Well, hello, Orlando. Thank you for coming. I am Dr. Jonathan Rutchik, and I'm very, very excited to be here speaking about EMG and NCV at 2024 ACOM. I am very privileged to be asked to lecture and offer this lovely space where I will talk all kinds of neurology and EMG and emphasize my enthusiasm for occupational medicine and neurology. I went to Columbia College, went to Hahnemann, did neurology at Mount Sinai, and then went to Boston University where I did a neurology, neurotoxicology fellowship, occupational medicine and an MPH. I've been in San Francisco now for more than 23 years and have a private practice pretty much. And I see patients with all kinds of problems that are neurological and worker injury, concussion, upper extremity, lower extremity, toxicology, and do a lot of EMGs. And I teach nurses, students, and residents. So we're going to talk today about a bunch of things, upper extremity, lower extremity, how to interpret data, and how you can really have more confidence in looking at an EMG, ordering an EMG, why, when, how, and how to be scrutinous of an EMG as it's so important to do because quality matters. We have a laborer who was hung while wearing a protective vest. By the way, some of these cases will be hard, some will be easy, so don't worry if they're a little bit over your head. We're going to start with hard, go to easy, and move around. The exam showed weakness of the elbow and wrist flexion. You can't really see a picture of me that's large, so I guess I won't gesture. But wrist flexion and extension, sensory loss in C6-7 dermatomes, and a reduced reflex. So really assessing reflexes is important. So getting those skills up to par is helpful, comparing left to right, being aware what's going on. The NCV showed reduced median ulnar motor amplitudes and sensory amplitudes. The radial was normal. Anybody know what's the most common nerve entrapped in the upper extremity? Anyone want to throw it out? Median, thank you. It's not the radial. Radial is the most spared, right? So that kind of helps you. And comparing left and right is always key, but looking at radial sensory gives you a sense as to whether is there a florid sensory neuropathy. So it's helpful. But the EMG showed all kinds of abnormalities. So where do you localize this? Here's a video, and let's hope that this will work. Yes, it does. Although we don't have volume. I don't really have the ability to go forward, I guess. The next session will begin shortly. Hello? Someone else is talking. You'll see that his left arm, he has really extensor weakness of the left wrist soon, as soon as we move a little forward here. Real kind of a flaccid wrist. So when you see a flaccid wrist, you're thinking a Saturday night palsy, the first thing you might think about. So people can actually lay on their arm or sleep on their arm, especially those who are drunk, and they may very well have a wrist radial palsy. But this is more than that, because we have more than simply the radial, as we learned from the EMG results a moment ago. Really has flaccid left wrist. Sometimes it's difficult to video because I use my left hand to video and my right hand to show. He's also got clearly other radial motors, supinator and other kinds of, uh, and brachioradialis. He can't really bring his left arm up. Uh, he's talking about his sensation. There is really a sensation in the whole palm. Reflexes were definitely reduced. You don't need a big hammer like I have, but you need to spend some time putting your finger on that tendon and trying to see if you can see the difference between one side and another. You know, I'm a big proponent of putting the finger on the tendon. You can also do it in other ways, but you gotta get your own method that works for you. He has atrophy in that web space between the first finger and the thumb. So that's also important to be an observer before you're an examiner. Be an observer. So when you look at the brachial plexus, it's crazy complicated, but in this situation, you see the yellow lower anterior medial part. Do I have a way to, do I have a way to point? I don't know what I'm pointing at. The front button. I don't seem to have, I don't know what you mean by that. Above the green is not a button. Now I shut it off. This goes backwards. Above the green, there's no other button. This could be a pointer, but I don't know where I'm pointing. Nope. Anyway. So the yellow lower anterior medial. So this gentleman, you can see the way the medial cord gets the ulnar nerve. So we had median and ulnar involved. So we have the medial cord, which can go affect the median and the ulnar. So thinking about this whole lower trunk, the underarm area where the guy was hung, he got a sort of a brachial plexus injury that led to motor weakness. Now a lot of us in clinics see patients who have just numbness, and it's a vague numbness, and they're referred to me for brachial plexitis or brachial plexopathy, but if they have no motor weakness, it's very difficult. So you can kind of use your gestalt when you think about where the sensory loss is to think, is it lower, middle, or upper trunk, or what you know, your Klumpke's palsy versus the Erb's palsy, versus upper versus lower from all the other histories and things we've learned. But looking at the brachial plexus is important in the anatomy. So the NCV will be abnormal for multiple nerves. So if you have multiple nerves that are abnormal, is it both the median and the elbow, the wrist and the elbow entrapped, or is it in fact more proximal? That then leads to your interest in the needle testing, which should be abnormal in multiple muscles that are in different nerve and root distributions. So it's kind of a complicated result. And needle EMG is difficult to find abnormal. You don't always find it abnormal. So you're in this vagary, and then you consider whether you can really do a MR neurogram or MR of the brachial plexus. So the