A big selling point for the mTrigger biofeedback system is that it gives patients something to look at during their therapeutic exercises. It’s a simple but critical function of the tool, and one of the primary drivers behind mTrigger‘s development. So why do we think visual feedback is so important to achieving outcomes? In this article, we will discuss how visual feedback affects cognition during motor tasks and why that can be beneficial during physical therapy!
The Train feature in the mTrigger app displays a microvolt meter that increases and decreases with muscle contraction and relaxation respectively. If the patient reaches full muscle activation, the bar hits the green “success” zone; the app also sounds an optional tone when the green zone is reached to reinforce that the patient has achieve the desired level of activation. The low end of the meter displays red bars, and the mid-level area is orange and yellow. As patients perform exercises – whether isometric or dynamic – they can watch this microvolt meter elevate and drop corresponding with their physical effort. If they are not hitting the green zone, they have to contract harder to get it there! If their activation is high when it should be low, as would be the case in active inhibition or relaxation training, they can physically see the activation level of their muscles and work to bring it down.
The microvolt meter provides visual feedback that helps patients understand what is going on inside their body as they are contracting and relaxing their muscles. Biofeedback does the important work of tapping into a person’s somatic awareness and ability to control their body by making the invisible visible. Actively being in touch with this cognitive/motor relationship improves functional control over motor skills.
A 2013 fMRI study [1] aimed to demonstrate the difference in brain activity during force-dependent motor tasks with visual feedback and without. When visual feedback is present, the parts of the brain that feed off of visual stimulation such as the parietal, frontal, and occipital lobes are activated. This subsequently engages the motor areas of the brain. Giving a patient something to look at during an exercise that’s related to motor tasks increases activity in 22 areas of their brain and improves their motor skills. The results of the fMRI study showed that visual feedback activated the ipsilateral putamen: the part of the brain that controls the visuomotor transformation process. 
It also activated the bridge between cognitive and motor processes called the rostral premotor cortex (“The rostral premotor areas may provide context-dependent connectivity and mediate information flow between the cognitive and motor networks” [4]). From these findings, it can be concluded that visual feedback activates and encourages the neural network that links cognitive and motor processes, therefore helping the brain control a physical activity carried out by the musculoskeletal system! Voluntary activation depends on the brain’s ability to control the muscles of the body; when we strengthen this connection, we reinforce natural recruitment patterns that lead to healthy, long term function.
Additionally, visual feedback creates goal-oriented movement by giving patients something the work towards. In mTrigger‘s case, patients are working towards getting into the desired zone on the microvolt meter! Once they hit the green zone, for example, the correctness of their movement is supported via positive reinforcement and visual reward. Reinforcing a behavior is known to increase the likelihood of adoption of that behavior. If the patient’s muscle contraction is reinforced with a signal they can witness, the patient then feels successful, and they will be far more likely to repeat that muscle contraction again in the future. We have created a positive feedback loop that keeps patients motivated and cognitively engaged while ensuring that they are activating accurately (learn more about how neural feedback loops work in our Gamification article). More correct reps means better muscle memory and halo effect, such that the results of visual feedback are felt even beyond the real-time interaction.
Visual processing is absolutely essential for reinforcing motor learning. Therapists wants their patients to contract a muscle with a specific level of activation to improve control and strength of that muscle. Improved control and strength is the intended outcome of the exercise. When the patient hits the green zone, the intended outcome becomes the actual outcome because they contracted hard enough to reach the target goal! Visual feedback improves effort and accuracy, and makes real-time results tangible. The activation meter is crucial to this process, because without it, patients wouldn’t be able to recognize that they reached – or exceeded! – the target goal. Patients have to see what is going on with their muscles to learn certain muscular behaviors that enable their recovery and return to function.
The mTrigger biofeedback system has a mobile app and games designed to give patients visual feedback during therapeutic exercise. Visual feedback is known to form connections between the cognitive and motor processes in the brain. It also reinforces behavior, making it more likely for patients to perform muscle contractions correctly in the future. Visual feedback is essential to motor learning – mTrigger puts visual biofeedback in the palm of your hand so you can deliver better outcomes to your patients.
REFERENCES:
[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4486386/
[2] https://www.sciencedirect.com/science/article/pii/S0042698915000243
[4] https://pubmed.ncbi.nlm.nih.gov/21382425/
Article written by Sarah Green | Edited by Amy Lalime
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