Paraplegics Take a Step to Regain Movement

Estimated reading time: 7 minutes

The Walk Again Project has brought together more than 100 scientists from 25 countries, who first made news at the 2014 World Cup in São Paulo when Julian Pinto, a young paraplegic man, using a brain-controlled robotic exoskeleton, was able to kick a soccer ball during the opening ceremony.

The Walk Again Project also launched the neuro-rehabilitation study in São Paulo that year. The eight patients spent at least two hours a week using brain-machine interfaces, or devices controlled through their brain signals. All began the program by learning how to operate their own avatar, or digital likeness, in a virtual reality environment.

The patients wore fitted caps lined with 11 non-invasive electrodes to record their brain activity through EEG. Initially, when participants were asked to imagine walking in the virtual environment, scientists didn’t observe the expected signals in the areas associated with motor control of their legs.

“If you said, use your hands, there was modulation of brain activity,” Nicolelis said. “But the brain had almost completely erased the representation of their lower limbs.”

After months of training, scientists began to observe the brain activity they expected to see when the patients’ thought about moving their legs. “Basically, the training reinserted the representation of lower limbs into the patients’ brains,” Nicolelis said.

As they progressed, patients graduated from virtual reality to more challenging equipment that required more control over their posture, balance and ability to use their upper limbs, including two commercially available walking devices used in some physical therapy centers in the United States: the ZeroG and the Lokomat. Both use overhead harnesses to support a patient’s weight as they build strength and proper gait after paralysis due to injury or neurological conditions such as stroke.

The patients rotated through other training systems that applied robotics, including the exoskeleton Pinto wore at the 2014 World Cup.

During most of their training, the participants also wore a sleeve equipped with touch-technology called haptic feedback to enrich the experience and train their brains, Nicolelis said. Haptics use varied vibrations to offer tactile feedback, much like the buzzing jolts or kickbacks gamers feel through a handheld controller.

Each sensation is unique. So when the avatar walked on sand, the patient felt a different pressure wave on the forearm than when they walked on grass or asphalt, Nicolelis said.

“The tactile feedback is synchronized and the patient’s brain creates a feeling that they are walking by themselves, not with the assistance of devices,” Nicolelis said. “It induces an illusion that they are feeling and moving their legs. Our theory is that by doing this, we induced plasticity not only at the cortical level, but also at the spinal cord.”

Next steps 

Nearly all of the patients described in the study have continued their rehabilitation, now exceeding two years of training, Nicolelis said. He and colleagues plan to publish additional data about participants’ continued progress. They also plan to create a new trial with patients who suffered more recent spinal cord injuries to see whether quicker treatment can lead to faster or better results.

The team also continues efforts to adapt technologies that are accessible for patients around the world who don’t have access to physical therapy centers with the latest equipment. Perhaps the best answer is haptic sleeves, which by comparison are affordable and something a patient could use at home, Nicolelis said.

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