New hope for victims of spinal cord injury

 

A HUSBAND and wife research team from Arizona State University have combined medicine and engineering to devise a unique system of recovery after spinal cord injury.

People who have been involved in car accidents and cannot walk, children with cerebral palsy and sufferers of neurodegenerative conditions like Parkinson’s disease, may benefit from the revolutionary technology.

Speaking at NUI Galway (NUIG) last week, Prof James J Abbas and Prof Ranu Jung explained how electrical stimulation of paralysed muscles can help restore mobility – allowing people to walk again in certain cases, and to exercise and improve quality of life in others.

The couple, who work at Arizona State University’s Centre for Adaptive Neural Systems, were hosted by NUIG’s National Centre for Biomedical Engineering Science (NCBES) for their lecture.

As they explained, disability’s impact extends from the individual to the healthcare system and society.

Neurological disabilities are devastating in terms of their impact on lifestyle, the duration of their impact and the costs associated with the disability.

The research agenda for the Centre for Adaptive Neural Systems (ANS) “intersects bioengineering, neuroscience and rehabilitation”, they explained.

Its multidisciplinary team comprises engineers, clinicians and scientists with a wide range of expertise from electrical, mechanical and biomedical engineering, to neurosurgery and physical therapy, and neuroscience, physiology, exercise science and kinesiology.

Not only are they designing and developing new neural prostheses and advanced mechanical prosthetic systems, but they are also focusing on complementing the work of therapists to restore mobility and “functionality”. As Prof Abbas told the NUIG audience, muscles are so complex that most engineers would never design them.

Prof Jung, his partner, explained that their research studies began with lamprey eels, which can still move without the brain. The spinal cord contains two “brain segments”, and even half of a segment can provide rhythmic activity, they noted.

The US army had commissioned them to produce a neuromorphic control system for powered limb splints. In developing this work, they focused on the fact that spinal cord injury has two phases – the initial impact from a bad fall or car accident or gunshot wound, and the second injury caused by inflammation and a “response cascade”.

They found that if they could minimise the secondary injury, they could encourage nerves to re-organise – similar to the work done by physiotherapists.

If healthy cells in muscle were stimulated sufficiently, they could re-activate sufficiently to help people in wheelchairs to stand, even take steps. The challenge was to identify how much stimulation to give, using a train of short low-level electrical pulses.

The couple took a “pattern generator” model of movement, combined it with an adaptive filter or “pattern shaper” to suit an individual, and developed a device, drawing on algorithms and electronic circuits that mimic the functionality of neuromotor control systems. Their neuromorphic adaptive controller ensures that muscles contract at the right time and this in turn helps to “re-organise” the spinal cord through repeated movements – on a treadmill or other exercise machine. Tests on rates showed that even after only one week with the adaptive controller, improvements in movement could be detected.

“Whereas therapists can repeat movement patterns with patients, they can’t compete with electrical stimulation to produce the same effect,” they explained. They are now working on neuromotor therapy for children with cerebral palsy.

Prof Lokesh Joshi of the NCBES described the Jung-Abbas team as “truly translational and unique” in combining electrical and mechanical engineering, physiological science and clinical research.