Amyotrophic Lateral Sclerosis (ALS)

Amyotrophic lateral sclerosis (ALS), also known as motor neurone disease (MND) and Lou Gehrig's disease, is a specific disease which causes the death of neurons controlling voluntary muscles.

Motor Amplitude in ALS

What is the motor amplitude? Is it pathologically higher or lower than normal in ALS/MND?

Answer 1:

The motor unit potential (MUP) gets higher in MND. While the compound muscle action potential (CMAP) is normal initially, but in advanced disease gets lower (even absent) due to severe loss of axons.

Answer 2:

SNAPS or sensory nerve action potentials should be characteristically normal in ALS as the disease affects the anterior horn cell, (Amyotrophy) a motor neuron disease. If the SNAP is abnormal consider a concomitant neuropathy of different etiology or revise your diagnosis to something other than ALS

Abnormal motor units in ALS

I have read there is a connection (in ALS) between abnormal motor units (large amplitude) and the appearance of fasciculations- which means if there are ALS fasciculations – there will also be abnormal units – Is that true? And if not, how much time would it take for abnormal units to appear if there are already ALS fasciculations? (Weeks, months..)?


Fasciculations (at least Motor Neuron fascics) are a sign of ongoing reinnervation and can actually begin distally in regenerated nerve fibers. By the time fascics develop in ALS, you should see a good deal of neurogenic potentials


What do you mean by neurogenic potentials? Do you mean neurogenic units – the abnormal motor units (amplitude etc.)? Second, so according to your answer if a person fasciculates for months and It is due to ALS (malignant fasciculations)- His motor units should be abnormal (huge amplitude and so on)? How much time on average does it take from the beginning of ALS fasciculations to the appearance of abnormal motor units (neurogenic units)
* I am asking it because I have read that abnormal motor units (huge amplitude.) are more common with chronic long standing denervation


Yes neurogenic units means polyphasic units, later on with high amplitude. In my experience, I see the neurogenic units before I see the fascics, or very close to them in time

Are there 2 types of fasciculations in ALS?

I know that fasciculations in ALS are due to nerve irritation (the same as in benign fasciculations?)- However in one of the posts it was said that fasciculations are due to ongoing reinnervation (the ones seen in EMG) are there two types of fasciculations in als?


No, in ALS (even normal or other conditions), it is one kind of fasciculation. Clinically this refers to visible twitching of the muscle and are seen in the EMG needle examination as fasciculation potentials. Fasciculations may mimic normal or abnormal motor unit potentials (MUPs) as seen in on-going reinnervation. There is no “infallible” way to tell whether the fasciculating discharge by itself is benign or malignant. The decision is made by what kind of company they keep. In a study in 1993, a total of 121 patients with benign fasciculations were followed up to 32 years, none developed ALS (Blexrud et al, in Ann Neurol 1993;34:622-625).


Referring to your answer: in ALS – Do you find fasciculations only when there is on going reinnervation? Isn’t it possible to find/have them during denervation – before reinnervation starts?
And if so, I know It is common for people with ALS to have them as a very very early sign – does it mean that when they feel/notice them- they are already in the reinnervation phase (after denervation)? And if so, how come fasciculations are an early sign of ALS (as reinnervation takes place much later)


Yes, I agree that patients with ALS may present with fasciculation. In one report (letter), 6.7% of ALS patients had fasciculations as an isolated, initial manifestation of the disease (Eisen and Stewart. Ann Neurol 1994;35:375-376). Practically, all the patients I have seen got the fasciculation (if present) with other signs of denervation and neurogenic MUPs of variable degree. About your point do fascics specifically occur before or after the onset of reinnervation in ALS, I do not know. However, the single fiber EMG jitter reveals that reinnervation could be detected in the fourth week (increased jitter) after muscle transplant in healthy nerve and muscle fibers.

Interference pattern in ALS

In anterior horn cell disease, there is a reduced recruitment (not full interference pattern) does it matter how long does it take for a person to build the full interference pattern (by increasing exertion)? Because I read somewhere that ALS patients just cannot build the full interference pattern, even after a lot of time because they lack these motor units. So, FOR ALS DIAGNOSIS, does it matter how long does it take to reach it? I mean, Is it true to say that if a person has anterior horn cell degeneration – he will never be able to reach a full interference pattern, even after minutes?
*I know that in muscle fatigue, there is a full interference pattern, however it takes much more time to reach it – is that true?


Yes, in ALS there is motor units loss, therefore, those patients have a reduced interference pattern or reduced recruitment. Whatever they do, they do not reach the full recruitment pattern. This is very much noticeable if there is significant motor units loss. As a matter of fact this is also true for other neuropathic conditions, for instance, peripheral neuropathy. So, reduced recruitment is not specific for ALS.

Fasciculations and ALS

A couple of questions:

1) I have at least a thousand fasciculations a day. How come during the 3 EMG’s (2 partials, 1 full) no fasciculations were detected? Seems impossible.
2) Besides random fasciculations, I frequently have fasciculations right after moving a muscle. Is this more problematic than a “random” fasciculation?
3) Is it likely that twitching can occur for six months without loss of strength and still get diagnosed with ALS???


Actually it is not always surprising if the concept of EMG needle recording is understood. If the tip (or the recording pick up area) is far from fasciculating potential, then you do not see any fasciculations on the screen. For the second question, yes it is possible, and that is why a follow up EMG is usually needed. Regarding time period after onset of twitching without weakness or an abnormal EMG, it is difficult to be absolutely precise in time. But several months are usually acceptable by the time fasciculation is seen, but provided no other clinical/EMG findings.

Thoracic paraspinals EMG Specificity in ALS

Is it true that in ALS there is a specificity of the thoracic paraspinals and that they are almost the first ones to show prominent denervation (PSW, fibs etc..) – my neuro told me that if I had ALS, He would have seen that immediately when sticking the needle there. What is your experience in this specificity (thoracic paraspinals show denervation FIRST and most profound one). HAVE you seen any ALS patients who had denervation in limb muscles but had completely clear thoracic paraspinals then (in your long experience).


