Treatment of Cognitive and Sensorimotor Deficits in Parkinson's Disease With High Definition Transcranial Direct Current Stimulation

The purpose of this research study is to examine the effects of transcranial Direct Current Stimulation (tDCS) on verbal retrieval and cognition and sensorimotor control and to determine if tDCS can be used as a way to improve retrieval, sensory, and motor abilities in individuals with Parkinson's disease (PD).

Study Overview

• Status: Not yet recruiting
• Conditions: PARKINSON DISEASE (Disorder)
• Intervention / Treatment: Device: Sham transcranial direct current stimulation; Device: transcranial direct current stimulation

Detailed Description

Objective: Based on models of semantic memory retrieval developed, under which the pre-supplementary motor area (preSMA) of the dorsomedial frontal lobes play an important role, the study will examine the treatment of cognitive deficits in PD with HD tDCS applied to the preSMA to improve function in neural circuits supporting verbal retrieval. In addition, as the preSMA is implicated in motor planning and sequencing, the study also will explore whether HD tDCS applied to the preSMA will have an effect on speech and gait.

Specific Aims:

1. Examine the therapeutic effects on verbal retrieval function by modulating the preSMA using HD tDCS.
2. Examine the therapeutic effects on speech production and processing by modulating the preSMA using HD tDCS
3. Examine the therapeutic effects on gait and balance by modulating the preSMA using HD tDCS

Hypotheses:

1. : Active HD tDCS (1 ma anodal HD tDCS to the preSMA compared to sham) will improve verbal fluency (i.e, phonemic and category fluency on Controlled Word Association Test) as primary outcome measures.
2. : Active HD tDCS (1 ma anodal HD tDCS to the preSMA compared to sham) will improve speech sequencing.
3. : Active HD tDCS (1 ma anodal HD tDCS to the preSMA compared to sham) will improve general motor sequencing

• Study Type: Interventional
• Enrollment (Estimated): 20
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Diagnosed with PD having a verbal fluency deficit
• 50 - 90 years old
• Capable of understanding and signing an informed consent (able to answer consent comprehension questions)
• Fluent in speaking and reading English

Exclusion Criteria:

