Excitatory Prefrontal Weak Current Stimulation in Vegetative Patients

Study Overview
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Brief Summary
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In response to conscious EEG findings related to detectable cognitive function that reliably denote awareness in vegetative state patients, in the current study, we will assess the covert conscious EEG activity (as well as standard clinical overt measures) and neuroplasctic propensity (i.e., changes in EEG spectral power synchronization values following tDCS intervention) in vegetative-state patients receiving repetitive transcranial direct current stimulation (tDCS) treatment over frontal motor areas for a period of two weeks. In support of this approach, a recent tDCS study with vegetative and minimally conscious patients implied that a twenty minutes anodal stimulation (i.e., excitatory stimulation) to the left dorsolateral prefrontal cortex (DLPFC) significantly increased CRS-R scores versus sham (placebo: non-active stimulation) stimulation condition. It was noted that this tDCS effect was more pronounced in minimally conscious state patients versus vegetative state patients excluding effects of chronicity or etiology. Thus, the investigators in this study suggested that tDCS could be effective in improving cognitive recovery in severely brain-injured patients. However, their findings would benefit neural activation correlates that could support their conclusion regarding the effectiveness of this type of non-invasive intervention in promoting neurocognitive recovery. Most importantly, tDCS is safe for use in humans, has no adverse effects, is considered the most non-invasive transcranial stimulation method because it uses extremely weak currents (0.5 to 2 mA), and, is known to only temporarily shift the neuron's membrane potential towards excitation/inhibition. In regard to the method's potential to induce functional recovery in vegetative state patients, recent clinical studies indicate that tDCS could counteract the negative effects of brain damage by influencing neurophysiological mechanisms, and is likely to contribute to the formation of functionally meaningful connections and the maintenance of existing pathways .

Official Title
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Excitatory Prefrontal Weak Current Stimulation in Vegetative Patients:Potential to Induce Modulation in Neurocognitive Features of Awareness

Conditions
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Disorder of Consciousness, MMN, Modification of Cognitive Status Indication, Anoxic Brain Damage, Trauma, Brain, Vegetative State, EEG; Paroxysms, Occipital, Epilepsy of Childhood, Cortical Atrophy

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: Anoxic brain damage/TBI/CVA/progressive dementia/encephalopathy Vegetative state patients or minimally conscious state according to CRS-R criteria Ages 18 to 90 Consent for participation in clinical study (e.g., informed consent) by legal guardian of patients. Exclusion Criteria: Intracranial metal implants Implanted devices that may be affected by tDCS (pacemaker, medication pump, cochlear implant, implanted brain stimulator) Active medical condition that would preclude medical stability for the study, including significant ECG abnormalities, cardiac arrhythmia, uncontrolled high blood pressure Participation in other research studies

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 90 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
Intervention Model: Single Group Assignment
Interventional Model Description: open lable treatment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: active treatment<br>open label experimental treatment | Device: Transcranial direct current stimulation<br>* Non-invasive brain stimulation or neuromodulation.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| JFK COMA RECOVERY SCALE - REVISED | JFK Coma recovery Scale - Revised scores for diagnosing disorders of consciousness. This cynical assessment scale examines reflexive behaviors such as response to pain and startle, and touch. The CRS consists of 25 hierarchically arranged items that comprise 6 subscales addressing auditory, visual, motor, oro- motor, communication, and arousal processes. Scoring is based on the presence or absence of specific behavioral responses to sensory stimuli administered in a standardized manner. The lowest item on each subscale represents reflexive activity, whereas the highest items represent cognitively mediated behaviors. sub scales represent motor function, auditory function, visual function sub scales and arousal sub scales. The low scores indicate low levels of functioning and the higher score indicate high levels of function an awareness. Maximum score is 23 and a minimal score is 0. | 24 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| MMN ERP amplitudes | Prefronal-Temopral cortex neuroplasticity and reactivity to sound : size of early auditory processing ERP amplitudes. If the negative change in ERP amplitudes is larger than in indicates better change-detection and neurplasticity. | 2 weeks |