Virtual reality helped improve nerve function in paralysed people

Friday August 12 2016

"Virtual reality has helped eight paralysed patients regain some feeling in their legs in 'a big surprise'," Sky News reports.

Researchers using virtual reality (VR) combined with a robotic exoskeleton were surprised to find participants regained some nerve function.

The people, eight in total, with paralysis and loss of sensation of both legs (paraplegia), were taking part in the Walk Again Neurorehabilitation programme. Paraplegia is usually caused by a spinal injury so nerve signals from the brain cannot reach the legs.

The programme combined the use of an exoskeleton designed to respond to electrical signals of the brain with VR that provided both visual and haptic stimulation. Haptic refers to the sensation of touch; it is haptic technology that causes smartphone screens to "respond" to your touch.

The technologies were combined to create a simulation of physical activity, such as taking part in a virtual football match.

Researchers expected the training would improve proficiency with using the exoskeleton. They were pleasantly surprised to discover it actually improved real-world nerve function.

All patients showed improvements in their ability to feel sensation and improved their control of key muscles as well as improving in their ability to walk.

The researchers have hypothesised that the virtual activity could help rekindle nerve connections in the spine that have previously lain dormant.

Participants had been paralysed for between 3-15 years. The research team are now planning to use the same technique on people who have only been paralysed for a short time, to see if beneficial effects are more significant.

Where did the story come from?

The study was carried out by researchers from a number of institutions, including the Associação Alberto Santos Dumont para Apoio à Pesquisa, University of Munich, Colorado State University and Duke University. Funding for the study was provided by the Brazilian Ministry of Science, Technology and Innovation. The authors declared no conflicts of interest.

The study was published in the peer-reviewed journal Science Reports, on an open-access basis, so it is free to read online.

The UK media reported on these results accurately and included quotes from the study authors expressing their disbelief in what they saw. "In virtually every one of these patients, the brain had erased the notion of having legs. You're paralysed, you're not moving, the legs are not providing feedback signals." said Professor Nicolelis, he went on to say: "By using a brain-machine interface in a virtual environment, we were able to see this concept gradually re-emerging into the brain."

BBC News also hosts a short video of one of the participants, who had previously been paralysed for years, taking some tentative steps on a treadmill.

What kind of research was this?

This study is a case report of eight people with paraplegia that aimed to explore to what degree brain-machine interfaces, combined with a VR rig, could help people with spinal cord injuries regain their ability to walk by using a brain-controlled exoskeleton.

Paralysis is loss of the ability to move one or more muscles. It may be associated with loss of feeling and other bodily functions. In this study participants had paraplegia – were paralysed in both legs. There aren't usually any problems with the leg muscles themselves, only somewhere along the course of transmitting sensory or motor nerve signals to or from the spinal cord and brain.

People with paraplegia are usually able to lead a relatively independent and active life, using a wheelchair to carry out their daily activities.

To establish whether this technology would work on a larger scale or on people with different levels of paralysis, further clinical trials would need to take place. 

What did the research involve?

The researchers recruited eight people with paraplegia who had chronic spinal cord injury.

Participants wore caps fitted with electrodes to read their brain signals and were asked to imagine moving their arms to create brain activity. Once this was mastered, the participants learnt how to use their own brain signals to control an individual avatar or robotic leg by imagining that they were moving their own legs. They were "connected" to the avatar through the use of a VR headset, that provided images, as well as a number of haptic sensors giving tactile feedback. So it both looked and felt like they were moving their legs.

These signals were read by the electrodes in the cap and used to control to the exoskeleton.

The researchers investigated more complex activities over the course of the study to ensure cardiovascular system stability and patient postural control. This involved various gait training robotic systems.

The six stages of activity were:

  • the patient was seated and their brain activity was recorded using an electroencephalogram (EEG) while they controlled the movements of a human body avatar in the VR environment
  • as above but whilst standing
  • training with body weight support system on a treadmill
  • training with body weight support system on an over ground track
  • training with a brain-controlled robotic body weight support system on a treadmill
  • training using a brain-controlled robotic exoskeleton

Clinical evaluations were carried out on the first day of the trial and then at 4, 7, 10 and 12 months. These evaluations included tests for:

  • level of impairment
  • temperature, vibration, pressure and sensitivity
  • muscle strength
  • trunk control
  • independence
  • pain
  • range of motion
  • quality of life

What were the basic results?

The eight participants in the study carried out 2,052 sessions, totalling 1,958 hours. After 12 months of training with robotic devices all patients made neurological improvements in terms of being able to feel pain and touch. 

Patients also improved their control of key muscles and made improvements in their ability to walk. As a result of this study, half of the participants had their level of paraplegia changed from complete to incomplete. 

How did the researchers interpret the results?

The researchers conclude: "Overall, the results obtained in our study suggest that [brain-machine interfaces, BMI] applications should be upgraded from merely a new type of assistive technology to help patients regain mobility, through the use of brain-controlled prosthetic devices, to a potentially new neurorehabilitation therapy, capable of inducing partial recovery of key neurological functions.

"Such a clinical potential was not anticipated by original BMI studies. Therefore, the present findings raise the relevance of BMI-based paradigms, regarding their impact on SCI (spinal cord injury) patient rehabilitation. In this context, it would be very interesting to repeat the present study using a population of patients who suffered a SCI just a few months prior to the initiation of BMI training. We intend to pursue this line of inquiry next. Based on our findings, we anticipate that this population may exhibit even better levels of partial neurological recovery through the employment of our BMI protocol."

Conclusion

This study reported on the use of brain controlled devices in eight people with paraplegia to establish whether they may be able to regain their ability to walk by using a brain-controlled exoskeleton.

The study found that all patients made neurological improvements in terms of being able to feel pain and touch and had improved their control of key muscles and made improvements in their ability to walk.

These results would appear to chime with the known plasticity of the nervous system and brain. It can continue to change and adapt to different environmental stimulus. So it may be possible that damaged nerve pathways that have been dormant for many years could be rekindled through these types of activities.

However, whilst this technology is exciting and could provide hope for people with spinal cord injury, it is still in the very early stages. These findings are based on just eight people. Many more stages of testing will be needed in people with different causes and severities of paraplegia to confirm whether this does have true potential and who could gain most benefit. For now, it is too soon to know if and when and it could become available.

The cost of VR technology continues to fall, while its sophistication continues to rise. So its use in mainstream rehabilitation at some point in the near future is certainly not in the realms of fantasy.   

Analysis by Bazian
Edited by NHS Choices