• A potentially confounding psychological or neurological disorder, including, epilepsy or other seizure disorders; severe traumatic brain injury (based on the Ohio State TBI Identification Method); brain tumor; stroke; present drug abuse/misuse; or Huntington's disease. Participants being seen in the PIs clinics will be assessed for these issues as a part of the standard clinical assessment.
• Additionally, exclusion criteria include cranial implants or skull defects that affect tDCS administration; and use of medications that interact with or potentially interact with tDCS effects, including, anti-convulsants, carbamazepine, sulpiride, pergolide, lorazepam, rivastigmine, dextromethorphan, D-cycloserine, flunarizine, ropinirole, or citalopram
• Patients with a diagnosis of just dysarthria or who have a deep brain stimulation (DBS) device will be excluded.
• Additionally, non-English speakers will be excluded because not all of the screening forms, questionnaires, and tests are available in languages other than English.
• Individuals with cognitive impairment, as indicated by a score of 22 or less on the Montreal Cognitive Assessment, will be considered for exclusion due the concern of a reduced ability to consent. Participants with a score of 22 or less will only be able to participate if they have an accompanying study partner/caregiver with them and we can obtain the written consent of both the participant and the participant's accompanying study partner/caregiver who will be the participant's spouse, adult child, parent, or adult sibling. If they do not have an accompanying study partner/caregiver, they will not be allowed to participate at that time. However, they will be allowed to come back at a later date with an accompanying study partner/caregiver and move forward with the consent procedures and study as above.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Sham Comparator: Sham transcranial direct current stimulation; Sham transcranial direct current stimulation will be delivered via a Neuroelectrics Starstim tES. The sham setup will consist of anodal electrode Fz (International 10/10 System for electroencephalography electrode placement) and electrodes F7, FP1, FP2, and F8 as returns. All electrodes are 1 cm diameter Ag/AgCl electrodes and make contact with the scalp via connective gel. Stimulation will linearly ramp up from 0 milliamps to 1 milliamp over 60 seconds, ramp down to 0 milliamps over 60 seconds and then be left off for 20 minutes.	Device: Sham transcranial direct current stimulation; Sham transcranial direct current stimulation will be delivered via a Neuroelectrics Starstim tES. The sham setup will consist of anodal electrode Fz (International 10/10 System for electroencephalography electrode placement) and electrodes F7, FP1, FP2, and F8 as returns. All electrodes are 1 cm diameter Ag/AgCl electrodes and make contact with the scalp via connective gel. Stimulation will linearly ramp up from 0 milliamps to 1 milliamp over 60 seconds, ramp down to 0 milliamps over 60 seconds and then be left off for 20 minutes.; Other Names: sham tDCS; Sham trascranial electric stimulation; sham tES
Experimental: Transcranial direct current stimulation; Transcranial direct current stimulation will be delivered via a Neuroelectrics Starstim tES. Stimulation will consist of 1 milliamp stimulation, with anodal stimulation delivered at electrode Fz (International 10/10 System for electroencephalography electrode placement) and electrodes F7, FP1, FP2, and F8 as returns. All electrodes are 1 cm diameter Ag/AgCl electrodes and make contact with the scalp via connective gel. Stimulation will linearly ramp up from 0 milliamps to 1 milliamp over 60 seconds, then remain at 1 milliamp of stimulation over 20 minutes, and finally ramping down at to 0 milliamps over 60 seconds. Other Names: tDCS 1 milliamp tDCS High definition tDCS High definition transcranial direct current stimulator, Neuroelectrics Starstim tES, SN E20200930-10	Device: transcranial direct current stimulation; Transcranial direct current stimulation will be delivered via a Neuroelectrics Starstim tES. Stimulation will consist of 1 milliamp stimulation, with anodal stimulation delivered at electrode Fz (International 10/10 System for electroencephalography electrode placement) and electrodes F7, FP1, FP2, and F8 as returns. All electrodes are 1 cm diameter Ag/AgCl electrodes and make contact with the scalp via connective gel. Stimulation will linearly ramp up from 0 milliamps to 1 milliamp over 60 seconds, then remain at 1 milliamp of stimulation over 20 minutes, and finally ramping down at to 0 milliamps over 60 seconds.; Other Names: tDCS; tES; transcranial electric stimulation

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Treatment group differences in change from Baseline to 1-week Post-Treatment on Category Fluency	valuation of treatment group differences in change on Category Fluency from baseline to 1-week post-treatment. Metric: Number of Correct Items Generated (minimum=0 words; no maximum)	Outcome measures will be assessed as change over a period of 6 weeks: Change from baseline to 1-week Post-Treatment
Treatment group differences in change from Baseline to 2-months Post-Treatment on Category Fluency	Evaluation of treatment group differences in change on Category Fluency from baseline to 2-months post-treatment. Metric: Number of Correct Items Generated (minimum=0 words; no maximum)	Outcome measures will be assessed as change over a period of 13 weeks: Change from baseline to 2-month Post-Treatment
Treatment group differences in change from Baseline to 1-week Post-Treatment on Phonemic Fluency	Evaluation of treatment group differences in change on Phonemic Fluency from baseline to 1-week post-treatment. Metric: Number of Correct Items Generated (minimum=0 words; no maximum)	Outcome measures will be assessed as change over a period of 6 weeks: Change from baseline to 1-week Post-Treatment
Treatment group differences in change from Baseline to 2-months Post-Treatment on Phonemic Fluency	Evaluation of treatment group differences in change on Phonemic Fluency from baseline to 2-months post-treatment. Metric: Number of Correct Items Generated (minimum=0 words; no maximum)	Outcome measures will be assessed as change over a period of 13 weeks: Change from baseline to 2-months Post-Treatment