If you look at the WFN El Escorial criteria for diagnosis of ALS; as follows: 1. LMN signs (by clinical, electrophysiological, or neuropathological exam) in 1 or more of 4 regions (bulbar, cervical, thoracic and lumbosacral) 2. UMN signs (by clinical exam) in 1 or more of the 4 regions. AND Progression of signs within a region and progression to involve other regions. Therefore, from item one we cannot say that thoracic paraspinal abnormal EMG is specific for ALS, otherwise we do not need other factors to diagnose the disease, and may have false positive diagnosis. However, let me address this point in a different way, they are very useful muscles when a cervical or lumbosacral radiculopathy is a strong consideration, then an abnormal EMG in the thoracic paraspinals would indicate a more widespread neurogenic involvement in favor of ALS, as radicular thoracic lesions are uncommon or rare by comparison to cervical or lumbosacral lesions.


So, Isn’t it true that there is some specificity for the thoracic paraspinals in ALS denervation?


I too have read about the specificity of the paraspinals, and probably know where you saw it.

However, at the MDA clinic my EMG was overseen by well known author, who has written some of the standard texts on EMG and disease processes and he said this was just a “neurological wives tale.” In addition, in one study I found on about 750 PALS, only about 50% showed denervation in the thoracic paraspinal muscles vs. 90%+ showing denervation in their arms.

Fibrillations and Fasciculations in ALS

In a previous post, I brought a citation from “Cecil” textbook of medicine which claimed that in the course of lower motor neuron injury (ALS and related conditions), fibrillations appear first and later fasciculations. Is this true??? Have you seen such pattern with your ALS (or other lower motor neuron) patients?


Yes, I have seen such pattern of appearance of fibrillation first. It is however the combination of findings that is the usual pattern

Peripheral neuropathy versus ALS/MND
I know there are theoretical ways to distinguish (in EMG) peripheral neuropathy (where there is a damage to the peripheral nerves) and ALS (where there is a primary damage to anterior horn cells (CNS). however I know fibs and positive sharp waves as well as reduced recruitment are features of both. So how is the distinction and later the diagnosis made by EMG and NCV – How can you know where is the source of the damage to nerves (central or peripheral) because in both conditions there are exact signs of denervation?
* My question refers to peripheral neuropathy of the kind, which is predominantly motor (so you cannot distinguish by lack/presence of sensory signs) and is quite widespread. How the distinctions are made?
I refer in my question to AXNONAL neuropathy with actual damage to the axons (NOT demyelination where it is obvious due to very slow velocities.)


In ALS or peripheral neuropathy the diagnosis depends on the history and clinical presentation. Some points to differentiate: the reflexes are brisk in ALS while they are absent in neuropathy. In EMG, in axonal neuropathy and ALS you may have the same findings. But the examination of sensory nerve action potentials is important. They are normal in ALS but they are affected in neuropathy.

Motor neuropathy and ALS

You said that ALS and axonal neuropathy cannot be distinguished by EMG due to similar findings but what about nerve conduction velocity – I read that in ALS they are normal (not slowed) aren’t they ALWAYS slowed in motor axonal neuropathy? (Is it possible to have motor neuropathy of axonal type with normal velocities)??? The question is about the velocities because as far as I am concerned the CMAP (amplitude of motor nerves) is very reduced early in both conditions so you cannot rely on that. (Correct??)


Yes, the MCV may be normal or slightly slow in either conditions because of the low motor amplitudes in both. But the sensory nerve response is normal in ALS but affected in neuropathy.


About these distinctions you mentioned:
1. ARE THE SENSORY POTENTIALS ALWAYS ABNORMAL IN NEUROPATHIES? ALSO IN PURELY MOTOR NEUROPATHIES (or there is not such a thing purely motor neuropathies???) * are there any neuropathies with motor symptoms only and motor emg abnormalities only?

2.and what about fasciculations – are they present also in motor neuropathies (because if not it can be one distinction) what is the percentage of patients with motor neuropathies who have fasciculations?


Thank you. To clarify myself, the ALS/MND require certain criteria for diagnosis; presence of Lower Motor Neuron (LMN) findings in at least 2 limbs, Upper Motor Neuron findings in at least 1 limb and progression. Now, going to your point about the SNAP, it is always normal in ALS but it may be normal in neuropathies including motor neuropathies. Therefore, if it is normal then it cannot be used in that case to differentiate. About the fasciculation, it is characteristically present in ALS but it is not the only condition they are present in. So it is not a distinction criterion. Last point I am not sure about the frequency of fasciculation in motor neuropathy.

The electrophysiologic diagnosis of ALS

My symptoms are fasciculations and minor cramps I read somewhere that a clean EMG after 6 months of symptoms rules out almost completely the diagnosis of ALS –

1.Does it fit with your clinical experience?
2.Is it possible in your experience that after 6 months of fasciculation the EMG will show nothing but fasciculation (no fibs and positive waves) but later would show ALS (fibs and positive sharp waves or psw)
3. when you say that somebody with fasciculations has inconclusive EMG what do you mean? Does the definition of “inconclusive” in relation to possible diagnosis of ALS includes actual fibrillations and psw or anything else – what would be inconclusive in relation to a person with fasciculations and suspected ALS?


ALS is an elimination diagnosis, that is that we only make it after having ruled out other (and there are many) conditions which can mimic it. Unfortunately, frequently fasciculations have been the only thing identified with ALS. So the short answer to your question is do not mind so much the EMG as much as you should mind what your neurologist tells you and if you don’t think you’re getting the right answers, by all means seek a second opinion.


So do you mean that frequently ALS patients do not exhibit PSW or fibrillations in their EMG exam?


No, on the contrary, the fibs and PSW are frequently seen in combination with fasciculation in ALS patients. If the EMG is free from fibs and PSW it is reassuring.

