Bionic Arm Helps Patients Regain Use of Hands
John R. McGuire, MD
Medical College of Wisconsin Physiatrist;
Medical Director, Stroke Rehabilitation
A new device called the “NESS H200” gives fresh hope to stroke victims and others who have lost hand function. A simple unit that slips over the forearm and wrist, the H200 provides neuromuscular stimulation that supports therapy and can even help restore independent function. Froedtert Hospital is one of only two beta test sites in the nation for this exciting new device.
Q. Who can benefit from the NESS H200?
The H200 is primarily for people who have lost hand function due to stroke or brain injury. In addition, it can help patients who have sustained spinal cord injuries at the cervical level.
Q. How does the device work?
Basically, the H200 provides electrical stimulation to the muscles of the forearm and hand. The stimulation helps the muscles directly (it actually stimulates the muscles to contract), but there may also be some carry-over in the sense of reorganizing the brain to re-enable function. We know that intact areas of the brain can take over the function of injured areas of the brain.
The device allows patients to perform functions such as grabbing objects and releasing them. The major advantage of the H200 is that it is custom-fitted to the patient. The patient can actually put on and take off the device by him or herself — the design ensures that the electrodes are in the right position for optimal stimulation.
With the more consistent stimulation, some patients experience a return of function that was not there before. They can actually use the affected hand “outside the device” — in other words, when they are not wearing the device.
Q. How long does it take before patients see this improvement?
It usually takes at least a couple of weeks before there is some return of function outside the device. It does not work for everybody, but it is worth a try for many patients. Often, a trial with the device is done to see if we can get some stimulation in their fingers.As long as we are able to get some consistent stimulation for those muscles, that patient may be a candidate for the device.
Q. How much improvement can patients expect?
We see varying degrees of improvement. Some people experience very little, while others can get up to 50 percent improvement in function.
Q. Can you give an example?
A high school girl we are working with suffered a brain injury about eight years ago when she was in a car accident. Because of spasticity in her left hand, she does not have much use of that hand. Botox injections helped loosen up her hand, but it remained non-functional. She also had electrical stimulation over the years, but it never yielded much improvement.
We got her started with the H200 and she has done very well. She is able to use her hand both in and outside the device, including picking things up. Outside the device, depending on the task, she has achieved at least 25 percent to 50 percent of full function.
Q. Can a patient leave the device on permanently?
The H200 is not designed for permanent use, but people have used it that way because they are able to do more when they are wearing it. We have found that patients are actually leaving the device on for two or three hours a day, as opposed to just once or twice a week.
It really wouldn’t harm you if you used it as a permanent device. The only issue would be that it could irritate your skin if you left it on all the time.
Q. What steps does the patient go through?
Patients are fitted for the device at the hospital in the neuro rehab outpatient clinic by an occupational therapist who has been certified in the application and training process of the H200. We have a formal program that includes teaching the patient special hand exercises that involve reaching for objects, grasping them and releasing them — for example, bringing a cup to your mouth. The patient does the exercises at home, coming in periodically to make sure everything is fitting right. A patient’s exercise program will occasionally need to be upgraded. One nice thing is that the device can tell us how much a patient is using it.
Q. Where could this technology lead in the future?
The same company that makes the H200 has a similar device for the legs, though it is not yet approved by the FDA. It is the same idea — it stimulates the muscles that lift up the foot and push it down.
Probably even more exciting is the concept of implantable electrodes that let us get direct stimulation to the muscle. These are on the horizon. With some patients, you see, we cannot give them enough stimulation through the skin. The idea is to implant “bions” in the muscle to provide direct stimulation and then “program” the muscles to contract the way we want them to.
Q. Could this help a patient who was completely paralyzed?
If we could implant enough bions safely and program them properly, it is conceivable that we could actually get the patient moving again. We are probably years away from that right now. One limitation is simply how long we can leave the implant in the muscle.