Science

Paraplegic man walks again thanks to new technology

A study at the University of California has allowed a paraplegic man to walk again by utilising his brain signals to control the muscles in his legs. While similar experiments and technology using brain signals have been used for movement after paralysis or amputation before, this is believed to be the first time ambulation has been achieved in a person with a spinal cord injury without the use of prosthetics or an exoskeleton.

The patient was initially trained to control walking and idling (staying still) in a virtual reality environment via a cap which monitors changes in electronic signals from the brain. This served two purposes – both training the patient in how to operate the system but also in re-stimulating the areas of motor control related to walking, believed to be supressed after spinal cord injury and paralysis. Once he became proficient at this, he then performed suspended walking tasks, before finally walking along a 3.66 metre course on his 20th session, with the aid of a walking frame and a harness to relieve some of his weight.

The system works by the ‘EEG’ cap transmitting the signals to a computer, which codes these as ‘walk’ or ‘idle’. This command is then sent to a control box positioned on the patient’s belt, and then activates electrodes that stimulate the anterior muscles of the patient’s leg.

Though the patient controls his legs with thought, one of the researchers told Radio 4 that “It’s not so much that he’s thinking ‘move the right leg and than move the left leg’… really he has the control of a general concept of walk or not walk.”

Though a fantastic achievement, this is really a ‘proof of concept’ study to show that further research is necessary and worthwhile to further develop brain-computer interface technology for walking. The current, non invasive, technology is highly cumbersome, however if it can be proved to work for a wider population of people with spinal cord injury, a permanent, invasive form of this therapy may be developed. Dr Nenadic said, “We are in the process of designing an implantable version of the system that can yield brain signals of higher quality and thus facilitate more accurate control. The implant could also be used to deliver sensory feedback to the brain, so that the subjects could feel their legs as they are walking.”

Though this may seem like an extreme (and expensive) solution, the bulk of medial costs for paraplegic patients actually come from conditions relating to inactivity or wheelchair use, such as osteoporosis, respiratory illness or pressure ulcers. In addition, surveys have indicated that patients with spinal column injuries consider restoration of walking to be a priority in their quality of life, and 60 per cent would be willing to have such an implant fitted.

Though this is only the first step in such technology, it is proof that what seems impossible may be achieved within our lifetimes.

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