I am a 45 year female who has always been active and healthy until last spring. My symptoms started in April with a heavy and weak feeling in my right forearm. Over the next few weeks the same feeling spread to my left forearm.

Over the summer both upper arms and my left leg became weaker. I started seeing a neurologist near my home in July who detected atrophy in my hands and forearms. I have muscle twitches that come and go in all my limbs. Some days I have no twitches, and others I have a lot. There's no pattern to the twitches, but the weakness never goes away.

I also have a heavy feeling on the left side of my mouth which makes it feel as if it is drooping, although it doesn't look like it is.

All blood tests (and there have been many) have been normal.
Spinal tap normal.
All MRI tests normal.
I was even treated for Lyme, even though I tested negative, but it didn't help so the doc stopped the meds.

I have had two abnormal EMGs, the first in August at the U. of MD. showing chronic systemic nerve damage.
The second abnormal EMG was in January at Johns Hopkins and it showed short duration small amplitude motor unit potentials in the proximal muscles consistent with a muscle disease.

I had a muscle biopsy of my left upper arm 2 weeks ago at Johns Hopkins. Results are normal, although they're still waiting for metabolic stain results, which I believe tests for metabolic myopathies.

My neurologist at Hopkins is not ruling ALS out, but won't be more specific until comlete biopsy results are in.
But it seems that other illnesses have been ruled out and I know that ALS is a diagnosis of exclusion.
Has anyone diagnosed with ALS had an abnormal EMG that showed short duration small amplitude units?

My arms are so weak that typing is quite difficult and my legs are getting so that climbing stairs is exhausting. I'm frustrated that this has been going on for nearly a year and I still don't know the cause. Any advice or insight will be most appreciated.