--to see if there are cervical spine issues, given the start of your symptoms and the progression from up to down?

The unfortunate thing is that problems with spinal cord or nerve root compression can almost exactly mimic those of peripheral neuropathies, especially when the onset is not slow or gradual. I know I have had symptoms that have been very hard to distinguish--right now I am in the middle of a painful, burning upper body/arm flare that I think is attributable to cervical/thoracic outlet/brachial plexus injury as opposed to a more systemic process, though I am undertaking investigations to see if this can be confirmed.