Cerebellar Transcranial Direct Current Stimulation in Parkinson's Disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder and affects approximately 1 million people in the United States with total annual costs approaching 11 billion dollars. The most common symptoms of PD are tremor, stiffness, slowness, and trouble with balance/walking, which lead to severe impairments in performing activities of daily living. Current medical and surgical treatments for PD are either only mildly effective, expensive, or associated with a variety of side-effects. Therefore, the development of practical and effective add-ons to current therapeutic treatment approaches would have many benefits. Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that can affect brain activity and can help make long-term brain changes to improve functions like walking and balance. While a few initial research studies and review articles involving tDCS have concluded that tDCS may improve PD walking and balance, many results are not meaningful in real life and several crucial issues still prevent tDCS from being a useful add-on intervention in PD. These include the selection of stimulation sites (brain regions stimulated) and tDCS electrode placement. Most studies have targeted the motor cortex (brain region that controls intentional movement), but there is evidence that the cerebellum - which helps control gait and balance, is connected to several other brain areas, and is easily stimulated with tDCS - may be a likely location to further optimize walking and balance in PD. There is also evidence that certain electrodes placements may be better than others. Thus, the purpose of this study is to determine the effects of cerebellar tDCS stimulation using two different placement strategies on walking and balance in PD.

Additionally, although many tDCS devices are capable of a range of stimulation intensities (for example, 0 mA - 5 mA), the intensities currently used in most tDCS research are less than 2 mA, which is sufficient to produce measurable improvements; but, these improvements may be expanded at higher intensities. In the beginning, when the safety of tDCS was still being established for human subjects, careful and moderate stimulation approaches were warranted. However, recent work using stimulation at higher intensities (for example, up to 4 mA) have been performed in different people and were found to have no additional negative side-effects. Now that the safety of tDCS at higher intensities is better established, studies exploring the differences in performance between moderate (i.e., 2 mA) and higher (i.e., 4 mA) intensities are necessary to determine if increasing the intensity increases the effectiveness of the desired outcome.

Prospective participants will include 10 people with mild-moderate PD that will be recruited to complete five randomly-ordered stimulation sessions, separated by at least 5 days each. Each session will involve one visit to the Integrative Neurophysiology Laboratory (INPL) and will last for approximately one hour. Data collection is expected to take 4-6 months. Each session will include walking and balance testing performed while wearing the tDCS device. Total tDCS stimulation time for each session will be 25 minutes.

Study Overview

• Status: Completed
• Conditions: Parkinson Disease; Brain Stimulation; Cerebellum
• Intervention / Treatment: Device: Sham transcranial direct current stimulation; Device: Transcranial direct current stimulation at 2 mA; Device: Transcranial direct current stimulation at 4 mA

Detailed Description

Parkinson's disease (PD) is the second most common neurodegenerative disorder and affects approximately 1 million people in the United States with total annual costs approaching 11 billion dollars. The most common symptoms of PD are tremor, stiffness, slowness, and trouble with balance/walking, which lead to severe impairments in performing activities of daily living. Current medical and surgical treatments for PD are either only mildly effective, expensive, or associated with a variety of side-effects. Therefore, the development of practical and effective add-ons to current therapeutic treatment approaches would have many benefits. Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that can affect brain activity and can help make long-term brain changes to improve functions like walking and balance. While a few initial research studies and review articles involving tDCS have concluded that tDCS may improve PD walking and balance, many results are not meaningful in real life and several crucial issues still prevent tDCS from being a useful add-on intervention in PD. These include the selection of stimulation sites (brain regions stimulated) and tDCS electrode placement. Most studies have targeted the motor cortex (brain region that controls intentional movement), but there is evidence that the cerebellum - which helps control gait and balance, is connected to several other brain areas, and is easily stimulated with tDCS - may be a likely location to further optimize walking and balance in PD. There is also evidence that certain electrodes placements may be better than others. Thus, the purpose of this study is to determine the effects of cerebellar tDCS stimulation using two different placement strategies on walking and balance in PD.

Additionally, although many tDCS devices are capable of a range of stimulation intensities (for example, 0 mA - 5 mA), the intensities currently used in most tDCS research are less than 2 mA, which is sufficient to produce measurable improvements; but, these improvements may be expanded at higher intensities. In the beginning, when the safety of tDCS was still being established for human subjects, careful and moderate stimulation approaches were warranted. However, recent work using stimulation at higher intensities (for example, up to 4 mA) have been performed in different people and were found to have no additional negative side-effects. Now that the safety of tDCS at higher intensities is better established, studies exploring the differences in performance between moderate (i.e., 2 mA) and higher (i.e., 4 mA) intensities are necessary to determine if increasing the intensity increases the effectiveness of the desired outcome.

Prospective participants will include 10 people with mild-moderate PD that will be recruited to complete five randomly-ordered stimulation sessions (baseline/SHAM, unilateral tDCS montage at 2 mA, unilateral tDCS montage at 4 mA, bilateral tDCS montage at 2 mA, and bilateral montage at 4 mA), separated by at least 5 days. Each session will involve one visit to the Integrative Neurophysiology Laboratory (INPL) and will last for approximately one hour. Data collection is expected to take 4-6 months. Each session will include gait (30-meter walk test [30mWT], 6-minute walk test [6MWT], Timed Up and Go [TUG]) and balance testing (standing on a force platform with either a firm surface or a foam surface) performed in conjunction with one of the five randomly-ordered stimulation conditions (SHAM, unilateral 2 mA, unilateral 4 mA, bilateral 2 mA, and bilateral 4 mA). Total tDCS stimulation time for each session will be 25 minutes. Gait characteristics (i.e., gait speed, stride length, step length, toe-off angle, etc.) and distance walked during the 30mWT and 6MWT will also be determined with inertial sensors (OPAL motion sensors).

