 It's the year 1771 when the physicist Luigi Galvani realized that the electrical stimulation in the leg muscles of dead frogs could cause them to twitch. Fast forward a few decades later, around the mid 19th century, where the scientist Carlo Mattecui realized that he could measure the current across a muscle fiber from a nerve signal. This was the humble beginnings of what would become to be known as electromyography or EMG for short. EMG has come a long way since then and has drastically changed the field of neurology. So what exactly is EMG done for us then and what will become of this technology? You might be asking, well, that's what we're about to find out. Picture the following scenario. You begin having sudden muscle weakness in your extremities which persists for a few months. So you decide to go see the doctor who wishes to perform an EMG test on you. He sends you to a special room where you lie flat on the table and have a needle electrode inserted into you. The technician operating the test requests you periodically contract and relax the muscles around the area where the needle is inserted, allowing the EMG to record the electrical activity of the muscle when it is resting and when it is contracting. This process is then repeated for all of your limbs, allowing your doctor to get a better look at what exactly is going on with you. In a nutshell, this is how EMGs work their magic for hundreds and thousands of patients worldwide who are suffering neuromuscular ailments. Of course, there's no need to be so invasive. Nowadays, there is more and more research on non-invasive methods of EMG signal acquisition. The most common method involves placing an adhesive electrode such as a silver chloride electrode, which by the way is a very popular choice for electrode type over the area of interest. When a nerve impulse or as it's more commonly known an action potential propagates through the motor neuron, it can cause a change in membrane potential across the neuron membrane due to an influx and efflux of certain ions. The electrode placed over or inserted into the muscles able to detect these membrane potential changes and convey it in the form of a signal. This signal is then run through an amplifier to magnify it and is then able to be displayed on either an oscilloscope, which is a device that can show voltage variation over time or on a computer screen of a device that is hooked up to the amplifier circuit and running a software like LabView, which can display voltage changes over time. But we aren't finished yet. The raw EMG signal we have is a mess of a bunch of muscle fiber action potentials jumbled together in the graph along with these contaminations of the signal due to uncontrollable motions or in some cases, electrode placements which are slightly off. These contaminants are what are called noise. Using some fancy algorithms, the EMG signals can be decomposed into its individual action potentials. But that's not all. Researchers can use computational algorithms such as fast Fourier transform to track the frequency change in muscle contraction, which is very useful for figuring out things such as the strength and speed of muscle contraction as well as when the muscle begins to fatigue. For the sake of time and simplicity, we won't be going in-depth into the mathematics and inner working of EMG signals in this video, but it's important you still understand the basics of the software side of EMG so we can go more in-depth in later videos if needed. Anyways, now that that's out of the way, it's time to answer the question you've all been the most eager about. What does the future of EMG look like? Well, the future of EMG is going to be on your arm. No, seriously. Right now, the main focus in EMG is to create ultra-thin and portable sensors so that patients can monitor themselves anytime, anywhere. For example, at UT Austin, using carbon-conductive tape laser-cut into a specific design, in Tegaderm patches, researchers have managed to develop a wearable and water-resistant EMG sensor. This ultra-thin EMG sensor can remain on the skin for up to a week and can be connected to a computer where LabView is used to record and store the EMG data, which can then be decomposed and processed in MATLAB to detect the frequency change in muscle contraction over time. However, the ultra-thin sensor at the moment is confined by the fact that it needs to be connected to a computer to transmit EMG data. So there is now research being done on creating circuitry for efficient wireless transmission of the signal to a computer or mobile app, where it can be processed and viewed by the patient's physician. So what exactly do researchers hope to do with such breakthroughs? Well, this will change the game when it comes to diagnosis and managing conditions. For example, the initial weeks after a stroke are crucial for the patient to be able to train their neural circuits to improve motor function. Use of ultra-thin portable EMGs would be able to provide more in-depth information to the patient's physical therapist and neurologist on how well the patient's motor functions are recuperating, as well as whether or not the patient is on track to a full or near full recovery. That's only scratching the surface. Remember how we talked about detecting the frequency change in muscle contraction over time? Well, researchers are also working on computational algorithms to be able to detect when a muscle is fatiguing based on contraction frequencies. This would be of great use to individuals like athletes who wanna track how well their performance is on field or maybe an ALS patient who wishes to be able to keep track of his or her muscle performance over time. However, the biggest potential here is in prosthetics. The potential for EMG in prosthetics is so great, we need a separate video to cover it, which is why it's our personal pleasure to introduce Patrick Kelly from Corpus. Also inserted EMGs, which is a needle or wire stuck into the skin. That lets the user analyze deeper or more delicate muscles that might be overpowered by the bulkier muscles during surface EMGs. These things are mostly used for neurological studies and sometimes in PT clinics. One field that uses EMG extensively is the field of biomechanics. To show you how they use it, I'm gonna walk you through a study which I've linked down in the description along with all my other. And don't forget to stay tuned for more science videos.