tACS Modulates Speech and Cognitive Impairments in People With PD by Targeting the Medial Frontal Cortex

November 16, 2025 updated by: Ke Dong, MD

Modulation of Executive Functions and Speech in Parkinson's Disease by Theta tACS Targeted at the Medial Frontal Cortex

This clinical trial aims to study whether transcranial alternating current stimulation (tACS) applied to the medial frontal cortex (MFC) can improve speech and cognitive function in people with Parkinson's disease (PD), and to evaluate the safety of tACS. The main goals are to answer the following questions:

  1. Can tACS stimulation of the MFC improve executive functions in people with PD (such as reasoning, planning, inhibition, and complex problem-solving)?
  2. Can it improve the integration of auditory information and speech motor control during communication?

Researchers will compare the effects of real tACS versus sham (placebo) stimulation to see if real stimulation leads to better speech and cognitive outcomes in PD patients.

Participants will:

  1. Receive one extra 20-minute session of either real or sham tACS each day for two weeks
  2. Attend clinic visits before stimulation, right after the 2-week period, and again at 1 month and 3 months for assessments and tests
  3. Have their executive function scores, speech performance, and related brain activity recorded

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

28

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 Locations

  • China
    • Guangdong
      • Guangzhou, Guangdong, China, 510000
        • Department of Rehabilitation Medicine, The First Affiliated Hospital, Sun Yat-sen University

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

Yes

Description

Inclusion Criteria:

  1. Clinical diagnosis of Parkinson's disease.
  2. Aged 35-80 years.
  3. Absence of non-PD neurological disorders.
  4. No hearing impairment, dementia, psychiatric abnormalities, or history of neurosurgical treatment.

Exclusion Criteria:

  1. Pregnancy.
  2. Any contraindications to electrical stimulation.

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: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: 6Hz-group
Other: 6Hz-tACS
tACS applied to the MFC at a frequency of 6 Hz, using a high-definition 1×4 electrode configuration with individualized current intensity, delivered for 20 minutes.
Sham Comparator: Sham-group
Other: Sham-tACS
Except for turning down the current intensity to zero during the 20-minute period, all other parameters are identical to those in 6Hz-group.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Verbal Fluency Test (VFT)
Time Frame: Assessments were completed at baseline, after two weeks of stimulation, and at 1- and 3-month follow-ups.
The VFT assesses abilities such as thought initiation, rapid word retrieval, and cognitive flexibility. It has two parts: 1.Phonemic Fluency Test (PFT), people needed to name as many Chinese words as possible beginning with "fa" or "xiao" within 60 seconds. 2.Semantic Fluency Test (SFT), people needed to name as many items as possible from categories such as "fruits," "vegetables," "animals," and "occupations" within 60 seconds. The number of correct and non-repeated words produced within the time limit were recorded.
Assessments were completed at baseline, after two weeks of stimulation, and at 1- and 3-month follow-ups.
Digit Span Test (DST)
Time Frame: Assessments were completed at baseline, after two weeks of stimulation, and at 1- and 3-month follow-ups.
The DST assesses working memory and selective attention. People repeat a series of numbers in the same order (forward) or reverse order (backward) as spoken by the examiner. The maximum correctly repeated sequence length was recorded.
Assessments were completed at baseline, after two weeks of stimulation, and at 1- and 3-month follow-ups.
Trail Making Test (TMT)
Time Frame: Assessments were completed at baseline, after two weeks of stimulation, and at 1- and 3-month follow-ups.
The TMT assesses complex visual scanning, conceptual tracking, cognitive flexibility and divided attention. It has two parts: TMT-A: People draw a trail by connecting 25 Arabic numbers in ascending order. TMT-B: the trail alternates between connecting 12 Arabic numbers and 12 Chinese characters. The time taken to complete each task is recorded.
Assessments were completed at baseline, after two weeks of stimulation, and at 1- and 3-month follow-ups.
Speech motor integration ability as assessed by a well-established paradigm: frequency-altered feedback (FAF) task
Time Frame: Assessments were completed at baseline, after two weeks of stimulation, and at 1- and 3-month follow-ups.
In the FAF task, participants needed to sit in a sound-attenuated room and produce the vowel /u/ according to instructions. The acoustic signal is recorded and randomly shifted in pitch by an external device. The pitch-shifted voice is then fed back to the participant. This unexpected pitch perturbation elicits either an opposite or a following acoustic compensation response. The amplitude and timing of this response are recorded and used to assess the participant's speech-motor integration ability.
Assessments were completed at baseline, after two weeks of stimulation, and at 1- and 3-month follow-ups.

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
The event-related potentials (ERPs) components recorded by Electroencephalography (EEG)
Time Frame: Assessments were completed at baseline, after two weeks of stimulation, and at 1- and 3-month follow-ups.
During the FAF task, cortical electrical activity associated with the pitch perturbation event was simultaneously recorded. Using the perturbation onset as the zero point, a time window ranging from -500ms to 700ms was defined. The peak amplitude and latency of N1 and P2 components were extracted within 80-180 ms and 160-280 ms time windows after the perturbation onset, respectively.
Assessments were completed at baseline, after two weeks of stimulation, and at 1- and 3-month follow-ups.
The hemodynamic responses in the executive process as assessed by Functional Near-Infrared Spectroscopy (fNIRS)
Time Frame: Assessments were completed at baseline, after two weeks of stimulation, and at 1- and 3-month follow-ups.
The fNIRS monitoring was conducted during a VFT task consisting of multiple 30-second blocks. The average change in oxygenated hemoglobin concentration during the task was recorded.
Assessments were completed at baseline, after two weeks of stimulation, and at 1- and 3-month follow-ups.

Collaborators and Investigators

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

Sponsor

Ke Dong, MD

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)

August 1, 2023

Primary Completion (Actual)

May 1, 2025

Study Completion (Actual)

August 1, 2025

Study Registration Dates

First Submitted

September 26, 2025

First Submitted That Met QC Criteria

November 16, 2025

First Posted (Actual)

November 20, 2025

Study Record Updates

Last Update Posted (Actual)

November 20, 2025

Last Update Submitted That Met QC Criteria

November 16, 2025

Last Verified

September 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • Nos.82172528

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

All IPD that underlie results in a publication.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • ICF
  • ANALYTIC_CODE
  • CSR

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

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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