As I stated earlier, your concerns are legitimate and I think a person should have the test you mentioned. Thanks for pointing it out - I will be sure to include it in my recommendation for Lyme's and link to the site(s) you gave.
You should be well aware that an individual supplement maker cannot afford the kind of research you are talking about. However, due to the extremely small particle size (as small as 0.64 nanometer) it is believed that US and Mesosilver do cross the blood brain barriers - in amounts small enough to not have any toxicity but sufficient to have therapeutic value. The literature does agree that the old supposition about silver and the blood-brain barrier is no longer correct.
Given the unknown factors, I will include the warnings as stated. It would indeed be a tragedy for someone to believe they were being cured for years while mentally declining.