paraspinals will be spared. You're sticking needles in their muscles around their paraspinals and their neck, and they may be spared where there may be abnormalities in the muscle. So it's kind of a complicated thing. So we go back to the beginning, and we think, what is an EMG? EMG is a term that usually includes NCV and EMG. So NCV, nerve conduction velocity, EMG, electromography. Electromography meaning muscle, nerve conduction velocity assessing the cable. But usually EMG means both. So evaluation of muscles and nerves, two parts, EMG and NCV, shocks, soft shocks, and thin needles. You're looking at motor and sensory nerves for the NCV. NCS is another term, nerve conduction study. And they really should only be performed by board-certified neurologists or physiatrists, rehab medicine people. Soft shocks, thin needle, where really one should be done without the other, testing the nerve cable. Thin needle is really assessing the connection between the nerve and the muscle. You're assessing whether there is spontaneous activity, which would be an acute denervation, or more chronic problems from polyphasia. We'll get some good examples of that. So you're testing median, ulnar, and radial nerves in the upper extremity, nerves we know, and that kind of evaluates for entrapment at the wrist or elbow, median neuropathy, carpal tunnel, ulnar neuropathy, radial neuropathy, plexopathy, cervical radiculopathy. For the legs, perineal and tibial nerves, superficial perineal is the sensory of the perineal that continues. There's a saphenous that assesses the medial aspect of the lower extremity. And sural nerves are the longest and largest nerve fiber, so they would be the first to be abnormal for a sensory neuropathy. Those are important. The H reflex is the same thing as the ankle jerk. So there's a sensory input into the dorsal root ganglion, coming then away, afferent to the motor muscle. So you're assessing, pretty much firstly, sensory neuropathy when you look at the lowers, which is extremely common, lumbar plexopathy, radiculopathy, injury to the perineal nerve, which could be a trauma to the knee, or tibial nerve, which could be an injury at the foot, but that's rarer. So sensory nerves are much more susceptible to industrial entrapments. Tarsal tunnel, not something you really see very often, but you hear about it a lot, and that can be affected and assessed by a nerve assessment. So NCV testing is data dependent, must be clear and reproducible. That means you've got to look at these waveforms. And if you get these NCVs that don't have waveforms, in my opinion, that's not a really helpful study. So insurance companies and adjusters, I try to speak to them about the fact that they really should look for data, and they should require that these NCVs include data so they can look and see whether the quality exactly matches the numbers, whether the numbers mean anything. We'll see some of this experience. Temperature should be controlled. Measurements are important to compare standardized normals. A technician can be experienced and be certified, and tests should be compared bilaterally so you know that there is an abnormality versus a non-abnormality. If you have someone with symptoms of your wrist for both sides, but they're both abnormal, then what is the positive predictive value of surgery for the symptomatic side? It's probably or might be low. So this information is helpful and maybe even helpful in the realm of approval or denial of a surgery. So you can see in this slide how poor quality testing can lead to a weak or an abnormal nerve conduction with a lower amplitude, let's say, because if you stimulate 0.5 centimeters laterally or even 1 centimeter laterally above or below the nerve, you're getting a different waveform. So obviously the person doing this must be experienced, and this is also why there are these gadgets which have been criticized because they don't always get optimal nerve person and so on speak. The MA can do it. Well, the MA may or may not know where the optimal location is or conceivably get the optimal waveform. So data needs to be reproducible. The needle is even much more complicated because putting a needle in someone's muscle, one needs to know if they're in the right location to activate that muscle. It should be performed bilaterally. Bilaterally, again, you're looking at abnormality versus non-abnormal, and you need to sample a sufficient amount of muscles to make certain you're doing enough. If you consider a median neuropathy, but there's also maybe neck pain, which in workers' comp there are many patients with the whole gamut of thumb, wrist numbness, elbow pain, and neck pain, you're looking for everything really. So you want to assess multiple nerve roots by the needle, C5, the deltoid, C7, C6, the brachioradialis, and maybe both sides. So it really indicates completeness, and it really does evaluate the motor aspect of the nerve injury. So EMG may not be helpful in a mild injury, but they may uncover a nerve root injury that was not uncovered by the NCV, indicated when diagnosis is unclear and we need to determine location and chronicity. So, you know, we'll talk about acongylins and MTUS and all that. So those specific recommendations are really when, let's say, the MRI doesn't show anything specific or it's normal but the symptoms are still radiating, or there's lumbar abnormalities, but again, the MRI might be normal or might be vague. So this is a slide just to remind us of the dermatome and how C2, 3, 4, you know, kind of in the chest, 5 is the deltoid area, 6 really goes to the thumb, so it can really mimic a CTS, 7 is that middle finger, 8 is the smallest finger, and maybe T1 is up in the medial forearm. On the leg, you're seeing, you know, 2, 3, 4 across the knee and medially, 5 laterally to the leg, S1 can be under the foot. So remember these kinds of things you can separate. The cardinal rule of NCV and EMG is