Motor Learning and tDCS in Parkinson's Disease

Study Overview
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Brief Summary
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The present study sought to examine the efficacy of single session transcranial direct current stimulation applied over the primary motor cortex in people with Parkinson's disease on sequential motor learning performance.

Detailed Description
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Parkinson's disease is characterised by deficits of motor control triggered by impaired basal ganglia function, such as bradykinesia and tremor. Beyond the visibly recognisable motor symptoms of Parkinson's disease, the ability to learn a sequence of movements is also compromised and poses a significant barrier to effective rehabilitation. In healthy individuals, transcranial direct current stimulation applied over the primary motor cortex during motor task practice has been shown to significantly improve motor learning compared to placebo conditions. The present study sought to examine the effect of a single session of transcranial direct current stimulation applied over the primary motor cortex in people with Parkinson's disease on sequential motor learning performance. Participants learnt two finger tapping sequences, with task difficulty indexed by sequence length, and task consolidation further examined using a dual-task paradigm. Task related cortical haemodynamic activity was recorded using functional near-infrared spectroscopy.

Official Title
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The Effect of Single Session Transcranial Direct Current Stimulation on Sequential Motor Learning in Parkinson's Disease

Conditions
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Parkinson Disease

Intervention / Treatment
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* Device: Transcranial direct current stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Right-handed (Edinburgh Handedness Inventory; ≥50) Cognitively capable (Montreal Cognitive Assessment (MoCA); ≥23) Mild to moderate Parkinson's disease severity (Hoehn and Yar disease stage 2-3) Exclusion Criteria: History of stroke Comorbidity Cephalic implants

Ages Eligible for Study
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Minimum Age: 40 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Anodal tDCS<br>Anodal electrode (35 cm2 sponge electrode) placed over C3. Cathodal electrode (35 cm2 sponge electrode) placed over the right supraorbital area. 20 minutes of stimulation at 2 mA with a 30-second phase-in and phase-out period. | Device: Transcranial direct current stimulation<br>* Transcranial electrical stimulation device. A weak direct electrical current, up to 2 mA, is passed between two electrodes placed on the scalp. Electrodes are housed in 35 cm2 sponges saturated with 4 ml of saline solution (0.9 % NaCl) per side, per pad. Stimulation is phased in with a 30 second ramp up period prior to the specified stimulation period and phased-out with a ramp down of the current following the specified stimulation period. For sham stimulation, the ramp-up and ramp-down periods are retained, but stimulation is switched off for during the specified stimulation period.<br>* Other names: tDCS;|
| Active Comparator: Cathodal tDCS<br>Cathodal electrode (35 cm2 sponge electrode) placed over C3. Anodal electrode (35 cm2 sponge electrode) placed over the right supraorbital area. 20 minutes of stimulation at 2 mA with a 30-second phase-in and phase-out period. | Device: Transcranial direct current stimulation<br>* Transcranial electrical stimulation device. A weak direct electrical current, up to 2 mA, is passed between two electrodes placed on the scalp. Electrodes are housed in 35 cm2 sponges saturated with 4 ml of saline solution (0.9 % NaCl) per side, per pad. Stimulation is phased in with a 30 second ramp up period prior to the specified stimulation period and phased-out with a ramp down of the current following the specified stimulation period. For sham stimulation, the ramp-up and ramp-down periods are retained, but stimulation is switched off for during the specified stimulation period.<br>* Other names: tDCS;|
| Sham Comparator: Sham tDCS<br>Anodal electrode (35 cm2 sponge electrode) placed over C3. Cathodal electrode (35 cm2 sponge electrode) placed over the right supraorbital area. Stimulation was phased in for 30 seconds up to 2 mA and then switched off. Stimulation was again phased in for 30 seconds following 20 minutes of no stimulation. | Device: Transcranial direct current stimulation<br>* Transcranial electrical stimulation device. A weak direct electrical current, up to 2 mA, is passed between two electrodes placed on the scalp. Electrodes are housed in 35 cm2 sponges saturated with 4 ml of saline solution (0.9 % NaCl) per side, per pad. Stimulation is phased in with a 30 second ramp up period prior to the specified stimulation period and phased-out with a ramp down of the current following the specified stimulation period. For sham stimulation, the ramp-up and ramp-down periods are retained, but stimulation is switched off for during the specified stimulation period.<br>* Other names: tDCS;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline sequential finger tapping performance | A skill index reflecting the accuracy and speed of which participants perform a specified finger tapping sequence. | Two assessments: Baseline / pre-intervention, and immediately post-intervention | 
| Change from baseline oxygenated haemoglobin response | Task related changes of oxygenated haemoglobin as measured using functional near-infrared spectroscopy. | Two assessments: Baseline / pre-intervention, and immediately post-intervention | 
| Change from baseline shape-counting error | The percentage of shape counting error during dual task assessments. Sequential finger tapping + visual shape counting task. | Two assessments: Baseline / pre-intervention, and immediately post-intervention | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Parkinson's disease, Transcranial direct current stimulation, Motor sequence learning