The National Institute of Neurological Disorders and Stroke, part of the National Institutes of Health, is looking for individuals to participate in clinical studies. Participating in clinical trials allows you to play an active role in research on the nature and causes of many disorders of the brain and nervous system, and to possibly help physician-scientists develop future treatments. The information below is designed to help you quickly learn about actively recruiting research studies for which you or someone you know may be eligible.


The passage of weak DC currents across the head (DC polarization) has been done for centuries with various effects reported. Many of the reports and studies of DC effects in humans are, however, archaic, anecdotal, uncontrolled, or scientifically baseless. Recently, it has been shown by objective means, in controlled experiments, that this type of treatment has robust and lasting effects on the excitability of the motor cortex in healthy humans. In vitro and animal experiments have revealed little about the mechanism of this effect, but neither has convincing evidence of toxicity been found at moderate doses. Therefore, we are becoming interested in whether this type of treatment can be used to improve cognitive processing in individuals with brain lesions, particularly of the prefrontal cortex. The purpose of this project is to prepare the way for clinical trials by beginning to establish the safety of this technique in humans and then to look for preliminary evidence of potentially useful effects on cognition when moderate doses are applied to the prefrontal cortex. First, we propose to test the safety of 20 min of anodal and cathodal DC applied the left prefrontal area, at 1 mV, by looking for clinical-level effects on verbal fluency, cognitive processing speed, EEG, mood, or motor reaction speed after exposure. The duration of exposure in this study will match the time required to gather preliminary efficacy data in healthy controls and patients. Then, in a dose-finding study, we propose to find the anodal DC amperage necessary for producing a clear effect on excitability, as measured by an increase in the amplitude of the motor evoked potential to transcranial magnetic stimulation. Then, if no significant adverse effects are in the first two studies, a preliminary efficacy study will look for differences in these measures between groups receiving anodal, cathodal, and sham DC of the left prefrontal cortex during stimulation.

Eligibility Criteria:

INCLUSION CRITERIA: Participants will be right-handed healthy volunteers aged 18-80 with greater than or equal to 12 years of education. Subjects must perform within one standard deviation of the mean on screening with the verbal fluency test. EXCLUSION CRITERIA: Current serious medical or psychiatric condition of any kind. History of any significant trauma or medical condition affecting the brain or skull. History of epileptic seizure. History of significant psychiatric illness, i.e. requiring medication or hospitalization. Current use of neuroactive medication or recreational drugs. History of attention deficit-hyperactivity disorder (ADHD), learning disorder, or any other cognitive deficit. Pregnancy. Presence of metal in the head other than dental hardware. Broken skin in the area of the stimulating electrodes.

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