Proper muscle signal calibration is key to successful prosthesis control

At this point, your prosthetist has already done a great job of making sure all of the Coapt electrode contact points will stay in contact with your skin. This is absolutely critical. Now for your part: making sure you effectively calibrate the system as needed, so that it can really get to know your muscle signal patterns. Good prosthesis control depends on good calibration from you. This section has everything you’ll need to know about performing a great calibration for the best prosthesis control.


Calibration: Get to know the basics

Calibration is how the Coapt system learns your muscle signals patterns. Specifically, the patterns that you will use to control your prosthesis. The better you calibrate, the easier it will be to control. Calibration should come easy. You will be prompted (either by movements of your prosthesis or instructions on a screen) to make and hold muscle contractions exactly the way you would to naturally replicate the motions of your prosthesis. As you hold these contractions, the Coapt system listens and learns these signals in order to compute a memory of what your patterns look like. After any calibration, the Coapt system uses these memories to understand how you are controlling your prosthesis in real time.

If Coapt calibration is new to you, some helpful hints to keep in mind: make sure the muscle contractions you calibrate with feel similar to the contractions you will want to use it with; try to make sure you do each motion differently enough; and try to make the same motion feel consistent each time.

Calibrating control with the press of a button

Somewhere on your socket, you should have access to the Coapt Complete Calibrate button. This oval unit has one pressable button, a Coapt logo, and a multi-colored LED. It also makes a series of audio cues when pressed for operation by ear (see the quick reference guide for the meaning of the audible tones and LED colors).

This pressable button serves a very important purpose. It lets you calibrate without the software or app. Use this any time you have a desire or need to update and adapt your prosthesis control on-the-go. To start this style of Calibration, press and hold the button for about two seconds until you hear it beep once. Release your hold on the button, and your prosthesis will begin to move on its own. The following minute or so is what we call Prosthesis Guided Calibration (PGC). PGC is when the prosthesis goes through a sequence of motions on its own (like it’s being remotely controlled) and you simply follow along with your corresponding muscle contractions. For example, if the prosthetic wrist is turning up, hold your intended muscle motion for an upward wrist. Same for hand actions, and so on. As you hold these corresponding muscle signal contractions, Coapt PGC is recording, building, and adapting the pattern recognition memory to match.

Once PGC goes through all of its pre-selected motions (these are settable in the Coapt software), it will sound a short jingle and then return prosthesis control to you.

This is when it’s great to see if the Control Coach® white LED is blinking. If so, Control Coach® has useful calibration performance info waiting in the Coapt software application.

Calibration “Undo” can be performed using the Complete Calibrate button on the prosthesis, too. Simply hold it down for about 6 seconds (until you hear a double beep and see the LED flashing blue) and let it go. This will jump the calibration back to what it was just before the most recent calibration activity.

Calibration “Reset” can be performed using the Complete Calibrate button on the prosthesis, as well. To reset ALL calibrated motions using the Coapt button, hold it pressed for about 10 seconds (until you hear it play a short melody) then release. This will reset the system back to a starting state and turn the button’s LED magenta. Don’t expect control of the prosthesis when the LED is magenta—the control memory is empty and it will have to get at least one calibration to operate a prosthesis again.

Calibrating control on-screen (via mobile or desktop)

In case you’d prefer to calibrate your Coapt system by watching on-screen prompts, great calibration tools are provided in the Coapt software interface or app.

Coapt user using software to calibrate

To use the PC software, make sure that you have an available Coapt Bluetooth radio dongle, and then make sure you download and install the Coapt Complete ControlRoom software here.

To use the iPhone/iPad application, visit the Apple store and get the Coapt Complete ControlRoom app.

Calibrating all motions using the software:

Once you’ve established a Bluetooth connection to your Coapt system, navigate to the “Calibrate” panel. This is a screen area where your available prosthesis motions can be selected/deselected for calibration, and where an orange button labeled “Calibrate Enabled Motions” sits. When you press this button, be ready, because the sequence for calibration will promptly begin. During the calibration sequence, you will see on-screen prompts of what to do. Follow along by holding your muscle patterns for each motion when prompted and relaxing when it instructs. At the end of the calibration sequence, prosthesis control will be returned to you, and your Control Coach® quality ratings will be updated.

Calibrating individual motions from the software:

While you are in the “Calibrate” panel, you will see that each available prosthesis motion has a small arrow icon next to its name and quality rating. Clicking on that arrow brings up your detailed Control Coach® information for that specific motion. Here Control Coach® will have feedback for you, if applicable. Clicking the “Add Data” button is how you can add calibration muscle signal data for this one motion — once it is pressed, an empty circle appears. As you hold your muscle contraction steady for this motion, the circle will begin filling up with orange segments. Make sure you hold your signals until the whole circle fills.