really the bottom, when in doubt, don't over-call. This is really much for an EMG-er, but it's an extension of the clinical exam. So you have a clinical exam, and these NCV and EMG tests, pretty much neurologists, those who have experience with NCV and EMG, use them really to extend that clinical exam, to support it, to refute it, and to see what's going on, if it's objective testing or not. So that's really where a neurologist comes into play to help, or a physiatrist. Okay, good morning. So we're going to demonstrate some lower extremity testing. We have video. We have audio. This woman has an interesting numbness in her knees. Unusual presentation after fall. So those, I'm not going to go backwards. Those in the room who see patients and view records, numbness in the knees. Huh? Sorry, I'm going to go back and do that again. How do we, no. I don't want to miss it. Anybody help? IT person? Oh, there we go. Good morning. So we're going to demonstrate some needle EMG testing on this patient. So patients come in all. Who had some challenges with her hand, and over time she had a carpal tunnel surgery. But now is back to work. Patients in industrial medicine have every problem in the book. You can't be distracted. I guess we lost audio. Huh? Okay, so if you can come over here, Karen. I'm going to basically look for the landmarks of upper hip, and then go towards the midline. So when I use a needle, I'm trying to see if I'm in the right muscle. I want to see the screen light up when they give me full power. But they often don't give me full power. I'm then looking for a wave form that I'll explain. Whereas tibialis anterior would be lumbar 4 or this could be lumbar 2, 3, 4 and venogastric BS1. Let's just demonstrate a paraspinal. I'm going to have you roll towards me and bring these to your belly and I'm going to demonstrate just the right lumbar paraspinal for now. Okay, so if you can come over here Karen. I'm going to basically look for the landmarks above her hip and then go towards the midline and be two finger breaths away from the spinous process. Making sure not to speak myself always or speak to the patient inadvertently. So at the top of the hip. I think the audio is different from the video. There's something going on here. Okay, and sometimes, bear with me dear. Yep, the audio is different from the video. I don't know. Strange. So I'm demonstrating a lower extremity EMG. I'm in the medial gastroc right now, which is an S1 root muscle. And it's a tibial innervated muscle. So I'm assessing the left and the right medial gastroc. Now I'm assessing the peroneus longus, which is probably the muscle I find the most abnormalities because it's an L5 muscle and I'm assessing to see if they give me the full screen here or at least give me full power. So I know that my needle is in the right spot in the muscle, the belly of the muscle. And then I'm kind of trying to see whether at rest I find any spontaneous activity like a blip, blip, blip, blip, or when he shows me a little bit of power, whether I'm looking at an individual waveform and I see polyphasia, which is rather than simply the up, up, down, up, but an up, down. And we'll see this. I've got great slides keeping going. I think we'll keep going. This is an upper, demonstrating upper EMG. Good morning. So we're going to demonstrate some needle EMG testing on this patient who is a correctional officer who had some challenges with her hand and over time she had a carpal tunnel surgery but now is back to work. Her previous studies after the surgery have been normal. Her NCV today is normal. But we're going to demonstrate the needle exam of this patient. And so what we do when we do a needle exam is sample a certain amount of myotomes. We're going to sample the cervical 6 myotome, because median nerve symptoms may be mimicked by cervical 6 radiculopathy. We'll do C7, because it's close, and some C5. And we'll do some cervical paraspinals. And we'll do both sides. We'll just do this relatively quickly. So first of all, I'm going to do the brachioradialis. What a good patient. No pain, no blimps, nothing. Most people really tolerate this extremely well, by the way. Every three to six months, I have someone that says, absolutely not. But pretty much. We'll also try to move it a couple times to see if there's spontaneous activity. So you see how quiet it is when she's not active. That's a healthy muscle. Relax. You see that the muscle is activated, so I'm in the right muscle. You're showing the screen as well, Walter? Thank you so much. And then I'm going to try the C7 extension with the wrist on this side. Bring your wrist up like this. Good, relax. So obviously, I have to have an awareness and knowledge of what dermatome each muscle group has. She's right hand dominant. Her right arm is larger than the left, which is pretty normal. We'll do the C7 triceps. Push into your leg. Full screen means it's in the right muscle. And she's not pushing. And then I'm having her quiet to see. There's one motor unit, which is a good way to demonstrate this. So push a little into your knee. You'll see there's one motor unit. We'll freeze the screen. We can see that it's a lovely down, up, down. Are you able to see that, Walter? Yes, okay. So we'll unscreen it. The down, up, down is normal for a motor unit. This is the deltoid, which is a cervical five root. Push against me. Great, relax. So I'm sampling, you know, when I'm in the muscle, I'm sampling usually in multiple directions with that one needle. In, in, I move it slightly. Based on my impression of what's going on, I may literally move it six times without taking the needle out or less in each direction. We'll move on. So hand and wrist pain. Obviously we know that it's a complicated topic. You know, it can be the thumb. It can be the joint. It can be the connective tissue disorder. But radiating pain to the hand, neck versus the median nerve. The median nerve dermatome