So today I had another appointment for the research study arm. I am going to repeat some details already mentioned in order to refresh memories for those that have been following....currently I have been using whats called a 2 channel system to operate the controls of the bionic hand, and electronically rotating wrist in the prosthesis. 2 channel simply means to muscle signals. To be literal that means, one muscle will control the opening of the hand, and the second muscle(second channel) will operate the closing of the hand. I also control the rotation of the wrist as well, one muscle spins the wrist one direction, while the other channel(muscle) rotates the wrist the opposite direction. I can also control the thumb, which can be swung over for a pinch type grip. That control is also made using the same 2 muscles, this thumb swing operation is initiated bu flexing BOTH muscles called a “co-contraction”. Sooo, when I want to rotate the hand to a certain angle, I fire a muscle fast, and firmly, then once at the angle I desire, I relax that muscle, then immediately I can flex my muscle lightly, and slowly to operate the opening of the hand, then relax for literally a split a second, and then fire the other muscle to close the hand. Hopefully this is all making sense. When I say I “relax”...this is literally only long enough to not give any muscle signal to the “electrodes” that gather the muscle signals...a program exists on a laptop that allows you to see these signals, looked like a graph with little lines climbing up, and down in real time...like a lie detector I guess you can say, or old cassette tape screen.
Here is the difference now...the research study arm we are currently building, has 12 channels! Yes 12, so I went from 2 to 12, pretty crazy since I have been using 2 for 30 yrs. My brain is simply programmed to want to only use those 2 usual muscles I have ALWAYS used. Anyways, the difference, and reasoning behind so many channels(muscles) is that you can now sort of mimic the use of a prosthetic hand, and if it were a REAL hand. What I mean is, the actual muscles you would use to control a REAL hand you can use them to control the hand. So if you used “this muscle”, “that muscle”, muscle “k”, and muscle “x” to control a fist, and rotate the wrist at the same time clockwise, you can program the fake arm/hand/wrist to actually DO that...this technology is called “pattern recognition software”.
Here is how it is all configured, and programmed. As mentioned prior, you connect via bluetooth to a laptop with software made by the company of the pattern recognition software electrodes. Once this is connected, you see a cartoon graphic arm/hand on the screen, and a graph showing in real time your muscle signal strengths for EACH “channel”. You then create a pattern of muscles you will flex, for a very specific movement of the hand, and wrist. 12 channels, mean you can do 12 gestures, or grips, or movements! You then add these patterns into the software, and the prosthetic learns it.
What is also a benefit versus the 2 channel I currently use....the 2 channel requires VERY firm muscle flexes, and some require a long hold of that muscle flex. Basically, you hold that muscle flex until the hand is done with what you are telling it to do. For example, you hold that muscle until the hand is tightened down onto an object you want to pick up. With pattern recognition software, you only need to fire the muscles “mildly”, like a weak lousy limp handshake type grasp...
The hand I plan on getting, has over a dozen programmable hand gestures to add into the hand. Like a pinch grip, a key grip, middle finger, etc....with this pattern recognition software I can enter the hand into these grip patterns in probably half the time as the current 2 channel system.
I am honestly VERY fast, and natural at the control of my prosthetics now, so this software will be a challenge, which is exciting. I will need to reprogram my brain, and go against all I have been doing forever. I do not have to use this new system though, but I want to stay current with the new tech that being created.
Another big plus, is these new electrodes as you see pictured, the small black circle ear bud looking things...are so small, and low profile, compared the typical rectangular 3/4” x 1.25” electrodes. You do not even know these new electrodes are against your skin! No more skin irritations.
oh, and the odd looking 90 degree elbow looking beige piece at the end of my arm is a check valve, restricting air to exit the arm/socket creating a suction to keep the socket on firmer
