SOME SEVERELY IMPAIRED stroke survivors are regaining function in their arms after sometimes decades of immobility, thanks to a new video game-led training device. 

When integrated with a customised video game, the device, called a myoelectric computer interface, helped retain stroke survivors’ arm muscles into moving more normally. 

Most of the 32 study participants experienced increased arm mobility and reduced arm stiffness while they were using the training interface. Most participants retained their arm function a month after finishing the training. 

Many stroke survivors can’t extend their arm forward with a straight elbow because the muscles act against each other in abnormal ways, called “abnormal co-activation” or “abnormal coupling”. 

This device identifies which muscles are abnormally coupled and retrains the muscles into moving normally by using their electrical muscle activity to control a cursor in a customized video game. 

The more the muscles decouple, the higher the person’s score. 

“We gamified the therapy into an 80s-style video game,” senior author Dr Marc Slutsky said. 

“It’s rather basic graphics by today’s standards but it’s entertaining enough.” 

The researchers have paired with a company on an early version of a wearable device to study at-home use with patients. The device communicates wirelessly with a laptop or tablet and the goal is to make this a completely wireless, wearable device.

“The beauty of this is even if the benefit doesn’t persist for months or years, patients with a wearable device could do a ‘tune-up’ session every couple weeks, months or whenever they need it,” Slutzky said. 

Only about 30% of stroke patients in the US receive therapy after their initial in-patient rehabilitation stay, often because their injury is too severe to benefit from standard therapy, it costs too much, or they’re too far from a therapist.

Slutzky is also studying this method on stroke patients in the hospital, starting within a week of their stroke.

Study participants

Patients in the study were severely impaired – could only slightly more their arm and extend their elbow – and had had their stroke at least six months prior to beginning the study. The average patient was more than six years out from their stroke and some were decades out.

After Slutzky’s intervention, study participants could, on average, extend their elbow angle by 11 degrees more than before the intervention

This type of treatment only requires a small amount of muscle activation, which is advantageous for severely impaired stroke patients who typically can’t move enough to even begin standard physical therapy, according to the authors. 

To identify which muscles were abnormally coupled, study participants attempted to reach out to multiple different targets while the scientists recorded the electrical activity in eight of their arm muscles using electrodes attached to the skin. 

Then, to retrain the muscles into moving normally, the participants used their electrical muscle activity to control a cursor in a customized video game.

The two abnormally coupled muscles moved the cursor in either horizontal or vertical directions, in proportion to their EMG amplitude.  

The goal was to move the cursor only vertically or horizontally – not diagonally – to acquire targets in the game. To get a high score, participants had to learn to decouple the abnormally coupled muscles.

Participants were broken into three groups – 60 minutes of training with their arm restrained, 90 minutes of training with their arm restrained, and 90 minutes of training without arm restraints.

Overall, arm function improved substantially in all groups and there was no significant difference between the three groups. 

The study, conducted by Northwestern Medicine scientists, was published in the Neurorehabilitation and Neural Repair journal.