Every year some 160,000 people suffer strokes that leave them paralyzed on one side of the body. Mechanical engineer Michelle J. Johnson of Stanford University and biomedical engineer Machiel van der Loos of the V.A. Palo Alto Rehabilitation R&D Center have come up with a simple therapy that could help get stroke patients to use both arms again.

Their treatment uses an automobiledriving simulator, but with a twist Johnson and Van der Loos created a split steering wheel with sensors and force-feedback devices in its left and right sides. Their device is called Driver's SEAT, for Simulation Environment for Arm Therapy. While subjects steer the virtual car, the wheel senses how much they are using each arm. If they work the wheel with their weak aim, it moves fluidly. If the subject uses his normal arm to do all the steering, however, the wheel becomes extremely hard to move. "It's like when your power steering is broken. You really have to yank on that wheel," says Johnson. These force cues train patients to learn to use their paralyzed arms again a deceptively difficult task.

It may look like fun, but it's therapy: a stroke survivor uses a special steering wheel to retrain her weak arm.

A big challenge in stroke recovery, according to Johnson, is getting patients to use their weakened arms right away. If they start doing tasks one-handed, those habits are hard to break. One promising experimental treatment is to place the good arm in a sling for two weeks and conduct intensive rehabilitation therapy, but this approach requires a lot of time and motivation. "We saw that we could automate this and couch it in something entertaining," Johnson says. "Driving is something that all stroke survivors, if they used to drive, want to do again. So we wanted a fun exercise task without needing constant intervention from the physical therapist." In preliminary trials with eight stroke survivors, the steering wheel helped them increase the use of their weak limbs. Johnson says this shows that the device has the potential to help stroke survivors regain some limb movement even after six months or more of paralysis.

Related Web Sites:

"Driver's SEAT: Simulation Environment for Aim Therapy," M.J. Johnson, H.F.M Van der Loos, C.G. Burgar, and L.J. Leifer, 1999 International Conference on Rehabilitation Robotics, Stanford, CA.
Abstract - Full Text (PDF)

The Driver's SEAT project page.

Michelle Johnson's Web page.

For more information about strokes, visit the American Stroke Association's website.