Scientists from Oxford University say that a particular variant of transcranial direct current stimulation (tDCS) has a positive, long-term effect on the ability of stroke victims to move their arms when combined with a nine-day course of physical therapy.
The experimental treatment involves attaching electrodes to a person’s head and running direct current through the leads while the patient undergoes a series of therapeutic exercises meant to help limbs weakened or paralyzed by stroke. Crucially, according to the researchers, the anode (positive electrode) is attached to the side of the head where the patient’s stroke damage occurred. Variations in electrode polarity and placement maybe one reason that tDCS’ effects on memory and cognition have been so inconsistent.
Twelve patients were treated, while twelve experienced a sham treatment—they got the physical therapy and wore the electrodes, but no current flowed.
On two of three measures of recovery, patients that received tDCS during their therapy were significantly better off even three months later. In fact, the difference between those in the therapy and conrol groups only grew more pronounced as time went on. MRI scans of the patients’ brains showed that those in the tDCS group had more activity in the relevant brain areas for motor skills than those in the control group.
The Oxford scientists hope that tDCS can make a little therapy go a long way. “For stroke patients, longer and more intensive training leads to greater recovery. However, cost and staff availability limit what can be provided,” Heidi Johansen-Berg, a professor of cognitive neuroscience at Oxford said in a press release. “That means that there is increasing interest in therapies that can be used to boost the effects of training.”
Johansen-Berg and her colleagues reported their results in this week’s issue of Science Translational Medicine.
tDCS isn’t the only technological fix in the works for stroke. Houston, Texas–based Microtransponder has been developing an implant to help remodel the brain after stroke or to battle tinnitus. That company’s system sends pulses along the vagus nerve in the neck and up into the brain while the patient undergoes physical therapy designed to improve movement. This stimulation is thought to release neurochemicals that make the brain better able to adapt and learn.
Samuel K. Moore is the senior editor at IEEE Spectrum in charge of semiconductors coverage. An IEEE member, he has a bachelor's degree in biomedical engineering from Brown University and a master's degree in journalism from New York University.