Self-administered tDCS for Parkinson's Disease Gait

Overview

This clinical trial investigates the efficacy and safety of self-administered transcranial direct current stimulation (tDCS) to improve single- and dual-task gait in patients with Parkinson's disease (PD). The trial specifically targets early-stage PD patients experiencing reduced walking automaticity due to basal ganglia dysfunction, requiring cognitive effort for habitual tasks like walking.

Overview

This clinical trial investigates the efficacy and safety of self-administered transcranial direct current stimulation (tDCS) to improve single- and dual-task gait in patients with Parkinson's disease (PD). The trial specifically targets early-stage PD patients experiencing reduced walking automaticity due to basal ganglia dysfunction, requiring cognitive effort for habitual tasks like walking.

[tDCS](https://en.wikipedia.org/wiki/Transcranial_direct_current_stimulation) is a non-invasive brain stimulation technique that uses low electrical current to modulate neuronal excitability. This trial explores whether tDCS can improve gait automaticity in PD patients, potentially reducing the cognitive burden of walking and fall risk.

Trial Details

| Parameter | Value |
|-----------|-------|
| NCT Number | NCT06324448 |
| Status | Recruiting |
| Phase | Not Applicable (Exploratory) |
| Sponsor | Seoul National University Hospital |
| Principal Investigator | Han Gil Seo, PhD |
| Intervention | Transcranial Direct Current Stimulation (tDCS) |
| Device | YMS-201B (Ybrain Inc, South Korea) |
| Enrollment | 24 participants (estimated) |
| Start Date | February 15, 2024 |
| Primary Completion | February 28, 2026 |
| Completion Date | April 30, 2026 |
| Location | Seoul, South Korea |

Mechanism of Action

tDCS Fundamentals

Transcranial direct current stimulation delivers a low-intensity constant current (typically 1-2 mA) through electrodes placed on the scalp. The effects include:

Rationale for PD Gait Improvement

In Parkinson's disease, gait dysfunction arises from:

• Dopaminergic neuron loss in the substantia nigra pars compacta
• Basal ganglia circuitry disruption affecting automatic movement
• Reduced walking automaticity requiring conscious attention to gait

Primary Motor Cortex (M1) Stimulation

• Anode placement: Cz (vertex)
• Cathode placement: Right orbital frontal cortex (Fp2)
• Current: 2.0 mA for 19 minutes
• Rationale: The primary motor cortex is involved in motor execution and may enhance motor output to compensate for basal ganglia dysfunction

Left Dorsolateral Prefrontal Cortex (DLPFC) Stimulation

• Anode placement: F3
• Cathode placement: Right orbital frontal cortex (Fp2)
• Current: 2.0 mA for 19 minutes
• Rationale: The dorsolateral prefrontal cortex is involved in executive function and attention, potentially improving dual-task gait performance

Why Dual-Task Gait Matters

Dual-task gait (walking while performing a cognitive task) is particularly challenging for PD patients because:

Study Design

Trial Characteristics

| Design Element | Details |
|----------------|---------|
| Type | Interventional |
| Allocation | Randomized |
| Intervention Model | Parallel |
| Masking | Triple-blind (Participant, Care Provider, Outcomes Assessor) |
| Purpose | Exploratory |

Treatment Regimen

• Duration: 28 consecutive days
• Sessions: Once daily (28 total sessions)
• Session length: 20 minutes
• Administration: Self-administered at home
• Device: YMS-201B tDCS device with saline-soaked sponge electrodes (6 cm diameter)

Two Experimental Arms

A control/sham arm is implied by the randomized, triple-blind design, though specific sham parameters were not detailed in the available protocol.

Eligibility Criteria

Inclusion Criteria

Exclusion Criteria

• History of seizure
• Parkinson's disease dementia (based on Korean-Montreal Cognitive Assessment cutoff scores)

• Metallic implants (cardiac pacemaker, artificial cochlea)
• Inflammation, burns, or wounds in stimulation area

• Severe dyskinesia
• Severe on-off phenomenon
• Plan to adjust medication at screening

• Other neurological, orthopedic, or cardiovascular comorbidities affecting gait
• Uncontrolled vestibular disease
• Orthopedic hypotension
• Paroxysmal vertigo

• Pregnant or lactating patients

Outcomes

Primary Outcomes

| Outcome | Timing |
|---------|--------|
| Timed Up and Go test (sec) | Immediate post-intervention |
| Timed Up and Go test under dual-task condition (sec) | Immediate post-intervention |

The Timed Up and Go (TUG) test is a simple assessment of functional mobility:

• Patient stands up from a chair, walks 3 meters, turns around, walks back, and sits down
• Time in seconds is the outcome measure
• Dual-task TUG adds a cognitive task (e.g., counting backward) during walking

Secondary Outcomes

| Outcome | Measures |
|---------|----------|
| Dual-task effect | Percentage change in TUG time under dual-task vs. single-task |
| Attention | Modified Attention Allocation Index (mAAI) |
| Gait parameters | Cadence, velocity, step length, stride length, swing/stance phase |
| Balance | Single-leg stance test |
| Executive function | Stroop test (attention, processing speed) |
| Psychomotor function | Trail making test (speed, attention, flexibility) |
| Freezing of Gait | New Freezing of Gait Questionnaire (NFoGQ) — 6 items, scores 0-24 |
| Mood | Geriatric Depression Scale (GDS) — short form, 15 items |

Assessment Schedule

All outcomes measured at:

• Immediate post-intervention (after 28 days)
• Follow-up (1 month post-intervention)

Significance for Parkinson's Disease

Current Treatment Limitations

Current PD therapies primarily address:

• Dopamine replacement (levodopa, dopamine agonists) — motor symptoms
• Deep brain stimulation — advanced cases, motor fluctuations
• Physical therapy — gait training, balance exercises

Potential Benefits of tDCS

Comparison with Other Non-invasive Approaches

| Modality | Mechanism | Current Evidence |
|----------|-----------|-------------------|
| tDCS | Electrical modulation | Growing evidence for PD motor symptoms |
| rTMS | Magnetic stimulation | Some evidence for motor symptoms |
| TUS | Ultrasound | Early-stage research |
| Exercise | Activity-based | Strong evidence for gait/balance |

• [Parkinson's Disease](/genes/ar)
• [Basal Ganglia](/brain-regions/basal-ganglia)
• [Substantia Nigra](/brain-regions/substantia-nigra)
• [Dopamine](/proteins/d1-dopamine-receptor)
• [Motor Cortex](/brain-regions/motor-cortex)
• [Prefrontal Cortex](/brain-regions/prefrontal-cortex)
• [Transcranial Direct Current Stimulation](/genes/ran)
• [Gait Dysfunction in Parkinson's Disease](/genes/ar)
• Freezing of Gait
• [Clinical Trials in Parkinson's Disease](/genes/ar)
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Parkinson's Disease](/genes/ar)

External Links

• [PubMed](https://pubmed.ncbi.nlm.nih.gov/)
• [KEGG Pathways](https://www.genome.jp/kegg/pathway.html)

Contact Information

• Principal Investigator: Han Gil Seo, PhD — hgseo80@gmail.com
• Study Coordinator: Seo Jung Yun, MS — seojungyun@snu.ac.kr
• Phone: 82-2-2072-1659
• Institution: Seoul National University Hospital, Seoul, South Korea

References