http://www.ncbi.nlm.nih.gov/pubmed/8649547

Some old article about amantadine. It claims that since usage of amantadine life span has extended by 10 years. So in some way there might be some neuroprotection involved.

I also found a new article from 2011 still claiming amantadine to be neuroprotective:

http://www.ncbi.nlm.nih.gov/pubmed/21586298