• Study Type: Interventional
• Enrollment (Actual): 7
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Iowa
    • Iowa City, Iowa, United States, 52242
      • University of Iowa

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 50 years to 90 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• 1) Adult (50-90 yrs) with a positive diagnosis of Parkinson's disease from a movement disorder specialist
• 2) an unchanged regimen of dopaminergic medication for at least the last 3 months
• 3) able to independently walk for 6 min
• 4) without other chronic psychiatric or medical conditions
• 5) not taking any psychoactive medications

Exclusion Criteria:

• 1) pregnant
• 2) known holes or fissures in the skull
• 3) metallic objects or implanted devices in the skull (e.g., metal plate, deep brain stimulator)
• 4) current or previous injuries or surgeries that cause unusual gait
• 5) score less than 24 or 17 on the Montreal Cognitive Assessment or telephone-Montreal Cognitive Assessment, respectively
• 6) experience freezing of gait
• 7) a diagnosis of dementia or other neurodegenerative diseases

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Sequential Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Sham and Experimental Sessions; 50% of participants will have a unilateral cerebellar montage with the anode (active electrode) three cm lateral to the inion on the side ipsilateral to the more PD-affected side and the cathode (return electrode) on the ipsilateral cheek. 50% of participants will have a bilateral cerebellar tDCS will have both electrodes placed 3 cm to either side of the inion, with the anode assigned to the most PD-affected side and the cathode assigned to the less PD-affected side. Stimulation is turned (2 mA) on for the 30 seconds at the beginning and the end of the trial, but it turned to 0 mA in the intervening time. A unilateral cerebellar montage will be applied. tDCS intensity will be 2 mA. Bilateral cerebellar tDCS will be applied. tDCS intensity will be 2 mA. A unilateral cerebellar montage will be applied. tDCS intensity will be 4 mA. Bilateral cerebellar tDCS will be applied. tDCS intensity will be 4 mA.

Device: Sham transcranial direct current stimulation; Uses weak electrical current (2 mA intensity) at the beginning and the end of a given stimulation period to control for potential placebo-like effects or participant expectation bias.; Other Names: Sham tDCS; Device: Transcranial direct current stimulation at 2 mA; Uses weak electrical current (2 mA intensity) to either increase or decrease brain excitability and improve functional or cognitive outcomes.; Other Names: tDCS; Device: Transcranial direct current stimulation at 4 mA; Uses weak electrical current (4 mA intensity) to either increase or decrease brain excitability and improve functional or cognitive outcomes.; Other Names: tDCS

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Speed Walked During 30 Meter Walk Test	Walk as fast and as safe as possible over 30 meter	10 minutes
Time to Complete the Timed Up and Go Test	From a seated position, stand up, walk 5 meters, turn around, walk back, and sit back down in the chair.	10 minutes
Movement of the Center of Pressure (2D; Forward-backward, Left-right) While Standing on a Firm Surface (Force Platform) for 1 Minute	Stand as still as possible on a firm surface for 1 minute with the eyes open. Calculate the area of an ellipse that contains 95% of the 2D trace of the center of pressure movement.	1 minute
Movement of the Center of Pressure (2D; Forward-backward, Left-right) While Standing on a Foam Surface (6 cm Foam Pad Placed on Top of Force Platform) for 1 Minute	Stand as still as possible on a foam surface for 1 minute with the eyes open. Calculate the area of an ellipse that contains 95% of the 2D trace of the center of pressure movement.	1 minute

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Movement of the Center of Pressure (1D; Forward-backward) While Standing on a Firm Surface (Force Platform) for 1 Minute	Stand as still as possible on a firm surface for 1 minute with the eyes open.	1 minute
Movement of the Center of Pressure (1D; Left-Right) While Standing on a Firm Surface (Force Platform) for 1 Minute	Stand as still as possible on a firm surface for 1 minute with the eyes open.	1 minute
Movement of the Center of Pressure (1D; Forward-backward) While Standing on a Foam Surface (6 cm Foam Pad Placed on Top of Force Platform) for 1 Minute	Stand as still as possible on a foam surface for 1 minute with the eyes open.	1 minute
Movement of the Center of Pressure (1D; Left-Right) While Standing on a Foam Surface (6 cm Foam Pad Placed on Top of Force Platform) for 1 Minute	Stand as still as possible on a foam surface for 1 minute with the eyes open.	1 minute

Collaborators and Investigators

• Sponsor: Thorsten Rudroff
• Investigators: Principal Investigator: Thorsten Rudroff, PhD, University of Iowa

Study record dates

Study Major Dates

• Study Start (Actual): December 1, 2019
• Primary Completion (Actual): April 1, 2020
• Study Completion (Actual): April 1, 2020

Study Registration Dates

• First Submitted: August 2, 2019
• First Submitted That Met QC Criteria: August 2, 2019
• First Posted (Actual): August 6, 2019

Study Record Updates

• Last Update Posted (Actual): November 10, 2022
• Last Update Submitted That Met QC Criteria: October 16, 2022
• Last Verified: October 1, 2022

More Information

Terms related to this study

• Keywords: transcranial direct current stimulation; walking; balance
• Additional Relevant MeSH Terms: Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Parkinsonian Disorders; Basal Ganglia Diseases; Movement Disorders; Synucleinopathies; Neurodegenerative Diseases; Parkinson Disease
• Other Study ID Numbers: 201906759

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No

Drug and device information, study documents

• 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.: No