Reduced Interference Pattern (IP) in ALS?
Is reduced IP seen in the beginning of ALS or only later on? (Is it one of the first things to appear on EMG with ALS patients?)


I would think that reduced IP is perhaps a “later” EMG sign in ALS. However, it’s appearance early or late, on one the hand, does not have a diagnostic value similar to spontaneous activity. On the other hand, a reduced IP may be variable and changes with the patient’s cooperation, the strength of the muscle, pain and the presence or absence of disease of the upper motor neuron such as spasticity.

Can we depend only on EMG “without NCV” in diagnosis of ALS?

Is it possible to have an EMG test checking for ALS without an NCV? (I understand that by leaving out the NCV part other possibilities may be undetected, but the major concern is ALS)


I am afraid we cannot do that because a normal sensory nerve conduction studies are essential part in electromyographic findings in ALS.

Abnormal foot movements after EMG & NCV; is it due to the test?

I had an EMG and nerve conduction test done for ALS because of some minor fasciculations The EMG found fasciculations, no fibrillations, so the neurologist felt I was clean. But just 4 days after the test my foot, where most of the testing was done on, (at least five separate sets) started vibrating and fasciculating like crazy. It then spread after a month to my other foot. Is this not an uncommon reaction to the test?


This is not a common reaction to the test; in fact I have never seen it happen. I cannot tell you what this is due to but if you feel that this is way out of the ordinary for you (and it has lasted this long) I would get in touch with your doctor and tell him/her about it.

Time lag before detection of positive sharp waves
In your quite lucid explanation you make mention that fibrillations cannot be picked up until about 2 months after injury. I was wondering how long a lag exists till the EMG can pick up positive sharp waves. Also, I’ve seen differing opinions as to whether patients can actually feel the fibrillations and the waves themselves. What is your opinion on this? Thanks very much.


Fibs and positive waves are seen at about the same time. In fact it’s been argued that fibs are positive waves, which are seen from a different vantage point by the needle. People cannot feel either fibs or positive waves, what you are referring to is fasciculations, which are much larger contractions of muscle, and which patients can usually feel.

Fasciculations Frequency “definition”

I have read in “principles of neurology” that benign fasciculations tend to be more frequent and constant in location than the malignant ones. What do they mean by FREQUENT? 1. More frequent in EMG: once it fires the frequency of each “muscular jump” is higher (shorter intervals between each fasciculation) 2. Or, maybe they mean the clinical way: that the patient gets them more, feels more fasciculations in a given muscle -the frequency of each such “battery” of fasciculations is higher. HE gets more twitches?
What do you think they mean 1 or 2?


It is 2, referring to frequency in clinical way


So according to your clinical experience: the random twitchers, those who get them few times a day only and every time in totally different location (a twitch in the calf muscle once every hour or less, for example)- these are the twitchers who should worry more about als? * More than the twitchers who have them continuously in the same muscle?


Yes, this is true, it is good clinical assumption to follow, but it is not perfect, as surprisingly some patients with ALS are oblivious to their fasciculations.

Contraction fasciculation versus spontaneous ones

I have read there are two types of fasics: spontaneous ones that fire with no relation to contraction of muscles and the contraction ones: which are rhythmic firing of motor unit – observed during weak contraction. The latter are seen in ALS and a compression of nerve root.
My question is: 1. So, are there two kinds of fasics. Both happen in the course of als?? (or the spontaneous happen less) 2.The contraction fasics-How will they be heard electromyographically (rhythmic popping??) I am a bit puzzled because I once read that fasciculation are random pops in EMG while normal motor unit firing are rhythmic popping and that is the way to distinguish fasciculation from normal motor units activity – so How come contraction fascics (malignant!) also produce rhythmic popping?


You are right, there is something called contraction fasciculations, BUT this has nothing to do with ALS and it is not spontaneous. As a matter of fact we should not confuse it with the usual spontaneous fasciculation. This contraction fasciculation is merely a motor unit contraction visible underneath skin seen initially during a slight voluntary muscle effort.


1.What exactly are the contraction fasciculation (I read they are rhythmic twitches seen in weak contraction – Is that true?) 2.what is their pathological significance? Are they never consisting a part of ALS or other LMN degeneration? 3. How do you here them in the EMG (rhythmic popping)??


Practically I do not look for it in ALS and I have not seen among the EMG criteria to diagnose ALS. Historically, it was described by Denny-Brown and Pennybacker in 1938 (Brain 1938;61:311-334) and also by Milner-Brown et al, J. physiology (London)1973,228:285-306.

Fasciculations following muscle activity with normal EMG

I have had muscle twitching all over my body for 3 months now. I have had about 4 normal neuro exams and 2 negative EMG’s so far. I have noticed that many of my fasciculations occur directly after applying force to the muscle (i.e. when I lean on my elbow I get a twitch in my elbow, or when I make a muscle in my arm I often follow with a twitch in my bicep). Is this pattern more concerning than fasciculations that occur randomly in a muscle while at rest?
Thanks for your help


Please be reassured that these kind of twitching or fasciculations are not worrying at all, this is supported by the normal neurological examination and negative EMG on 2 occasions

Benign fasciculation syndrome (BFS)

Would you know the answer to this question? I have asked my neurologist, asked the MDA, and looked at a lot of reference material and cannot seem to find the answer. I checked your site, but still no luck. I have been diagnosed with Cramp-fasciculation syndrome/Benign fasciculation syndrome (BFS). On my EMGs, there were positive sharp waves from two different muscles (normal nerve recoupment and no fasciculations noted); my NCVs are all normal. I thought with BFS my EMGs should be normal and my NCVs abnormal? Thank you.


