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tDCS Brain Hacking Tech Boosts Stroke Recovery

Zapping the brain during therapy has long-lasting effects for stroke rehabilitation

2 min read
tDCS being performed on a healthy volunteer

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.

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Restoring Hearing With Beams of Light

Gene therapy and optoelectronics could radically upgrade hearing for millions of people

13 min read
A computer graphic shows a gray structure that’s curled like a snail’s shell. A big purple line runs through it. Many clusters of smaller red lines are scattered throughout the curled structure.

Human hearing depends on the cochlea, a snail-shaped structure in the inner ear. A new kind of cochlear implant for people with disabling hearing loss would use beams of light to stimulate the cochlear nerve.

Lakshay Khurana and Daniel Keppeler

There’s a popular misconception that cochlear implants restore natural hearing. In fact, these marvels of engineering give people a new kind of “electric hearing” that they must learn how to use.

Natural hearing results from vibrations hitting tiny structures called hair cells within the cochlea in the inner ear. A cochlear implant bypasses the damaged or dysfunctional parts of the ear and uses electrodes to directly stimulate the cochlear nerve, which sends signals to the brain. When my hearing-impaired patients have their cochlear implants turned on for the first time, they often report that voices sound flat and robotic and that background noises blur together and drown out voices. Although users can have many sessions with technicians to “tune” and adjust their implants’ settings to make sounds more pleasant and helpful, there’s a limit to what can be achieved with today’s technology.

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