Hello there Joel, I am SO sorry to hear about your wife's diagnosis. It is truly saddening.
I just wanted to point out a few things that hopefully in any small possible way can help, and possibly answer a question or two for you and for other's.
Your wife's first EMG showing negative (I'm assuming anyway) could have just been a case of misreading the results, or a hastily done procedure by a doctor that might have been in a hurry, or didn't think it was ALS and wasn't really checking as well as he could have checked. That is just an assumption. I really don't know, I am just trying to provide some possible answers, and help other people on here understand what might have happened.
As with anything, there is always the human error factor. We are after all, only human. Now, I am not saying your first doctor botched the EMG, but human error can, and does happen. There are just so many variables with an EMG. It isn't a simple "red light / green light" answer machine. It has to be "read' and there are all kinds of grey areas in between. In fact, some people with no "disease" at all have "dirty" or "slightly abnormal" EMG's, so with that, some doctors might see a slightly abnormal result and just blow it off as one of those people that have slightly abnormal readings.
That, there are also just odd things in this world that happen. People get cancer from getting exposed to chemicals and such, yet very young children who have never breathed any smog, been exposed to any chemicals or anything of the sort, get cancer. Not saying all cancers come from exposure to such substances, but the majority are.
Many things in life are not set in concrete. Most of the medical community goes by taking numbers from the masses and come-up with a diagnosis or conclusion from there. The fact of the matter is, in everyday life, all kinds of unexplainable and out of the ordinary thing happen to a few people around this world.
By the "physics" of a motor neuron disease such as ALS, it most certainly would have shown-up on an EMG. After all, if there is disease present, then a test will show it. You can't have symptoms of anything without some sort of underlying cause, so symtoms = something. This again is where human error can come into play, which can be a simple result of someone being in a hurry, to a slight malfunction or miscalibration of the test equipment, to just about anything. Again, I am just offering ideas as to what may have happened in the first EMG. Maybe the first results were slightly abnormal and the doctor just didn't consider it as enough to come to a conclusion. There are SO many things that could give us an answer.
My father died suddenly a few years ago of a heat attack. He dropped dead when he hit the floor. He never got a chance to leave work and spend time with our family before he left this world. I am not trying to make light of your situation, I am just pointing out there is a blessing in pretty much all things that happen, and having the blessing of enough time to quit work and see your family, get things in order, arrange things and so on, has it's up side as compared to someone being there one minute and dead on the floor of your home the next.
Again PLEASE do not take this as making light of what you two nice people are going through. Even with the best of what can happen, what you guy's are going through is nothing to make light of.
My wife has battled a severe case of SLE (Lupus) since she was 13. She has had all kinds of major surgeries, (hip replacement at age 20 from steroids eating her hip socket off, spleen removed at age 22, kidney surgery, over a year of chemo, she contracted TTP and was one of the first people to have Plasma Pheresis, and the list goes on and on).
Several times over the years, I have been told she wouldn't make it through the night. I have spent literally, months in hospitals and ICU's sitting and sleeping by her side. It is nothing very fun. We all go through times like these sooner or later. The end is never pretty, no matter how it happens. To me, it's the one thing about life that really sucks. Sorry, I can't think of any better word to describe it.
The bottom line here is; we are ALL truly sorry about your wife's diagnosis. You are not alone. Some of us have walked in your shoes and have lost loved one's. Some without the blessing of being able to spend time with their family before leaving. What you two are going through is dreadful. I just want to wish you two THE VERY BEST. What is, is, and we can't change that. We may never know what actualy happened in the first EMG, and for those out there that want to hound this for an exact answer, we may never know the real answer, Not because the answer isn't there, but because what did happen (such as possible human error or equipment malfunction) may not be able to be documented, so PLEASE don't go pounding this thing into the ground looking for THE answer. There are more important things to be focusing on here, and helping a fellow person on this forum is one of them.
If there is ANYTHING I can do for you two, please do not hesitate to ask and I'll do whatever I can. Our hearts go out to you and your wife. Please know that! We wish you two the very best.