The term benign fasciculation syndrome (BFS) is used when the patient has fasciculation but no neuromuscular disorder is found. In this case the EMG may show fasciculations only but no positive sharp waves or fibrillations. The nerve conduction study (NCS) is normal, while the Cramp/fasciculation syndrome may have muscle aching, cramps, stiffness, and exercise intolerance. Again in this condition as BFS, the EMG may show fasciculations only, otherwise, no other EMG signs, and the NCS is also normal.


Thank you, but I am confused. My two EMGs clearly had positive sharp waves in two different muscles. My NCS were all normal. At first my doctors were thinking early signs of ALS. It has now been a year and a half but still no weakness. I have tremors in my hands when I try to hold something; sharp, very localized pains in my arms above and below my elbows and in my hands, fasciculations virtually everywhere from my feet to my face, and have become very exercise intolerant. I can still lift a lot of weight, etc., but just can’t do any repetitions. With my EMG findings, how could I have BFS or Cramp/fasciculation syndrome? Thanks in advance.


May I know what muscles had the positive sharp waves?


Sure: Quoting my medical records: May 17: “Right triceps: plus two positive sharp waves with trains of positive sharp waves present demonstrating increased insertional activity. The motor recruitment while having many small motor units, showed no evidence of increased polyphasic motor activity or abnormal recruitment patterns.” Left triceps: “plus one positive sharp waves with trains of positive sharp waves present. This demonstrated increased insertional activity. The motor recruitment was normal, with no evidence of increased polyphasic motor activity or abnormal recruitment patterns.
March 26: Triceps, right, 2-3+ positive waves and 1+ fibrillations
March 5: Triceps, right, plus 2 positive sharp waves, motor recruitment normal; – right medial gastrocnemius – one train of positive sharp waves, motor recruitment normal.
I have consistently had increased insertional activity in most muscles tested in each of my 4 EMGs. My last EMG noted no positive sharp waves – just increased insertional activity. In each of the muscles that have had positive sharp waves I have a “stabbing” feeling – in the triceps above the elbow; and the same localized pain in the forearm below the elbow.
I have had a spinal tap to rule out MS; all sorts of blood work to rule out heavy metal poisoning, etc.; brain scan; c-spine MRI (showing a slight stenosis but no impingement of the spine). I am a Persian Gulf Veteran and have tested positive by an DNA PCR test for the mycoplasm fermentans that has been linked to “Gulf War Syndrome” and am on a 1 year course of antibiotics in a study on that.

Comment 2:

I’m sorry, I also forgot the following: Feb. 5 – my NCS noted mild slowing for the ulnar motor nerve across the elbow; during exam, very active positive Tinel signs present over the median nerve on the right and the left wrist and over the ulnar nerve over the right and left elbow
– my reflexes are consistently +3 all over; once I was noted as having a Babinski reflex, once a Hoffman reflex
– when I exercise, after a few minutes I get a burning sensation (like if I were lifting weights and got to the point of muscle failure)
– I have a tingling sensation in my 4th and 5th fingers of my right hand, sometimes my right index finger.
In reading about ulnar neuropathies, I seem to have some of the symptoms – the tingling of the 4th and 5th fingers, elbow soreness (about 1 inch above the elbow), there is a history of diabetes in my family, and I used to lean on my elbows alot while I type (I have stopped doing that). Are my EMGs/NCS consistent with ulnar neuropathies?
Again, I have no weakness, no bulbar signs of ALS (occasional slurring of words, but I have always done that when I am tired); lots of fasciculations; and a lot of pain from those very specific parts (feels like someone comes up and stabs me with an ice pick – when it strikes, I will drop what I am holding, etc.).
I am currently on Gabapentin for the tremors (I would pick up something, and sometimes my hand, fingers, etc. would start to tremor, the more I held on, the worse it would get).


Do you recall the sounds of the sharp positive waves and fibrillations in your EMG, how did they sound like?? How long each has lasted


It just sounded like a lot of static, no popping or anything, just loud static. That is all I remember; before each EMG I had an NCS, which when I was shocked in my arm, my leg, would fly up, etc. By the time I had the EMGs, all of my nerves were on end, and the EMGs really hurt, a lot!!


Now that I think of it, the static at times would sound liking rapid popping – no break in between – this would occur on the muscles where the sharp waves were

Answer 2:

How did the fibrillation sound like?? You say static. Could you distinguish what it was made of or was it just static sound like a “dead heart” on ECG? Most importantly, about the duration – was it short duration (3,4 seconds) and stopped quickly or was it for a long time??


I’m sorry; can’t remember the exact sound. It continued the entire time the needle was in – it did not stop.


Here is a link that actually shows videos of fibs, ps waves etc.

Here is a link to more videos of fibs, ps waves etc:

Answer 2:

Thank you for detailed information about your medical problem. I agree that it cannot be a pure BFS or cramp/fasciculation syndrome or ALS.


Thank you for your time. I guess I will just have to wait and see what develops. Hopefully I can report back in a few years that it is benign!

Can Fasciculations result from overexertion & how to exclude ALS?

I am a 49 year old, that works out all of the time and for the last 5 months have had fasciculations especially in my calfs. I had a normal Nerve Conduction and now they want to do an EMG. The only physical change is that I gained about 15 lbs after beginning to lift weights in February.

I never noticed the Fasics until my Flight Surgeon looked for them at my last flight physical.

My question is do you find that over exertion causes fasciculations, and is there something else I can try before the test? I’m also finding that I get cramps in my calfs and some soreness, (probably from to much exercise). According to my trainer my strength has increased substantially.

These are questions that are hard to ask and I am quite tentative about a ” lose – lose ” diagnosis. If its BFS there is nothing that can be done about it, and if it isn’t there isn’t.

Any Suggestions?


Too much exertion, or stopping exertion after having exercised for a long period, can cause fasciculations. Usually calf fasciculations and cramps tend to be benign. An EMG however would be a very good idea because it may explore whether or not you have fasciculations (that you are not aware of) in other muscles.

In the work-up for ALS there are many other signs and symptoms than fasciculations that lead to a diagnosis; so a good EMG and and a good neurological work-up are of the utmost importance before making a diagnosis.


