According to a new study, highly targeted electrical stimulation to the brain showed promise as a new treatment for the most common type of stroke.
The study is the first in humans to test the feasibility of using a targeted type of electrical current, known as high-definition cathodal transcranial direct current stimulation (HD C-tDCS), to treat acute ischaemic stroke.
In this new study, researchers tested HD C-tDCS as a novel therapy for acute ischaemic 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 type of noninvasive 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 that it could 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, called the penumbra, from irreversible injury.
This pilot included 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, and were within 24 hours of stroke onset.
Seven patients were randomised to receive active HD C-tDCS, 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.
Lead researcher of the study, Mersedeh Bahr-Hosseini, says: “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.
“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 3 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.
The researchers were able to efficiently provide the treatment in emergency settings, and patients tolerated the treatment.
Bahr-Hosseini says the most exciting discovery 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 0 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. She says: “That was also very exciting, because it showed a possibly true biological effect of the treatment.”
