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Transcranial Alternating Current Stimulation (tACS) in Aphasia

Sponsor
Medical College of Wisconsin (Other)
Overall Status
Recruiting
CT.gov ID
NCT04375722
Collaborator
(none)
50
Enrollment
1
Location
3
Arms
59.9
Anticipated Duration (Months)
0.8
Patients Per Site Per Month

Study Details

Study Description

Brief Summary

This study will assess the effects of transcranial alternating current stimulation (tACS) on language recovery after stroke as well as healthy language functions.

Condition or Disease Intervention/Treatment Phase
  • Device: tACS 10-Hz
  • Device: tACS 40-Hz
  • Device: tACS sham
 N/A

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 (NIH-NIDCD, 2015). 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 by providing brain stimulation concurrent with therapies. Transcranial direct current stimulation (tDCS) is one of the most widely used such technique. While tDCS has had relative success in chronic aphasia (>6 months after stroke), it has not been efficacious during subacute stages (<3 months after stroke). But enhancing language recovery early after stroke is desirable because of its potential impact on long-term language outcomes and quality-of-life.

The current study will investigate the efficacy of high-definition tACS (HD-tACS) to help restore neural oscillatory activity in aphasia. TACS differs from tDCS in that sinusoidal, alternating currents are delivered rather than constant currents. TACS can manipulate the ongoing oscillatory neuronal activity and potentially increase functional synchronization (or connectivity) between targeted areas. This feature of tACS is quite attractive, given the new body of evidence suggesting that language impairments stem from diminished functional connectivity and disruptions in the language network due to stroke. The selection of tACS frequencies in this study is guided by our preliminary work examining pathological neural oscillations found near stroke-lesioned areas (or perilesional) in aphasia. By exogenously tuning the perilesional oscillations with tACS, the investigators hope to up-regulate communication across these areas and other connected areas to improve language outcome. If successful, tACS will be a powerful and novel treatment approach with reverberating positive impact on long-term recovery.

The study will employ HD-tACS in a within-subject and sham-controlled design, using two frequencies (alpha/10 Hz and low-gamma/40 Hz) combined with language tasks and electroencephalography (EEG) to evaluate subsequent behavioral and neurophysiological changes. Investigators plan to recruit 50 participants: 25 stroke survivors with aphasia at lease 1 month after stroke, and 25 healthy controls.

Participants will complete language testing that covers a broad range of language functions, medical history, and MRI. Eligible participants will undergo active tACS at 10 Hz or 40 Hz, or sham-tACS. All participants will receive all three stimulation types during separate visits. The tACS administrator and participants will be blinded to the stimulation type. The order of stimulation type will be counterbalanced across participants. Washout period between visits will be at least 48 hours to minimize potential carryover effects. EEG will be acquired before and after tACS during periods of rest (resting-state) and during language tasks. Participants will complete a questionnaire at the end of stimulation visits to assess potential side effects of tACS. Total time enrolled in the study is expected to be 2-3 weeks, which may be longer depending on participant's availability.

Study Design

Study Type:
Interventional
Anticipated Enrollment :
50 participants
Allocation:
Randomized
Intervention Model:
Single Group Assignment
Intervention Model Description:
In the within-subject design healthy participants and stroke survivors will receive tACS stimulation at 10 Hz, 40 Hz, and sham settings in a randomized order with >48 hours washout period in between stimulation sessions.In the within-subject design healthy participants and stroke survivors will receive tACS stimulation at 10 Hz, 40 Hz, and sham settings in a randomized order with >48 hours washout period in between stimulation sessions.
Masking:
Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Masking Description:
Participant, care provider, investigator and outcomes assessor are all blinded. One study team member will be designated as unblinded.
Primary Purpose:
Treatment
Official Title:
Exogenous Tuning of Neural Oscillations as a Mode of Treatment in Post-stroke Aphasia
Actual Study Start Date :
Jan 4, 2020
Anticipated Primary Completion Date :
Jan 1, 2025
Anticipated Study Completion Date :
Jan 1, 2025

Arms and Interventions

Arm Intervention/Treatment
Experimental: tACS 10 Hz low frequency

High-Definition-tACS will be 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 10-Hz stimulation for 20-minutes with 1 milliampere (mA) peak-to-peak intensity. Stimulation will be maintained no longer than 20 minutes.

Device: tACS 10-Hz
Low frequency alternating current will be applied.
Experimental: tACS 40 Hz high frequency

High-Definition-tACS will be 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 40-Hz stimulation for 20-minutes with 1 milliampere (mA) peak-to-peak intensity. Stimulation will be maintained no longer than 20 minutes.

Device: tACS 40-Hz
High frequency alternating current will be applied.
Sham Comparator: tACS sham

High-Definition-tACS will be 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 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.

Device: tACS sham
Sham stimulation setting will be applied.

Outcome Measures

Primary Outcome Measures

  1. tACS frequency-dependent changes in language performance on object and action naming tasks [Immediate changes monitored after 20 minutes of tACS of each type]

    Improvement on noun and verb retrieval performance as determined by increases in accuracy and decreases in reaction time.

  2. tACS frequency-dependent neurophysiological changes [Immediate changes monitored after 20 minutes of tACS of each type]

    Concomitant frequency-specific EEG changes in spectral power and phase synchronization are expected.

Secondary Outcome Measures

  1. Individual differences in tACS responsiveness [Based on immediate changes monitored after 20 minutes of tACS of each type]

    tACS responsiveness depending on language impairment types, stroke lesion and language lateralization characteristics will be explored.

Eligibility Criteria

Criteria

Ages Eligible for Study:
18 Years to 85 Years
Sexes Eligible for Study:
All
Accepts Healthy Volunteers:
Yes
Inclusion Criteria:

Healthy Controls

  • 18 years of age or older

  • Fluent in English

  • No history of neurological or psychiatric disorders

Stroke Patients

  • Diagnosed with post-stroke aphasia by referring physician/neuropsychologist

  • Consent date >=1 months after stroke onset

  • Right-handed

  • 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

  • Any metal implants in the skull

  • Contraindications to MRI or tACS

  • History of seizures

  • History of dyslexia or other developmental learning disabilities

Contacts and Locations

Locations

Site City State Country Postal Code
1 Medical College of Wisconsin Milwaukee Wisconsin United States 53226

Sponsors and Collaborators

  • Medical College of Wisconsin

Investigators

  • Principal Investigator: Priyanka Shah-Basak, PhD, Medical College of Wisconsin

Study Documents (Full-Text)

None provided.

More Information

Publications

Responsible Party:
Priyanka Shah-Basak, PhD, Priyanka Shah-Basak, PhD, Medical College of Wisconsin
ClinicalTrials.gov Identifier:
NCT04375722
Other Study ID Numbers:
  • 36878
First Posted:
May 5, 2020
Last Update Posted:
Nov 30, 2021
Last Verified:
Nov 1, 2021
Individual Participant Data (IPD) Sharing Statement:
No
Plan to Share IPD:
No
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.:
Yes
Keywords provided by Priyanka Shah-Basak, PhD, Priyanka Shah-Basak, PhD, Medical College of Wisconsin
language
language impairment
transcranial alternating current stimulation
tACS
Additional relevant MeSH terms:
Aphasia

Study Results

No Results Posted as of Nov 30, 2021