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Stroke patients get movie tech

Hollywood blockbusters provide the world with popcorn-fuelled escapism. One of the greatest leaps forward for the movie industry in recent times has been computer animation.

Now researchers have begun to use the same techniques used to create the “human” movements of Gollum in The Lord of the Rings trilogy and Na’vi from Avatar to form better treatments for stroke patients.

The effort is among the most innovative uses of cutting-edge technology to treat stroke victims, which have emerged from a new and better understanding of how the brain can develop following a stroke.

The project to use modern film-making techniques in stroke treatment comes from the University of Gothenburg in Sweden, where researchers are using motion capture technology, similar to that used to convert actors’ movements into computer animation, to analyse the movements of stroke patients.

Margit Alt Murphy and her team at the university’s Sahlgrenska Academy have devised techniques to translate the movements of stroke patients into 3D animations to give them extra layers of detail about their mobility that doctors and physiotherapists are unable to notice with the naked eye.

“Computer technology provides better and more objective documentation of the problem, in terms of the everyday life of the patient, than human observation can provide,” says Ms Alt Murphy.

“With 3D technology, we can measure a patient’s movements in numbers, which means that small changes in the motion pattern can be detected and fed back to the patient in a clear manner.”

People can relearn actions, training a different part of the brain to do something they were capable of before a stroke

In a study, subjects were equipped with small, round balls on their arm, trunk and head and told to drink water from a glass. That action was filmed using high-speed cameras and infrared light reflected by the balls sent to a computer. The data was then used to build a 3D-animated image in the form of a stick figure.

“With 3D animation, we can measure the joint angle, speed and smoothness of the arm motion, as well as which compensating motion patterns the stroke patient is using. This gives us a measurement for the motion that we can compare with an optimal arm motion in a healthy person,” says Ms Alt Murphy.

But why is it important to detect, in such minute detail, what issues have been caused to a person’s movement during a stroke? The answer lies in the modern understanding of what happens to the brain following a stroke and how it is possible that it can “rewire” itself over time.

Experts say you can view the brain as a set of circuits that control thinking, movement, emotion and behaviour. During a stroke, blood and the oxygen it carries suddenly fails to reach areas of the brain, leading to the destruction of millions of cells. The damage can include paralysis, speech and visual problems as well as cognitive issues.

According to Thomas Carmichael, a neurologist at the University of California, Los Angeles, who has written papers on how the brain can rewire, the circuits nearest the area damaged by the stroke naturally form new connections with other areas of the brain. This means it is possible to train other brain centres to take over the functions that used to be controlled by parts that have died or been damaged during a stroke.

“What is happening is the brain is remapping and reorganising itself, and that is where recovery is occurring,” says Dr Carmichael.

Madina Kara, a neuroscientist at the Stroke Association, says the underlying reasons for this recovery remain uncertain. But what is clear is that people can relearn actions, training a different part of the brain to do something they were capable of before a stroke.

“People are recognising that the brain is ‘plastic’ or that it has a plasticity that means it has the ability to rewire itself,” says Dr Kara. “In order to do this it needs to receive that message. Like any learning, repetition of the message is key.”

This understanding has transformed treatment. In the past, victims were taught coping strategies, such as how to tie a shoe with one hand or operate a long-handled “reacher”.

But new technologies, such as virtual reality, are now opening up pathways to better treatment and recovery in place of labour-intensive therapies that are becoming harder to fund.

Researchers at the University of Illinois have taken patients into an Alice in Wonderland world thanks to a headset and electronic glove. Patients, who struggle to move an arm and grip objects, can get a therapeutic work out by “attending” the Mad Hatter’s Tea Party and pouring him a cup of tea, responding to the cartoon action on screen. Researchers believe it beats other therapies, such as moving objects from one box to another, because patients are less likely to get bored.

Teleconferencing, a fundamental element of e-health, is offering patients and doctors an easier way to conduct therapy sessions.

Last month, researchers at the National University of Singapore (NUS) showed off a “tele-rehabilitation system” which is made up three elements. First, a screen allows you to chat to a therapist over a video link on the internet, much like Skype. Second, doctors can check on a person’s movement remotely thanks to a series of sensors placed on the body which feedback to the surgery so therapy progress can be assessed. Finally, instructions can be relayed via an app that works on a tablet, such as an iPad.

It means that therapists can help patients without the sometimes difficult logistics and cost of travelling to and from clinics.

“Our approach makes use of affordable, wireless, lightweight motion sensors to guide the patient whenever they are doing their exercises,” says Yen Shih Cheng, assistant professor at the NUS Department of Electrical and Computer Engineering. “Video recordings of the patient performing the exercises are also saved for visual review later by therapists.

“The sensors produce metrics that can provide the therapist with a quick assessment of how many repetitions the patient has performed and which exercises the patient is performing correctly. The system also flags exercises that the patient may be performing incorrectly, which the therapists will be able to verify through video review.”

Understanding the granular detail of how a stroke affects a patient allows a powerful fusion of therapy and technology to create better, personalised treatments that can be vital in achieving more effective rehabilitation.