That being said, as someone who is in the process of being diagnosed, I think the term "clinical weakness" is a bit of a cop-out on the part of the nuerologists. In August, I could do 50 push-ups. In October, I could still do 30 with ease. Today, I did 2 push-ups and my arms were shaking on the first one. But of course, the neurologists say I'm not "clinically weak". One neurologist suggested that I might "just" have a primary muscular disease (in spite of dirty EMGs), and when I asked how we're going to treat it, he said, "Ibuprofen". So far, I've now had FIVE EMGs by 3 neurologists - 1 showed peripheral neuropathy of my legs, the other 2 were clean. One EMG of my arms showed chronic and acute denervation, the other was supposedly clean. I show them how I shake, how my muscles quiver, but all I hear is "you're not clinically weak". blah blah blah. Yes, I am getting bitter. Don't get me wrong - hopefully I'm never clinically weak and have to endure the hell of ALS. But there has to be some sort of recognition of problems before "clinical weakness", especially when there are obvious signs of problems such as EMGs, hyperreflexia, clonus, spasticity...
Clinical weakness, IMO, is just a cop-out. It's like they just want to let you suffer until you're so far gone that they can't do a darn thing for you anyway!