Neurophysiological Effects of tPCS and tDCS on Patients With Disorders of Consciousness

Study Overview
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Brief Summary
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This study aims at comparing the effects of transcranial direct current stimulation and transcranial pulsed current stimulation on neurophysiological outcomes on patients with disorders of consciousness. This study also aims to evaluate the effects of these techniques on patients' level of consciousness.

Official Title
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Neurophysiological Effects of tPCS and tDCS on Patients With Disorders of Consciousness

Conditions
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Disorders of Consciousness

Intervention / Treatment
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* Device: Active tPCS
* Device: Active tDCS
* Device: Sham tPCS
* Device: Sham tDCS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Fluent in English or French Legally authorized surrogate available to provide informed consent History of non-traumatic brain injury with loss of consciousness caused by stroke, cerebral hemorrhage, hypoxic ischemic insult, metabolic disorder or infection. Has been followed clinically on the CRS-R for a minimum two weeks and has undergone a minimum of 4 assessments with the CRS-R. Serial CRS-R scores show at least one subscale on which there is no behavioral sign of conscious awareness (ie, command following, visual fixation or pursuit, object localization or recognition, localization to noxious stimulation, object manipulation, automatic motor responses, functional object use, discernable speech, discernable yes no communication, based on clinically obtained scores contained in the medical record). CRS-R screening examination completed by research staff confirms the absence of a behavioral sign of consciousness on a least one CRS-R subscale. Medically stable (i.e., no systemic illness or disease) and capable of independent ventilation Exclusion Criteria: History of developmental, neurologic, or major psychiatric disorder resulting in functional disability up to time of enrollment. Evidence or surrogate report of uncontrolled seizure disorder Metallic brain implant or implanted electronic brain medical devices or pacemaker Subjects with craniectomy History of cranioplasty in the frontal region or recent cranioplasty that has not yet fully healed Pregnancy

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 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: Crossover Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Active tPCS / Sham tDCS<br>All subject will receive active tPCS and sham tDCS for 20 minutes simultaneously. | Device: Active tPCS<br>* A current intensity of 2na and a stimulation frequency range of 6-10 Hz will be used with a peri-auricular ear-clip electrode montage for 20 minutes.<br>Device: Sham tDCS<br>* Sham tDCS will consist of applying the same parameters as for active but the corresponding device will be turned off after 30 seconds as to simulate the initial sensation of the active current. A current of 2mA will still be used (but turned off after 30 sec). The electrodes that will be used will be the same as for the active tDCS condition and the electrodes placement as well.<br>|
| Experimental: Sham tPCS / Active tDCS<br>All subject will receive sham tPCS and active tDCS for 20 minutes simultaneously. | Device: Active tDCS<br>* A current intensity of 2mA will be used for 20minutes. The electrodes that will be used will be standard sponge electrodes. The anode will be place over the left prefrontal cortex and the cathode over the right supraorbitofrontal area.<br>Device: Sham tPCS<br>* Sham tPCS will consist of applying the same parameters as for active but the corresponding device will be turned off after 30 seconds as to simulate the initial sensation of the active current. A current of 2mA will still be used (but turned off after 30 sec). The electrodes that will be used will be the same as for the active tPCS condition and the electrodes placement as well.<br>|
| Experimental: Sham tPCS / Sham tDCS<br>All subject will receive sham tPCS and sham tDCS for 20 minutes simultaneously. | Device: Sham tPCS<br>* Sham tPCS will consist of applying the same parameters as for active but the corresponding device will be turned off after 30 seconds as to simulate the initial sensation of the active current. A current of 2mA will still be used (but turned off after 30 sec). The electrodes that will be used will be the same as for the active tPCS condition and the electrodes placement as well.<br>Device: Sham tDCS<br>* Sham tDCS will consist of applying the same parameters as for active but the corresponding device will be turned off after 30 seconds as to simulate the initial sensation of the active current. A current of 2mA will still be used (but turned off after 30 sec). The electrodes that will be used will be the same as for the active tDCS condition and the electrodes placement as well.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Signal coherence and EEG power as measured by Quantitative electroencephalographic analysis (qEEG) | EEG measures cortical electrical activity and examines the dynamic changes. | It will be measured over the course of about 3 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Coma Recovery Scale Revised (CRS-R) | The CRS-R is a standard clinical protocol used to assess patients' level of consciousness. This test measures the level of response to sensory stimulation, ability to understand language and to communicate. | It will be measured over the course of about 3 weeks |