Screenshot of the Controlroom software

Calibration Adaptation

Adaptive Advance is an important feature that is part of calibration. It’s an automatic, continuous-learning algorithm that knows exactly how to meld new calibration data into the existing state of your control. Since Adaptive Advance adapts and learns each time you calibrate any or all motions, it acts as a control companion that tracks natural changes over time. Each time calibration is performed, the Adaptive Advance algorithms know exactly what to do with your new data to improve control.

To turn Adaptive Advance on or off (it is on by default), use the Coapt software interface or app. Connect to your device with Bluetooth, navigate to the Calibrate panel, then click on the settings icon (looks like a cogwheel). In the menu that appears, use the On/Off toggle buttons by the Adaptive Advance label.

It can be especially helpful for new pattern recognition users to perform the calibration routine multiple times from a starting state. This allows Adaptive Advance to effectively “layer” extra information into a robust and functional control scheme.

Calibration Clearing/Resetting

Sometimes you may want or need to erase/reset the calibration control memory of your Coapt system. This can be helpful if there’s been a major socket change (such as electrode relocation) or simply if reliable control has become unstable. To help with this, there are a few convenient ways to reset all calibrated motions or to reset one motion at a time.

Clearing/Resetting ALL calibrated motions

To reset ALL calibrated motions to a blank starting state, you can use either the Coapt Complete Calibrate button on the prosthesis or use the software application. 

To reset ALL calibrated motions using the Coapt button, press and hold for about 10 seconds (until you hear it play a short melody) then let go. This will reset the system back to a starting state and turn the button’s LED magenta. Don’t expect control of the prosthesis when the LED is magenta—the control memory is empty and it will need at least one new calibration to operate a prosthesis again.

A finger holding the Coapt button for 10 seconds

A 6-note, high-pitch jingle after the button has been depressed for 10 seconds.

This indicates Calibration Reset. Letting the button go after this jingle will reset/erase the Coapt system to a blank starting state. The LED will turn solid magenta.

To reset ALL calibrated motions using the Coapt software interface or app, connect to your device with Bluetooth, navigate to the Calibrate panel, then click on the settings icon (looks like a cogwheel). In the menu that appears, click the “Reset ALL” button. This will reset the system back to a starting state and turn the Calibrate button’s LED magenta. Don’t expect control of the prosthesis when the LED is magenta—the control memory is empty and it will need at least one new calibration to operate a prosthesis again.

Clearing/Resetting just ONE calibrated motion

Any single motion can be independently reset. This won’t reset your other motions. This can be useful if you have one or more motions that you’d like to begin fresh with while keeping the rest as they are. To do this, connect to your device with Bluetooth and navigate to the Calibrate panel. Clicking on the small arrow icon next to a motion will bring up your Control Coach® information about that specific motion. Here, clicking the “Reset” button will set this motion to a blank starting state while leaving the other calibrated motions as-is. The control memory for the affected motion is now empty and it will have to get at least one calibration to be controlled again.


Calibration: Additional features

Calibration Undo’s

It’s absolutely ok if you mess up a muscle contraction or two during calibration—maybe you missed following a prompt, maybe you performed a different motion by mistake, maybe you even held a motion in a way that was too different from how you did it in the past, and so on. This is not a big deal—and no reason to let that affect your control in a bad way. At any time, the Coapt system lets you “Undo” your last (most recent) calibration activity, whether that was a single motion ‘Add Data’ or a full-sequence calibration. Undoing a calibration jumps your control back to the state it was in just before that last calibration activity. There are two ways to undo the most recent calibration activity.

Calibration Undo from the button on your prosthesis

To Undo the most recent calibration activity using the Coapt button, hold it pressed for about 6 seconds (until you hear it double beep and see the LED flashing blue) then let it go. It will take a moment to recompute and then return prosthesis control back to you.

Double high-pitch beep after the button has been depressed for 6 seconds (the LED is cyan while the button is being pressed), followed by flashing cyan.

This indicates Calibration Undo. Letting the button go after this double beep will “undo” the most recent calibration activity and return your control to the state it was just before that.

Calibration Undo using the software application

To Undo the most recent calibration activity using the Coapt software interface or app, connect to your device with Bluetooth, navigate to the Calibrate panel, then click the Undo button (it is an orange button with a circular arrow icon). It will take a moment to recompute and then return prosthesis control back to you.

Calibration Restore Points

Another convenient feature of Coapt calibration is the ability to store up to 3 calibration Restore Points. Restore points act as saved ‘snapshots in time’ of your control. Whenever you would like to save your current calibration—perhaps at a point when your control performance is noticeably dialed in—simply access the Coapt software software interface or app and store the current calibration state in an available Restore Point slot. To do this, connect to your device with Bluetooth, navigate to the Calibrate panel, then click the Restore Points button (it is an orange button with a bookmark icon). 

Whenever you have any Restore Points saved to memory, you can revisit this menu at any time to reload that control state and return to that control setup.