I dont know how you are all getting so confused here, I think when Aaron was reffering to Weakness he was suggesting Atrophy, which with ALS is wasting of the muscles causing permenant progressive weakness.
I agree that "percieved" weakness is the wrong word to use when describing BFS, the word percieved would suggest "its all in your head", the kind of weakness ppl get with BFS is more associated with Muscle Fatigue, which as most of you know is muscles getting tired easily, which as a matter of fact can be a early symptom of ALS, but muscle faitgue can be a symptom of many things, none more so than Anxiety, so dont all jump to conclusions *cough*KERRI*cough*
So I can see where Grym is coming from, it was worthwhile pointing out that "percieved weakness" is the wrong word to describe muscle fatigue, which is common in BFS. However....Percieved weakness IS a very real symptom and problem of BFS, but most likely linked to the mental exhaustion due to the Anxiety, BFS or any Neurological illness can cause. Percieved Weakness is common in everyday non-ill people too...have none of you ever sat down after a long days work and just felt like you cant physically get back up, coz you are so exhausted and your muscles just dont feel like they would carry you?? Well thats what percieved weakness is.
hope this helped clear things up