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Treatment group differences in change from Baseline to 1-week Post-treatment on Speaking Rate during overt reading	Evaluation of treatment group differences in change in speaking rate from baseline to 1-week post-treatment. Metric: syllables per second on a passage reading task (minimum=0; no maximum).	Outcome measures will be assessed as change over a period of 6 weeks: Change from baseline to 1-week Post-Treatment
Treatment group differences in change from Baseline to 2-months Post-Treatment on Speaking Rate during overt reading	Evaluation of treatment group differences in change on speaking rate from baseline to 2-months post-treatment. Metric: Syllables per second during a reading passage (minimum=0; no maximum).	Outcome measures will be assessed as change over a period of 13 weeks: change from baseline to 2-months Post-Treatment
Treatment group differences in change from Baseline to 1-week Post-treatment on Speaking Rate during self-generated speech	Evaluation of treatment group differences in change in speaking rate from baseline to 1-week post-treatment. Metric: Syllables per second during self-generated speech (minimum=0; no maximum).	Outcome measures will be assessed as change over a period of 6 weeks: Change from baseline to 1-week Post-Treatment
Treatment group differences in change from Baseline to 2-months Post-Treatment on Speaking Rate during self-generated speech	Evaluation of treatment group differences in change on speaking rate from baseline to 2-months post-treatment. Metric: Syllables per second during self-generated speech (minimum=0; no maximum).	Outcome measures will be assessed as change over a period of 13 weeks: change from baseline to 2-months Post-Treatment
Treatment group differences in change from Baseline to 1-week Post-treatment on Movement Disorder Society-sponsored Unified Parkinson's Disease Rating Scale Part III score.	Evaluation of treatment group differences in change in Movement Disorder Society-sponsored Unified Parkinson's Disease Rating Scale Part III score from baseline to 1-week post-treatment. Metric: Movement Disorder Society-sponsored Unified Parkinson's Disease Rating Scale Part III score (minimum=0; maximum=132)	Outcome measures will be assessed as change over a period of 6 weeks: Change from baseline to 1-week Post-Treatment
Treatment group differences in change from Baseline to 2-month Post-treatment on Movement Disorder Society-sponsored Unified Parkinson's Disease Rating Scale Part III score.	Evaluation of treatment group differences in change in Movement Disorder Society-sponsored Unified Parkinson's Disease Rating Scale Part III score from baseline to 2-month post-treatment. Metric: Movement Disorder Society-sponsored Unified Parkinson's Disease Rating Scale Part III score (minimum=0; maximum=132)	Outcome measures will be assessed as change over a period of 13 weeks: Change from baseline to 2-month Post-Treatment
Treatment group differences in change from Baseline to 1-week Post-treatment on Speaking Rhythm during overt reading	Evaluation of treatment group differences in change in speaking rhythm from baseline to 1-week post-treatment. Metric: coefficient of variation of syllable duration on a passage reading task (minimum=0; no maximum).	Outcome measures will be assessed as change over a period of 6 weeks: Change from baseline to 1-week Post-Treatment
Treatment group differences in change from Baseline to 2-months Post-Treatment on Speaking Rhythm during overt reading	Evaluation of treatment group differences in change on speaking rhythm from baseline to 2-months post-treatment. Metric: Coefficient of variation of syllable duration during a reading passage (minimum=0; no maximum).	Outcome measures will be assessed as change over a period of 13 weeks: change from baseline to 2-months Post-Treatment
Treatment group differences in change from Baseline to 1-week Post-treatment on Speaking Rhythm during self-generated speech	Evaluation of treatment group differences in change in speaking rhythm from baseline to 1-week post-treatment. Metric: Coefficient of variation of syllable duration during self-generated speech (minimum=0; no maximum).	Outcome measures will be assessed as change over a period of 6 weeks: Change from baseline to 1-week Post-Treatment
