Low copper raises a red flag when it comes to neurological issues. Iron, copper and zinc need to be in balance. How is your zinc?
Rare metabolic mutations can be involved in your body's ability to absorb and utilize copper. Unfortunately, restoring copper does not alway lead to improvement in symptoms but will stop further progression.
http://www.ajnr.org/content/27/10/2112.full
http://www.neurology.org/content/63/1/33
Hope you get this piece of the puzzle sorted out soon.