is really one, two, and three finger with half of a four. We know about this. Two point discrimination loss prior to pain and temperature is kind of the way that the chronology or the, you know, how things move in the direction of mild to moderate or severe. Thumb pad is innervated by the median nerve, but not after it goes through the carpal tunnel. So if you think about the thumb pad, that could be a C6 reduction of sensation rather than carpal tunnel. So numbness of the tip and the thumb pad could be C6. Numbness of the tip could median nerve. Numbness in only the thumb pad might be C6. The fifth tingling is more likely omar or it could be arguably cervical in origin, not median nerve. So a lot of people, you know, may have abnormalities in the EMG, but they're only talking about numbness in the fifth finger. So therefore, those who are considering authorizing surgeries should be skeptical and scrutinous of such that maybe this surgery, it's irrelevant that the numbness in the fifth finger, maybe there's an abnormal EMG that doesn't necessarily need surgery. Finkelstein's test affects, de-excesses the thumb. And so that also may be irrelevant to an abnormal EMG. The EMG is helpful and appropriate, but you don't need to go do surgery on carpal tunnel. That is being requested when you have a thumb pain issue. So we got to spend time with people and listen and examine them to see what the main problem is, even though they might have an abnormal test as the test is sensitive, but not necessarily specific. So assess your TINLs and Phalencine because those might be more sensitive and specific, both for the median neuropathy. We have just a great picture of the tendons and the ligaments, et cetera. We have a new case. Legal assistant, positive ANA, depression. Again, we're thinking about sensitivity and specificity, not just simply sensitivity. Neck tenderness, cold bluish hands, normal hair and nails, abnormal ANA. You know, you don't throw it out, but you have to think. Moderate CTS with hand warming. So this is a picture of what the motor study looks like. I'm stimulating at the wrist, I'm stimulating up higher in the crease for the median nerve and this is what the waveforms look like. A would be normal, B would be axonal, meaning that the amplitudes are low and there's something going on that is diffuse in that nerve, both distally and proximally. C means it's slow, maybe there's a demyelinating lesion, something, and D means that there might be some sort of cut or conduction block between the wrist and the elbow in the middle part of the forearm from a trauma or maybe from some kind of autoimmune process. So this can be helpful, this slide, to understand really what an abnormality of, let's say, the median or even, let's say, the tibial perineal could look like. A median motor study has this, you're stimulating proximally, you're stimulating distally, and you have this distance that you're calculating, distance equals rate times time. So you want the more proximal to be a similar amplitude as the distal so as to make sure there's no conduction block. Slow median sensory, it looks like this waveform, and you're looking, again, at the baseline to make certain that it's not a chicken scratch. You need to basically look at this waveform to see, just because there's a redness to the data, you want to see the waveform to see, is it really abnormal or is it just done poorly? Now, remember that the fourth digit is both median and ulnar. So you can stimulate the palm, as in the, let's say we're looking at the B, simulate the palm at S1, that's median stimulation, and get a waveform recording at the fourth finger. But you could also stimulate the ulnar nerve at S2 in B and get a waveform for ulnar. So you can then assess if the median is slower than the ulnar. Now, the ulnar can also be entrapped in an industrial, in a person who works, doing physical labor. So I like to use D1. D1 is median and radial, because radial is the least affected, and I can compare median and radial. In C here, however, you are stimulating a motor, mixed motor nerve, because that's where the lumbarcle is. So literally, there's the lumbarcle's curve and swanar fingers, and we can record at that lumbarcle and stimulate median and ulnar, because they would both be recorded for median and ulnar. And it's a motor, mixed motor, so you'll get less effect from a large diabetic neuropathy, which you may have. So C is very useful, too, but not often done. This is the D1 that I was talking about, where I basically stimulate S1, that's radial, S2 is median, and I look for a difference of more than 0.4 to support the abnormal median sensory. Orthodromic palmer is what I'm talking about. You can stimulate the palm and record on the median, stimulate the palm, record on the ulnar, and you look at different waveforms. But you can see how difficult sometimes these waveforms can be. You can see the ulnar palm, the baseline's not so great, but the peak is good, so it's real, and then you compare it to something else. So cross-risk comparisons are helpful. Sensory studies, distal latencies, then amplitudes. When you have a continuum of abnormality for median neuropathy, sensory studies, distal latencies. Motor latencies are later. EMG might be even later, with a reflex loss, et cetera. And this patient, she reports her symptoms are not worse when working. Tests are pending. Somewhat to prednisone taper, she responds. The NCV studies improved to category of mild after a number of months. So what do you do with this person? Can she work? You know, what do you do for surgery? What's gonna help? You know, in my opinion, you kind of give them a work restriction, see if it's better or worse the same. You see how time goes, get some therapy, maybe acupuncture, but it looks like this person could work and doesn't really need surgery because her symptoms aren't worse. So these are things you have to titrate and get a