Highly targeted electrical stimulation to the brain has shown promise as a treatment option for acute ischaemic stroke, according to a pilot study led by University of California Los Angeles (UCLA) Health researchers in Los Angeles, USA.
The study is the first in humans to test the feasibility of using high-definition cathodal transcranial direct current stimulation (HD C-tDCS) to treat acute ischaemic stroke, as per a UCLA Health press release.
In the study, which is now published in JAMA Network Open, researchers tested HD C-tDCS as a novel therapy for the most common type of stroke. They initially noted that electrical currents appeared to have an effect on the brain’s blood flow, and 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 from irreversible injury.
The pilot study involved 10 acute stroke patients who presented to the emergency department, or were admitted at neuro-intensive care and stroke units; were ineligible for currently available treatments like intravenous thrombolysis or mechanical thrombectomy; 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 haemodynamic brain scans that acute stroke patients receive upon arrival, the researchers located the stroke area with low blood flow to which the HD C-tDCS treatment was subsequently delivered.
“This treatment was aimed at being as targeted and as individualised as possible—only to the area of the brain that has low blood flow or is suffering from stroke,” said the lead researcher on this project, Mersedeh Bahr-Hosseini (UCLA Health, Los Angeles, USA). “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 a single milliamp of stimulation. In the remaining patients, the dose was escalated to two milliamps for 20 minutes.
Researchers were able to efficiently provide the treatment in emergency settings, and found that it was well tolerated by the patients. Bahr-Hosseini said the most exciting finding was that, in patients receiving HD C-tDCS, a median of 66% of the penumbra—the threatened brain tissue surrounding the core of the stroke—was rescued in the first 24 hours after stroke, compared to 0% in the sham group.
According to the haemodynamic brain scans performed soon after treatment, patients who received HD C-tDCS showed signs of improved blood flow that was greater in patients receiving two milliamps compared to one milliamp. In contrast, the blood flow decreased in the sham group.
“That was also very exciting, because it showed a possibly true biological effect of the treatment,” Bahr-Hosseini added.
Researchers are now planning a new multicentre study with Johns Hopkins (Baltimore, USA), Duke University (Durham, USA), and the University of Pennsylvania (Philadelphia, USA), to gather more data on the treatment’s safety and efficacy. The next study will also include patients who are eligible for clot-dissolving intravenous thrombolytics.
