My daughter wrote to the Italian authors of this paper seeking clarification :

http://www.ncbi.nlm.nih.gov/pubmed/23986125

They said it is best to have intramuscular injections twice weekly, 100 mg thiamine. If you have to make do with oral treatment they recommend 4 grams daily, of thiamine, 2 g in the morning and 2 g at lunch.

My daughter asked them to specify the form of thiamine and they said use water soluble as fat soluble DOES NOT cross the blood brain barrier. I take it that means thiamine is correct, Benfotiamine is not. They suggest using Solgar 500 mg caps. But Source Naturals b1 is cheaper.