sense of. Okay, so how old are you? I'm 32. And you just described that you fell. I fell. And carrying a box on your left wrist and some screws came out and punctured your wrist in this area. Yeah. And you actually had then, at that point, did you have weakness or just numbness? I have weakness and numbness now, but before the accident, nothing. And did you, this was how long ago from before that? It was a year ago. A year ago. Then you had surgery, how quickly after the injury? September 12th was the injury, September 18th was the surgery. Okay, so push against my finger up, just straight up. So you feel pretty good. Show me this thumb as well. So, look at both, and put both hands together. Okay, there you go. So maybe there's a little bit of atrophy here, but she's got good power. Push up here strong, okay. And, but she does have reduced sensation here compared to here, and this is also reduced compared to this. How about this, is this reduced compared to this? Yeah. Good, so that's important to notice. That's normal, this is not, because the nerve goes through the carpal tunnel this way, and gets there, but doesn't get this. It might get the tip, but not this part, and that's key. So then we noticed that we look on the nerve test, and we noticed that her left median motor left median motor looks pretty good with normal distal latency, and pretty robust amplitudes of seven. The other side is also seven, so that's refreshing. The right-sided sensory looks good, and fast, and big. Look at the baseline here, it looks nice. Is both slow. Look at the wackiness of that. And small, less than 20. So it's either very abnormal, or it's not well done. I repeated that a hundred times. Normal motor study, we may find some deviation. So let's, we're gonna do a little needle test. Can you just relax your hands? Okay. Okay. The purpose of our testing. Dr. Rutschke's one hand at this point. We're gonna get you ready. Just gonna clean you up here. Okay, let's see if we can find something. So the first thing we're gonna do is break your radialis. A little C6 muscle. And just pull up strong. Push up strong. Good. Sounds pretty good, relax. Okay. Push straight up. Good. Good, full screen, relax. Quiet stuff. And we'll do it for the pronator teres. And try to turn your hand in. Pronator teres and brachioradialis are good C6 muscles to assess. C6 is probably the most common abnormality in a radiculopathy. Do the first person around, see that? Push your finger against my hand. Now I'm sticking the FDI, which is an ulnar innervated and C8 muscle. Okay, let's see, this may be a little bit annoying. Push with my finger. Relax here. So that's an unusual sound. Push strong. Push, push, push. Relax. Good. I really am listening a lot to what I'm doing, as well as looking. Yeah, that's possibly a crunch. So you see how awkward that waveform is. Again, you can't always control the technical background noise that you're seeing these large waves. But you see how abnormal that's a polyphasic wave. I've got more stuff to show you as well. We'll keep going. Now, again, sensitivity and specificity. A lot of people are asking me how EMG's great, but what if you have an exam that shows something totally wacky? Uh-oh. Uh-oh. No. No. I don't know. Nope, that's not it. Anybody? Somebody? Sir? I press this again, I go to the next slide. I'm trying to show clonus here. Bingo. Unusual gait and clonus. Like, you know, an abnormality is helpful, but it's sensitive, not necessarily specific. So you have a strangeness. What do you do when you've got clonus? You might be a spinal cord injury. So the EMG shows something, but you may have a spinal cord injury, you know? Which might be congenital and unrelated to the worker injury. Let me hold my hand. Stand on your tiptoes, good. And then stand on your heels. Okay. And then try to walk on a straight line. Touch your toe to your heel. I can't forward this video here, can I? I guess not. Excellent. Okay, now put your feet together. Let's stand more into the room here. Stand more into the room. I'm not trying to get mad at the doctors, but like I tell them, I feel their presence. What am I doing, sir? Put your feet together. I know, I heard you. I was trying to say something. And put your feet all the way together. Have them touch. And close your eyes. Okay, and now have a seat. I'm sitting right over here on this bench here. Can you just- All right, so here's the kicker right here. You know, when I do an EMG and I just get to be asked to do the EMG, I'm always checking their feet and their reflexes. Why? The answer is this slide, this video. And you'd be surprised how often I see clonus. Look at that. What does that mean? It means it's a spinal cord injury somewhere. So there's more to the picture than simply an abnormal EMG. We move on. Ulnar nerve entrapment, pain in the elbow tingling in the fifth finger, carpenter's construction office workers, but it could be a C8 or T1, weakness spreading out fingers, numbness in the fifth finger, note C7, dermatone is really the D3, the middle finger, record ulnar motor. So there's some unusual tests I can do to assess the ulnar, just see if it's abnormal, even though it might be normal. And of course, you know, this entrapment occurs significantly that affects that fifth digit. There are a number of ulnar muscles. One of them is the flexor culpi ulnaris. So you have a median motor, forget the median motor in this picture, but you have a slow ulnar motor with a really low amplitude of 0.6 and ulnar motor distal latency and nerve conduction velocity that's slow. You can see how the left ulnar motor waveform is small compared to the right. Very important to look at these waveforms. I keep talking about it. This is what it looks like when you stimulate the ulnar, both sensory and motor. There's something called the dorsal ulnar cutaneous, which then, which basically goes to, does not go through the wrist. So if you have an