I had the NCS it was negative, and a EMG and the Dr. stated ” I needled the tibialis anterior, peroneus longus, gastrocnemius or soleus on either side, quadriceps, hamstrings, deltoid, biceps, triceps, and first dorsal interosseous on the left side. Most of the muscles showed small fasciculation potentials. No runs of fibrillation potentials or positive waves. No bizarre high frequencies discharges. No Myotonic potentials. The motor units that I saw were of normal amplitude and duration.”

He then suggested I stay with Acupuncture for a few weeks and see what happens. He also did a lower back MRI which was normal and a spinal X-ray and the only statement was” Small anterior Osteophytes are seen at T12 -L1 and L2-L3.

So my question is what do suggest I do about the Fasciculations / twitches and the leg stiffness that goes with it. I have been taking creatine 5 mg a day, and many non-synthetic vitamins prescribed by my nutritionist. Also I am working out with weights and seeing definite gains in strength, other than my legs.

What are your thoughts on acupuncture for this problem.

I am a pilot and taking certain medications is not an option, I would be glad to pay for your time for a phone consultation, if that is an option…

Answer 1:

I would suggest continuing the acupuncture. In general the presence of fasciculations without other EMG findings by itself is not significant. I do not suggest any specific therapy in your case for fasciculations.

Answer 2:

Findings such as the ones you describe could well be benign fasciculations. Usually, you would like to see large fascics and some other signs of denervation such as fibs and positive waves for this to be significant. A normal MRI and spine x-rays just indicate that the symptoms are most likely not coming from your back.

Is the EMGer that did the test on you your neurologist? Per my previous reply to your post, I had indicated that EMG is only a part of the work-up, it takes an experienced neurologist to put all of these findings together (and exclude other possibilities) to rule out ALS.

I usually advise patient with symptoms and findings such as yours to seek the advice of an experienced neurologist to look at the whole picture.

I can’t tell you what to do with the fascics. I usually recommend decreasing (not stopping) the weight training for a couple of weeks to see if the fascics change. That would be a way to find out.

Normal nerve conduction studies Rules Out MS and ALS?
My primary care physician recently ordered a conductive nerve study for me since I have had hand and feet numbness, twitching and weakness in the thighs.

The conductive nerve study was negative as all readings for all 4 extremities were within normal ranges. On the follow up visit when we discussed the test results he said that a normal (negative) conductive nerve study rules out central nervous illnesses such as MS and ALS. Is this the case or should I pursue the opinion of a neurologist?


Nerve Conduction Studies do not evaluate MS at all, and they are only part of the equation in ALS. Certainly, a normal study rules out neither. When the information you get from a primary care physician (regarding a neurological problem) is unsatisfactory, it is best to seek a neurological opinion.


You said that the NCS is only part of the equation for ALS. What are the other parts of the diagnostic equation for ALS?


The other parts of that equation are the Neurological and Physical Exams and abnormal EMG needle electrode examination.

Relative occurrence of fibrillations and positive sharp waves in ALS
I read in one of the articles which dealt with ALS that in ALS, the EMG show mainly sharp positive waves and fasciculations, and only sometimes fibrillations (which are less common in ALS than PSW AND FASICS) ACCORDING TO YOUR EXPERIENCE, IS it true? AND IF SO why PSW are seen in ALS much more than fibrillations)?


This is not true; the fibrillations are similar in occurrence to that of positive sharp waves in ALS.

ANA and Sedimentation Rate in MS or ALS

My primary care physician ordered an antinuclear antibody and sedimentation rate tests as part of a screening for the symptoms I presented. Both tests were normal as was my conductive nerve study (conduction on 4 extremities but not the inserted needle test).

Will a SED rate or ANA be elevated for either ALS or MS?

I have an appointment with a neurologist in 6 weeks (I was not able to get an appointment any sooner).

Any other advice? My chief complaint is weakness in the front of my thighs and muscle twitching primarily in the lower legs but shows up in the thighs when they are tired. Twitching has shown up on my upper arms and occasionally in my hands, back and face. Sometimes I might go a day or two without a noticeable any twitching but when I am fatigued twitching is more common.

I should mention that the twitching started after I had a reaction to Septra about 2 months ago. I don’t know if that was just a coincidence or not but the reaction was significant with burning gums, insomnia, loss of appetite and numbness in my legs from the knees down. Prior to that my main complaint was fatigue and numbness in my hands and feets. The numbness, which started about 4 months ago, seems to have gone away.

I should also mention that I have had what I would call long-term tiredeness, achiness, unrefreshing sleep and such for about the last 10 years. I had come to terms with those long-term symptoms but theses new issues are frightening.

I am a 43-year-old male with a desk job.

Thanks for your input. It is hard to wait so long to see the neurologist. I made the appointment over a month ago and still have 6 weeks to wait.


The sedimentation rate or ANA have no relation to either diagnosis. They are not part of tests done for those diseases. From your symptoms, it is a good idea to see neurologist. He would hopefully sort out your symptoms. He may also request an EMG, which should help to explain at least some of your symptoms.

Acute denervation in ALS

I know that according to most neurology books, in ALS both ACUTE AND CHRONIC DENERVATION ARE seen. However, I am not sure which one is most prominent in early ALS?

Actually, according to your own clinical experience How prominent is the acute denervation in early ALS? (PSW, fibs)

Have you seen any patients with MND (ALS, SMA, progressive muscular atrophy) who showed only chronic denervation (giant units) and no acute denervation at all in any of the limbs?

Is it possible with motor neuron diseases, according to your own experience? (Because It is not quite clear from the books)


It depends on the time of presentation. Generally speaking the denervation activity are seen at all times; either acute or chronic stages of MND. The changes of the MUP can tell you about chronicity. If they are high amplitude (giant MUPs), then indicate a chronic stage. Therefore, in early stages, mainly the denervation activity without much of MUP amplitude changes. While later on denervation activity still there in addition to high amplitude MUPs.


