Highly targeted electrical stimulation to the brain has showed promise as a new treatment for the most common type of stroke, according to a new study.
The pilot study was the first in humans to test the feasibility of using a targeted type of electrical current, called high-definition cathodal transcranial direct current stimulation (HD C-tDCS), to treat acute ischemic stroke, which accounts for around 85 per cent of all strokes.
In the new research, UCLA Health researchers tested HD C-tDCS as a novel therapy for acute ischemic stroke, in which a series of electrodes are strategically placed across the scalp to deliver a weak inhibitory form of electrical current to the part of the brain suffering from low blood flow.
This form of non-invasive stimulation has been used to treat certain neurological and psychiatric conditions, and the researchers had noted the electrical currents appeared to have an effect on the brain’s blood flow.
The researchers theorised it may be possible to use HD C tDCS to enhance blood flow to parts of the brain impacted by stroke and protect the threatened brain tissue, known as the penumbra, from irreversible injury.
The pilot study involved ten acute stroke patients who went to A&E or were admitted at neuro-intensive care and stroke units, were ineligible for currently available treatments, and were within 24 hours of stroke onset. Seven patients were randomised to receive active HD C-tDCS treatment, and three received ‘sham’ stimulation.
Using hemodynamic brain scans that acute stroke patients receive upon arrival, the researchers located the stroke area with low blood flow to where the HD C-tDCS treatment was delivered.
“This treatment was aimed at being as targeted and as individualized as possible, only to the area of the brain that has low blood flow or is suffering from stroke,” said lead researcher Dr Mersedeh Bahr-Hosseini, a vascular neurologist at UCLA Health.
“With this high-definition form of C-tDCS, we were able to refine this electrical field to focus it just on this area.”
The first set of patients, which included three patients in the treatment arm and one in the sham group, received 20 minutes of 1 milliamp of stimulation. In the remaining patients, the dose was escalated to 2 milliamps for 20 minutes.
Researchers were able to efficiently provide the treatment in emergency settings, and patients tolerated the treatment.
Dr Bahr-Hosseini said the most exciting finding was that in patients receiving HD C-tDCS, a median of 66 per cent of the penumbra – the threatened brain tissue surrounding the core of the stroke – was rescued in the first 24 hours after stroke, compared to zero per cent in the sham group.
According to the hemodynamic brain scans performed soon after treatment, patients who received HD C-tDCS showed signs of improved blood flow that was greater in patients receiving 2 milliamps compared to 1 milliamp. In contrast, the blood flow decreased in sham group.
“That was also very exciting, because it showed a possibly true biological effect of the treatment,” she said.
Researchers are planning a new multi-site study with Johns Hopkins, Duke University, and the University of Pennsylvania, to gather more data on the treatment’s safety and efficacy. The next study will also include patients who are eligible for the clot-dissolving drugs, known as intravenous thrombolytics.