ulnar that's slow, you don't know if it's the wrist or the elbow, you do a dorsal ulnar cutaneous study, which does not go through the wrist. And so if that is abnormal, it means it's an elbow problem. So there's some other unusual things we can do, some extra sensitive tests. Well, come on now. Nope. Okay. C8 versus ulnar weakness. Again, if you're spreading your fingers, that could be ulnar, but you're gonna look for the- Thumb and the first finger elevation to support whether it's C8 or ulnar. Spread your fingers, good. Bring your finger up, this finger up. Very strong. So strong extension of the finger, even though they can't do this, means it's likely ulnar. So again, the C8 is spread, elevation of finger and wrist, and thumb APB. So exam connects to the EMG, it's not alone one or the other. This guy has reduction of the radial weakness, so he's got radial nerve, could be C7. The first finger is C8, but the whole thing is C7. We're gonna keep moving. So EMG and NCV, evaluate quality intensity frequency when you're looking at pain, repetitive job activities, coincidental medical conditions, modified duty to other limb or not at all, concern for the other limb, physical therapy, alternative modules, predictor of potential delayed recovery. You realize this is an EMG lecture, but I'm continuously promoting the fact that this is basically an extension of your exam, and you're thinking of all these in the course of where treatment comes, how alcohol addiction and smoking, you know, connect to delayed recovery. Cascade of disability, these are things that are very important. Patients with persistent pain, sure you're doing imaging, you're doing electrodiagnostic, you're considering surgery. This is a bike messenger who fell on his right wrist, but he had tingling in his feet. Come on. Foot drop. They didn't do anything with the legs. Well, who knows why? It was denied. No one paid attention. Got surgery, but he has pain upon wrist flexion. Every sensory and motor nerve's abnormal. You know, I found diffuse neuropathy, not CTS, non-industrial condition. So it's one diagnostic tool of many. You have to examine a patient. Don't be so short-sighted. Neck pain, thumb pain, forearm, we talked about this earlier. It's a whole puzzle, sensitivity, but specificity, maybe a neck myelopathy, a spinal cord injury, plus they have numbness, and it could be from the myelopathy and radiculopathy. Multiple industrial diagnosis may be relevant in contributing to pain and work limitations. You can't really just do one small thing when you're asked to do carpal tunnel unless it's only that they have numbness in the first two fingers, which is rare. We have AA and EM, talking about bilateral studies, most useful and indicated when you have abnormal EMG, differentiate radiculopathy from polyneuropathy, motor neuron disease. Believe it or not, I've seen a handful of ALS, most recently. A couple of cases in the last 23 years, only a handful, but this year I've seen two. So when you're suspecting carpal tunnel, you've got to do bilateral. Again, you're trying to be stealth and such, but you also are looking to prevent unnecessary surgeries, and polyneuropathy is extremely common. So cervical radiculopathy is crazy common, but it's not as common as stroke. Recurrence is 31%. There's a lot of false positive rates with MRI. Testing can be helpful, but it's not going to be the end result. Your test is normal, I say, okay, but that doesn't mean you don't have problems. What do you mean my test is normal? A lot of people with radiating pain might have long head of the biceps tendinopathy. They don't have radiculopathy, or they have a mild radiculopathy that I can't find from my testing. So I have to be gentle and explain that because people get angry at me because I found their test normal. That doesn't mean I don't recommend surgery. I'm not the one recommending or not recommending, I'm just doing the EMG. So you refer to your doctor, you'll get therapy, you get acupuncture, you'll see a spine surgeon, and they'll consider what the options are for you. The EMG differentiates nerve roots, a C6 from a C7, a C6 from a C8, a C8 from a radial. These are important. An F-wave is assessing a proximal root, mostly used for things like Guillain-Barre or autoimmune stuff. Not so much used now in industrial neurology or even done in a regular EMG unless you really have a flaccid paralysis. But the axonopathy would be confirmed by needle, and you're assessing severity by the shock and the needle together. Do I press or wait? How old are you? Sixty. Okay, so you had a car accident? What kind of accidents? But the amount of abnormalities I see is extremely cool. It's amazing, you know? I see a lot of normal, and I see a lot of really abnormal, but it's often not textbook, so you have to really think where it fits. So weakness in biceps and brachioradialis, okay, C5, C6 radiculopathy, but severe, because the guy really can't do much with it. I can't really increase the volume here. But you can see real weakness in the brachioradialis, C6 muscle. No real attribute, though, so you're not sure if it exists, you're like, is he trying? And again, your ability to know whether someone's trying or it's breakthrough weakness is your experience. Breakthrough weakness means there's not really weakness, that's pain. So they give you one second of good power and you can't break it, that's real power, that's not weakness, or weakness from a joint, or a muscle, or pain. We're going to keep going. So this is a positive sharp wave on EMG, you can see at the bottom, so I'm putting the needle in the brachioradialis and he has an acute denervation based on all this crunchy, there you go, all the crunchiness that you can both hear and the positive sharp waves go downward, which means denervation within six weeks or so of an injury. But that doesn't mean it could be a longer, the injury could have been longer ago. It just