I was finally diagnosed with syringomyelia, and mine came on quick (from onset of neuro symptoms, vibrations, then fasciculations that intensified and traveled up as syrinx expanded) , weakness first, but by 4 months from onset of fasciculations i could see atrophy and still valiantly do my leg squats but no longer feel "the burn" in my lef left, it's half the size of my right and no longer hardens when i try to flex it...
the weird thing was it seemed like i had both upper and lower motor neuron symptoms, scary as crap as you can imagine but i tried to go with the flow and not jump to ALS...i have spasticity and hypertone but at the same time the muscles are fasciculating and wasting away, left side more than right though, right is just way behind...
hope that helps a little, i was expecting to see "spinal MS" (PPMS) because i also had this vice grip around my ribs for a year at that point...but the fasciculations and atrophy seemed not normal for MS, my mother and i were puzzled and hoping it was ALS
and it wasn't...still heavy news, but I'm grateful I have to adjust but can still be with my family. My heart goes out to all of you suffering and I pray that somehow this can be a victory in some other way in the lives you impact or within yourselves...by no means being contrite, just praying for you!
I have ALS and have had it for two years and as yet have no outside appearance of muscle attrition. Yet I have severe muscle weakness, severe cramps, twitching etc... in fact am in wheelchair. Everyone is different, but with ALS the nerve signals stop going to the muscles. The outside attrition of muscles takes more time. So I do doubt that it is ALS. There are many other nuerological problems with these symptons. But off hand could not tell you names. But as I said muscle weakness normally comes first with ALS and actual muscle loss occurs later. Hopefully in your case it will be a treatable nuerological problem. I wish you the best and wish I could answer your question better. Also trouble swallowing and headache also come along with ALS, in typical ALS.