Recent paper being published from Dr Ian Zagon:- (One of the founders of LDN)....
These results indicate that treatment with OGF or LDN had no deleterious long-term repercussions and did not exacerbate EAE, but i) halted progression of disease, ii) reversed neurological deficits, and iii) prevented the onset of neurological deficits and iii) prevented the onset of neurological dysfunction across a considerable span of time.
http://www.ncbi.nlm.nih.gov/pubmed/21256121