means that there's active denervation still going on. And sometimes you have to really move that needle around to see, and you could be there for minutes or a long time. So there's this question of how long I can use the needle for patient's tolerance versus, you know, because it's a needle. Indication for EMG, pain, radiating symptoms, nerve distribution, spasm, motor dysfunction, exam finding in a specific dermatome or motor myotome. But certainly I get EMGs requested to me for, I don't know, and they've approved, so I'm confused. AANEM talks about a cervical radic, may be useful when you have numbness, altered sensation. What does that mean? Weakness, cramps, fasciculations, muscle atrophy, hypertrophy. So it's pretty much indicated when there's chronicity to the problem and that there's a symptom that could be radicular, lumbar or cervical. Of course, you've got people who have conceivably hip problems. Don't forget that people with diabetes under-report their complaints, okay? And a lot of people are basically stoic and don't report their complaints. But then don't forget there's a knee and there's a hip, and all these things can be intermixed with symptoms. ACOM, EMG and neck pain, raise questions about whether there's an identifiable neurological compromise, may be helpful, failure to resolve after four to six weeks, not recommended if no upper extremity pain or no upper extremity numbness. ACOM, EMG and lower back pain, similarly, should not be performed in the first month unless they're pre-existing conditions. So I see people with all kinds of prior surgeries and it's worsened, or let's say I see them a year and a half later when it's either worsened or there's a question of neuropathy or there was an evidence of neuropathy before and I want to see if there's now a year, year and a half later, whether it's still neuropathy or the weight loss mattered or they're still working or it's worse. ODG, of course, comments on all this, cites AANAM, Washington State has cited requirement of positive EMG for discectomy, huh? So surgeons don't often ask for an EMG, it's surprising how people have had surgery and never got an EMG to rule out neuropathy at least because sensory neuropathy is crazy common and they have lumbar fusion or lumbar laminectomy but yet no one knows if the pain's because of sensory neuropathy, which it might be. And then I see them later and they have worsened symptoms but I find a whopping sensory neuropathy. So okay, 42-year-old landscaper, pain in the forearm, frequently use a finger to grip and tools to grip, inability to flex finger. This is a hard one everybody. Examination reveals flexor digitorum profundus weakness, D2, FPL weakness. So this is a kind of a cool anatomy case which talks about an unusual part about the medial forearm. A lot of things are abnormal, while stimulated medial nerve, a marked difference noted between the needle pronator teres, right versus left. So the inter interosseous nerve is basically, can be affected often in landscapers and people who do pinching and gripping. And I've seen a handful of these cases. It goes through the pronator teres muscle, it could be direct trauma, mimicked by an elbow dislocation so don't forget it, maybe partially involved. So you have the pincher and then you have pronator quadratus which is present with elbow flexion and pronation rather than pronator teres which is extension. So that's kind of a cool thing, pronator teres, pronator quadratus. Pronator quadratus is abnormal and to get that needle I poke through the radius and the ulnar bone, it's kind of a needle test. I'm not going to go through all the distal stuff here, but there's an anatomical review, medial nerve pearls I mentioned. Good slide. Apparently he had some sort of accident and you can see in the left arm below the biceps and he has weakness of pronation, weakness of first finger flexion and sort of thumb flexion. We've got to keep moving here. I don't know what my time is because the clock is kind of screwed up. So you have a proximal median innervated muscle that's abnormal from this trauma. I think this is also a landscaper injury. Look at the positive sharp waves. Sometimes it's really straightforward. I can see things like that. Other times I don't know and if I don't know I can't call it and sometimes there's weakness and it should be abnormal and I can't find it so I don't call it and sometimes I don't think there's a problem, but yet I find it abnormality. In this case you see the proximal motor, left median motor is small compared to the right. I'm not sure what I'm looking at right now, but I'm going to keep going because we have no time. Identify what is abnormal for the data and waveform. No particular waveform in its baseline. No comparison study. Is everything abnormal? Is there an examination and diagnosis? Is it industrial? This is kind of what we're thinking about or I'm thinking about when I'm looking at these kinds of patients. So people often have feet pain, heel pain. Don't forget Achilles tendinopathy. Don't forget plantar fasciitis. Pretty common. A foot drop can come from these kinds of traumas and chronic conditions and it's not necessarily needing tarsal tunnel surgery from a podiatrist. I'm being a little bit of a whiner today. So you have tarsal tunnel surgery that could look like sensory neuropathy, but if you don't do the sensory studies you're not going to know if they have a metabolic syndrome or diabetic neuropathy rather than plantar fasciitis or tarsal tunnel I should say. And surgeons do tarsal tunnel surgery. Podiatrists do. So if you have no sensories then it's not tarsal tunnel, it's freaking sensory neuropathy. And you can see conduction block, all kinds of things from axonal polyneuropathy that is in severity it varies. But in this case an early EMG would have saved surgery. The guy then falls after surgery, has further problems with his knees and his back. There's a lot