Treatment group differences in change from Baseline to 2-months Post-Treatment on Speaking Rhythm during self-generated speech	Evaluation of treatment group differences in change on speaking rhythm from baseline to 2-months post-treatment. Metric: Coefficient of variation of syllable duration during self-generated speech (minimum=0; no maximum).	Outcome measures will be assessed as change over a period of 13 weeks: change from baseline to 2-months Post-Treatment
Treatment group differences in change from Baseline to 1-week Post-treatment on Speaking Pause Time during overt reading	Evaluation of treatment group differences in change in speaking pause time from baseline to 1-week post-treatment. Metric: Pause time as percentage of total speaking time on a passage reading task (minimum=0%; maximum=100%).	Outcome measures will be assessed as change over a period of 6 weeks: Change from baseline to 1-week Post-Treatment
Treatment group differences in change from Baseline to 2-months Post-Treatment on Speaking Pause Time during overt reading	Evaluation of treatment group differences in change on speaking pause time from baseline to 2-months post-treatment. Metric: Pause time as percentage of total speaking time during a reading passage (minimum=0%; maximum=100%).	Outcome measures will be assessed as change over a period of 13 weeks: change from baseline to 2-months Post-Treatment
Treatment group differences in change from Baseline to 1-week Post-treatment on Speaking Pause Time during self-generated speech	Evaluation of treatment group differences in change in speaking pause time from baseline to 1-week post-treatment. Metric: Pause time as percentage of total speaking time during self-generated speech (minimum=0%; maximum=100%).	Outcome measures will be assessed as change over a period of 6 weeks: Change from baseline to 1-week Post-Treatment
Treatment group differences in change from Baseline to 2-months Post-Treatment on Speaking Pause Time during self-generated speech	Evaluation of treatment group differences in change on speaking pause time from baseline to 2-months post-treatment. Metric: Pause time as percentage of total speaking time during self-generated speech (minimum=0%; maximum=100%).	Outcome measures will be assessed as change over a period of 13 weeks: change from baseline to 2-months Post-Treatment
Treatment group differences in change from Baseline to 1-week Post-treatment on Freezing of Gate during the timed up and go task	Evaluation of treatment group differences in change in freezing of gate from baseline to 1-week post-treatment. Metric: Timed up and go time (minimum=0; no maximum).	Outcome measures will be assessed as change over a period of 6 weeks: Change from baseline to 1-week Post-Treatment
Treatment group differences in change from Baseline to 2-month Post-treatment on Freezing of Gate during the timed up and go task	Evaluation of treatment group differences in change in freezing of gate from baseline to 2-month post-treatment. Metric: Timed up and go time (minimum=0; no maximum).	Outcome measures will be assessed as change over a period of 13 weeks: Change from baseline to 2-month Post-Treatment

Collaborators and Investigators

• Sponsor: The University of Texas at Dallas

Study record dates

Study Major Dates

• Study Start (Estimated): May 1, 2026
• Primary Completion (Estimated): October 31, 2027
• Study Completion (Estimated): October 31, 2027

Study Registration Dates

• First Submitted: April 9, 2026
• First Submitted That Met QC Criteria: April 9, 2026
• First Posted (Actual): April 16, 2026

Study Record Updates

• Last Update Posted (Actual): May 12, 2026
• Last Update Submitted That Met QC Criteria: May 7, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Parkinson's Disease; transcranial direct current stimulation (tDCS); electroencephalography (EEG); verbal memory; presupplementary motor area (preSMA); speech sequencing; motor sequencing
• Additional Relevant MeSH Terms: Synucleinopathies; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Neurodegenerative Diseases; Movement Disorders; Parkinsonian Disorders; Basal Ganglia Diseases; Parkinson Disease; Therapeutics; Behavioral Disciplines and Activities; Electric Stimulation Therapy; Convulsive Therapy; Psychiatric Somatic Therapies; Electroshock; Psychological Techniques; Transcranial Direct Current Stimulation
• Other Study ID Numbers: IRB-26-35

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No