- Researchers from UCLA Health have conducted a pilot study on the effectiveness of precise electrical brain stimulation as a potential treatment for acute ischemic stroke.
- The study utilized a technique called high-definition cathodal transcranial direct current stimulation (HD C-tDCS), targeting the specific brain regions affected by reduced blood flow.
- Initial results showed promising outcomes, with a median rescue of 66% of the endangered brain tissue surrounding the stroke core in patients receiving HD C-tDCS.
The new study, published in
Acute ischemic stroke is characterized by a clot obstructing blood flow to a specific region of the brain and it is one of the most common forms of stroke, accounting for approximately
Many individuals are not eligible for the primary treatments presently offered for acute ischemic stroke, which include clot-dissolving medications and a device used to physically extract clots from the bloodstream, due to the time of onset of the event.
For example, some treatments, such as tissue plasminogen activator (tPA), are typically administered within 3 to 4.5 hours after the onset of the stroke, but many people do not reach the hospital in such a short time frame.
Furthermore, among those who do qualify for these treatments, only approximately 20–30% achieve a state of being free from disabilities 3 months following their stroke.
This technique involves positioning a series of electrodes on the scalp to administer a mild inhibitory electrical current to the region of the brain affected by reduced blood flow.
Although this noninvasive stimulation method has been previously used to treat specific neurological and psychiatric disorders, the researchers observed that the electrical currents seemed to have an impact on brain blood flow.
Based on this observation, the researchers hypothesized that HD C-tDCS could potentially improve blood circulation in stroke-affected brain areas and safeguard the vulnerable brain tissue, referred to as the penumbra, from irreversible damage.
The initial phase of the study included a cohort of 10 individuals who had experienced an acute stroke and either sought immediate medical attention in the emergency department or were admitted to neuro-intensive care and stroke units.
These participants were deemed ineligible for existing treatments and were within 24 hours of experiencing the onset of their stroke.
Out of the 10 patients, seven were randomly assigned to receive active HD C-tDCS treatment, while the remaining three received a simulated or “sham” form of stimulation.
By employing hemodynamic brain scans typically administered to acute stroke patients upon their arrival, the researchers accurately identified the region of the stroke that exhibited reduced blood flow, and subsequently directed the HD C-tDCS treatment to that specific area.
The implementation of HD C-tDCS allowed the researchers to fine-tune the electrical field and concentrate it solely on this specific area, refining its effectiveness.
During the initial phase of the study, the first group of patients, consisting of three individuals in the treatment group and one individual in the sham group, underwent a 20-minute session of stimulation at a dosage of 1 milliamp.
For the remaining patients, the stimulation dosage was increased to 2 milliamps and administered for a duration of 20 minutes.
The researchers were able to effectively administer the treatment within emergency settings, and the patients demonstrated good tolerance to the procedure.
Among patients who received HD C-tDCS, there was a median rescue of 66% of the penumbra, which refers to the endangered brain tissue surrounding the core of the stroke, within the initial 24 hours following the stroke.
In contrast, the sham group exhibited no rescue of the penumbra, indicating a stark contrast in outcomes.
The hemodynamic brain scans conducted shortly after the treatment revealed improved blood flow in patients who received HD C-tDCS, with greater improvements observed in those who received a dosage of 2 milliamps compared to 1 milliamp.
Conversely, the sham group exhibited a decline in blood flow. This is a significant finding, as it suggested a potentially genuine biological impact of the treatment.
A future study involving multiple institutions, including Johns Hopkins, Duke University, and the University of Pennsylvania, is being planned by the researchers to acquire additional data regarding the safety and effectiveness of the treatment.
Dr. Nishant Mishra, a neurology specialist at Yale New Haven Hospital and assistant professor at Yale School of Medicine, not involved in this research, explained the background to Medical News Today.
“Ischemic stroke is a significant disease burden worldwide,” he told us, “and only two interventions — thrombolytics and
“Based on the data from the animal studies, the authors hypothesize that cathodal transcranial direct current stimulation can offer a neuroprotective effect in patients with ischemic brain tissue at risk of infarction,” Dr. Mishra said.
“The neuroprotective effect is believed to be due to the inhibitory effect of the current on the post-stroke excitotoxic, inflammatory, and apoptotic pathways and through its vasodilatory effect on collateral perfusion,” he explained.
Dr. Adi Iyer, a neurosurgeon and interventional neuroradiologist at Providence Saint John’s Health Center in Santa Monica, CA, also not involved in the study, told MNT that “this is very exciting work on minimizing the damage to brain tissue during acute ischemic stroke.”
“Generally when a patient is having a stroke, a blood clot gets lodged in one of the major arteries of the brain resulting in a large territory of brain tissue at risk of irreversible damage. While we have advances in new therapies to remove blood clots in the brain with catheters and wires, there are often delays in performing this procedure, and some patients may not even be candidates for this.”
– Dr. Adi Iyer
Dr. Mishra cautioned that “whereas I find the hypothesis underlying this intervention promising, it is currently not ready for use in routine clinical practice.”
However, he also noted that “eagerly awaits the intervention’s safety and efficacy data from future larger clinical trials using a study design acceptable to our regulatory body.”
“We will be able to offer cathodal transcranial direct current stimulation to ischemic stroke patients currently ineligible for thrombolytic and/or endovascular therapy,” Dr. Mishra explained, as long as “future clinical trials demonstrate that the cathodal transcranial direct current stimulation is safe and efficacious in humans and the U.S. FDA clears this intervention.”
“This pilot study provides the authors with preliminary data to guide the design of a larger clinical trial to test the safety and efficacy of cathodal transcranial direct current stimulation in ischemic stroke patients,” he noted.
Dr. Iyer agreed, saying, “high definition cathodal direct current stimulation has tremendous potential to keep brain tissue viable while stroke patients are waiting to undergo clot removal, as well as for those who don’t qualify.”
“Because high definition cathodal direct current stimulation is non-invasive, I can envision that one day patients having strokes can be treated with this modality sooner in the emergency room or even in the ambulance on the way to the hospital to minimize their overall stroke burden.”
– Dr. Adi Iyer