifier Source: org_study_id