Exploring Mechanisms for Neuropsychiatric Symptoms of Parkinson Disease Using Transcranial Direct Current Stimulation

Study Overview
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Brief Summary
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This study evaluates the effect of transcranial direct current stimulation (tDCS) on non-motor symptoms of Parkinson's disease, including depression and cognitive symptoms. Participants are randomized to receive active or sham tDCS for 30 minutes over 10 treatment sessions.

Official Title
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Exploring Mechanisms for Neuropsychiatric Symptoms of Parkinson Disease Using Transcranial Direct Current Stimulation

Conditions
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Idiopathic Parkinson's Disease, Parkinson Disease, Depression

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: Abel to provide written informed consent is obtained in the English language Age 18 to 95 years old Movement Disorder Society Clinical Diagnostic Criteria for probable idiopathic Parkinson disease Report disabling depressive or neuropsychiatric symptoms prior to study entry Capacity to understand the nature of the study; Exclusion Criteria: Known structural brain disease such as a neoplasm, abscess etc. Pre-existing skull / scalp defects that would impede standardized electrode placement Current electronic or metal implants Diagnosis of Bipolar Disorder, Post-Traumatic Stress Disorder, a Psychotic Disorder or any other non-unipolar depressive disorder as a principal diagnosis in the 6 months prior to screening; Concurrent treatment with medication which may affect tDCS (benzodiazepines, anticonvulsants, dextromethorphan and pseudoephedrine) Endorse active suicidal ideation at enrollment or during any study visit, or have attempted suicide in the six months prior to screening; History of substance abuse or dependence in the 2 months prior to screening; Considered to be at significant risk of committing homicide; Unstable medical condition; Score less than 22 on the Montreal Cognitive Assessment (MoCA) Women of childbearing potential who are pregnant or are considering becoming pregnant during the length of the study; There has been a change in their depression or psychotherapy treatment regimen in the 2 weeks preceding screening;

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 95 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 |
| --- | --- |
| Sham Comparator: Sham tDCS<br>Sham transcranial direct current stimulation where current will be reduced to zero after standardized ramp up to 2 mA | Device: Transcranial Direct Current Stimulation<br>* Transcranial direct current stimulation (tDCS) is a commonly used non-invasive form of brain stimulation for studying motor functions in health and disease [36]. It involves the attachment of surface electrodes to the scalp through which very small electric currents (1 or 2mA) are applied via a current regulated device. The currents do not produce any sensation. The applied current affects excitability of underlying neural tissue.<br>* Other names: Neuromodulation;|
| Experimental: Active tDCS<br>Transcranial direct current stimulation according to protocol maintained for 30 minutes after ramping up to 2 mA | Device: Transcranial Direct Current Stimulation<br>* Transcranial direct current stimulation (tDCS) is a commonly used non-invasive form of brain stimulation for studying motor functions in health and disease [36]. It involves the attachment of surface electrodes to the scalp through which very small electric currents (1 or 2mA) are applied via a current regulated device. The currents do not produce any sensation. The applied current affects excitability of underlying neural tissue.<br>* Other names: Neuromodulation;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Participants Demonstrating improvements on Objective Rating Scales of Depression via structured interview | Primary outcome measure will be the number of participants who demonstrate remission of depressive symptoms OR improvement of 50% (i.e. response) on the Montgomery-Asberg Scale of Depression (MADRS) | 1 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Apathy Scores as measure by a self-report scale (the Apathy Scale) | The dimensional degree of change in Apathy symptoms as assessed via the Apathy Scale, a subjective self-report tool of apathetic symptoms | 1 months | 
| Subjective Depression Severity rated via self-report on depression inventory | Subjective severity of depression as measured via self-reported Beck Depression Inventory - II | 1 months | 
| Subjective reactive to pleasure (i.e. improvement of anhedonia) as rated via self-report | Monitoring degree of change of hedonic-tone scores via the Snaith-Hamilton Pleasure Scale (SHAPS) | 1 month | 
| Subjective improvement of Anxiety Symptoms via Rating Scale | The change in Parkinson Anxiety Scale (PAS) score per person and across sham v. experimental groups. | 1 month | 
| Performance on abbreviated cognitive battery | Objective improvement on measures of attention, verbal fluency, working memory and recall by various bedside cognitive tests | 1 month | 
| Improvement of Parkinsonian Motor Symptoms | Number of participants between arms and individual improvement of Movement Disorders Society Unified Parkinson Disease Rating Scale Part 3 (MDS-UPDRS Pt3) Score. | 1 month |