of, there is surgery for diabetic neuropathy discussed and described in the literature from now a handful of years. So you have some proponents for reducing pain in the feet from neuropathy by surgery. The literature is vague and not clear, but it is being done. So here's a person who had trauma to the heel and a foot drop, but when I examined them it was really heel pain and there was no foot drop. The EMG was normal, but there was sensory abnormality in the feet. Sensory, serosensory was slow, but plantar fascia was the problem, it wasn't a root problem or a perineal nerve issue. So a good exam would have led to a diagnosis that didn't lead to foot drop and maybe back surgery for something that didn't get better. And saved insurance significant money and inadvertent treatment. This is a police officer who was shot in the buttocks who did have symptoms both with inversion and eversion. You know, because you have the sciatic nerve that presents both, moves into the perineal and the tibial, so you need to be able to understand that inversion is tibial, eversion is perineal, but in this case he had weakness in both, which suggests it's more of a proximal sciatic nerve lesion. So don't forget inversion and eversion. Inversion I, tibial, eversion E, perineal. So the sciatic comes down and splits into perineal and tibial. So if you have both, that means it's either lumbar 5 root or higher sciatica. Thank you Michael for coming. See you soon. His dorsal flexors are normal. So do they do any surgery on your knee? No surgery. No, why not? Because they say if his dorsal flexion isn't there, it's pointless. Yeah, they want the nerve to repair itself first. Interesting. So when you look at the nerve test here, we're just doing this for teaching purposes, we do have the right side, the right side of the sural is quite normal compared to the left side, which is good. So the surals are both good, no neuropathy. Is robust on the right. The perineal is pretty good too. The right tibial looks good compared to the left tibial, but the right perineal is entirely absent. So the right perineal is absent. So the perineal nerve is affected in some way that can come from the root, the L5 root, or it may suggest a radiculopathy, that's kind of vague. We have basically, you see the way sciatic neuropathy can be the bottom of the foot and the L5 and S1 root, okay, L5 and S1, and you see how it breaks off in the left side part of the slide, to my left, yep, goes from the sciatic down, splits to the perineal and the tibial and then also the superficial perineal, which is the lighter nerve in the lateral aspect of the foot. Lumbar radiculopathy, radiating pain in the buttock, numbness follows the pattern, weakness, atrophy, reflex, loss. Perineal nerve may be an entrapment at the knee, may mimic a problem in the back, secondary to leg crossing or a kneeling injury. This is not uncommon. This shows an evidence of an H reflex, which as I mentioned earlier is the same as an ankle jerk. So you have a sensory input to the DRG, dorsal root ganglion, and then it comes out the anterior horn cell, giving you a motor contraction. Other pearls, straight leg raising test, Hoover's sign, everybody talks about. We talked about inversion and eversion. A lot of patients, they'll come with back pain and have incontinence because I get these very complicated patients, and what do you do about that? Is it a conus problem? Is it a cauda equina syndrome? So Hoover's sign is, look at A, I'm putting my arm under their left leg so I can see the power in their right leg, B. So if you want to show me power in your right leg, you're going to push down with your left leg. So use this frequently because you really need to know if there's effort. And of course it doesn't mean there's no effort if it's not there, but there's no effort. That's a positive Hoover's sign. Here's a polyphasic wave. You see the screen on the viewer's right, and you see how many ups and downs that waveform is to suggest a chronic nerve root impingement. So sometimes it's as beautiful as that, and you can see on the left side the active attempt at doing this versus the right side. So quality control. As we're on slide 102 of 104, so we're almost there. Board certified neurologist or physiatrist, history exam conclusion, temperature, looking at data, bilateral studies, availability of practitioner. Can you call or reach the person you have a question for? That's always a good sign when you want a specialty consult. Is that person available? I try to be. I have my phone, my cell phone on all my reports. I have trouble of course reaching out to others, but I do my best to be available so I can answer questions because I understand that this is a very complicated topic, and I'm trying to be helpful to help a patient with their next steps of moving forward. I always try to talk about this in any lecture I give more and more. This really is relevant to everything, certainly not specifically to EMG and NCV, but when you're seeing patients and you're talking about yourself, you think you're best about doing your best to be in your ideal body weight, exercising as much as you can, eating a plant-based whole food diet, not using tobacco, alcohol, and sleeping as best you can. This for me is primary, secondary, and tertiary prevention and treatment for people with all kinds of conditions, including upper and lower extremity pains and problems. So again, I would mention that I am very happy and privileged and grateful for the invitation to speak today, and I would love to meet each and any of you if you have any questions, and please enjoy your travels and be safe, and happy May. I had a big birthday recently, and so I send you all my best wishes and appreciation. Thank you so much. Thank you.

Dr. Jonathan Rutchik

EMG testing

NCV testing

neurological conditions

occupational medicine

nerve function

neuropathies

quality control

lifestyle factors