Thank you again for your reply!

My neurologist has told me that some MND’s are very slow (for example SMA) and there for the chronic changes there are prominent.

1. Does it mean you NEVER see acute Denervation in SMA (fibs, PSW) but only chronic changes, because they are very slow diseases?

2. And about the chronic changes in MND (ALS, SMA..) you mentioned huge amplitudes… but what about highly polyphasic, long duration units? Why aren’t they ever mentioned with ALS or SMA in most textbooks?

3.what would be abnormal amplitude in ALS/SMA?


First I would like to make myself clearer and try to explain my understanding to these interesting disorders. There are spectrum or range of diseases due to motor neuron affection (anterior horn cell diseases). This spectrum includes SMA, MND and ALS. The MND term is frequently used to mean ALS. SMA although is anterior horn cell disease but has only signs of lower motor neuron affection, absent reflexes and very slow progression. From the EMG point of view, MND or SMA all show denervation activity with neurogenic MUPs. The EMG is not enough to differentiate between MND and SMA, although generally the MUPs tend to be more complex and higher in SMA (slow progression). Clinical examination is important in this. Now, regarding the MUP, when it is chronic it becomes not only high but gets polyphasic and increased in duration. It is not mentioned in standard textbook may be because they are not specialized books. But this is known in EMG textbooks.


One of the things which also is not very clear from most text books is polyphasic units: I know that polyphasic units by definition are those with more than 5 phases. However, Are units with 3 or 4 phases are as completely normal as the mono and diphasic units?

I will put it this way: if you Do motor unit analysis to a patient and you find out that most of his units are of 3 and 4 phases (rather than 2 or 1) would you be more concerned?

Here is a quote from a manual that made me think that 3 and 4 phases are not as normal as 2 or 1:

“Fasciculation potentials can be monophasic or diphasic, looking like normal motor units…” – Does it mean that normal motor units are only these of 1 or 2 phases?


This is a good point. Let me just make a correction, potentials with more than 4 phases are called polyphasic. The units with 3 or 4 phases are normal. I will not be concerned if I see units of 3 or 4 phases rather than 1 or 2 phases.


Yet about the polyphasic units:

I read that some polyphasic units are also present in healthy people:

1. Is it true according to your clinical experience?

2. (Would it be 10%, 20%. of all MUPs in a muscle that would be considered normal), yet is it totally normal?

3. Does it mean that there is a constant reinnervation-taking place in each one of us? Does it happen with tensed muscles

4.Are the “normal” polyphasic units you see highly polyphasic or just 5,6 phases (board line) or both?

Thank you again; I just could not find the answers anywhere!


1. Yes, this is true.

2. This is also generally true.

3. This process is not usually a normal phenomenon. Reinnervation has to do with denervated muscle not with “tensed” muscle. It is the process which takes place by the surviving motor units after nerve damage to restore muscle function. It is a reaction of the healthy fibers to the loss of nearby fibers.

4. I do not know, although I did not see a “normal” highly polyphasic MUP, however, I think practically, it does not matter whether the MUP has 5, 6 or more phases. What matters is how many (%) are recorded out of 20/study.

Definite ALS and EMG/NCV

I was diagnosed definite ALS after one EMG/NCV exam and one clinical exam. I am 37 yr. old male. I show upper and lower MN involvement, hyperreflexia in affected limbs, bulbar signs. My EMG/ncv of affected areas showed: nerve conduction studies and latencies normal. Quiet insertion throughout, interference patterns decreased, some fibrillations and positive waves detected.:

The tests were interpreted thusly::

Fairly widespread changes in tongue, proximal upper limb particularly as well as lower limb consisting of relatively mild denervation and decreased motor unit output. May very well be MND.:

Does this one EMG rule out other syndromes entirely? Blood serum shows elevated anti gm1 antibodies. What about axonal motor neuropathies, or immune mediated demyelinating neuropathies?


MND is a diagnosis of exclusion, that means one must rule out ALL OTHER possible causes of these symptoms such as Thyroid/Parathyroid disease, Toxic Exposure, Motor Neuropathies with conduction blocks, Tumors, Acrylamide toxicity etc.. etc.. and is best done by a qualified Neurologist, after which I always advise my patients to seek a totally independent second opinion. So even though the EMG may be suggestive it is by no means diagnostic, until and unless all of the above has been ruled out.:

The elevated AntiGM1 antibodies can point to multifocal neuropathies, conduction blocks and the immune mediated neuropathies, all of which are treatable in one way or another.:

By the way, I saw no mention of fasciculations in the symptoms or EMG findings you describe. WHAT about real weakness (like foot drop…) WAS it detected by your neuros? And what about fasciculation (can you see, feel them)


Yes, fasciculations are abundant. There is muscle wasting in the left hand, arm and left leg. Foot drop is becoming apparent.


Insist on checking the possibility of multifocal motor neuropathy IT is very possible and less devastating than MND:

1.DO you get cramps, especially the ones that wake you up when you sleep at night?? :

2.and about your weakness… DO you find it difficult to open a jar use a key to open a door, or even walk- It is important to understand how profound is your weakness:

3.can you stand up without using your hands from sitting on the floor?? (Try it)


Answers to your questions::

1. I have cramps but not intense enough to wake me. :

2. My weakness is confined to the left side. Opening a jar, squeezing toothpaste are difficult with that hand. Although my left leg is affected I have no trouble ambulating. :

3. I can still get up from a sitting position.

LL weakness & EMG findings. Is it ALS?

Hi. I have been having progressive lower extremity weakness over the past three years. I have seen 3 ortho doc’s thinking it was my knee (I have a chronic ache in my left knee). Two days ago I underwent EMG and nerve conduction studies (very painful). The nerve studies were normal. The EMG revealed Fibrillations and positive waves in my calves, supraspinous muscles and deltoids. There was very little muscle fiber in my left calf. Are these findings consistent with ALS? How about MD? I am a 29-year-old female. What other testing can I expect?


