A spreading uncomfortable debilitating numbness starting at base of neck and runs down both arms to hands. Lasts up to 40 seconds. Cannot continue writing during an episode. Occurs sometimes months or up to 5 years apart and will happen 2 or 3 times a day for several days, sometimes longer. This started over 20 years ago. I had neurologist testing about 10 yrs ago, found nothing. What is the latest findings on this problem?