My husband has neuropathy from feet to chest. He was just diagnosed with a rare B12 deficiency where it shows up ok in blood but doesn't get into the cells. This is a relatively new thing being studied by only two hospitals in us UCSF being one. They have started experimenting on what happens with daily.high potency b12 injections for 30 days then 3 times a week. So thankful a local neurologist.had read about it and sent him to SF. It may be too late for him as the spinal cord is so involved but the fact he has an answer is something.