On one hand, the EMG findings are incomplete to draw a conclusion i.e. the motor unit potentials (MUP) description. On the other hand, the EMG findings must be taken in context of the clinical picture (history and examination) and not on its own, because those may suggest any of them or other diseases. I would recommend seeing a neurologist (if you have not yet seen one) before proceeding with other investigations.

I have twitching in right leg. Am I considered as having ALS?

I am quite nervous about this twitching I have been having in my right calf, along the side-front. You can see it jumping around. It’s 24/7. It’s been going on for about 2 months and progressively getting worse. I also have some twitching in my right arm and right buttocks, but not as severe. It never lets ups. I have a crampy feeling in the backs of both legs at times. At one time, my right calf felt as though it had a cramp, but it really wasn’t a ‘cramp’. Almost a burn. Also, my left shoulder seems to want to pop out of it’s socket in the morning. It feels as if there is a torn tendon or something. I see no atrophy and it feels as strong as the right shoulder. I have no weakness that I can tell. I went and saw a neurologist and he saw the twitching and said it was nothing to worry about and said; “YOU DO NOT HAVE ALS!”, firmly and positively. I completely disagreed about not having an EMG, so he finally gave in. I found this very strange.
I am very scared about ALS and my doctors ability. HE comes highly recommended and has diagnosed about 20 ALS patients in his life.
Should I be concerned?


Neurologists rely on many symptoms and findings to diagnose or rule out ALS. While twitching in the muscle (facics) can be a sign of the disease, not everybody who has them has ALS. If your doctor is familiar with the disease, the chances are he’s confident in what he’s telling you and you should feel assured. If not, you should seek a second opinion to allay your fears.

By the way, did your doctor tell you what he/she suspected as the cause of your symptoms?

Tissue Transglutaminase Antibody in ALS

Anyone knows of having a high titer of Tissue Transglutaminase Antibody and ALS. Thanks


There was a paper in the Archives of Neurology “Glutamate Transporters in Neurologic Disease by Nicholas J. Maragakis, MD; Jeffrey D. Rothstein, MD, PhD, March issue, 2001. “Glutamate is the primary excitatory amino acid neurotransmitter in the human brain. It is important in synaptic plasticity, learning, and development. Its activity at the synaptic cleft is carefully balanced by receptor inactivation and glutamate reuptake. When this balance is upset, excess glutamate can itself become neurotoxic”. Then there was a comment that Glutamate is increased in ALS “Evidence for glutamate contributing to motor neuron degeneration in ALS initially came from several studies that suggested that cerebrospinal fluid glutamate levels may be elevated in patients with sporadic ALS”, also “These earlier studies reported that motor cortex and spinal cord tissue glutamate levels were decreased 30% to 45% in patients with ALS” and “In those studies, a significant loss of high-affinity, sodium-dependent glutamate transport was found in ALS” “the loss of glutamate transport is seen both in familial models of ALS and in sporadic disease”. It was concluded that “Regardless of the mechanism, the loss of EAAT2 (excitatory amino acid transporter 2) glutamate transporter may contribute to a reduction in glutamate uptake with subsequent overstimulation of glutamate receptors, resulting in neurotoxic effects”. I hope this helps.

Fasciculations detection and ALS

I’ve read the material on this site regarding EMG, and have even had an EMG, but I still have some questions.

1. In the diagnosis of ALS an EMG is administered in order to detect fasciculations. Since fasciculations come and go and are not continuous, as I understand them, what would happen if the EMG were performed on a day or a time of day when the fascics were not present? Would you get a false negative?

2. When receiving my EMG the neuro had me exercise against resistance each muscle being tested (i.e. the muscle w/ the needle in it). Is this in an attempt to generate and then detect resulting fasciculations? If not, what is the purpose of exercising the muscles?

3. I postponed my 2nd EMG because of a lack of fascics that day. Now that I’m exercising more the fascics are recurring. I’m scheduled for a 03 May EMG. Does this strategy make sense or are there certain EMG-detectable symptoms that may not manifest themselves to the extent that I can physically sense them?


In response to your question:

1. In the diagnosis of ALS an EMG is administered in order to detect fasciculations. Since fasciculations come and go and are not continuous, as I understand them, what would happen if the EMG were performed on a day or a time of day when the fascics were not present? Would you get a false negative?

==> The EMG diagnosis of ALS rests on much more than fascics alone. It looks for denervation, active and chronic and the widespread distribution of the findings including in bulbar muscles such as the tongue. So fascics alone are not a diagnostic criterion to diagnose ALS by EMG.

2. When receiving my EMG the neuro had me exercise against resistance each muscle being tested (i.e. the muscle w/ the needle in it). Is this in an attempt to generate and then detect resulting fasciculations? If not, what is the purpose of exercising the muscles?

==> Yes, fascics are sometimes seen easier after exercise, so in all likelihood that’s what your doctor was looking for.

3. I postponed my 2nd EMG because of a lack of fascics that day. Now that I’m exercising more the fascics are recurring. I’m scheduled for a 03 May EMG. Does this strategy make sense or are there certain EMG-detectable symptoms that may not manifest themselves to the extent that I can physically sense them?

==> Again, while it is good to see and study fasics by EMG, the diagnosis is not usually based on fascics alone.

