Johnny Matheny's prosthetic arm controlled by Thalmic Lab armband

Kitchener's Thalmic Labs is helping bridge the gap between brain and muscle movement with a sensor armband that's been used to control an amputee's prosthetic arm and hand.

• LISTEN: Johnny Matheny speaks to Craig Norris on CBC-KW The Morning Edition

In 2008 Johnny Matheny, a bread sales and delivery driver in the U.S., lost the lower part of his left arm to cancer.

Since that time he has been trying to improve the quality of life for prosthetic-wearers. The first step was a surgery called TMR.

"Targeted Muscle Re-enervation," explained Matheny to CBC Radio Kitchener-Waterloo's The Morning Edition. "Even though the nerve endings that control the lower part of my arm were cut off, they're still there and can be re-used," he said. "They take them and re-implant them in muscles still left in the stump."

 As the person thinks about moving their missing limb, a minute electrical impulse travels from the brain to the re-implanted nerves. Sensors in the armbands register the impulse, correlate it to the missing muscles, and trigger a motor in the prosthetic limb to move in a similar manner to the missing flesh and bone.

"They did five different re-enervations in my stump," Matheny explained, "and this allows me to where I'm able to work my hand, wrist and elbow." 

"We started out using miles of electrical wires to connect the stump to my prosthetic," he said. "Then we moved up to wi-fi."

The next step was to replace single-use sticky electrical sensors attached to his arm stump with the wearable Myo armband from Thalmic Labs, which communicates with the prosthetic limb via BlueTooth. "It snuggles up against your muscles...just like a watch." Matheny said.

"It's very much more comfortable," he added. Typical prosthetic limbs use a suction or velcro to tether to the stump and prolonged wearing can cause skin irritation. 

'Like an infant'

"When you first lose a limb, the mind still sends signals down," Matheny said. "After a while if it doesn't get a result, it just shuts down–it doesn't send any more." 

"Once you get through the surgery and re-open the pathways again, then it's a learning process just like you're an infant. You have to start all over again," he said.

"The more you do it, the faster it comes back to you."

Military financing

Matheney has said that although his sons served in the military and returned unharmed, he is sympathetic to soldiers who've lost limbs and wants to help them regain as much of their former mobility as possible. 

 The U.S. Army financed the research and development of the prototype arm he uses.  

"The Armed Forces have already done their part," Matheny said, "but now the rest of it is going to be from individual donors, from corporations or whatever."

Matheny believes the surgery, mechanical and electronic technology have all been proven to work. 

The next step, beyond making the prosthetics convenient and move in a life-like way, he said, is to develop a covering that can be sensitive to touch. 

"To feel, as near normal as you can get, with a plastic arm."