Diagnosing HSP by elimination

Rick from NSW writes:

I have also had blood tests, lumbar puncture & MRI’s (Brain and Spine) and there were no abnormalities detected, yah-hoo – it was proven that I do in fact have a brain… an amazing finding considering some of the situations I got myself into in my younger years.

I was then told that the fact these tests were normal and my nerve conductivity tests as well as various other tests conducted by a Neurologist were abnormal, then it was possible to exclude a bunch of other neurological disorders and it was therefore “most likely” I have HSP.

Is it usual for a diagnosis to happen in this way??? This doesn’t seem or feel very definite.

I would love to hear your comments.