Widespread muscle twitching & scared to death of having ALS

Hello. I am a 27-year-old female who has been having muscle twitching in numerous locations on my body, for 8 months now. I’ve been to 1 neurologist who did the in office neuro exam (testing of reflexes, heel to toe walking, walking on heels & toes, he tested my feeling on arms, legs etc. and also my pupil dilation, along with my strength). When I asked him of the EMG ,he refused to perform one on me stating that “from what I observed it is unnecessary, and I am not going to put you through the pain. “Well, since then, I have tried my best to believe him, but I had finally built my courage up to going to have the EMG test done that day, I was so scared to walk out of that office without one because I knew that an EMG is what really determines if you have ALS, not a neurologist’s observance. I’m going for a 2nd opinion at the end of the month (another neurologist), and once again I am sick with fear. My twitches happen more on the left side, but do also happen on the right. It seems every muscle (butt, back, thighs, top of foot, wrists, eyes, jaw, and I could of sworn I’ve even heard them in my ear drum) has twitched at one time or another. The ones that occur on my left foot really scares me, because my big toe on that foot doesn’t point up as much as my right big toe does, leading me to think I have foot drop/big toe drop. A few of my toes went completely numb when I tried running a short distance one day. My left foot cramped up when I turned it suddenly while rollerbladig one day also. This all leads me to think there is something horrible going on with my left foot. Both my feet get so sore on the bottoms just from walking on them. I’m only 27 and I love to dance, walk, roller blade, and try to live good, but I feel like my body is old before it’s time. My twitches do sometimes get “calmer”, but they never stop completely, there’s usually one happening somewhere on me. That’s the way they’ve always been for 8 months now. Although my left foot, on the bottom, becomes awfully twitch-happy sometimes. I’m so frightened of ALS and have diagnosed myself as having this disease because with all my symptoms how could I not? My husband refuses to go to another neurologist with me, although he told me I needed to go because he is tired of seeing me cry. I know I should feel ashamed of diagnosing myself via the internet, and I do, but can you offer me some hope anyway or maybe a little encouragement to not be soo scared. I am a military wife with no family near to help me through, my husband is disgusted with me refusing to accept the benign diagnosis without the EMG, and I feel like my life will never return to normal again if I don’t get an EMG. Sorry so long. Please ,what advice would you give to your loved-one in a similar situation?


First things first: If you perform a search in this TeleEMG forum using the word ALS, you will find many postings dealing with this subject which would be of help to you (search button is on the top of this page)

Second, fasciculations and cramps are no the only signs of ALS, there are many others as you will see when you perform the search so your neurologist’s reluctance to call them ALS may be based on what else he/she found in the exam and history.

If you are concerned however, it is not a bad idea to seek a second opinion, and if you still hear this is not ALS, ask your doctor to explain to you what these symptoms are.

Does Clean EMG in one limb exclude ALS?

I was just wondering does a clean EMG/NCV on the L limbs after 6 months of fasciculations r/o motor neuron disease, or will it ONLY r/o LIMB ONSET MND? Would bulbar ALS be r/o with this EMG or do the areas corresponding to bulbar onset have to be tested? I have read conflicting information on this. Some say, bulbar is rapidly progressive, and would show some spread into the upper limbs. Others have responded to the contrary. Seeking clarification, thanks.


If the EMG is done in the comprehensive way, then a negative result is against MND. so, a clean EMG of one leg does not rule it out. The rule is, if an EMG is normal in one side go for the other side if MND is suspected. Also, to answer the second point, if the patient has presented with bulbar symptoms, then we examine the tongue muscle in addition to the extremities, even laryngeal muscles if needed (if no other EMG abnormalities are seen). I do the later muscles with help of an ENT surgeon.


Just a slight correction, I had my ENTIRE L side studied. I have a hx of Sjogren’s syndrome and was hospitalized 6 months ago with L sided weakness, and have residual hemianopsia in my L eye. During my hospital stay, I developed some ugly symptoms such as hyper-reflexia bilaterally, fasciculations, clonus and was on IV Solumedrol 1000 mgs x 5 days. The Neurologists and docs suspected neurogenic vasculitis. To this day, I have fascics, but have regained my strength and show no s/sx of atrophy. I still have residual hyper-reflexia, and b/c of the persistence of these sx an EMG was indicated. It showed, normal NCS and no fibs, PSWs or fascics and good motor unit potentials.
With this history, and the reason for my initial post, I feared MND. Am I correct to assume that you feel further EMG testing to be done? The entire L side being normal, would not r/o ALS? And if it were bulbar onset, I have some dysarthria, wouldn’t it be readily apparent through some limb denervation? (Especially, upper limb?) After 6 months time, with my strength returned to normal with no wasting or atrophy, and fascics declining, and a clean EMG on my L side (upper and lower). ALS is STILL a possibility? I’m concerned. Thank you. Karen, RN


The EMG is an extension of the clinical history and examination. At this stage with this history background, I am skeptical regarding the diagnosis of MND.

I have fasciculations without weakness, do I have ALS

I went to my neurologist for an EMG and 2nd opinion of my fasciculation. My fasciculations, which have been ongoing for 10 months now, the results were normal but a fasciculation was picked up by the needle in my calf that I did not feel. I assume this was normal, Am I correct in doing so? I know people that have ALS sometimes progress slowly, but my neurologist said that after nine months of twitching I would be showing some kind of symptoms somewhere if I had ALS. So far no weakness, no atrophy, normal LAB/blood work, and clean EMG except for fasciculations recorded and one on thigh seen by neurologist. The neuro also proceeded to show me this calf twitches, which said, had occurred since his late 20’s, he is now in his late 70’s. I asked him why mine have happened in every muscle possible, if they’re benign, and not just in the calves and feet like his. He had no idea why and also couldn’t tell me why my feet get sore; he just said ALS does not cause pain. When can I feel reassured that I don’t have ALS? It is so hard to do when the fasciculations never leave. I’m 27 and I have gained 15 LBS. Do people with ALS have trouble putting on weight when they can still eat? I want to diet and get back into shape, but have been too afraid to lose weight with this constant fear of ALS symptoms kicking in. What does slow progression mean. When it comes to ALS. It several months of years of fasciculations and then weakness? Please answer my questions if you can, I want so badly to get on with my life. Thank you again.


I cannot do better than your neurologist. I agree with him that you do not have ALS. He has given you the proper opinion.

Enter your email and stay up to date with TeleEMG